First light with Skywatcher ED72 - California Nebula

[GraemeH]

After receiving my shiny new ED72 for Christmas from my fabulous wife, the weather has been awful and its first outing was last night.

Details:
Scope: Skywatcher ED72
Mount: Nexstar Evolution on wedge
Camera: Canon 1100D (unmodified)
Guider: QHY5Lii-c on Skywatcher 9x50 finderguider
Exposures: 45 x 120", ISO 1600, no flats, no darks, no bias
Software: APT for capture, DSS for stacking, Photoshop for post processing

It's very noisy with nowhere near enough exposure time, but the clouds thwarted any attempts to continue further for now.

 

[PeterCPC]

Great result for an unmodified camera. Calibration frames would improve it. As for noise - have a look at Astroflat Pro.

Peter

[GraemeH]

9 minutes ago, PeterCPC said:

Great result for an unmodified camera. Calibration frames would improve it. As for noise - have a look at Astroflat Pro.

Peter

Thanks Peter - I've left everything attached as it was last night so might be able to take some flats today and see how they improve things. 

[PeterCPC]

Also consider dithering next time.

Peter

[GraemeH]

I always use dithering - this one is dithered maybe a little too aggressively.  Haven't found the right settings yet for this scope to keep the dither to around 10-20 pixels.  Some dithers moved by as much as 80 pixels with this one.

[Cozzy]

That's a very nice shot, very well done.

did you use a Field flattener with the SW72ED?

 

Tim

[GraemeH]

Thank you Tim. I think I'm getting a little better at this, but like all of us I guess, there's always room for improvement. 

I used the OVL flattener for this shot, but added an extra 5mm backfocus distance between the flattener and the camera based on some of the comments in another thread (that I think you have been active in). I haven't tried any other spacing distances, and I'm not sure I have the expertise to really robustly assess the image quality anyway. 

[Cozzy]

1 hour ago, GraemeH said:

Thank you Tim. I think I'm getting a little better at this, but like all of us I guess, there's always room for improvement. 

I used the OVL flattener for this shot, but added an extra 5mm backfocus distance between the flattener and the camera based on some of the comments in another thread (that I think you have been active in). I haven't tried any other spacing distances, and I'm not sure I have the expertise to really robustly assess the image quality anyway. 

Graeme,

for a first outing with it, it's a cracking image,  and ever  day is a school day, suppose that should night.

I used to shot at 1600 ISO but found it noisy,  so dropped to 800 ( depends what your shooting/condition/time available I suppose) which I tend to  default too., and use Noel's actions which work a treat.  I had  ago at the California nebula at the beginning of Feb similar exposure time to yourself and found it a mare to process due to lack of data and poor framing. 

look forward to seeing more when you get the clear skies to do it.

sorry meant to ask /query, why you didn't use your Canon 6D , was it a weight thing?

I'll not talk about the other thread , leave that where it is.

 

Tim

[GraemeH]

4 minutes ago, Cozzy said:

sorry meant to ask /query, why you didn't use your Canon 6D , was it a weight thing?

I had the 6D on my other scope at the same time trying to shoot M1 - unfortunately it was too windy to get any usable subs at over 2000mm focal length. 

[Cozzy]

Oh I see, that'll be the Celestron at F10 then.  One scope and camera at a time is trouble enough me, your a brave man firing two together. tracking must be fun.

 

 

[GraemeH]

You say brave, I think my wife thinks it's more 'stupidly masochistic'. 

[knobby]

Looking good Graeme, nice stars to the edge too, so the spacing looks good too.

[GraemeH]

55 minutes ago, knobby said:

Looking good Graeme, nice stars to the edge too, so the spacing looks good too.

At some point I'll give it a try with full frame too, but it certainly looks OK to my untrained eye for APS-C.

[Cozzy]

Graeme,

I hope you don't mind but I had go at processing the image you posted, I have sent you the results .

 

Tim

[GraemeH]

5 minutes ago, Cozzy said:

Graeme,

I hope you don't mind but I had go at processing the image you posted, I have sent you the results .

 

Tim

Don't mind at all, but I'm not seeing any messages in my inbox. 

[Cozzy]

something must have gone wrong earlier, I have sent again.

 

Tim

[dodgerroger]

Great result. This telescope is on my shopping list to piggy back on my lx90

[GraemeH]

I know multiple processes of the same image aren't allowed in the challenge rules, so I thought I'd just add what I think will be my final version of this one in the comments.  If anyone knows if swapping my initial entry for the reprocessed one is allowed please let me know.

 

[GraemeH]

As I may have already disqualified myself by adding a second version, I may as well add another.  I think this will be my final process of this image.

[dodgerroger]

Can I ask what bracket you used to piggy back the frac on your sct?

[GraemeH]

5 minutes ago, dodgerroger said:

Can I ask what bracket you used to piggy back the frac on your sct?

I don't - I have them on separate mounts.