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#1
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ASTRO: Kohoutek 2-1 (PN in Auriga)
Kohoutek 2-1 is a rather large (3 arcminutes) and rather faint planetary nebula, but definately not an extremely weak object. It surprised me when I found it somewhere in the internet about a year ago because I would have thought that I would have heard of such a nice PN.
I imaged it in two nights at the end of November and two at the end of December. Taken as usual from Berlin with my 10" Meade ACF at f/8, mount was a Skywatcher AZ-EQ6. Exposure time was: OIII: 100x5min with ASI1600 camera, 10x10min with Trius SX694 Ha: 61x5min ASI1600, 4x10min Trius SX694 RGB: 4x2min each with Trius SX694 Image scale is 0.75 arcseconds/pixel. Stefan |
#2
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Nice. So how does the CMOS camera compare to the CCD?
I'm starting to see a few take this one but none any better than this yet were done from darker skies. Rick Quote:
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#3
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The CMOS does quite well. Uncalibrated images look clearly inferior but after calibration the ASI1600 is almost as good as the Trius SX694. This was the first time I have compared both cameras in the same night and the comparison has some flaws (was experimenting with gain and temperature of the ASI also), but still I see an advantage for the ICX694 in long (10 minute) exposures. For short exposures the ASI is much much better due to it's low read noise.
I have attached 80 minutes of OIII data, taken in the same night with the same telescope. The ASI had 16x5 minutes while the SXV had 8x10 minutes. But that is no disadvantage for the ASI as it is easily background limited in five minutes even with narrow band and f/8. I only had the ASI at -10 celsius though which is a slight disadvantage as it cools as well as the Trius, which was at -20 celsius. |
#4
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-20C is warmer than my ambient temperature!
Looks like the Trius picked up a bit more nebula in the same time. Least I see the fainter parts better. How's the QE compare? Rick Quote:
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