• Choose a month

  • Rapt in Awe

    My Journey through the Astronomical Year

    Think of this as a "companion text" to this, the main web site. Not required reading, butI hope you'll find it interesting and helpful.

Vega brings us the Summer Triangle – and continues to do so right into winter!

Vega is the guidepost star for June, heralding the rising of the Summer Triangle which stays with us right until winter! Look for it in the eastern sky about 45 minutes after sunset. (Click for much larger image.)

Vega is the guidepost star for June, heralding the rising of the Summer Triangle which stays with us right until winter! Look for it in the eastern sky about 45 minutes after sunset. (Click for much larger image.)

In these June nights when it isn’t really dark untila fter 10 pm  – at least for those of us on Daylight Savings Time – the Big Dipper pointing  to Arcturus and Spica are still high inthe sky, but brilliant Vega – magnitude zero – is well up in the east and bringing with it the other two stars of the Summer Triangle.  Deneb and Altair.  We’ll focus on those two next month. This month it’s enough to remind yourself of where to find Arcturus and Spica, then move on to Vega. And while you’re at it, see if you can notice the color difference between Arcturus and Vega – but wait until Vega is high enough so it now longer twinkles and changes color in the thick atmosphere near the horizon.

We call these three the “summer” triangle, but the truth is, they dominate our sky for a full six motnhs. You can see them in the east  on the night of the Summer Solstice – June 21 – and in the West around the Winter Solstice near Christmas. In fact, they’re stillt here a month later, but by then Altair is starting to get lost in the twilight, though Vega is still high enough in the northwest to see easily.

Add a couple of asterisms!

While I feel the guidepost stars are the most important to learn, if you really want to find your way about the night sky it’s also helpful to learn some key asterisms.  For June there are two to add to your memoru banks – the Keystone of Hercules and  the half circle of stars thata re the core of Coronoa Borealis – the Northern Crown.

Once the sky has really darkened on a June evening, look for the Keystone and the Crown on a line drawn between the two, bright guideposts stars of Arcturus and Vega.  (Click image for much larger chart.)

Once the sky has really darkened on a June evening, look for the Keystone and the Crown on a line drawn between the two, bright guideposts stars of Arcturus and Vega. (Click image for much larger chart.)

Once the sky has really darkened – between 10 and 10:30 on June evenings in Westport, MA  – draw an imaginary line between Vega and Arcturus.

Now look for our two helpful asterisms along this line.

The Keystone of Hercules is made up of four stars of magnitude 3-4 that form a perfect keystone, its narrow end to the south. (The star in the southeast corner is faintest – magnitude 4. The star in the southwest corner is the brightest.)

The second asterism to seek out, the Northern Crown, has one really bright star of second magnitude. Its other stars are magnitude four and five, so your eyes must be dark adapted to see this. If you live in suburban, light-polluted skies, try this. Find its brightest star, then with binoculars look first for the arc of three stars trailing off to the east, then the arc of two stars to the west of this dominant star.

Note: The typical binocular field will capture just half of this asterism at a time.

A dreamy, planet-filled, midsummer night!

The sky will be filled with planets about 45 minutes before daybreak - BUT, only Jupiter and Venus will be easy to spot witht he naked eye. You might spot Mars, but binoculars will help and they certainly are needed for the rest. Neptune will be right next to Jupiter looking like a faint star, Uranus will be brighter, but refer to the chart for it. Mercury? You'll need ideal conditions to see it and that slither of Moon.

The sky will be filled with planets about 45 minutes before daybreak on the morning of June 21 - BUT, only Jupiter and Venus will be easy to spot with the naked eye. You might spot Mars, but binoculars will help and they certainly are needed for the rest. Neptune will be right next to Jupiter looking like a faint star, Uranus will be brighter, but refer to the chart for it. Mercury? You'll need ideal conditions to see it and that slither of Moon. (Click for much larger view.) This an all other charts here are screen shots taken from Starry Nights Pro software and slightly modified for this use.

June 20-21, 2009 – Midsummer Night –  is the shortest night of the year, but it is chock full of planets – all of them! ( Yes, we had a similar opportunity in May, and that was great fun – but it gets a tad better in June and there’s something a bit magical about Midsummer Night!)

In the hours before midnight you can enjoy Saturn in the western sky and as it sets shortly after midnight,  you can enjoy Jupiter and Neptune rising in the East. Pluto is there as well, low in the west, but it is so faint you’ll need a large telescope and lots of patience to track it down. Uranus will be the next one up, rising about 1 am, but not becoming easy to see for another hour or two. By 3 am Mars and Venus will have broken the eastern horizon. I don’t know how easy it will be to spot Mars with the naked eye. It will be just one degree from brilliant Venus and although it will be first magnitude, that will still be five magnitudes dimmer than Venus! In binoculars, however, it should be easy.

The difficult catch will be Mercury. My best guess is about 45 minutes before local sunrise (about 4:25 am for me in Westport, MA) it may be high enough if there are no clouds on the eastern horizon and the sky may still be dark enough. The thinnest of crescent moons may be a guide, assuming you can see it! Mercury will be about six degrees below the Moon and to the right – close enough to fit with the Moon in a wide-field binocular view, though typical 10X50 binoculars will not fit the two in the same field. Still, at zero magnitude it will be bright. Both of these are north of east – Mercury at about azimuth 67° and the Moon at  about azimuth 62°.

Frankly, I’ll consider myself very lucky if I spot Mercury – and I probably won’t have the patience to hunt for Pluto. If the skies are clear enough to see it, there will be too many other things to catch my interest, particularly near the southern Milky Way. But it would be kind of fun to pull an all-nighter – especially since this is the shortest night of the year – and to see all of what are currently called “planets” on the same evening. So if the weather is cooperative, I’ll probably start observing about 11 pm EDT.  And I’ll do my observing at a favorite location near the ocean where I have a great view of the eastern horizon – in fact, all horizons!

The charts which follow provide a guide to finding Neptune and Uranus.

Finding Neptune is easy, as long as you remember that at magnitude 8 it is much fainter than 5th magnitude Mu Capricorni, or the moons of Jupiter, all of which will be visible in a small telescope, or good binoculars held steady.

Finding Neptune is easy, as long as you remember that at magnitude 8 it is much fainter than 5th magnitude Mu Capricorni, or even the four brightest moons of Jupiter, all of which will be visible in a small telescope, or good binoculars held steady. Jupiter itself is second only to Venus in brightness at magnitude -4.6 (Click for much larger view.)

Uranus is a challenge to find with binoculars, though at magnitude 6 it will appear reasonably bright. Theproblem is, it's in a section of the sky without bright, maked eye guide stars. I dentify thegeneral search region by looking at the large chart at the start of this post. Then use this chart and search for the rectangle of 5th magnitude stars. Find themand it's a short star-hop up to Uranus.

Uranus is a challenge to find with binoculars, though at magnitude 6 it will appear reasonably bright. The problem is, it's in a section of the sky without bright, naked-eye guide stars. It does fit on aline between Jupiter and Venus and is about 27 degrees from Jupiter on that line. Identify the general search region by looking at the large chart at the start of this post. Then use this chart and search for the rectangle of 5th magnitude stars. Find them and it's a short star-hop up to Uranus which will appear to be the twin of the star closest to it. (Click for a much larger image.)

Dawn patrol: 5 Planets and a crescent moon – this will be cool!

OK, I’m normally up at this hour so it’s a no brainer for me – I’m heading to the Allens Pond Bird Sanctuary parking lotwhere there’s a great view of the eastern horizon, preferably on the morning of May 21. That’s when I expect a wonder-full view of five planets and the waning crescent moon. I plan to be there at 3 am, but it should get especially interesting between 4 am and 4:30 am. Later than that? Well, we’ll be in a race with the dawn – everything will get higher, as dawn approaches, making it easier to see –  BUT – so will the Sun which rises that day at 5:19 am. So the sky will get lighter making things harder to see.  And, of course, there’s always the weather question – but in this case, all the players will be around right into early June in approximately the same positions, except, of course, the moon. So while I will aim for May 21, weather will determine the actual observing date.

All of this is local time and date for 41.5 north latitude and 71 west longitude. But a good guide for elsewhere in the world is to simply find out the time of local sunrise, then start looking 90 minutes  before that. All the action as viewed from the Northern Hemisphere is  between east and southeast and the territory will be nicely defined – and easily found – by bright Jupiter,  brilliant Venus, and the Moon. This makes it an excellent opportunity for folks not familiar witht he outer planets Neptune and Uranus to take alook for them.

The more difficult targets will be Mars and Uranus – Neptune, since it will be so close to Jupiter, should be relatively easy – though binoculars will be needed for Uranus and Neptune and, of course, a small telescope willmake it all more fun. Here’s a chart from Starry Nights software  for what I expect to see, given clear skies of course:

(click for larger chart)

(click for larger chart)

For me the key is to look at this chart – look at the sky – and then keep firmly in mind what is really going on – which is this:

(click to enlarge)

(click to enlarge)

To understand how this display relates to what we actually see in the sky, consider that the Earth is rotating counterclockwise, and all the planets are revolving around the Sun counterclockwise.

That means that as the Sun slips below your horizon on the May 20 Saturn will already be high in your western sky. It will set by 2:30 am. But at around 4 am on May 21 you will encounter Jupiter and Neptune first and they will be highest. (That’s what the first line projecting from Earth represents.) Then as you let your eye move towards the horizon – counterclockwise, towards the Sun – you encounter Uranus, Venus. and last, Mars – as shown by the other lines. Not shown is the Moon which will be in line between Venus and Mars.

This representation is modified slightly from Solar System Live.  While all the planets are roughly on the same plane, if their orbits are represented by a blue line it means they are above the plane of the Earth. If it is represented by a green line – as is the case with the five morning planets on May 21, it means they are below the plane of the Earth.

The most difficult planet to find is likely to be Uranus. If  we have exceptionally clear skies and you have exceptionally good eyes you may be able to see it with your naked eye – but for most people in most locations binoculars will be essential. Here’s a typical 7-degree binocular field showing Uranus and stars to magnitude 8 from Starry Nights software. The star 24 Piscium is the brightest in the field at magnitude 5 – the other named stars in the circle – and Uranus – are magnitude 6. Fortunately, the general position of this field is easy to see by drawing a line between Jupiter and Venus (see the first chart). As you move from Venus up towards Jupiter, count three binoculars fields along this line  – Uranus  should be in the third field. Notice that Uranus is the last “star” in an arc of four reaching upward from the bottom of the field – the forth one being just below the field if you put Uranus at dead center.

(click to enlarge)

(click to enlarge)

Neptune is much easier to find. See this posting for details on it.

This is a good event for naked eye and binocular users. Yes, a small telescope will help. Jupiter and Venus will be fun to see in a telescope. Neptune and Uranus are too small to show anything except a tiny disc and Mars is a long way from us showing a disc only one-eighth that of Jupiter, so no details will be visible there either.

Interesting note: A friend in Austrailia said he would look for this, so I made him a quick chart for how things would look at 6 am in Australia on May 21. Compare that chart (below) with the view we get (first chart on this post) in North America.  Note how high Fomalhaut is for them – not to mention Jupiter and Neptune – and, of course, they look to the northeast as we look to the southeast.

The view from Sydney, Australia on the morning of May 21. (Click for larger image.)

The view from Sydney, Australia on the morning of May 21. (Click for larger image.)

Step 7: How bright is that star?

magnitude_scale

We’ve been rating stars by their brightness for at least 2,000 years and the operation is really quite simple, though the whole system may seem backwards to you. In any event, it’s worth learning because the different brightness of stars is one of the main ways we can tell one from the other and make some sense out of the night sky.

