Monday, February 20, 2012

See the New Moon with Mercury this week

The New Moon of Adar will be visible on the evening on Thursday Feb 23 from about 5:30pm – 7:00pm.

Here are 3 diagrams showing the relative positions of the Moon, Mercury and Venus for Thu, Fri, Sat this week at about 6:15pm

On each evening Jupiter will be the next bright "star" just above Venus. So you can bag a peak at 3 planets at once!




(Charts by Stellarium

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Wednesday, February 8, 2012

For a less challenging target than Uranus, check out Mars.

Mars is back!

About every 2 years, the Earth passes Mars on the inside track around the Solar System, and we arrive at our closest approach to Mars, when it appears at its brightest in the sky. Although this opposition won't be until the beginning of March, Mars is already bright and high by about 9pm local time. Given our recent cold and cloudy weather, I have not had a chance to see it yet this year. However, over the next few nights, the Moon will help us find Mars as it passes near, and Mars will be by far the brightest 'star' in the neighborhood, as shown in this chart from  S&T

Watch the Moon advance eastward past Regulus and Mars. (This scene is drawn for the middle of North America. European observers: move each Moon symbol a quarter of the way toward the one for the previous date. The blue 10° scale is about the size of your fist held at arm's length. For clarity, the Moon is shown three times actual size.)

As described in the caption, here in Israel, like Europe, we adjust the position of the Moon. Thus on Friday the 10th the Moon will be just below the position shown for the 9th and still be a good signpost.

Hopefully, I'll post more on Mars in the coming weeks.


Best chance to spot Uranus is Thursday night

Uranus is not usually counted among the planets that are visible to the naked eye. However, it is just barely visible if you know where to look, have perfect vision, and go to a very dark area (such as the desert).  The ancients undoubtedly saw it but did not recognize it as a planet (from the Greek, "wandering star") because it is so dim and moves very slowly. 
With a good pair of binoculars, you can probably spot Uranus tomorrow, February 9th, even if you do not live in the middle of the desert, thanks to a great sign-post, the planet Venus, which will be passing by.  Tomorrow night, Venus will pass just half a degree (the width of the full Moon) below and to the left of Uranus.  

Here is a star chart showing what these two planets will look like through a pair of 7x50 binoculars.

The chart also shows some other "regular" stars in the same field of view with their magnitudes, (the numbers next to the objects in the chart) but Uranus is the only "star" visible right above Venus   Remember, though, that Venus looks about 10 times brighter than Uranus, so Uranus may still be hard to pick out.

The best time for viewing is soon after sunset when the sky is not quite dark so the glare from Venus will be less, but not so early that Uranus will be invisible against the blue sky.  If you wait too long, the two planets will be lower and harder to see through the haze of our atmosphere. Between 6 and 6:30PM ought to be ideal.

So get ready, and let me know if you succeed!

P.S. If you miss the planetary conjunction on Thursday, you could try again on Friday. By then Venus will have continued its quick movement through the skies, and will appear above and to the right of Uranus and a tiny bit farther away, as shown here: