A Line of Bright Planets in the Evening

A nice lineup of three bright planets will be forming in the sunset over the next couple weeks. There will be three bright planets, Mercury, Venus and Jupiter, and a faint planet in the lineup, Uranus. Together they will nicely outline the ecliptic in the evening sky.

Tonight you can see this lineup taking shape, looking low, just above the glare of the setting Sun you might pick out Mercury. It is only 10° from the sun this evening, but getting higher each day. High above, Venus and Jupiter can not be missed, Venus at about 40° elevation at sunset, with Jupiter even higher at 60° elevation. Venus shines much brighter than Jupiter at about -4.2 magnitude while Jupter is only -2.3 magnitude. Uranus is hiding about halfway between Mercury and Venus at a mere 5.9 magnitude.

Over the next two weeks Mercury will climb higher, reaching maximum elongation on March 5th. At the same time Jupiter and Venus will draw closer, having a separation of about 9° on the 5th. The pair will be closest on March 13th, at about 3° separation. As March slips by, Mercury will drop back into the Sun’s glare and Jupiter and Venus will separate once again. Still, the bright pair dominating the evening sky through much of the month.

While the lineup is still prominent, the Moon will swing through the alignment from February 22nd to the 27th. On February 22nd a 1.8% illuminated Moon will pair up with Mercury, just 6° away. On the 24th and 25th the Moon will sidle up to Venus, under 5° away on the 25th. On the 26th the Moon will be near Jupiter, with under 4° away and 25% illuminated.

One last dance of the alignment will occur on March 25th when a crescent Moon will join Jupiter and Venus. The planets will be about 10° apart with a 11% illuminated Moon in between them. A very nice trio indeed.

Late February and much of March will be a nice show for sky watchers. Make a point to get out and look!

Mercury in the Sunset

A crescent Mercury, 16Apr2010
Earlier this month, as Mercury was slipping back into the glare of the Sun, I had an opportunity to shoot some webcam material of the planet in hopes of getting an image of the crescent shape. The resulting image does not look like much, but I have to think it really isn’t all that bad.

The photo does represent Mercury fairly well, at least the normal view you get in a telescope. As the innermost planet does not get very far from the Sun, it is typically seen quite low on the horizon. This leads to poor views seen through a great deal of atmospheric distortion.

What the photo does not show is the chromatic distortion, this was corrected during processing of the photo. The atmosphere will also break up the color, refracting the light when an object is low on the horizon. The processing software allows realigning the color planes, correcting much of the effect.

Mercury Transit

About a dozen times a century Mercury passes in front of the Sun as seen from Earth. The event is observable with a modest telescope and a solar filter, Mercury can be seen as a small black dot crossing the surface of the Sun. If half of those happen when the sun is below your horizon the average person will have the chance to observe five or six in a lifetime. Since the next opportunity will not occur until May 9th, 2016 I didn’t want to miss this one!

Photographing a Mercury Transit
90mm refractor Violet Haze photographing the transit
I took the day off.

Considering that Mercury never gets very far from the Sun means that most of the time you can observe Mercury it is low on the horizon and is typically seen through a great deal of atmospheric distortion. A transit is one exception to this, during a transit mercury is a sharp disk, very different from the multicolor jello ball that is usually seen.

The 2006 Transit was well timed for observation across western North America, starting just after noontime and ending at 5:09pm MST. This put the Sun high in the sky for all but the last part of the event. Our weather cooperated as well, delivering a cloudless blue sky the entire day in place of the clouds that had been forecast. The air was reasonably steady as well allowing good photographic and observing conditions.

I took advantage of the weather and photographed almost the entire transit, all but the very end when the sun sank below the trees in my neighborhood. I used the Canon 20Da and setup a timer to shoot every 5min. The only issue was the inability to do a polar alignment on the mount when setting up in the middle of the day. The result was I had to manually guide the scope every 10-15 min to keep the sun centered.

I got plenty of good photographic material, enough for a few single photos as well as an animation of the transit. A transit is an impressive demonstration of the scale and arrangement of our solar system. Not hard to visualize the reality of those textbook drawings of planetary orbits after you have had such an opportunity to see the real thing.

No complaints on my second Mercury transit.

Mercury Transit 8Nov2006
The Mercury transit of 8 Nov 2006 in progress. Mercury is about halfway between the center to the bottom, a large sunspot complex is visible on the left edge. Photo with a 90mm APO refractor, a Thousand Oaks full aperture filter and a Canon 20Da camera.