Stars are ranked in brightness by a numbering system called “magnitude” – the lower the magnitude number, the brighter the star. Generally, the brightest star we see is magnitude 0 and the dimmest we see is magnitude 6. If that feels backwards to you, think of it this way. Stars of magnitude 1 – very bright – are “first class” stars. Dimmer stars are magnitude 2 – “second class” stars, etc.

Simple – yes, but of course there are exceptions and several ifs, ands, and buts that make the whole business of brightness quite fascinating!

First, 10 stars ( if you include our Sun) are brighter than magnitude 1 – so they are magnitude zero and if brighter than that,  we go into a minus system. Magnitude -1 is brighter than 0, which is brighter than one.

The brightest star we see is our Sun. It is magnitude -26.7! The next brightest object is the full Moon, at magnitude -12. Then comes the planet Venus at -4.7 (sometimes) and Jupiter, usually about -2.3 or -2.4.  Other than the Sun, the  brightest star in our sky is Sirius, at magnitude -1.46. We don’t get to an actual  magnitude 1 star until Betelgeuse, which is magnitude .5.  Confused? Don’t be. We call Betelgeuse first magnitude because it falls in the range of .5 to 1.5. No star is exactly a “1” in brightness, though Spica comes very, very close at .96.

Of approximately 6,000 stars bright enough to be seen by the average person from some spot on Earth, only 22 are of first magnitude or brighter. Quite an exclusive club!  These include all the ones we learn as signpost stars and, of course, some of them are visible only from the Southern hemisphere.

While most books will tell you that the faintest star we see with the unaided eye is magnitude 6, this too is only an approximation and doesn’t really represent today’s  world that well.  Generally speaking, in our light-polluted regions, the faintest star we are likely to see is magnitude 4. If you live well away from city lights, you probably see to magnitude 5.   On mountain tops, well above the thicker parts of our atmosphere and free of light pollution, some observers with excellent eyes and skills can see stars as faint as magnitude 8.5 with the unaided eye. In my own area, which is semi-rural, I’m very happy when I can see a magnitude 5 star with my naked eye.

With binoculars or telescopes we see stars that are much fainter, but that’s another story. Here we’re focused on what we can see with no optical aid.

Many familiar star patterns are made up primarily of second magnitude stars, such as Orion’s Belt and most of the stars of the Big Dipper.  The North Star (Polaris) is second magnitude as well as one other star in this asterism. But the other five stars in the Little Dipper  are magnitudes 3, 4 and 5. This makes the Little Dipper a good object to use to get a sense of magnitude.

On a star chart it is common to represent magnitude by making circles of difference size to represent the star and its brightness. That really isn’t the same as brightness, but it does give us an idea of what to expect. So, for example, here’s how the Starry Nights Software represents the stars of the Little Dipper.

Study the four stars that make up the cup of the Little Dipper for agood idea of the magnitude scale. It includes magnitude 2,3,4, and 5 stars.

Study the four stars that make up the cup of the Little Dipper for agood idea of the magnitude scale. It includes magnitude 2,3,4, and 5 stars.

You’ll find that when you get to know stars of different brightness, the magnitude system makes general sense to our eyes. That is, there seems to be about the same gap in  brightness between a magnitude 1 and a magnitude 2 star as there is between a magnitude 2 and magnitude 3 star.

While the magnitude system has been around since the early Greeks, it was given a mathematical foundation about 150 years ago when it was decided that there would be a gap of 2.512 times between each level of brightness. That means a first magnitude star is 2.5 times as bright as a second one – and exactly 100 times as bright as a star at magnitude six – five magnitudes fainter.

At that time it was thought this logarithmic progression matched the way the human eye responded to brightness. It does so, but only approximately.  Still, the system is convenient, stars are routinely listed this way, and the system easy enough to become acquainted with while observing.

One last note – don’t expect to simply walk out of your nicely lit house and see faint stars. At first only the brightest will be visible to you. Your eyes need time to adjust to the dark. After about 15 minutes you’ll see much fainter stars and after about half an hour you can assume that the faintest star you see is the faintest you will see that night.

But also keep in mind that what you can see at any given moment varies in a number of ways, including:

  1. How good your eyes are at detecting faint objects.
  2. How clear your skies really are – astronomers quickly learn that all “clear” nights are not created equal!
  3. Your physical condition at the moment, including how tired you are and whether or not you have been recently drinking alcohol or smoking, both of which can impair night vision.
  4. The height of the star above the horizon – when you look at stars near the horizon, you are looking through a lot more air then when you are looking at stars directly overhead.
  5. Your experience in looking at faint objects   – yes, you can actually learn to see dim objects by looking slightly to one side of them, a technique called “averted vision” that takes practice to do well.

All of this helps make star-gazing more fun. Variety is, indeed, a tasty spice, and no two nights of observing are exactly the same.  Nor is it all as cut and dry as it seems.  An experienced, older observer can actually see more, in some instances, than a younger, inexperienced observer whose eyesight is technically better.

Neptune – meet Jupiter! All the angles on an AM event

September update: Neptune continues a relative close relationship with Jupiter in September 2009 and will be getting closer again later this year. To see Neptune’s position  in September 2009  go here and scroll down to the section on “Finding Neptune.”

Jupiter passes so close to Neptune this month (April 2009) you’ll be able to see both planets at the same time in binoculars or a small telescope – assuming you don’t mind getting up before the Sun 😉

OK, maybe you do mind getting up before the Sun – so don’t bother with this one. There will be two more opportunities this year, once in July and once in December. (Yes, planetary conjunctions tend to come in threes.  My own rationale for trying to catch this in May is based on the fact that these are normal hours for  me and even if they weren’t, our weather is so fickle I don’t pass up good opportunities – who knows what July and/or December will bring!)

