MHaneferd

On 17/10/2021 at 13:37, nephilim said:

200 x Bias

Looks impressive!! 
 

I am pretty new to this, but I am curious of why did you do so many Bias frames?

8 minutes ago, StuartT said:

it’s actually my fourth DSO. I started out with astrophotography in august.

You nailed it this time!

It is very beautiful. You have really got the details and edges sharp.

6 hours integration time @ 35sec subs would be over 600 light frames @ 50MB each!!?!? 

Thanks again. I’ll buy two strips to be at safer side and just see. Hopefully it manage the winter here..

Thanks for quick reply. I am still a bit worried that the dew heater strips do not warm tube and glass enough. The worst thing is if it freezes.

Winter is coming and I struggled the past days with dew on my Skywatcher 120ED. I have tried to use a self made isolation dew-cap around it, but not good enough (still dew)

I have browsed trough the forum and read about dew heaters vs. Dew shield, and figured out that I probably need a dew heater. The temperature here can range from minus 5 to minus 35 degrees celcius, but I dont think I’ll be using the scope when passing minus 20.

My question is, which dew heating option would handle minus 10 to minus 20 degrees celcius for my scope? I am afraid that the temperature loss will make the strips not functioning well when passing minus 10 degrees, but I might be wrong?

I guess my scooe is around 45cm circumference outside the tube.

I am using 220V with adapters to everything else, so power is not an issue. 

2 hours ago, Lee_P said:

My telescope is a "closed system" so to speak

Thanks again @Lee_P ! I suspect that my filterwheel might do some dust trick to my sensor when I turn it from 1 to 2 and 3.. I will try an over three days shot (after the rainy weeks) with none filters attached to see. 
 

37 minutes ago, bobro said:

To keep things simple I've settled on 2-3 min subs as appropriate for my setup

Do you differ alot of sub-exposure time when it comes to. Hanging filters, or do you try to keep it the same? 
 

@bobro and, thaks for the image adjustments.. You really nailed it! I understand now that image adjustment is another expertise that will take me years to learn… And, thanks for that, so I can improve over the next decade 😃

@Lee_P But, if you use flats for severa hours of imaging, the dust particles should stay at same spot over all 20 hours? I am just thinking that if I move the scope in and out for two sessions on the same M31.. the dustparticles will probably move. And how will the flats be intrepeted then in the stacking??

1 hour ago, Lee_P said:

just one more night

But, if you do several nights.. How do you manage flats? Do you take a set of flats and darks after each night, or do you do that at the end? 

@Lee_P, I think it can be better. It’s what you are saying the longer integration time, the  better signal to noise ratio can be achived. As I had to scrap 50% of the frames, and I suspect the remaining percentage also have som dizzy cloud in them, I will test another go for two minute subs over several hours. Just have to wait for clear sky again.. going to rain for 14 days now 😳

Thanks @Ouroboros. I just listened to Dr.Robin Glovers video as a podcast while painting my cabin today. I defiantly have to look at it on YouTube. I am not sure if a formula will help getting the exact sub-shot-time, since when I look at my sky. It seems to be more light polluted in the southern direction than the northern.. And, I also feel that there is a ratio on how many files my computer can handle, compared to noise / exposure time ratio.. So, I will try to follow @Lee_P's two minute exposure times. I will test both lower and higher to see the results...

Anyways, the Andromeda shots last night, got a bit blurred due to clouds. So after removing the most blurred, and the ones with satellite tracks (6 of them), I ended up with 49 frames out of 100. all at 2 minutes subs. I got the blacks over the night, but when I was going to take the Flats. The sky where quite moisture and wet, so I gave that up. 

So this is the result of 49 frames at 2 minutes subs, with gain 100 + 100 darks. Stacked with ZWO ASIDeepStack_1.5 . As you can see, there are some dust spots. The result has not been edited in any ways, it is just the JPEG from the ASI Deepstacker:

18 minutes ago, iantaylor2uk said:

There is a spreadsheet for ZWO cameras

Thanks.. after hefty googeling, I found these ones for my ASI2600, 

https://drive.google.com/drive/u/0/mobile/folders/1CnKISk-4X0pTo6emReMIO099JlgPHIT6?usp=sharing

@iantaylor2uk interesting. What is the reason for extending the sub time depending on filter type?

16 minutes ago, Lee_P said:

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

Not sure about that. You have the little galaxy upper left, but my focal length are clipping it 😳

@Lee_P The satelite photo was taken 21:38 (CET)

By the way, Here in Oslo, it is not the light pollution that bother me most, it is rather the weather 😳

@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.

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..

4 hours ago, lainev said:

ASI385

That was quite nice photo Congrats!!

Did you use any filter with the ASI?

@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
 

I use ASI Studio, There is a litte Fits viewer thats nice, but you cannot export to anything;

https://astronomy-imaging-camera.com/software-drivers
 

You can also browse the whole toolset from NASA on FITS files. There you find viewers, converters, etc:

https://fits.gsfc.nasa.gov/fits_viewer.html
 

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!

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??

@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?

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

Thanks alot for the added info!

I have to check that cygnus wall out myself 😊. I probably use 2 hours to find it in the mist… 😳

I really liked that one.

can you explain a newcomer like me how you get your scope to point directly to the wall? Is there any star or something you reference? Or are you just moving the mount till you hit it?

can you also elaborate about how many shots? Shutter speed and gain?

Any filters?
 

I have a similar camera and a smaller size of the scope (120 ED)