Transit of Mercury

Yesterday saw the planet Mercury transit the face of the Sun from our unique perspective here on earth.  Slightly more common than a Venus transit which will not happen again in our lifetimes (see this post and this one as well), Mercury transits the Sun 12 or 13 times each century, always in May or November.  The apparent size of Mercury is rather small against the Sun, approximately 1/5 that of Venus.

We had a few programs running simultaneously yesterday for the transit-  up at the summit of Mount Lemmon the SkyCenter hosted a special program for visitors, and we also conducted an outreach event for students at Canyon View Elementary school.  The Sky School was hosting a group of 5th graders from Canyon View at our mountain based program, where I was operating the telescopes.  I set up at the Babad Do'Ag pullout approximately 2.5 miles up the Catalina Highway where we begin our Sky School programs with an exploration of the concept of a Sky Island.  Mercury began its transit prior to local sunrise and the transit is approximately a 7 hour event. I was all set by 5:30 AM and enjoyed watching the shadow profile of the Santa Catalina Mountains slowly creep across the Tucson basin as the Sun rose.  At left is the Coronado 90mm Hydrogen Alpha telescope we used for visual observation, as well as my 90mm Stellarvue triplet, 2x barlow and Canon 6D that I used to take pictures of the transit.  (Many folks ask about utility of the pink foam...it is simply to shade my camera in the Sun!)

Here are a few of the excited 5th graders observing the transit, I enjoyed the amazement of the student in the grey and red shirt exclaiming "It's so small!!"

I took a large number of images (approximately every 10 minutes until it was over) and processing them will require some time.  I did process one from near mid-transit and it is presented below.  As always, click the image to enlarge it and if your browser automatically re-sizes images you may need to click it again.

So there you have it- a fun and science filled day sharing the wonders of our Solar System with a group of our future scientists and leaders!

Planetary aesthetics

If you have been watching the evening skies this past month you know that we have had some very nice alignments of Jupiter, Venus and Mercury following sunset.  While Jupiter is now departed from view, Venus and Mercury remain and this week were joined by a fresh crescent moon.  This past Saturday I was at the Arizona Sonora Desert Museum doing some astronomy outreach in support of the UA Cancer Center and took the image below.  Venus is the lower planet and Mercury the upper.  Click to enlarge to full size!

Two nights later (this past Monday), I took this image from in front of my house where the planets were joined by the crescent moon, making a nice triangle.  If you click to enlarge to full size and look closely, you will see above the moon another interloper in the image, a bat!

Planetary conjunctions!

Today I returned from LA to the comfy confines of Tucson and my observatory.  As the sun was setting and I was noting the beautiful colors in the Belt of Venus I was reminded of how lucky I am to live in an area with such open horizons and frequently clear atmosphere.   The evening was so nice I decided to take a picture of the planetary conjunction in the west  from my home so as to capture many of the colors in the sky that I could simply not capture from the middle of LA.  The image below was taken at 8:13 MST (0313 UT) with my canon T2i and a 24-105mm zoom lens at 88mm.  The image was .8/sec, ISO 200 at f/4.5.  Click on the images to enlarge them and if your browser automatically re-sizes images you may need to click them a second time.  The images are identical with the exception of the labels on the right hand image.

As it happens, I discovered on my cameras memory card another conjunction image that I had taken earlier in the month, on May 13th at 0332 UT when the Moon was very close to Jupiter.  Jupiter is the bright dot near the lower right of the image (click to enlarge):

This was a 1 second exposure at f/4 with a Canon 15-85mm EF-S lens set at 85mm, at an ISO of 400.  I am quite happy with the exposure on the moon, particularly in that one can appreciate not only the Earthshine, but also some of the detail on the lunar terminator.  For instance you can see how some of the crater floors are not yet illuminated by the rising Sun, resulting in a scalloped look to the bright terminator.  Below is a full resolution crop of the moon from the above image...as always, click to enlarge.

Good night moon!