The date to aim for is May 27, but a week either side of that will  work for either binocular or telescope view. Why bother? Because it’s events like these that give you a handle on size and distance of various objects and Neptune just isn’t that easy to find onits own, so this is a good way to go about finding it. But let’s look at the particulars. Here are a couple of charts made from Starry Nights software. The first shows you a naked eye view of the sky on May 27, 2009 at 4 am EDT  from about 42 degrees north latitude. The lesson here is simple, look low in the southeast – you may spot brilliant Venus very close to the horizon in the east and you certainly should see Jupiter, roughly a quarter way up the sky and just south of southeast. Nothing else will be nearly as bright as these two, though Venus will have Jupiter beat by about two magnitudes.  (The first magnitude  “star” near Venus will be Mars.)

naked eye view of Jupiter, Venus and Mars. Though Neptune is there, it's too faint to be seenw itht he naked eye.

Naked eye view of Jupiter, Venus and Mars. Though Neptune is there, it's too faint to be seen with the naked eye, though it should make n easy binocular target. (Click image for large version.)

This second view (below) shows what you’ll see in binoculars on May 27. A few days before that Jupiter will be even closer to the 5th magnitude star Mu Capricorni which is just a bit brighter than Jupiter’s brightest moons. Each day after May 27 it will be moving a tad to the east -left.  Neptune, at 8th magnitude, will be significantly fainter and appear  like a star in binoculars. It should be easier to see than Jupiter’s moons simply because it’s not so close as to be caught in the glare of the giant planet.  But it will certainly be easier to see in a low-power, wide-field telescope view. (Aim for a field of view of close to one degree to capture both Jupiter and Neptune nicely. )  Neptune should have a bluish hue and will show a tiny disc of about 2.3 seconds of arc in diameter.

Jupiter and Neptune as seen in binoculars on May 27, 2009, low in  the southeast about 4 am.

Jupiter and Neptune as seen in binoculars on May 27, 2009, low in the southeast about 4 am.(Click to enlarge.)

So what can you expect to see in the telescope? Not much. Jupiter’s disc is 41 seconds in diameter at this point. It’s largest moon, Gannymeade, shows a disc of about 1.5 seconds and Neptune’s disc is just a tad larger than that at 2.3 seconds. Why so small? After all, isn’t Neptune one of the “gas giants.”

Yes. But first off, it’s is significanty smaller than Jupiter – roughly one third the size. (It’s still about four times the diameter of Earth, however. For a neat guide to the sizes ofthe planets, see this Web site.)

Jupiter is about three time the diameter of Neptune and both are far, far larger than the Earth.

Jupiter is about three times the diameter of Neptune and both are far, far larger than the Earth.

But look at the distance. Jupiter is at 5.2 astronomical units  from Earth this month – Neptune is at  more than 30 astronomical units – almost six times as far away.   (An astronomical unit is about 93 million miles, the distance of the Earth from the Sun.) Does that make sense, then? Do the math! it’s simple.

Move Neptune as close to us as Jupiter and it would appear to be roughly six times larger. Six times 2.3 is 13.8. We said Jupiter was about three times bigger than Neptune. Three times 13.8 is 41.4 – and Jupiter shows in our sky a disc of 41.6 seconds at the end of the month.  Don’t you like those numbers? All approximations, but they come out very close and thus make sense.

So, will you really see the disc of Neptune? Yes – but after getting your wide angle view of both planets at once, pump up the power to get a better view of Neptune. It won’t be great – but hey, remember – you are seeing it by reflected sunlight that has taken over four hours to reach Neptune and another fours hours to bounce back here to you.

And what about Mu Capticorni? Well, it’s a nice little power house as well. As you look at it, recall that it is about 90 light years away, yet it appears about as bright as our Sun would appear  if our Sun were just 30 light years away! That means that like so many of the naked-eye stars we see, Mu is significantly brighter than our Sun.  All of that is neough to get me out of bed at 3:30 am and trundle on out to catch the sight.  Besides – I love mornings – especially those last couple hours of darkness – so peaceful, so quiet, so rich in contemplative ambiance.

Observing plans for April 2009

 

M105 and two companions, NGC3384  and NGC3389 three of the galaxies oyu may see this month - but don't expect them to look like this terrific picture take by Jim Misti. Live telescope view are in black and white and very dim - but startling still, because they are live - you are interacting directly with the photons fromthes egalaxies.

M105 and two companions, NGC 3384 and NGC 3389, three of the galaxies you may see this month - but don't expect them to look like this terrific image take by Jim Misti of Misti Mountain Observatory.. Live telescope views are in black and white and very dim - but startling still, simply because they are live - you are interacting directly with the photons from these incredibly distant and huge galaxies.

This is the month for galaxies, but only with binoculars and telescopes. For the unaided eye, though, it’s the month dominated by the Lion with a great line up of planets as well. Mercury puts in an excellent performances, Saturn dominates in the evening, and Jupiter and Venus put in brilliant appearances before dawn.

 

Here’s a summary of some prime April observing targets for unaided eye, binocular, and telescope. First, the unaided eye list. (All charts with this post are screen shots  – with some  modifications by me  – from Starry Nights Pro software. They are  made for my latitude, 41.5-degrees north – however they should serve as a reasonable guide for anyone within 10 degrees of latitude either direction. To find your latitude, go here.)

Unaided eye

Mercury is a primary target during the last half of the month because it’s generally so elusive, but this is an especially good appearance. See this post for description and chart.

Saturn

Saturn is easy if you are familiar with Leo - and even if you're not, it is one of the brightest "stars," high in the east as the twilight ends.

Saturn is easy if you are familiar with Leo - and even if you're not, it is one of the brightest "stars," high in the east as the twilight ends.

Venus and Jupiter 

Early riser? Check out Venus and Jupiter. Look  low in the east (Venus) and southeast (Jupiter) as per this chart. (With really steady binoculars or a small scope you can see one or more of Jupiter's four largest moons.)

Early riser? Check out Venus and Jupiter. Look low in the east (Venus) and southeast (Jupiter) as per this chart. (With really steady binoculars or a small scope you can see one or more of Jupiter's four largest moons.)

Arcturus – April signpost star

The signpost star for April – the one to be sure to learn if you are just starting out – is Arcturus. Just follow the arc of the Big  Dipper’s handle to find Arcturus. (Go here for detailed description and chart.)

