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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

NGC-7380 / The wizard Nebula

  • Posts: 319
  • Thank you received: 25


Equipment

Imaging telescope / lens Celestron Schmidt-Cassegrain (SCT) 8"/2032 mm 8SE
Imaging camera ZWO Optical ASI183mm Pro (CMOS)
Mount Equatorial Sky-Watcher HEQ5 Pro
Guiding telescope / lens Celestron Schmidt-Cassegrain (SCT) 8"/2032 mm 8SE
Guiding camera ZWO Optical ASI120MM Mini (mono) (CMOS)
Filters ZWO Optical Luminance (UV/IR block) 1.25"ZWO Optical Red 1.25" 90%ZWO Optical Green 1.25" 90%ZWO Optical Blue 1.25" 90%
Accessories Off-axis guider ZWO OpticalFocal reducer Celestron 0.63xFilter wheel ZWO Optical 1.25"Automatic focuser JMI MotoFocus+
Processed with PixInsight (Pleiades Astrophoto) 1.8

Frames / Subs

Lights (filter Luminance) 31 x 90 sec
Lights (filter Red) 30 x 90 sec
Lights (filter Green) 30 x 90 sec
Lights (filter Blue) 30 x 90 sec
Darks 26 x 10 sec
Flats 50 x 0.01 sec
Bias 61 x 0.001 sec
Total lights integration time 3:01 hours


Acquisition

Date Tue Nov 3rd 2020
Seeing 3 / 5
Transparency 3 / 5
Sky Darkness #4 Rural/suburban transition - 6/9
Camera Sensor Temperature -10.0 ºC
Binning 2x2
Gain 200
3 years 4 months ago #62509
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  • Posts: 2247
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hello Mohamed,

I think this is defo out of focus, have you checked your backfocus? Are you at the right distance for your camera?
The following user(s) said Thank You: Joaquin
3 years 4 months ago #62535

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Replied by Doug S on topic NGC-7380 / The wizard Nebula

I think this image is out of focus, but more importantly, your telescope appears to be significantly out of collimation and/or your focal reducer is not well matched (possibly both). If you look at the image near the bottom left, the stars appear to be slightly out of focus, but they're reasonably round. Now compare this region to the top, right, and especially top right. See how the stars have significant coma (comet shapes)? As you move about the field away from the lower left, the stars increasingly appear comet shaped (clear sign of coma aberration). You might try to first remove your focal reducer and try a test shot again to see if it improves the flatness of the field. If it does not, you will need to tune up your telescope's collimation. Cheers, Doug
Last edit: 3 years 4 months ago by Doug S.
3 years 4 months ago #62562

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Hello Stephane & Doug,

I agree. The image is out of focus AND out of collimation. This was the 1st test with my new ASI183mmPro. I'm still trying to get the best of it but Pixinsight is really confusing to use (maybe I don't have the PI gene). I have another better sets that I shall try to process later, and most importantly I'm trying to change the Analog motor focus I have now with myfocuser2 as advised by Stephane earlier.

Your feedback is always appreciated...
3 years 4 months ago #62636

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ok so you have 2 issues, collimation and focus, I would say that you need to get the collimation spot on or you'll be chasing your own tail for the focus.
A quick search on Google starizona.com/tutorial/collimating-a-schmidt-cassegrain/
3 years 4 months ago #62674

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Thank you Stephane. The link had a magic word for collimation which is "Tighten the screws". I was concerned that if I tighten them I would damage the 2ry mirror, but it didn't :)
3 years 4 months ago #62909

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