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  • 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.

Events-February 2010 – Happy Valentines Day Jupiter – we’re onto you!

Ah, to be romantic in mid-winter!  And this year, on February 14th, we have Jupiter  – king of the gods – being joined by Venus – goddess of love, beauty, and fertility –  beside the soft glow of a slim crescent moon! Is that appropriate, or what? (OK, we’ll ignore the fact that Jupiter is married to Juno.)  The question is, will we be able to see this little tryst? Or will it be so close to the horizon – and the Sun – that it will remain a figment of our imaginations. One thing I’m sure  of – it will be a challenge. Other challenges this month for naked eye and binoculars include:

Jupiter, Venus, and the Moon

Sky and Telescope describes this encounter this way: “Venus and Jupiter appear 2 degrees apart on February 14th, when an ultraslim young Moon joins them in a tight formation.”  Yep! “ultraslim” is right. When I asked Starry Nights Pro to show me this scene I couldn’t even see the moon it was so slim! That’s because I’m on the East Coast. West Coast observers will see a moon that’s a bit older – and thus larger – so they will have a better shot; but I’ll try. Here’s the screen shot from Starry Nights for 15 minutes after sunset at my latitude, about 42 degrees north.

Click image for larger view. Printer-friendly version linked below.

Click here to download a black-on-white (printer-friendly) version of this chart.

If you want to see this live, you first need an unobstructed western horizon. Then, a lot of luck in terms of no clouds. If you meet those two requirements, then a good pair of binoculars, or a small telescope would be handy. Be careful though – make sure the Sun has fully set before you start looking. I plan to wait 5 minutes, then I’ll start scanning the horizon. I expect to pick up Venus first.  Jupiter will be a bit higher, but also dimmer, so it should pop out second and be in the same binocular field of view as Venus. I expect the moon will be last to put in an appearance, but if I put Venus to the left side of my binocular field, I should be able to pick up the Moon on the other side.

Normally, of course, Venus and Jupiter are easy targets – downright dazzling. But now we’re talking about finding them in bright twilight and very near the horizon. Thirty minutes after sunset Venus will be barely one degree above the horizon – that’s about the width of your pinky held at arm’s length – without gloves!  And Jupiter will be about three degrees above the horizon. Venus sets just 38 minutes after the Sun and Jupiter about 50 minutes. See why it’s going to be hard to surprise these celestial lovers?

But if you get clouded out, don’t despair – they actually get closer during the next couple of days, though the moon will quickly rise much higher and so not be an intimate part of the picture. Now if it’s clear enough to see these three – or even two of them, then I’m going to wait another 50 minutes to see if I can detect the elusive zodiacal light.

See the Zodiacal Light

Now this is something much different. You don’t need a totally clear horizon to see the zodiacal light, or binoculars, but you do need total darkness and that means little-to-no light pollution. I feel I have a good shot at it from my favorite ocean-front observing point where I have a clear horizon to the west with no cities to create light domes there. Evenings in February and March – and mornings in September and October – are the best time for folks at mid-northern latitudes to look for this.

The zodiacal light is roughly the same intensity as the Milky Way, so if you can see the Milky Way from your chosen location, then you should be able to pick up this faint glow.  Like the Milky Way, it stretches over a good deal of sky. It is widest near the horizon and gets narrower as it rises towards the zenith.  You want to look for this roughly 80 minutes after sunset. You can check for an exact time for your location by getting information from here on when astronomical twilight ends. (The drop-down menu on that page specifies the times for astronomical twilight.)  As astronomical twilight ends you want to start looking. As with any faint object, your eyes need to be dark adapted, so I am assuming you have been out for at least 15 minutes with no white light to dazzle you. If you try to look for this earlier, you may confuse it with twilight. Much later and it is not as bright, for what we are seeing is sunlight reflecting off  interplanetary dust particles – dust particles that orbit in the same plane as the planets – the area we call the zodiac – and thus the name for this phenomena, zodiacal light.

If you see it,  reflect on this explanation from Wikipedia:

The material producing the zodiacal light is located in a lens-shaped volume of space centered on the sun and extending well out beyond the orbit of Earth. This material is known as the interplanetary dust cloud. Since most of the material is located near the plane of the solar system, the zodiacal light is seen along the ecliptic. The amount of material needed to produce the observed zodiacal light is amazingly small. If it were in the form of 1 mm particles, each with the same albedo (reflecting power) as Earth’s moon, each particle would be 8 km from its neighbors.

For the metric-challenged (that includes me) that means one dust particle every five miles! And that causes all that light?! Awesome!

Watch the bright Asteroid Vesta dance through Leo

This spring you get a chance to follow one of the brightest asteroids as it dances about the constellation Leo. This will be particularly easy to find with binoculars on the night  of February 16 (February 17 UT) , or the night before or after that one.  The fast-moving asteroid will be close then to the second brightest star in the easy-to-spot asterism of Leo’s Sickle. To find this, look east about three hours after sunset. Here’s what you should see with the naked eye.

Click image for larger version of this chart. Chart was developed form Starry Nights screen shot.

Click here to download a black-on-white (printer-friendly) version of this chart.

Once you are sure you have found Gamma Leo, then look at it in your binoculars.  You should see something like what is shown in the circle, though your binoculars may show a somewhat larger field. What is neat here is that Vesta is moving right between Gamma and 40 Leonis and it will take it about three nights to complete the journey.  You can start looking for Vesta earlier, however, if you want. It will enter the field of view shown at the lower left about February 7. And it will leave the circled region, exiting to the upper right, on about February 25. It would be fun to spot it on several nights and use the printer-friendly chart, linked below, to mark your own observations of its movement.

Click image for larger view. Printer-friendly link below. (From Starry Nights screen shot.)

Click here to download a black-on-white (printer-friendly) version of this chart.

Catch the Demon in Demise

I wrote about Algol the “Demon Star” in the posting for October, but it’ s still well placed for viewing in February, and if you look at the right time, you’ll catch it in mid-eclipse, which is cool.

Every 2.3 days Algol dims like clockwork, but it is only at its dimmest for about two hours, so to see it in this condition you really need to be watching at the right two hours. Fortunately, there are several places that will give you a list of times when this occurs – but many of them will be while normal people are sleeping – and many more will be during daylight hours. However, each month there should be one or two dates when it is really a good time for you to catch Algol doing its thing.

Most of the listings I know of for Algol “minima” give date and time in Universal Time. What I like about the one at Sky and Telescope magazine, is it will calculate a list of coming Algol minima for you – and give you the Universal Time, plus your local time. So it’s easy to glance over it and see when it will be most convenient – weather permitting – for you to take a look. In my case, February 2010 gives me a couple of opportunities worth noting:

  • 02/07/2010 @ 09:45 pm
  • 02/10/2010 @ 06:35 pm

You can learn much more about the minima of Algol – and get specific predictions for any date with translations to your local time  by visiting this page at Sky and Telescope.

2 Responses

  1. […] more detailed information on this, see the February posting here. Possibly related posts: (automatically generated)In like a […]

  2. […] The zodiacal light is available any time of year, but is much easier to detect in the evening sky about 80 minutes after sunset in February, March and April – with March being the best. For more details about what it is and how to observe it, see this posting. […]

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