Getting to know the Big Bear

Everyone knows the “Big Dipper” - but several cultures saw this asterism as a bear - with a curiously long tail -  part of the larger constellation known as Ursa Major - the Big Bear. April is a good time to try to see the bear as he claws his way up the sky in the northeast.

Everyone knows the “Big Dipper” - but several cultures saw this asterism as a bear - with a curiously long tail - part of the larger constellation known as Ursa Major - the Big Bear. April is a good time to try to see the bear as he claws his way up the sky in the northeast. (Click picture for larger image.)

Now THAT’S a Lion!

Ahhh . .. a constellation that looks as it should! Leo.

Ahhh . .. a constellation that looks as it should! Leo.

If you already know the bear, it’s time to meet the Lion – Leo.  Leo contains the signpost star for March, Regulus, as its brightest member. The whole Lion image works for me, but I’m also used to thinking of  Leo as two distinct asterisms that are easy to recognize and remember – the sickle and the triangle. If you put them together they make a pretty credible lion.  The  sickle marks the lion’s head and  mane,  the triangle is his  rear haunches. And that last star at the east end of the triangle – well, it’s name is Denebola and “Deneb” means “tail.” When it comes to constellations it doesn’t get much better than this – even “Regulus” makes some sense, for it’s Latin for “little king” or “prince.” (I get the feeling Leo would accept the “king” part, but take issue with the “little.” )

Other signposts 

There are a  lot more signposts stars  and easy asterisms available in the hours of late twilight and full darkness. Here’s a list of key stars and asterisms you can see in the April evenings – assuming you have already learned these in previous months: In the north: Polaris, the Pointers, the Guardians of the Pole, the Handle of the Dipper, Mizar.

Roughly, from east to west: Arcturus, Spica, Regulus, Castor and Pollux,  Procyon,  Betelgeuse, Orion’s Belt,  Rigel, Aldebaran.

Zodiac – ecliptic

The Zodiac in the evening sky in April  is marked, from east to west by: Virgo, Leo, Cancer, Gemini, and Taurus. (Learning these constellations – their order and some rough idea of what they look like – is a helpful key to learning the rest of the night sky. For one thing, this is where you will find the Sun, Moon, and planets.)

Advanced naked eye observer targets

M44, the Beehive, can be found on this chart between Leo and Gemni.This is much dimmer than the Pleiades and the Hyades, two clusters you may already know. In fact, it will be just a faint, hazy patch.

M44, the Beehive, can be found on this chart between Leo and Gemni.This is much dimmer than the Pleiades and the Hyades, two clusters you may already know. In fact, it will be just a faint, hazy patch. (Click chart for larger image.)

 

M44, the Beehive, can be found on this chart between Leo and Gemini.This is much dimmer than the Pleiades and the Hyades, two clusters you may already know. In fact, it will be just a faint, hazy patch.

M45, the Pleiades, is getting low in the northwest, but still visible, as is the slightly higher – and physically closer cluster – the Hyades.

M42 – the star birth region in the sword of Orion – looks like a fuzzy star to the naked eye.

Coma Berenice

Find Arcturus, find Denebola - connect those two with an imaginary line, then travel along it a bit more than half the way from Arcturus to Denebola. Go up a bit and you should see a fine sprinkling of stars, visible in dark skies with your naked eye, but certainly visible with binoculars. This is Coma Berenice.

Find Arcturus, find Denebola - connect those two with an imaginary line, then travel along it a bit more than half the way from Arcturus to Denebola. Go up a bit and you should see a fine sprinkling of stars, visible in dark skies with your naked eye, but certainly visible with binoculars. This is Coma Berenice.

Melotte 111 – better known as Coma Berenice – is  following close behind Leo in the east.

For binocular and  wide-field  small telescope users

The easy list for binocular users repeats many of the objects on the  unaided eye list.  A few of these are actually best seen in binoculars and small, wide-field telescopes, so they are not just for beginners.

The objects that really look great in binoculars, include from east to west – Coma Berenice (Mellotte 111), M44 – the Beehive, the Hyades, and , of course, M45 , the Pleiades.

The previous charts in the naked eye section takes care of Coma Berenice and the Beehive. If you want a farewell look at  Orion’s Belt (surrounded by an open star cluster that doesn’t get the attention it deserves), or the Hyades, and the Pleiades, don’t wait too long. They’re still visible in the west, but getting lower each night and by the end of the month are really too low for a good look. Our chart (below) shows them in the middle of the month when they’re still high enough – assuming you have a clear western horizon – to see well.  (If you make a special trip to a spot with a clear western horizon to catch Mercury in the western sky shortly after sunset, hang around for it to get darker  so you can say farewell to these winter friends. )

lookwest1

Look west at 9 pm in the middle of the month for a farewell tour of some wonderful winter star clusters - Orion's Belt, the Hyades, and the Pleiades. (Click for a large image.)

There are several other objects that can be found with binoculars. I don’t regard binoculars and small telescopes as the best way to see these objects, but I think looking at them this way is important for two reasons. First, finding these with low-powered, wide field instruments will increase your finding skills and your general knowledge of the sky. Second, we all need to look at these in low-powered, wide field instrumens from time to time to give us a sense of context – otherwise the telescope views of them become abstract and disconnected from reality – sort of like watching TV.

Binocular finds

 

Mizar - a double star and then some in the Big Dipper's handle.

Mizar - a double star and then some in the Big Dipper's handle.

The easiest to start with this month is Mizar, the famous double star in the handle of the Big Dipper. If you have good eyes and your skies are steady you can “split” Mizar and its wide companion, Alcor, with your naked eye. Certainly you can split it with any size binocular. Try your naked eye first. No luck. Try binoculars. Got it?  OK, now that you know what you’re looking for, try it with your naked eye again. In even a small telescope, Mizar itself splits nicely into a handsome pair of stars.

How about an engagement ring – sort of?

A broken engagement? I have difficulty completingi n my imagination the "engagement ring" that makes a diamont of Polaris. Still, it's a nice grouping of 7th and 8th magnitude stars and perhaps I', justb eing too literal.

