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Old 09-10-2020, 12:11 PM
Startrek (Martin)
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NGC 300 Spiral Galaxy in Sculptor

Gave the new ZWOASI2600MC a work out last night on a very dim spiral galaxy in the constellation of Sculptor NGC 300. At magnitude 9 this Galaxy is quite dim with a very low surface brightness, a challenging target for most beginners like me.
Conditions weíre tough with seeing and transparency about a 6 out of 10 plus wind gusts to 25 km/hr until late
Captured at my weekender on the South Coast NSW Bortle 3 ( no moon )
8Ē f5 Bintel GSO newt on an EQ6-R mount
ZWOASI2600MC camera, Ascom control at Highest Dynamic Range ( Gain 0 offset 50 ) , cooled to -15C
40 x 5 minute dithered guided subs
20 x darks ( didnít need to use them )
No flats ( no need for them )
Goto and tracking EQMOD StellariumScope and Stellarium ( found the Galaxy in 2 minutes , so accurate this software )
Frame , focus and Capture APT
PHD2 guiding , started at 1.20 to 1.40 total rms with the wind knocking RA around a bit and later on in the night the wind stopped and guiding was incredible 0.75 to 0.80 total rms ( Dec 0.55 and Ra 0.65 )
Stacked in DSS
Processed in Startools V1.6 OSC linear data set
The image suffered from a bit of star bloat due to poor guiding early on plus a bit of read noise ( might try Unity gain on next attempt) so used a heavy deconvolution, wavelet sharpening and de noise to tidy it up as best I could

Comments Welcome
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  #2  
Old 09-10-2020, 01:16 PM
jahnpahwa (JP)
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Yeah, looks great. A few galaxies coming through in the background there too. I would love to see you hammer a field like this for 10+ hours and see what you come up with!
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Old 09-10-2020, 01:24 PM
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PKay (Peter)
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9 out of 10 M.

Had to reserve a point so you can do better :-)

Very good result and well done.
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Old 10-10-2020, 05:39 PM
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looks fantastic, delicate and detailed. Curious about 0 gain for max DR as the 2600 (like the 533) jumps up in DR at unity gain to nearly max levels... wondered whether it is worth it for a target like this to go at 0 gain for the tiny extra DR over unity?. I am really just learning this stuff so have no real idea. Good insight on read noise and star bloat as well; wasn't aware of that.
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Old 11-10-2020, 02:52 AM
Fernando
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Martin congratulations again!You and the ZWO2600MC Pro are doing really well!
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Old 11-10-2020, 07:06 AM
Startrek (Martin)
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Thanks All for the lovely comments

Robert,
Apologies for confusing you about the Gain, I should have said Gain 100 instead of Unity Gain. This camera doesnít have Unity Gain as such. The settings for Unity Gain and Highest Dynamic Range are the same
At HDR ( 0.76e ) you get get full well depth on each pixel or max dynamic range but increased read noise
At Gain 100 you only get well depth of 30,000e but much lower read noise , still good dynamic range
Itís a bit of a gamble
ZWO advise use either settings in Ascom at HDR or Unity Gain( same as HDR) or Gain 100
Hope that makes sense

Also when I said guiding causes Star bloat , I should have said atmospheric conditions cause Star bloat which in turn affect your guiding

Cheers
Martin
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Old 11-10-2020, 01:16 PM
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Quote:
Originally Posted by Startrek View Post
Thanks All for the lovely comments

Robert,
Apologies for confusing you about the Gain, I should have said Gain 100 instead of Unity Gain. This camera doesnít have Unity Gain as such. The settings for Unity Gain and Highest Dynamic Range are the same
At HDR ( 0.76e ) you get get full well depth on each pixel or max dynamic range but increased read noise
At Gain 100 you only get well depth of 30,000e but much lower read noise , still good dynamic range
Itís a bit of a gamble
ZWO advise use either settings in Ascom at HDR or Unity Gain( same as HDR) or Gain 100
Hope that makes sense

Also when I said guiding causes Star bloat , I should have said atmospheric conditions cause Star bloat which in turn affect your guiding

Cheers
Martin
got it now, thanks martin
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Old 12-10-2020, 01:59 AM
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Very nice work again Martin
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Old 12-10-2020, 07:33 AM
Startrek (Martin)
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Very nice work again Martin
Thanks LIS
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Old 13-10-2020, 03:07 PM
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Zubenel (Wes)
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love those multiple arms. Nice take
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