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Ceph and Cass

127 Mak M27


JamesF
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My attempt at M13 last night was rather disappointing and I'm not sure what I can recover in processing. This however I am rather more pleased with. It's 20 subs of 45 seconds of R, G and B (I also have L, but I've not done anything with it yet) , unguided. At the moment I'm finding that 45 seconds is marginal for unguided imaging at this focal length. This is a 50% rescale to keep the file size under control a bit.

m27-2013-08-07.png

I'm debating what to do with the luminance data. It's tempting to try to just mask it into the nebula and leave the field stars alone, but actually I'm not sure that 15 minutes is enough to make a difference anyhow.

(Actually, I'm even more pleased with it than I might otherwise be as it was my first night using AA5 for capturing and filter wheel control. That's all I'm using it for at the moment -- stacking the frames was done in DSS and merging the RGB in PS, but I will try to work that out in AA5 too, I think.)

James

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Focus was as good as I could get it with a Bahtinov mask on Vega. I think there might be a slight fuzziness that's been introduced by stacking frames that have very small amounts of trailing. The seeing wasn't exceptional and the Milky Way was nowhere near as well-defined as the two previous nights, so that may indeed also have been a factor. Certainly I lost all my blue subs of M13 last night because of atmospheric conditions, but it was getting low by the time I'd finished.

I think I'm going to have to sort out guiding though. I'm sure that's the largest source of error for the moment. And it would allow me to capture longer subs, which would do no harm at all.

James

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Focus was as good as I could get it with a Bahtinov mask on Vega. I think there might be a slight fuzziness that's been introduced by stacking frames that have very small amounts of trailing. The seeing wasn't exceptional and the Milky Way was nowhere near as well-defined as the two previous nights, so that may indeed also have been a factor. Certainly I lost all my blue subs of M13 last night because of atmospheric conditions, but it was getting low by the time I'd finished.

I think I'm going to have to sort out guiding though. I'm sure that's the largest source of error for the moment. And it would allow me to capture longer subs, which would do no harm at all.

James

Certainly guiding would help, but the stars show no signs of trailing with this current set-up and sub-length (at least to my un-trained eye :))

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I shall have a go with the Bahtinov grabber application next time. And perhaps check the FWHM figures too, though I know Olly reckons they're not that useful at longer focal lengths.

James

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Great image James, guided or not.

I like AA5 and the new SP2 service pack helps too.

Are you using 2 instances of AA5 for guiding or just the second camera option?

I download Maxim DL demo yesterday but not sure its a major advantage to AA5

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It seems to make sense to try to use a single program for both guiding and imaging at first, though I'll have to look into what's possible with the kit I have or how much more I need to make it work.

I was planning on making a finder-guider with the mono Firefly MV camera I have, but that appears unreliable with PHD. There is a bodged up ASCOM driver for it however, so it may work with AA5. Failing that I may be able to use my ASI120 assuming AA5 can work with it, but spacing will be tight and I'd prefer not to keep swapping it between guiding and planetary imaging as I'd have to unscrew the T-thread each time to remove/replace the 1.25" barrel, potentially letting dust onto the sensor.

An OAG may be a possibility that wouldn't need the ASI120 taking apart, as long as I can find enough guide stars (and if AA5 will play with the camera), but failing that I think I might have to look at buying a dedicated finder camera. A Lodestar would be nice, but a QHY5 might suit my pocket rather better :)

James

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