A broken engagement? I have difficulty completing in my imagination the "engagement ring" that makes a diamond of Polaris. Still, it's a nice grouping of 7th and 8th magnitude stars and perhaps I'm, just being too literal. In any event, here's what you should see in binoculars or a small telescope. You can complete the ring with one of the two stars I've pointed to - but which one? For me, neither gives a really satisfying result. But this little asterism is a nice way to confirm, when using binoculars, that you indeed have Polaris in view.

Meanwhile, in a galaxy far away . . . 

Want to go galaxy hunting? It is, indeed, mind bending to see objects that are millions of light years away and contain billions of stars while using nothing more than a good pair of binoculars, or a very small telescope.

In ordinary binoculars these objects are all a challenge and require dark skies. They become easier if you can mount your binoculars – or use a small, wide-field telescope – and especially easier if you can boost your power to 20-30X.

 

To find M51, first find Alkaid, the bright star at the end of the Dipper's handle. Get that in sight and look for the 5th magnitude star 24 CVn. It forms a large triangle with two dimmer stars of about 6th magnitude. A small triangle of still dimmer, 7th magnitude stars, is my favorite guide. But you do need clear skies and good, steady binoculars -and then you will only "detect" it - not really observe it. (Click for larger image.)

To find M51, first find Alkaid, the bright star at the end of the Dipper's handle. Get that in sight and look for the 5th magnitude star 24 CVn. It forms a large triangle with two dimmer stars of about 6th magnitude. A small triangle of still dimmer, 7th magnitude stars, is my favorite guide. But you do need clear skies and good, steady binoculars -and then you will only "detect" it - not really observe it. (Click for larger image.)

Of my short list, I think the easiest target is M51, the Whirlpool galaxy, which is really two galaxies in collision. It’s easy because you can start with the bright star at the end of the familiar handle of the Dipper, Alkaid.  The chart tells you where to go from there. If you have the ability to adjust your power – and thus your field of view – start with low power and first find the two triangles of stars shown. Center the smaller triangle in your field, then increase your power and M51 should be visible – though it’s helpful to know what to expect (two very dim, small clouds almost blending together) and averted vision helps significantly. Don’t expect miracles – you’re dealing with light that’s been traveling for something like 15 million years – it’s bound to  be a little weary. 

M81, 82 – ear mites in the Great Bear

 

It's almost the same distance from corner to corner in the Big Dipper's cups as it from Dubhe to M81 - roughly 10 degrees. Drawing an arrow through these bright stars isn't precise, but it gets you in the neighborhood and you should look for 24 UMa, a star that just a tad too dim to be called 4th magnitude, but in clear, dark skies would be visible to the naked eye and certainly will show up well in the binocular field.

It's almost the same distance from corner to corner in the Big Dipper's cups as it from Dubhe to M81 - roughly 10 degrees. Drawing an arrow through these bright stars isn't precise, but it gets you in the neighborhood and you should look for 24 UMa, a star that just a tad too dim to be called 4th magnitude, but in clear, dark skies would be visible to the naked eye and certainly will show up well in the binocular field. Click for larger chart.

 

I love M81 and M82 because they are two very different galaxies that fit in the same field of view, but finding them is a challenege – no convenient bright stars nearby.  I use two reminders. One is “the Great Bear has ear mites.” Not sure who first said that, but these two huge, dynamic galaxies do seem like mites stuck behind the Bear’s ears – assuming you know the figure of the Bear.  If you don’t surely you do know the asterism of the Big Dipper and if you cut across the “cup” diagonally as the chart shows, you get yourself pointed in the right direction. Don’t epect to see these with low power. I can just make them out with my 12X36 image stabilized binoculars. Having larger, higher-powered binoculars mounted so they are steady is critical – or better yet, a small, wide field scope where once again you can increase to 20-40X. Once in the neighborhood, use this chart to zoom in a bit and see the relationship between the two galaxies. They won’t look like their pictures – but even at low power,  one should appear roundish and the other more cigar-shaped.

 

The smaller circles show a typical small telescope field at roughly 24X. Note the north-south between the two, as well as their relationship to the star UMa 24. Can you see a difference in brightness? in shape? (Click for larger chart.)

The smaller circles show a typical small telescope field at roughly 24X. Note the north-south alignment between the two, as well as their relationship to the star UMa 24. Can you see a difference in brightness? in shape? (Click for larger chart.)

 

 

These two are about half as far from us as M51. Well, that actually depends on what you take as their distances. See, galaxy distances are real approximations and there is serious disagreement among folks who know much more than i do. So one book I trust tells me M51 is 37 million light years away, another I trust says 15 million. And this pair – well, a good ball park figure is about 9 million.  There’s also disagreement about brightness, but of these three, M1 is the brightest, M82 the faintest – M51 falls inbetween. But that ,too, is debateable as we’ll see with out next pair – uh, trio of galaxies.

The pair that’s a famous “triplet”

What may be an easier pair – not really brighter, but easier to find this month – are M65 and M66 in Leo – the famous Leo Triplet. How can a triplet have just two galaxies? It doesn’t. But the third one is notoriously more difficult to see, though quite large

If you find these two, try to decide which is brighter. See, my “experts” disagree. One auhor I respect as a super observer has them one way. Most authorities – and another author I respect – sees them as just the opposite. I can’t make up my mind. I’ve recorded them both ways in two different years and now I know too much to trust my judgment. That is, I’m prejudiced by what I’ve read and what I think I’ve seen. You probably aren’t – so which is brighter – M65 or M66 – and which is which? For that you need to pay attention to the charts and which way is east.

You have an extra aid in finding these two this year because Saturn’s in the vicinity. But even without Saturn, it’s simple – just locate the triangle that represents the haunches of Leo the Lion.

 

Draw a line between the star marked "Chertan, Chort" at one corner of the Leo Triangle and the 4th magnitude star Iota Leonis - both should fit in your binocular field of view.  You'll find the Triplet on that line, halfway between. But they are faint and it takes dark skies and steady binoculars to see them. A small scope is better. (Click to enlarge.)

