Cassiopeia Observatory

Comets Lovejoy and ISON

Posted: 11 November 2013

Sunday evening, 10 November 2013, was cloudy, as seen in this sunset photograph taken with my iPhone 5s:

Cloudy skies continued into the night, but the sky was clear when I woke up at 0300 MST to hopefully image some comets. The observatory was opened Monday, 11 November 2013, at 0325 MST, 59°F. Briefly viewed Mars, 83X, at 0333 MST. No details were seen. I then powered on the GC Wi-Fi Adapter and used SkySafari Pro on the iPhone 5s to GOTO Comet C/2013 R1 (Lovejoy). Viewed the comet at 83X. The coma was nicely visible, with a short tail faintly visible.

I added a focal reducer to the 8" LX200-ACF and attached the D7000 DSLR at prime focus using an off-axis guider. Did a focus test image on the star Regulus using the Bahtinov Mask. Slewed back to Comet Lovejoy; it was easily seen in the camera viewfinder. A faint guide star was found.

At 0350 and 0355 MST, took 1 minute, ISO 6400, guided exposures of Comet C/2013 R1 (Lovejoy). This animated GIF shows the movement of the comet in 5 minutes:

I repositioned the comet in the viewfinder to better capture the long tail. However, no guide star was located this time. Did some more imaging. This 2 minute, ISO 6400, unguided image shows the long dust tail. If you look closely, you can see the faint ion (gas) tail just to the right of the dust tail.

This next photo was taken with the iPhone 5s and shows a 3 minute, ISO 6400 exposure of Comet Lovejoy as seen on the D7000 DSLR screen:

At 0421 MST, I did a GOTO Comet C/2012 S1 (ISON) using SkySafari Pro. The comet was currently behind the hill to the east and would rise up through a tree.

At 0431 MST, I viewed Comet Lovejoy using 7x50 binoculars. The head was easily seen but no tail was visible in binoculars. At 0435 MST, I began searching for Comet ISON through the tree limbs using the 7x50 binoculars. The Zodiacal Light was now visible to the naked eye. At 0442 MST, the neighbor to the north turned on his two extremely bright, horizontally aimed, floodlights. (Gross.) At 0443 MST, while seaching for Comet ISON in the binoculars, the International Space Station (ISS) crossed the binoculars field-of-view (FOV). The neighbor turned off his floodlights at 0451 MST. (Thanks neighbor.) At 0504 MST, using the 7x50 finderscope on the 8" telescope as a guide, I finally located Comet ISON with the 7x50 binoculars. The comet was very faint and difficult to see just above the tree. Now that the comet was above the tree, I began imaging.

This is a guided (on a star, not the comet), 2 minute, ISO 6400 exposure at prime focus + focal reducer of Comet C/2012 S1 (ISON):

With astronomical twilight soon to start (at 0526 MST), I removed the camera from the telescope. I viewed Comet ISON using the 24mm eyepiece + focal reducer. The comet's head was nice, with a long faint narrow tail visible. The comet's rapid motion was evident as I watched it in the eyepiece. I then removed the focal reducer and resumed Comet ISON viewing, 83X. At 0539 MST, while viewing Comet ISON, a faint satellite crossed the eyepiece FOV. At 0540 MST, the sky was getting noticeably brighter. I began closing up the observatory.

Photos from "The Last A-7D Pilots Reunion", held last week, are now posted on my A-7D web site. Have a look.

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