First time using this camera and first time with clear skies in over a year here when i am not at work.
Taken with an ZWO asi2600mc at -10c with no filters
Tried again with Optolong L-Pro fliter but did turn out so well, think the clouds must have rolled back in
Scope is Skywatcher Esprit 150
Mount is Ioptron CEM120
30 X 180 Second exposures
30 X 180 Second Darks
30 X Flats
30 X Dark Flats
50 X Bias frames
Kind of put them all in and stacked with Deepsky Stacker and processed with Startools
Not sure if i am suppose to use all of those calibration frames with this camera or not, so just put them all in.
Any advice / comments / suggestions is all welcome.
Thanks.
Peter.
Might be some black clipping and that means loss of data.
And always use calibration frames. You don't have to take new ones all the time if using the same setup. I redo mine every few weeks.
Also I have found that 10 subs is usually enough for flats, bias and darks.
I don't use dark flats.
For that particular camera, you don't need darks or dark flats. Just flats and bias frames.
I use 40 flats, and 100 bias frames. And if you're moving the setup between shoots, then retake your flats every time
It's a good start, but you can push this image more to get detail in the darker areas without blowing out the core. Especially with that camera and it's very high dynamic range.
Appreciate all the feedback, anything is good.
Forgot to say it was also taken during the full moon.
Still learning the steps with Startools also.
Might try restacking with just flats and bias frames to see what the difference is.
Appreciated.
Peter,
Nice Carina but should be brighter for those sub lengths
Maybe cloud caused your subs to be muted with DR
Did you use AutoDev or Film Dev to stretch it ?
I’ve used the 2600MC for nearly 2 years now
In regard to calibration frames -
1/ You don’t need darks as this camera has extremely low dark current and zero amp glow
2/ I experimented with calibration for a month or so with Flats and Dark Flats Flats and Bias and found Flats and Bias worked best for my set up ( 6”, 8” and 10” Newts )
3/ Calibration frames take no time at all so I found the following quantities worked well to create a nice even flat field
40 x Flats
60 x Bias
I don’t use Masters, I take new calibration frames each session ( that’s just me )
I use APT Flats Aid tool to capture my Flats
I set the ADU target range to 20,000 to 21,000 which gives me a histogram range of 8000 to 32,000 or up to half way which works well
Flats exposures without filters are usually 0.5 sec
Flats exposures with L Extreme filter are usually 5 to 7sec
Bias exposure setting is 0.000032 which is the minimum exposure for the 2600MC
Appreciate the advise Martin,
I think most of my errors is in the processing with Startools.
I started of with bin 25% just to make it easier on the computer.
I then did the AutoDev, Wipe then did the Film Dev
I think i should try just doing the AutoDev instead of the Flim Dev next time.
I am sure now that i messed up the Flats, as i also use APT Flats Aid tool to capture my Flats, except i set the value to 30,000
It should of been set to 22,000
Will also change that and re run them.
Appreciate all the feedback, found a few errors that i have done, so very much appreciated.
I will fix them and try another run.
Peter,
The amount of Binning should be based on your resolution and sampling ( not whether your computer can handle Startools)
I usually Bin default 50% as I’m oversampled and can afford to trade resolution for noise, plus I still get round stars zoomed in , not blocky stars zoomed in. If your undersampled then a lower Bin should work ok.
I find Film Dev blows out your stretch across the whole image where as with AutoDev you can set a Region of Interest ROI with your mouse and control where you want more dynamic range around an object rather than waisting it in black interstellar space and stars. “Ingnore fine detail” setting works well too from 2 to 5 pixels and gives a good balance of detail
I always use AutoDev for first stretch ( inspection) and AutoDev for final stretch
Using APT Flats Aid make sure what ever you set your Target ADU say 30,000 or in my case 20,000 that you check the Histogram by pressing the Local button. This should show your 3 peaks ( RGB ) across the whole range of the camera’s ADU 0 to 65,536 and they should sit around 1/4 to 1/2 way across.
As long as the left side ( black point ) is around 8000 to 9000 and the right side ( white point ) is around 30,000 to 35,000 ( or up to half way across the Histogram ) the your flats should be ok
Make sure you have the later or latest version of APT as the older ones didn’t allow you to see the whole ADU range across the Histogram
See attached example of my Flats Aid Tool and Histogram
In regard to sampling and image scale your Esprit 150 has a native focal length of 1050mm
So if you using no reducers etc your image scale would be -
3.76 x 206.3 / 1050 = 0.72 arc sec per pixel ( oversampled )
Therefore under average to good conditions you would benefit greatly by using Bin 50% default ) in Startools
With my Newts my image scale is between 0.88 to 0.62 arc sec / pixel and Bin 50% default works a treat
Appreciate all your advice Martin,
It is a learning curve.
I am still trying to get my head around the Flats Aid Histogram, been trying out a few combinations to see what changes with what, didn't try that Local Button.
I am using APT 4.01
It appears i need to work on my Flats a bit going from what you have there.
Mine are a bit more to the middle, I am guessing that is due to either too high a ADU or too bright a light.
I either need to lower the ADU to something similar to what you have or dim the light source a bit more to get the histogram more over to the left.
Peter,
Your flats show a range from 17,000 to 43,000 ADU which has pushed you to 3/4 along the Histogram. Best to stay around 1/2 way or 30,000 to 35,000
When I started taking flats mine were up at 42,000 to 48,000 when I set the target ADU to 30,000 to 32,000. They were over exposed
As soon as I dropped the target to 20,000 to 21,000 , adjusted the illumination, my Flats at 8,000 to 32,000 ADU worked out ok , not perfect but did the job
