Observing with Street Lights

Observing with Street Lights
Dark sky sites not always necessary to see the Milky Way (This image was taken ouside of a B&B in Julian, CA)

Monday, May 9, 2016

Transit of Mercury, One good image before we got clouded out, same luck for Larry in San Diego, Scientist scribbling equations on plane gets questioned as suspected terrorist

Greetings from Palmia Observatory

Well, the most promising image(s) for this week are for the transit of Mercury.  Did you have any luck with the weather and capture the transit? The forecast was for some sun and some clouds and yes, that forecast was mostly right except for the mostly being cloudy part.

I slept in and just finished my first cup of coffee and found
the sun was shining bright so set up the tripod and the 600 mm lens and took the first image at 7:20 AM.  There is one large sunspot still looking about in the same location as found in last week's test image.  At first, I didn't see any indication of Mercury, but then discovered that the transit was near the lower limb of the sun.  Wow, there it was, a little tiny dark, circular spot!  See the first attached image.
Transit of Mercury photographed at Palmia Observatory
Transit of Mercury

Then, after a second cup of coffee, I took the second image 30 minutes later at 7:55 AM.  See the 2nd attached photo
Transit of Mercury
Hey, this was looking pretty good and I might be able to track the transit all the way to the end at 11:42 AM.  But, it was not to be.  The clouds came back and closed in and hid the sun from view.  All that could be done was wait.  And wait and wait and wait until finally the transit was over.

I got an email from Legacy Coder, Now Studying Physics Full Time, Larry, that he had got an image or two but the clouds had covered up his San Diego area viewing site.  Thanks Larry. Then Math Whiz, Dave, reported that the clouds closed in the Long Beach area.  Thanks Dave.  I didn't hear anything for the public viewing party at UCI, but I assume the clouds shut down that viewing too.  Darn, the transit of Mercury won't be back until November 2019.  Maybe our other associates outside of Southern California, like Science Nerd and Theater Impresario, Scott, who is in Japan this week, had better luck.

Well, I kept popping out for a look at the sky and finally at 3:55 PM, the sky opened up just enough to get a good view of the sun with just a few, wispy clouds. I wanted to get at least one photo after the transit, primarily to assure myself,that the little black spot was really Mercury and not some bug or other obstacle on my lens. This photo is shown as attachment 3. 
Post Transit of Mercury
Yes, the sunspot is still there and the little black spot caused by Mercury has moved past the limb of the sun.

So, luck was not with us, but look a little bit closer to the three images we were able to capture.  You probably noticed how the sunspot appears to move from the 2nd image to,the third image.  This is not due to the motion of the sunspot on the sun's surface, although the spots do move, but due to camera frame rotation.  All images were taken with the DSLR on an Altitude-Azimuth mount so as the day progressed the images suffer from frame rotation, which is why astroimagers like to use an Equatorial mount.

This issue of frame rotation reminds me of a project that I considered last year, which was to measure the rate of motion of sunspots.  There are so many other effects, like frame rotation, and effects of the motion of the earth in its orbit that have to be taken into account.  I had discussed this with Still into Control, Expert, Gene, and we had tentatively decided to try to unravel all of the trigonometric transformations involved in making this measurement.  But, we conveniently forgot about starting this project.  Anyway, if anyone recalls how the motions of sunspots are estimated based on observations let me know?  Maybe it's easier than I imagine.  I know that the professionals publish the celestial sphere projections of the suns north and South Pole, and supposedly we could transform telescope angular measurements back and forth to get actual sunspot motion. Let me know.

Well, that's probably enough for this week.  The observatory staff is busy planning for our flight to Switzerland next week for our Rhine river cruise.  Some people pay more attention to airplane accidents prior to their travel.  I normally don't get caught up in that, but one news item caught my attention.  It seems that one airplane passenger was busily trying to solve some differential equations and his seat mate became alarmed and thought he was scribbling some terrorist coded message.  When the other passenger asked to get off the plane out of fear, the whole flight was delayed until the authorities could resolve what was going on.

Wow, When I'm on the plane I'm also always scribbling and reading texts with all sorts of equations hiding some sort of hidden message that I've trying to solve.  I guess I've been quite lucky in that no one has tipped off the authorities. 

 The rest of the unfortunate story can be found at:



Until next time

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