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Buzzard75

NGC 7822 - My First Narrowband

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I could sit and play with this image all day and probably never be 100% happy with it. I'm afraid if I play with it too much though, I'll just end up completely destroying it. I still haven't fully grasped PixInsight and have only used it a couple of times with mixed results. I guess the beauty of digital data is that it can always be undone or started over again. This is not only my first narrowband image, but it's also my first image using a monochrome camera and the iOptron CEM40EC mount. I was shooting unguided and I wasn't quite sure how long to expose for. I only did 20x180s exposures in Ha, SII and OIII for a total integration time of three hours. More and longer exposures would certainly help, I'm sure. I'll definitely come back to this one. I'm extremely happy with the roundness of the stars. The CEM40EC tracks extremely well and there was very little drift at all. I only had to shave a little bit off the edges after stacking. I cropped to remove some 'amp glow' that didn't come out even after using my calibration frames. My understanding is this camera suffers from bad glow on the right edge. Next time I'll push the exposures and see just how long I can go unguided before I start to see star trails with the mount.

ZWO ASI183MM Pro
ZWO 7nm Ha, SII and OIII 1.25" filters
William Optics RedCat51
iOptron CEM40EC
20x180s each; Ha, SII, OIII
3hrs total integration
Captured with APT
Stacked and processed in PixInsight

 

Image11 (2).jpg

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I think that is a nice image, with this narrowband which I do not understand, I never know what colour things are meant to be anyway.

Alan

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Posted (edited)

Nice first NB ,i was amazed at the detail in my light polluted sky even with the moon behind me got great results.

I have this camera we should start a help thread for 183 owners to share tips?

I like what i see with the W/O Redcat51,how is it?

Have you seen this

exposure tables 183 chip

Roger

Edited by apophisOAS
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Posted (edited)
6 hours ago, alan potts said:

I think that is a nice image, with this narrowband which I do not understand, I never know what colour things are meant to be anyway.

Alan

That's the beauty of narrowband I guess. Things can be whatever color you want them to be by changing the channel proportions using Pixelmath in PixInsight. I attempted the SHO Hubble palette at first, but with so little SII and OIII data, it was extremely green. I opted to add some Ha to the R and B channels and drop it from the G to even the colors out and make it somewhat more realistic.

3 hours ago, apophisOAS said:

Nice first NB ,i was amazed at the detail in my light polluted sky even with the moon behind me got great results.

I have this camera we should start a help thread for 183 owners to share tips?

I like what i see with the W/O Redcat51,how is it?

Have you seen this

exposure tables 183 chip

Roger

I live in Bortle 5 skies with lots of street lamps visible from my driveway. It's pretty awful. The data was captured over this past weekend on Saturday when the moon was pretty big and high during most of my session. I love the Redcat51. It's such a small, portable scope and extremely high quality. I'm amazed at how much light such a little scope can actually pickup. I've used it for both astrophotography and visual including night time and solar viewing with a white light filter. It's an extremely versatile scope and I'm extremely happy with it. It works really well on my small iOptron SkyGuider Pro as a grab and go rig.

I've seen similar charts for other cameras, but not this one in particular. I know that narrowband requires much longer sampling than broadband and I probably should have gone longer than 180s. I just wasn't sure of the unguided capabilities of the mount yet and wanted to be sure I had something useful at the end of the night. Like I said, next time I'll push the mount harder and expose for longer to see how long I can really go unguided before I get star trails. My thoughts are that if I get my polar alignment dead on, with a short focal length, I should be able to sample for five or six minutes at least, perhaps longer. At unity gain, which is 111 for this camera, that would put me more inline with those charts.

Edited by Buzzard75
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