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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 2013 – now that’s close but Mercury will be more fun!

Here’s a prediction: The news media will focus about mid-month on a tiny object you can’t see – and ignore a dazzling appearance by zippy Mercury and its meeting with Mars that you can see!

The tiny object you can’t see is asteroid 2012 DA 14  and it will get all the attention because it will be passing very, very close to Earth – well, very close in space terms – something like 18,000 miles in real terms.  No, don’t get nervous – it won’t hit us. (Of course, I’ve read three different predictions of how close it will come, but what’s a small error among friends 😉 Anyway, to put that in perspective, that’s about 60 times farther from us than the International Space Station, but closer to us than our geosynchronous satellites orbit and roughly one-twelfth the distance to the Moon.

NASA chart - click for larger image

NASA chart – click for larger image

Yep, that’s close. But when it happens, this asteroid – which is roughly about half the size of a football field – will be magnitude 8 – barely visible in good binoculars – and at that, visible only to observers in Europe and Asia who look in just the right place at just the right time.  (To find out where to go – and what to input – in order to learn where and when to see it, read this Sky and Telescope post.)

Now Mercury is a sight worth seeing – and not half as challenging

OK – a much, much easier target, though whimsical and quick in its own right – is Mercury, which does a little dance with Mars early this month before climbing into easier view a week later – then doing a heavenly Cheshire Cat act andvanishing almost as quickly as it appeared, which is why we frequently put the word “fleeting” in front of the name “Mercury.” And finding Mercury low in the southwest will be a great warm-up exercise for Comet PanSTARRS – scout out a good observing spot with unobscured western horizon to see Mercury and you have your ring-side seat for Comet PanSTARRS in March!

Start on February 7th and/or 8th

Mercury and Mars on the evening of February 7, 2013 about half an hour after sunset.

Mercury and Mars on the evening of February 7, 2013, about half an hour after sunset.

Here’s the drill:

  • Find an area with an unobstructed western horizon.
  • Go out just before sunset and note where on the horizon the Sun sets – it will be about halfway between west and southwest.
  • Wait half an hour and look for Mercury to emerge in the twilight less than a fist – about seven degrees – above the horizon and just a tad south of where the Sun set.
  • Use binoculars. Though you probably will be able to see Mercury with your naked eye – it is magnitude minus one –  Mars at magnitude one (more than six times fainter) will be much more difficult. But if you can find Mercury in your binoculars, you should see Mars as well. One quibble – they are very close to each other, and you may need to mount your binoculars on a tripod to split them – or even use a small telescope. Exactly how close depends on exactly where you are viewing from – they will be a bit closer for viewers on the West Coast than for those on the East Cast of the US.

As the twilight deepens they will be easier to see – but at the same time they will be getting closer to the horizon and thus more difficult to see because you are looking through more disturbed air at that point.  This is exactly the kind of race you are likely to have next month with Comet PanSTARRS, which will be near the western horizon after sunset and will get easier to see as twilight deepens – and yet, more difficult to see as it moves lower. With such objects there is always a time – totally unpredictable because it depends on local conditions – when you have the best view.

If the weather doesn’t cooperate, try the same drill on either of the next two nights. Mercury will be zipping by Mars. They actually are so close on February 8 it will take a small telescope to “split” them – they will be like a double star.  On February 9 Mars will be below Mercury and should be easy to see again in binoculars.

Best View of Mercury Alone

From the 11th – when Mercury is quite near the Moon – to the 20th, Mercury will be quite easy to see.

On the 11th it’s about five degrees below a very thin crescent Moon – should be able to just squeeze the two in a typical, low-power binocular field of view.

Each night Mercury will continue to be higher at the same time – about 30 minutes after sunset – BUT it is toying with us because as it gets higher it also gets dimmer! On the 11th it is still about minus 1 in brightness.  By the time it reaches its peak in height – around the 16th-to-18th – it has dropped to near magnitude zero. It continues to be quite high up through the 26th, but by that time it has dropped to magnitude 2 – a real challenge to pick out in the twilight.

Bottom line – try to catch it near Mars – that’s really fun. And if you miss that – try to catch it between then and the 19th or 20th. Oh – and if you do have a small telescope, it will make an interesting sight during these twilight hours. Talk about the Cheshire Cat, it will be smiling at us – really! Around the 12th it will look a bit like a quarter moon – half  lit. Twelve days later it will be just a thin crescent – which is why, of course, it is getting dimmer! So the smile gets bigger as the celestial cat vanishes. Oh my!

What else is there?

Well you can’t ignore Jupiter, high in the southeast evening sky with its four major moons continuing to dance about it. It resumes its eastward movement against the background stars, very slowly moving closer to Aldebaran.

And Saturn is putting in a solid appearance in the morning sky. At mid-month it is due south and about 35 degrees above the horizon two hours before sunrise.

And on the moonless evenings early – or late – in the month, don’t miss the chance to see the Zodaical Light.  Best time to look is 80 minutes after sunset. It will be a faint, conical glow rising up from the western horizon – about the brightness of the Milky Way.  You do need skies free of light pollution to pick it out. For more on the Zodaical light, see this post from last year – scroll down to the heading “Basking in the Zodaical Light.”.

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One Response

  1. Reblogged this on EOΣ.

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