Draw a line between the star marked "Chertan, Chort" at one corner of the Leo Triangle and the 4th magnitude star Iota Leonis - both should fit in your binocular field of view. You'll find the Triplet on that line, halfway between. But they are faint and it takes dark skies and steady binoculars to see them. A small scope is better. (Click to enlarge.)

Please note the directions on our chart. In the sky, northis always towards the North Star, Polaris. But when you are facing the earthly direction of south – as you will be when looking at Leo – east is to your left. East/west is  important here because M65/M66 line up pretty much east/west with M66 the eastern most of the two. NGC3628 is to the north. You won’t see it in binoculars. You may in a small telescope. It is fairly bright – but it’s large and it’s light is spread out, making it ghostly.  It’s also an edge-on spiral, which doesn’t make it any easier to see – long and thin in a generally east/west direction.  Here’s a closer view of these three.

 

My guide for finding these in a small,low-powered telescope is the "J" asterism to the right. The brightest star in its magnitude five, the others seven and eight. Once I've located that I'm sure I have the right field for the fainter galaxies.  Note that the ghostly member of the three is to the north. (Click to enlarge chart. )

My guide for finding these in a small, low-powered telescope is the "J" asterism to the west. The brightest star in it is magnitude five, the others seven and eight. Once I've located that I'm sure I have the right field for the fainter galaxies. Note that the ghostly member of the three is to the north. (Click to enlarge chart. )

There’s another nearby trio of galaxies in Leo that this time includes four! Hey, if a pair can be a triplet, then a trio can be a quartet -w ell,a ctually, a quintet, but that fifth one is really elusive.  But we really re toeing the line between telescope and binocular targets here and I count these give much more on the telescope side of the line. 

Objects for amateur telescopes

We’ve already looked at many of these objects with the naked eye or binoculars. You can use the charts above  to find these same objects for telescopic viewing. 

This group need a wide field, low-power eyepiece in your scope to appreciate – M45, the Pleiades, M44 the Beehive, and the Hyades.  Orion’s belt really needs and especially wide field – 2 degrees or more – and Coma Berenice is a better binocular target –  few scopes can get that low and wide to show it to advantage. Of this group, the best telescope targets are M45, the Pleiades – though they getting awfully low – and M44 the Beehive, which is very well placed, high in the sky, for study.

The Beehive is also known as “the manger” and I wonder if it should be called a “Christmas Tree.”  Looking at it with a low-powered, 50mm scope recently – the Sparrow Hawk – I certainly saw it that way. See this recent blog post for  more on the Beehive as a Christmas tree – with charts.  Wonder if anyone else see it this way? Depends, I think, on how large a scope you use.  There are also some interesting multiple stars in this cluster, though I haven’t finished the write-up of my recent observing of them. Stay tuned. The one write-up I did find on the subject was misleading. 

The art and craft of Galaxy observing

Step 1 – Lower your expectations. Galaxies are not ogoing to look like their pictures. Here the camera does much better than the human eye, gathering much more light and revealing all sort of faint detail. 

Step 2 – Raise your expectations. No kidding. It’s a mental game, I know, but darn it, you are actually, physically interacting with stars whose energy was released in your direction millions of years ago.  I know this sounds a bit mystical, but having your brain pinged by these photons need to be appreciated for what it is – awesome!

Step 3 – Dark adapt, dark adapt, dark adapt – and protect your dark adaption. Don’t even use a red light unless you have to, and then close or cover your observing eye. 

Step 4 – Take your time. Sit down. Study. relax, Study. Use averted vision, of course – move your eye and let the galaxy move. Jiggle the scope -gently tap its side. To see and record the kind of detail an excellent observer records takes hours. So don’t think a quick peek is going to do it for you.

Step 5 – Experience counts – sorry – but it does, My old and weakening eyes see more than many a much younger newcomer with much better vision simply because I’ve been there before. I know what to expect. So be patient. It will come to you and if your eyes are younger and better you will soon see much more than I do. 

Finally, don’t lose sight of your goals. You need dark skies, of course – but don’t write off galaxy hunting only because you don’t have the darkest skies possible.  You can still see them. But having more telescope helps. Stephen James O’Meara did his observing for his excellent books with a 4-inch refractor – but he was halfway up a mountain under extremely dark skies in Hawaii. However, what he saw an awful lot of people on the light polluted East Coast of America should be able to see – with a typical 8 or 10-inch reflector.

One other thing you’ll learn when hunting galaxies is the meaning of the word “transparency.” It seems amply clear – no pun intended. But honestly, I would not blame the beginner – or even intermediate observer – who thought one clear night was much like another. They are not. there are nights of exceptional transparency and with experience you’ll come to recognize them. 

In any event, go with what you have. Don’t try to set a world record – just enjoy what you can see. For me the ultimate goal remains – be rapt in awe – and for that I can deal with something far, far below ideal conditions, equipment, skills, and experience.

Galaxy targets

Our galaxy targets for the month are essentially the same as those listed under binocular observing and the same charts apply. we will, however, go after one more group in Leo.

These galaxies are all visible in the most modest amateur telescopes under good dark skies – anything from 50mm on up. But I would advise the beginner to start by using the largest telescope you can.  I feel my skill in observing galaxies was fed by switching back and forth between my 15-inch reflector and much more modest instruments, including refractors of 102, 80, 66 and 50mm. But first comes the largest instrument simply because it gathers more light and size still counts – the larger the aperture the more you’ll see. Period. but I’ve spend loads of time with the pristine, high contrast images of a good small refractor and feel that has taught me as well. There’s no single, perfect solution.

Also, contrary to what some people think, galaxies can benefit from at least a reasonable amount of magnification. With binoculars you generally detect the presence of a galaxy. With a small telescope you can start to observe it. You can evaluate its shape and details and make a rough judgment call on its classification – elliptical, spiral, irregular. But don’t expect details to jump out at you. It takes sharp focus, concentration, and time. Trying to draw what you see also helps significantly – even if you’re the world’s worst artist. 

