NGC7000 , my first DSO attempt

[MHaneferd]

Starting yeaterday evening, I tried to capture the NGC7000 with my ASI2600MC on the Skywatcher Esprit 120ED with zwo duo-band filer. I used ASIAiR pro for capturing lights, flats, bias and darks. And stacked them in ASI Studio. 

the settings I used where 10minutes x 20. I had to throw away 12 of the images due to clouds and one due to satelite flybys..

I was a bit disappointed, since I just got alot of stars, and some nebula. But I guess that I need a less focal length than 840mm for that nebula. And pehaps shorter time than 10 minutes??

This is the jpeg that ASI Deepstacker created;

 

[Ouroboros]

@MHaneferd    Yeah, it’s a bit big as a target at that focal length. I just about fit it  in at 510mm on my ASI2600. You might do well with the Cygnus Wall in NGC7000 though. 

I think you’ve got  good quality data though. What processing have you done after DSS? Your guiding must be good.  What made you choose 10 minutes?  I used 5 minutes on the North America Nebula (unfiltered) and that seemed OK. But I haven’t had my ASI2600 very long and I’m still wondering what is the most suitable sub-exposure duration.  

[Lee_P]

This is a good start! Given your telescope's focal length, you might do well to centre in on a particularly interesting part of the nebula, like the Cygnus Wall.

You need a much longer integration time though. As you suggest, shorter exposure times work well with a modern camera like the 2600. I use that camera too, and shoot 2-minute subs -- but lots of them! Aim to get five hours of good quality data in your image, then you'll have something nice to play about with in post-processing.

This photo just posted by @StuartT might be of interest to you: same camera, similar telescope. 

 

Edited September 24, 2021 by Lee_P

[Ouroboros]

How did you settle on 2 min subs, @Lee_P?  Oh, and at what gain?

Edited September 24, 2021 by Ouroboros

[MHaneferd]

@Ouroboros I am just very new to this, so I tough I needed long exposure time to get the faint areas. 
some other settings I used, where;

Gain: 40

Dithering (1) default.

Mount: EQ6R Pro

@Lee_P , I’ll try 2 mins.. What Gain settings do you use?

the stuff:

[Lee_P]

2 minutes ago, Ouroboros said:

How did you settle on 2 min subs, @Lee_P?  Oh, and at what gain?

Gain 100. As for 2-mins, I mention that in this article, (point 3, near the end): http://urbanastrophotography.com/index.php/2021/06/14/how-to-get-long-integration-times/

[Lee_P]

10 minutes ago, MHaneferd said:

@Ouroboros I am just very new to this, so I tough I needed long exposure time to get the faint areas. 
some other settings I used, where;

Gain: 40

Dithering (1) default.

Mount: EQ6R Pro

@Lee_P , I’ll try 2 mins.. What Gain settings do you use?

the stuff:

Are you using an electronic filter wheel with your OSC camera?

[MHaneferd]

Yes, I figured out that I wanted to try out two different filters, and due to my laziness and interest for electronics, I purchased the seven holed filterwheel from ZWO. Also because if I suddenly want to purchase a mono camera. Anyways, I think I’ll stick to the colorized version first and make that work good first 😊

[Ouroboros]

1 hour ago, MHaneferd said:

@Ouroboros I am just very new to this, so I tough I needed long exposure time to get the faint areas. 
some other settings I used, where;

Gain: 40

Dithering (1) default.

Mount: EQ6R Pro

@Lee_P , I’ll try 2 mins.. What Gain settings do you use?

the stuff:

Nice bit of kit. It’s always interesting to see how others solve the problems of where to put the guide telescope, ASIair, finder scope etc. 

[Lee_P]

@MHaneferd @Ouroboros Just following up on the "why gain 100" question, from ZWO's website: "The ASI2600MC Pro has excellent performance with a dynamic range of up to 14stops. When the gain value is 100, the magical HCG high gain mode is turned on, the readout noise is greatly reduced, and the dynamic range is basically unchanged. It is recommended to set the gain to 0 or gain 100 in deep space."

 

[MHaneferd]

The challenge I find is where to put all the wires.. 😳 

[MHaneferd]

@Lee_P Thanks.

I guess I van test those setting out on an object to see if there any  noticable difference.

BTW: I used Gain 40 , so thats what happen when I dont read the manual 😳

Is ther a formula for shutter speed, gain and aparture on these dedicated cameras? Like there are on DSLR’s?

 

Edited September 24, 2021 by MHaneferd

[Ouroboros]

47 minutes ago, MHaneferd said:

@Lee_P Thanks.

I guess I van test those setting out on an object to see if there any  noticable difference.

BTW: I used Gain 40 , so thats what happen when I dont read the manual 😳

Is ther a formula for shutter speed, gain and aparture on these dedicated cameras? Like there are on DSLR’s?

 

I’m a bit puzzled because as I understand it the ASIair only allows the ASI2600 to be set at the gains of only 0 or 100.

Edited September 24, 2021 by Ouroboros

[Lee_P]

49 minutes ago, Ouroboros said:

I’m a bit puzzled because as I understand it the ASIair only allows the ASI2600 to be set at the gains of only 0 or 100.

