3 replies to this topic

[mrmusclesrocks]

Hi everyone,

 

A recent offer has come up to my table, including it would be putting a Moravian C4-16000 on my current ASA12N with the 3in corrector. 

 

First of all, I am not even sure I can accommodate the camera since it is larger format than full frame and needs at least a 52mm imaging circle to maximize quality, while my ASA12N has an imaging circle of only 50mm. 

 

Second, the four sensors into one with a combined 16bit ADU is a bit strange to me, and as far as I know would be very different than my QHY600M which I bin at 2. I assume darks would be a necessity with maybe even bias as well. Would image quality be affected?

 

Anyone, I would love to know anyone else's thoughts on this, and what I should do. 

 

Clear skies,

Michael

[Jared]

ASA12N with the 3" Wynn corrector is f/3.6 or thereabouts, yes? So a focal length of around 1,100mm? Personally, I would not want nine micron pixels with an f/3.6 scope. In particular, I would not want the GSENSE4040 with its four quadrants exhibiting different bias signals. When making pretty pictures, image quality is definitely affected (though some have worked around the issue--don't happen to know how). I would stick with the QHY600. 

 

Obviously, one could have a specific requirement, especially a scientific requirement, that would make the C4 a great match for you, but the fact that you are asking the question suggests you are an ordinary deep sky imager like most of us. 

 

Also, you mentioned you usually shoot your QHY600 binned 2x2. I would not recommend that with your OTA. You are likely giving away some resolution unless your seeing conditions are really bad, and you aren't gaining anything in terms of full well capacity or read noise. The only advantages to 2x2 binning with the QHY600 are faster image processing and lower storage requirements. You have a 300mm aperture scope--it can yield an amazing amount of resolution as long as it is well collimated, well guided, and well focused. Certainly good enough that 0.7"/pixel is probably not over sampled. 

[andysea]

The 4040 also has extremely high dark current compared to the Sony IMX offerings. That would give me pause. 

[mrmusclesrocks]

ASA12N with the 3" Wynn corrector is f/3.6 or thereabouts, yes? So a focal length of around 1,100mm? Personally, I would not want nine micron pixels with an f/3.6 scope. In particular, I would not want the GSENSE4040 with its four quadrants exhibiting different bias signals. When making pretty pictures, image quality is definitely affected (though some have worked around the issue--don't happen to know how). I would stick with the QHY600. 

 

Obviously, one could have a specific requirement, especially a scientific requirement, that would make the C4 a great match for you, but the fact that you are asking the question suggests you are an ordinary deep sky imager like most of us. 

 

Also, you mentioned you usually shoot your QHY600 binned 2x2. I would not recommend that with your OTA. You are likely giving away some resolution unless your seeing conditions are really bad, and you aren't gaining anything in terms of full well capacity or read noise. The only advantages to 2x2 binning with the QHY600 are faster image processing and lower storage requirements. You have a 300mm aperture scope--it can yield an amazing amount of resolution as long as it is well collimated, well guided, and well focused. Certainly good enough that 0.7"/pixel is probably not over sampled. 

Yeah I agree. 

 

I am binning since 1x1 binning would have seeing close to .7", and bin 2 is at around 1.14", and Trevinca isn't usually very close to that 1.14" anyway. Bin 1 would be more in like Chile. I don't mind losing some resolution to more SNR, I have used Bin1 on good seeing vs Bin 2 and the resolution difference is hardly noticeable, but the SNR difference is.

 

I guess it really just depends on the target I am shooting.