So go  after M51, M81, M82, M65, M66, NGC3628 – see what you can learn to see. Then for a different experience turn your gaze to another triplet in Leo – M95, M96, M105 – and its companions.

The triplet that’s a quint

 

The key is to find Rho leonis, a star that's on the bright side of 4th magnitude and fairly isolated. USe it to draw inoyur mind a flashlight beam that is bounded by two of the triangle stars that make up Leo's haunches and these galaxies fit nicely in that imaginary beam. Click to enlarge.

The key is to find Rho leonis, a star that's on the bright side of 4th magnitude and fairly isolated. USe it to draw inoyur mind a flashlight beam that is bounded by two of the triangle stars that make up Leo's haunches and these galaxies fit nicely in that imaginary beam. Click to enlarge.

 

I find M95 and M96 a relatively easy pair, though about twice as far apart as nearby M65 and M66, so you need a low power field of at least two degrees to capture  this pair of galaxies and their companions.   If you can get   a wide enough field on a large enough telescope that should include M105 which always strikes me as a double galaxy. It has a quite bright companion right next to it that, while mentioned in most text, does not  seem to get the attention it deserves. It is NGC 3384. There’s a second companion, but this one is inconspicuous – NGC3389.  It is 12th magnitude and only going to show up in larger scopes under good conditions. But stop and think a moment – we are talking about being able to see four entire galaxies, each with billions of stars, in the single field of view of a small telescope – and maybe see a fifth galaxy as well! That’s awesome by my definition!

So we’ve progressed from seeing a single galaxy in collision with a second (M51); to seeing two distinctly different, large galaxies, M81 and M82; to seeing three galaxies in the same field of view M65,M66, and M105 with a fourth thrown into the mix – NGC3384_ and maybe a fifth – NGC3389!

Does it get any better than this? Well – yes.  If the sheer acumulation of galaxies is your goal, wait unti we tiptoe through the Virgo Cluster – but that’s at its prime for May.  For now, we’ll be satisfied by seeing part – and it  is just part – of what the Bear and Lion have to offer. 



 

 

Follow the arc to Arcturus!

Prime time in April finds the familiar Big Dipper high in the northeastern sky and its gracefully curved handle provides a gentle arc that points us right to our April guidepost star – Arcturus.

If you continue that arc it will lead you to the May guidepost star, Spica – but don’t worry if you don’t see Spica this month – it is low in the southeast, but it will get higher.  Meanwhile, Saturn is as bright as any of our guidepost stars, about halfway up the sky in the southeast about 45 minutes after sunset. About another 15 degrees above and to the right is Regulus, the dominant star in Leo.

Click image to see a  larger version.

Click image to see a larger version.

Here comes Mercury – zip – there goes Mercury!

Fleet messenger that he is, Mercury put in a very nice appearance during the last half of this month and should be quite easy to find if you look on the right date and the right time in the right place.

For example, from Westport, MA on April 16 at 8 pm EDST we will find Mercury in Aries at Azimuth 285 degrees and Altitude 9 degrees – in other words about a fist and half north of due west and about a fist above the horizon and in the twilight sky shining at close to magnitude -1. That means it will look almost as bright as Rigel and Aldebaran, two bright stars in the general region that it will form a triangle with. (Technically, Mercury is  tad brighter – but those stars are higher and in darker sky, so they’ll be easier to see than Mercury which will, of course, be nearer the Sun. )

mercury_09

For the next 30 minutes we get one of those interesting races – assuming we have clear skies to the West – where Mercury rushes towards the horizon – making it harder to see – but at the same time the sky around it gets darker – making it easier to see. By 8:30, though, it will be less than 4 degrees above the horizon – and that usually is too low to see unless you have a really unobstructed and clear horizon.

There are other days, however – and the general rule will apply. Start looking a half hour after sunset, look just to the north of west, and expect to see it roughly 10 degrees above the horizon. This will hold true right up to about May 4. SOme other highlights of this appearance:

April 26 – Mercury will have climbed to about 13-degrees above the horizon a half hour after sunset and the 2-day – very thin – crescent moon will be just 4 degrees above it.  Nice photo op!

April 29, 30 – Bincoulars or a small telescope at low power will show that Mercury has joined up with the Pleiades – just one degree to its north as they both move closer to the horizon. Start viewing baout 8:10 om EDST.

May 4 – Now, half an hour after Sunset (8:16 pm EDST in Westport, MA) Merucry is a bit less than 10 degrees above the horizon. With each day it will get more difficult to see.  So long little messenger – hope you bring good news to everyone! See you inthe dawn sky shortly!

Comet Lulin an easy binocular object now (February – 2009)

I looked for Comet Lulin when I went out at 3:30 this morning and although I had forgotten to check it’s exact position, just knowing it was roughly between Saturn and Spica was enough. I swept the sky in that direction with my 12X36 binoculars and it popped right out. I haven’t tried for this comet before. It’s been visible for several weeks, but I knew it was now getting near its peak.

I must say I was a bit surprised by its size. From pictures I had seen I expected something smaller with maybe a hint of a tail. Instead what I saw reminded me of  Comet Holmes, though, of course, dimmer and smaller.  Holmes had a wonderful halo effect – strong core and significantly weaker, but distinct shell. (See my pictures here.) Lulin was more a blob – appearing in binoculars much as the globular cluster M5 does – only larger.  It had a definite nucleus, but the surrounding matter was brighter in relation to the nucleaus than was the case with Holmes.  I tried, after my eyes dark adapated, to see it with the naked eye. No luck. My guess is it is roughly magintude 5.5 which for an extended object is well below naked eye visibility for my skies – and my eyes.

But it’s nice in binoculars and real nice in small telescopes – and while I was looking at 3 am, it’s well placed in the evening sky by about 9 pm and will get better over the next week or two as it passes near Saturn and eventually the Behhive – M44.

For more details and a timetable see my earier post here.

%d bloggers like this: