Monday, March 26, 2012

What A Difference A Day Makes!

One of the Nightly Observing Program guides had a family emergency, so I filled in for him on one of his shifts last week.  As a result I went up to work the program 2 nights in a row on Thursday and Friday.  After a winter storm had dumped about 10 inches of snow the previous weekend, warm weather had returned quickly and the piles of snow, in some places 5 feet high were melting quickly at the 7,000 foot elevation of the mountain.  The other benefit of the storm was the air was absolutely cleansed and we had high hopes for a spectacular night.  I took a camera along in case the seeing was good - was hoping to get some "family portraits" of the 4 bright planets in the evening sky.

Another of the guides took sunset tour duty, so I went to the scope to catch some shots of Jupiter and Venus before they got too low.  Unfortunately, while the sky was very clear, turbulence in the atmosphere played havoc with the "seeing" and the planets were not very sharp.  I took some portraits regardless.  All of these, including Mars and Saturn at the conclusion of the program, were taken at the same scale - the 16" telescope at the Cassegrainian focus with a 2.8X Barlow lens, making it equivalent to something like a 9,000 mm telephoto lens!

Jupiter is at upper left, and one of its moons Ganymede is just above the upper left limb.  Upper right is brilliant Venus - since it circles inside the earth's orbit it goes through phases like the moon.  It is currently at its greatest eastern elongation in the evening sky, so is nearly exactly half illuminated.  A little later at the conclusion of the program, I grabbed a few frames of Mars, here shown at lower left.  Barely seen at top is the northern polar cap, with some diffuse dark and bright markings.  And while it was low, Saturn is included here, though pretty fuzzy...

The next night (Friday) we had some haze buildup, and even a few clouds in the western sky that actually blocked the setting sun, though they didn't affect the observing at all.  But the atmospheric stability was much better and the seeing was quite good.  I set up the camera for some time-lapse work while I was busy with the program, but afterwards, I had some friends join Melinda and me for some after-hours observing.  Towards the end of our evening, about 2am, we turned to Saturn before leaving and we were just astounded by the quality of the view.  Shown here is the average of a few frames with the Canon XSi.  Realize that a DSLR is not the optimum camera for planetary images - webcam imaging, where thousands of images can be stacked for spectacular results is the now-preferred method.  Check out what advanced amateur Jerry Lodriguss is doing on Mars and Saturn - using the video output of a DSLR!

I also took some longer exposures (4 seconds) which showed Saturn's moons in the vicinity.  Here at right is a stack of 5 images, rather severely windowed to show some ring detail as well as the moons.  From the bottom going CCW is Dione, Tethys, Enceladus (right next to ring at lower right) and Rhea at top.

I've got to learn some of the webcam techniques on those rare occasions when the seeing is great, the optical quality and chance for great results is too great to pass up!  Images are courtesy of the NOP program/NOAO/NSF.


Andrew Cooper said...

Actually a DSLR can do a very good job at planetary, as you mention... In video mode. I have had very good results with my 60D. Jerry Lodrigruss has an article in this month's S&T on how to do it.

Dean said...

Thanks for pointing that out - my cameras have video output as part of live view that can be used by some software packages. I saw that Jerry had the article coming out when I linked to his images in the post. I need all the help I can get, so am looking forward to his article! -Dean

Astroweis said...

Hi Dean

Wow, great images. Seeing must have been superb.
I can hardly wait to return to Kitt Peak for some observing fun.