Cassiopeia Observatory

Mercury, ISS, Jupiter, StarStaX Software, Full Moon

Posted: 26 February 2013

I opened the observatory Monday, 25 February 2013, at 1806 MST, 63°F. The sky was clear, with a slight breeze blowing. After powering on the 8" LX200-ACF, I first updated the TLE for this night's pass of the International Space Station (ISS). At 1816 MST, viewed Mercury, 77X and 133X. A thin crescent was visible, but with low contrast against the bright sky at sunset.

I grabbed a quick iPhone 4 afocal video, 133X, handheld. Due to the low altitude in the sky, most images were a blurry mess, but I did locate one reasonably good frame (cropped):

While observing Mercury, I also began preparing the D7000 DSLR for prime focus imaging of the ISS pass. At 1840 MST, Mercury showed a surprisingly good view at 267X, although it was now very low in the sky. Took my last look at Mercury at 1844 MST, and then slewed to Sirius, which would be my imaging focus test object using the Bahtinov Mask. At 1856 MST, with the eastern sky brightening due to the rising just past Full Moon, I mounted the D7000 at prime focus of the 8" and did a focus test image. I locked the telescope focus and tweaked the finderscope alignment. At 1918 MST, the moon was rising over the hill to the east. All was ready for the upcoming ISS pass.

The ISS pass started a little over one minute earlier than the AutoStar tracking predicted. I started the tracking. Tracking was not very good and the pass was a northerly one, meaning that the AutoStar tracking would go berserk as the ISS neared the North Celestial Pole. And I would lose sight of the ISS in the finderscope as the finderscope went between the mount fork arms; such is life with northerly passes using a polar mounted telescope. I did an HD video recording, 1/2000sec, ISO 2500, at prime focus of the 8". Due to the ISS distance for most of the somewhat low elevation pass, most frames in the video did not show any significant detail. However, one frame, cropped and upscaled 300%, showed some of space station structure:

After the pass was completed, I slewed the telescope to Jupiter, high in the sky, for some imaging. I did both prime focus and prime focus + 2X Barlow Lens single frame and HD video recording at various exposure settings. This image of Jupiter, prime focus + 2X Barlow Lens, is a composite of a 1 second, ISO 800, exposure and a 1/200sec, ISO 800, exposure. It shows the four moons (1 second) and Jupiter (1/200sec).

This image, cropped and upscaled 150%, is a stack of 1349 HD video frames, 1/30sec, ISO 800, using Keith's Image Stacker:

I recently became aware of a new imager stacker for Mac OS X, Windows, and Linux called StarStaX. It is still in development but I thought I would try it. StarStaX is designed to merge single frame sky images into star trails. It can also be used for stacking images to increase the effective exposure or enhance sharpness. Since the moon was full when I downloaded the application, I decided to first try StarStaX to stack images of Jupiter. A quick look through the online manual provided all that was needed to start using StarStaX. Since StarStaX does not work on movie files, using GraphicConverter, I saved 1494 individual frames from the same movie as used for stacking with Keith's Image Stacker. And unlike Keith's Image Stacker, StarStaX does not allow cropping before stacking. Add and Multiply did not yield a usable stacked image. Average worked better:

But the resulting image was not as sharp as with Keith's Image Stacker. I will stay with Keith's Image Stacker for planetary video image stacking. I will do more tests of StarStaX once the moon is out of the sky and report results.

At 2007 MST, I viewed Jupiter and the four Galilean Moons, all nicely within the same field-of-view at 267X.

I slewed to the moon and viewed it at 77X. A slight terminator was visible, about 7 hours after Full Moon. I took a quick tour of the terminator and the lunar limb using 133X. I then added a focal reducer and visual back, and mounted the D7000 DSLR at prime focus. This (cropped) image, 1/800sec, ISO 100, shows the nearly Full Moon:

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