Thursday, May 31, 2012

Nosedive Towards Syzygy

For those observant among you, the brilliant planet Venus has dominated the evening sky since last fall.  But in 5 days, on Tuesday, 5 June, it passes between Earth and Sun for a special inferior conjunction, actually passing over the disk of the Sun as seen from some parts of our planet.  While you might think that a transit is a common occurrence, because of Venus' orbital inclination, it is actually a rare event.  While the last one was 8 years ago (but not visible from the western U.S.), the next one isn't until 2117, so likely not again in our lifetime!  There is a nice synopsis of the event, as well as the timeline in the U.S. in this SKY and Telescope link.

For the last few days, Venus was still visible in the evening sky, but while it was still brilliant, it has been diving towards the sun the last couple weeks.  It was easily visible in early twilight as we arrived home from California Monday evening.  Tonight Melinda and I took a short outing to a local park to try to see it and image it once more before the transit in 5 days.  We brought along our little Meade 80mm F/6 apo refractor (480mm focal length, 670mm w/the 1.4X converter) to try to image it and get a sense of their relative scale in the sky.  Today we've been suffering smoke from some fires in southwestern New Mexico, so the skies were pretty murky, but we managed to get some good solar images with the converter, along with some small sunspot groups.  But would we be able to spot Venus?

Fortunately, I thought to bring some binoculars along, and we started searching shortly after the sun dropped below the horizon.  I knew it was within 10 degrees of the sun, so had a limited window to observe it.  About the time I thought we had missed it, Melinda picked it up in the binoculars - once spotted, easy to see in the murky sky, not only the planet, but the skinny crescent as well!  I had pre-focused the scope, so aligned it, checked exposure levels, and popped off a half dozen shots.  While it looked great in the little scope and binoculars, I was never able to see it naked eye, though with her new eye lenses, Melinda picked it up a couple times.  The images shown here are at the same scale to give an idea of the silhouetted size of Venus during the transit next week.  Be sure to click the images for full-size viewing.

We hung out for it to set a little lower, and I caught a few frames with it setting against some distant trees in the park, without the 1.4X converter.  Also faintly visible in silhouette against the twilight sky are the out-of-focus blur of bats feeding in the area.  We'll likely not see Venus again until Tuesday afternoon a few minutes after 3pm when it appears against the Sun's disk!

1 comment:

David A. Harvey said...

Nice post Dean - great pics of Venus.