Look to the West!

Venus has been in our evening sky now since last Fall. The brilliant beacon is about to leave the western sky and zip to the morning sky as it moved rapidly in its orbit, moving ahead of the earth, then appearing in the morning sky. "Inferior" conjunction is is less than 2 weeks on 3 June. BUT, there is another show tomorrow and Friday, 21 and 22 May, when it appears to pass Mercury.  The innermost planet is on the far side of its orbit, moving away from the Sun, so the two will appear to align from our vantage point. 21 May they will be only 1 degree apart (twice the moon's diameter), and only a little further the 22nd. Be sure to go out and look!

Tonight I went out to take a few photos, and found a suitable AZ backdrop - a forest of cacti! At left is shortly after sunset.




And I haven't even mentioned the neatest part - Venus (and Mercury) goes through phases like the moon! Because its orbit takes it between the sun and earth, Venus' "dark" side is displayed towards our view, so only a narrow brilliant crescent is visible. Venus is so bright because of its cloud cover, so is always bright, and interestingly always about the same brightness - when it is on the far side of its orbit, a full but small disk, or nearing inferior conjunction when it is the skinniest of crescents but very large. It is so large the crescent shape can be seen even in binoculars. Tonight I got the brainstorm to try to photograph it with the 300mm lens - what to use as foreground - how about a saguaro with a bouquet of flower buds atop it? At left is shown a large part of the frame with Venus appearing over the saguaro. At rights the full-resolution crop of the image with the crescent more clearly seen. It can be seen pretty easily in binoculars as it nears the closest point in its orbit to the earth.




It finally got dark enough that could record both Venus and Mercury (considerably fainter) clearly. I happened to check and found out that the International Space Station (ISS) was going to move between the two planets in 12 minutes! How lucky is that?! Unfortunately, the ISS was 900 miles downrange, off the California coast west of San Francisco, accounting for its faint appearance. But it was caught in the 2.5 second camera exposure...

It was quite windy, so the spindly arms of the ocotillo were moving a lot, showing as blurs in the exposure. Tomorrow Venus/Mercury will be much closer. The sharp-eyed among you can likely spot the streak of the ISS, but in case you can't, a labelled version is at right...

So do check out the western sky the next couple days. I'll likely have a photo or two to post!!!