Cassiopeia Observatory

Copernicus, Jupiter Dual Moon Shadows, and Meteor Watching

Posted: 4 January 2012

I opened the observatory Tuesday, 3 January 2012, at 1801 MST, 64°F. The extensive clouds that appeared mid-afternoon were moving off to the east. The clearing skies in the west would allow me to make another attempt to image the International Space Station (ISS) with the 8" LX200-ACF at prime focus + 3X TeleXtender. At 1804 MST, slewed to the moon and began setting up for the ISS pass. Updated the ISS TLE in the AutoStar and mounted the D7000 DSLR. Used the moon to focus and locked it. Checked the finderscope alignment. Did a quick test exposure of the moon. Then waited for the ISS pass to start. The pass started a little earlier than predicted by the TLE and tracking was horrible. After about 3 minutes I gave up; tracking was just too bad and the finderscope was moving between the mount fork arms. The pass was a very bright and long one. Unfortunately, what few frames that captured the ISS were too noisy at the exposure used (1/3200sec, ISO 5000) and no details were visible. I will try again on a future ISS pass. There was one positive to having to abort the imaging part way through the pass: I was observing the pass with my eyes and just as the pass neared its end, a bright slow meteor appeared beneath the ISS and moving in the opposite direction. Nice.

As the sky was now clear, I knew this was going to be a long night since I planned to observe the Quadrantid Meteor Shower after midnight. I briefly went back to the house to heat up some tea. I returned to the observatory at 1857 MST and viewed Jupiter at 77X. Three moons were visible. Ganymede was currently in transit across the planet's disk but I was unable to see it. The Great Red Spot was just appearing at the limb at 206X. Jupiter's moons would be putting on a good show so I spent a lot of time observing Jupiter this night. Seeing began getting a little worse as I was observing Jupiter, but at 1937 MST, I picked up Ganymede just 13 minutes before the transit would end. I was using the 9.7mm (206X) eyepiece plus a moon filter. Ganymede was in the south polar region and became visible due to "limb darkening" on Jupiter.

At 2000 MST, I went to the moon and with the 9.7mm eyepiece + moon filter, I began looking for a good high magnification imaging target. I picked the Crater Copernicus (of course). Switched to the visual back and mounted the D7000 at prime focus. I then waited a little bit before starting imaging and during this time I set up a chair on the observatory patio for use to watch for meteors. I sat there until 2033 MST and saw one non-Quadrantid meteor. It followed a similar path as the meteor seen near the end of the ISS pass. I then began imaging the moon at 2035 MST. This is a 1/400sec, ISO 400, exposure:

I added a 9mm eyepiece for eyepiece projection imaging of the Crater Copernicus using the "Hat Trick" method. This exposure was at ISO 400 and cropped from the full-frame image:

I removed the camera from the telescope and at 2052 MST, I began observing Jupiter again at 206X + moon filter for the start of the Europa transit (2054 MST). Europa was easy to see after 2nd contact due to limb darkening, but by 2105 MST, it was getting more difficult to see. I began getting ready to do some iPhone 4 imaging of Jupiter when I noticed something on the observatory dome near my head. With my red flashlight on the object I could see that it was a large spider. Here's a photo taken with the iPhone with a 1.25" eyepiece for scale:

With the spider dealt with, I mounted the iPhone 4 on the 8" telescope using the MX-1 Afocal Adapter and began a series of test video recordings at 444X + moon filter in preparation for the dual moon shadow transits later. At 2150 MST, I resumed Jupiter observing, 206X + moon filter. I could no longer see Europa in transit. I went out on the patio to watch for more meteors. By 2213 MST, I had seen no more meteors and returned to the observing Jupiter. Still no Europa. Seeing was definitely getting worse. At 2234 MST, observed the start of the occultation of Io by Jupiter. At 2240 MST, I returned to meteor watching. Saw two meteors, both non-Quadrantids, one of which was brighter than the star Sirius. Returned to Jupiter observing at 2252 MST for the start of the Ganymede shadow transit (at 2304 MST). The shadow became visible at 2308 MST, near the south pole. Europa was also now visible (due to limb darkening), as its transit neared its end. Next would be Europa's shadow transit starting at 2326 MST. At 2329 MST, Europa's shadow became visible. There were now two moon shadows (Ganymede and Europa) visible on Jupiter's disk. At 2341 MST, even though seeing was very bad, I took a 30 second iPhone 4 video recording of Jupiter at 444X + moon filter using the FiLMiC Pro iOS app. This is a stack of the 735 frames using Keith's Image Stacker, showing both shadows. Ganymede's is near the south pole and Europa's is on the right below the South Equatorial Belt.

At 2358 MST, I ended Jupiter observing and imaging, and went out on the patio for Quadrantid Meteor Shower watching. I stayed until 0100 MST. The peak was forecast to be at 0020 MST. During this hour of observing, I saw one faint meteor, and it was a non-Quadrantid. Grumble.

At 0105 MST, I took a last look at Jupiter, low in the west. I then went to Mars, now rising in the east. Due to the poor seeing, I could not see any details on the planet except the North Polar Ice Cap, which was very evident at 206X and 354X.