Just leave it on 100, job done.

[Ouroboros]

3 minutes ago, Lee_P said:

Just leave it on 100, job done.

Yeah. That’s what I’ve done so far. In Cornwall though under Bortle class 3 skies I’ve wondered whether to go for gain 0 to take advantage of the full dynamic range. I guess the thing is to try it. 

[MHaneferd]

1 hour ago, Ouroboros said:

I’m a bit puzzled because as I understand it the ASIair only allows the ASI2600 to be set at the gains of only 0 or 100.

I was actually thinking the same.. I have not found out why, but if the magic happens at gain 100 on ASIAir, it’s good for me… Just to speculate, can it be a percentage measurement of max gain on the camera??

[MHaneferd]

3 hours ago, Lee_P said:

Gain 100. As for 2-mins, I mention that in this article, (point 3, near the end): http://urbanastrophotography.com/index.php/2021/06/14/how-to-get-long-integration-times/

I really liked that article. I did not find anything about the gain at the end, but I got the point of short subs. That makes perfectly sence when the sky have some cluttered clouds flying by.. I experienced that with my 10 mins.subs.

Also loved the Pier!! That is something I will build at my skiing-cabin in the mountains. That was quite awesome!

[Lee_P]

1 hour ago, MHaneferd said:

I really liked that article. I did not find anything about the gain at the end, but I got the point of short subs. That makes perfectly sence when the sky have some cluttered clouds flying by.. I experienced that with my 10 mins.subs.

Also loved the Pier!! That is something I will build at my skiing-cabin in the mountains. That was quite awesome!

Thanks! I meant that the reference to 2-min subs was near the end of the article. I don't mention gain as that's not specifically about getting long integration times. A pier is indeed fantastic, I highly recommend them!

[Ouroboros]

This afternoon I watched Dr Robin Glover’s video and noted down formulae etc.  I reckon with the ASI2600MC on my set up consisting of the SkyWatcher ED80 (F/6.4) under Bortle class 3 skies that the optimum sub-exposure length is 90s. This assumes I’m happy to accept 5% extra noise as the cost of taking shorter subs. That is considerably shorter than the 300s I have been taking. It seems to me the limiting factor for me might be the number of subs my MacBook can process in a reasonable amount of time. The 38 subs of NGC7000 I recently processed were taking quite a chunk of time - especially the stacking in PS.  Tripling the processing time would be unacceptably long I feel. I think I’ll have to compromise. There’s no problem with taking slightly  longer subs except possibly more drop outs due to planes/clouds etc. PS makes a good job of getting rid of satellite trails I find. Perhaps 200s is a good compromise.

[MHaneferd]

@Ouroboros Is there a formula for exposure times? Or is it in the video you mentioned? Link?

I will try out a lot of exposures at gain100 @2min as described by @Lee_P. I just hope that the PC dont melt..

I was thinking of either give the NGC7000 another shot, by moving to the cygnus wall, or try the pin-wheel galaxy.

All credits to @StuartT for giving me these coordinates to the wall;

RA 21h 0m 2s
Dec +43d 41m 42s
 

[StuartT]

On 24/09/2021 at 17:21, Lee_P said:

This photo just posted by @StuartT might be of interest to you: same camera, similar telescope. 

Thanks for the shout out 🙂

59 minutes ago, MHaneferd said:

All credits to @StuartT for giving me these coordinates to the wall;

RA 21h 0m 2s
Dec +43d 41m 42s
 

Pleasure! Look forward to seeing what you get. I only use 35 sec subs with my 2600MC Pro, as I have not reached the stage of guiding yet...

[MHaneferd]

Okay.. the sky is a bit light and some clouds covering the ngc7000. Started to do stuff at 21:00.

I tested out Gain100 with four different exposure times on the Andromeda (M31)

60sec:

 

120 sec:

180sec:

300sec with an UFO:

From 60 to 120, I notice a differnce,  but between the rest it is not that much.

I have now set up 100 shots@120sec. So, I am quite exited for the result…..hopefully if the skys cleared. 
 

I checked the Bortle map, and it seems that I am in a 8-9 😳 Might have to move up to my cabin. There it is measured «only» 4..

Edited September 25, 2021 by MHaneferd

[Lee_P]

@MHaneferd Neat test! Remember that it's the total integration time that counts though. In principle your 100 x 120-second integration should be very similar to 200 x 60 seconds, or 40 x 300 seconds. 

[MHaneferd]

@Lee_P Yes! I understood that part, and with all the UFO’s (Satelites?) which I remove , I can achive more effective integration time with quality pics.

I still have to check the end result, so my brain accept it as a fact 😃

I might do the same with lesser and lesser exposure time if the result is good.

[Lee_P]

@MHaneferd Good idea, I did the same experiment when I first got the camera. That helped me settle on 120s.

That does look like a satellite in your 300s shot; what time was it taken?

I'm in Bortle 8 too. It's a pain, but we can still get good images with long integration times. You'd get there faster from your cabin though!

FYI your 120s sub looks better than my 120s sub:

Edited September 25, 2021 by Lee_P