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Comet C/2012 S1 (ISON), NGC2684 Galaxy

Posted: 6 April 2013

The observatory was opened Friday, 5 April 2013, at 1819 MST, 82°F. The sky was mostly clear, but there were some clouds low in the western sky. I delayed opening the dome due to a strong breeze that was blowing 30 minutes before sunset. I opened the dome at 1851 MST and powered on the 8" LX200-ACF. At 1853 MST, viewed Jupiter, 77X; four moons were visible.

At 1930 MST, slewed to the star Capella, which would be my focus test star. Mounted the D7000 DSLR at prime focus using the off-axis guider. After doing a focus test image with the Bahtinov Mask, I connected my iPhone 4 to the telescope using the SkyWire serial cable. I then used SkySafari Pro to GOTO Comet C/2012 S1 (ISON), still a very small and faint comet. I located a good guide star and at 2000 MST I did a 10 minute, ISO 6400, guided exposure. I did another 10 minute exposure at 2030 MST. The comet motion (at center) is easily seen in this cropped animated image:


This is the image captured at 2030 MST, with a magnified view of the comet in the inset. The comet tail is clearly visible.


While I was imaging the comet, clouds had arrived at Orion in the southwestern sky. Fortunately, they were not in the northern sky where I would be imaging my next target, NGC2684 galaxy (small, faint). I found a good guide star and did this (cropped) 5 minute, ISO 6400, guided image:


When I completed imaging of NGC2684, the clouds were now in most of the southwestern quandrant of the sky. Slewed to NGC4244 galaxy to re-do the image I had acquired on 2 April, which was trailed due to a poor guide star selection. This time I found a better guide star but framing was not very good. Unfortunately, clouds were approaching that area of the sky so I decided to take the shot anyway. This is the full-frame, guided, 5 minute, ISO 6400 image:


Will try again on the next session.

At 2111 MST, the clouds were now in most of the western half of the sky. I decided to defer the rest of my planned imaging to another session and call it a night.

The observatory was closed at 2135 MST, 61°F.

On Thursday, 4 April, I added some Javascript to the Cassiopeia Observatory Data page (button in the Nav Bar) to show the times for the end and start of Astronomical Twilight at the observatory. Thanks to Vladimir Agafonkin for creating and sharing the code. Unfortunately there is a slight problem with the code; the times shown are correct only for users in the same time zone as the observatory, which is Mountain Standard Time (MST). Users in other time zones will see an incorrect hour shown. I hope to get this fixed soon.

I'm checking out two newly received products: a Wi-Fi adapter for GOTO telescopes, and a new star diagonal and 2" eyepiece. I'll report on them soon.

Comments are welcome; use the Comments section below, or you can Email Me. Thanks.

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