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My first image of 2016! It's been cloudy here for months, but we finally have a few days and nights of clear skies. It's wicked cold and windy, so I'm using the William Optics Star71 to make relatively short exposures with less sensitivity to seeing. I got a couple of hours of H-a that are reasonably good the first night, but the OIII and SII are pretty fuzzy, so I used H-a as luminance. This works well on this target, although it might be a little misleading: The blue region is not so much indicating the presence of oxygen as it is the presence of hydrogen and absence of sulfur.

WO Star71 at f/4.9
QSI683wsg with Astrodon 3nm filters
AP Mach1 mount
H: 8 x 15min, O: 4 x 30min, S: 4 x 30min

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Comment by Greg Marshall on January 13, 2016 at 1:04pm

Thanks, Phil. I have since captured some sharper SII and OIII frames, but haven't processed them yet. Given that the OIII is extremely weak, it may be that using H-a as luminance is still the best technique.


Comment by Philip A Cruden on January 13, 2016 at 12:31pm

Great! capture Greg. I love the color. I know what you mean about the weather. We had full cloud cover here in AZ for about 2 weeks. We are clear now so it is time for me to align my scope for the winter season. Cheers, Phil


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