Only one transit observation has trickled in from John Kalas, but will include a surprise below. I’ll include a couple pictures too. Here is John’s:
Mercury Transit – 5/9/16
I awoke at about 7:00 am and took my 11×80 giant binoculars with solar filters out in the backyard to assess the transit and make the big decision of whether or not to lug out the telescope. I should have set up the telescope the night before and left it parked overnight, so it would be accurately aligned for the transit but I was lazy.
The transit was about mid-way, so I decided to get out the scope. By about 8:00 am, the Astro-Physics 130mm refractor with a Thousand Oaks white light solar filter on an A/P 600 mount was ready-to-go. On went the Canon 60Da DSLR camera at prime focus and I started experimenting with the manual settings of exposure time and ISO speeds. After several trips into the house with the camera’s memory card to review the images on the computer, I settled on 1/8000th of a second exposure time and an ISO of 1600. Being that I didn’t have a precise polar alignment, I had to slightly re-align the sun in the camera’s view finder for every shot. Shown here is the start image and the last image.
A Few Shots from the Mercury Transit
With the Mercury transit already underway at sunrise, I was visualizing a shot of “Mercury rise” as it cleared the Catalina Mountains, so on Saturday I scouted a few locations for a clear view – tough to find in the metropolitan area with trees, power lines and easy access. I finally found one near the east end of Roger where it meets the Rillito Wash near UA Farms.
Since I never use an alarm clock, I actually had to test it to see if it worked for my 4:50 wake-up call so I could drive the mile or two and set up. Conditions looked great – the picture at left shows my setup – the TEC 140 (plus 1.4X Canon extender) on my Alt-Az mount, with the location on the right slope of a hill. The shot, close to my visualization, except for perhaps a saguaro or two, is shown at right. Mercury had just cleared the slope at lower left.
What is interesting to me are some of the atmospheric effects of the low sun. We all know about the “green flash” as the atmospheric dispersion gives any setting object a green or blue upper edge and a red lower edge. You can see it on the above image. But if you examine the image of Mercury, or even the sunspot, you can see the inky spot has a reddish upper edge, and blue/green lower! Of course it is caused not by the black dot, but rather the illuminated upper edge of the lower edge of Mercury is green… An enlargement is shown at left.
At his point I retired to home, where I had setup and aligned the AP1200 the night before in the back yard. Spending about 30 minutes figuring why the scope wasn’t tracking (Duh – in my sleep-addled state I’d hooked it up wrong!). Eventually I got underway – fortunately the trees blocked the low sun, so I got going about mid-transit. So I’ve got hundreds of images thru the thing – perhaps they’ll get turned into a movie someday. Shown here is a 2-image stack very near 3rd contact showing a full-resolution shot of the TEC+1.4X extender+Canon XSi camera. I couldn’t be happier with the resolution, just my processing skills how to proceed with a few hundred images!
I hope all who had a chance to observe had a great Transit!
Oh Yea – the surprise!
Since Tom Polakis just spoke to the TAAA 5 weeks ago about time-lapse imaging, I’ve absolutely GOT to show you his treatment of today’s transit! Using a Lunt100, he took high-speed video of the last 10 minutes including egress, and used about half the frames to make 31 frames of fantastic! Gif is shown here, and the link to his pbase gallery is here. “Mike drop” here… Just amazing!