large pixel duo imaging camera - c1000mm focal length

[iapa]

I have several OTAs

200P-DS , Quattro F4, adì C8 XLT (with ff/fr)

these are in the 1000-1200 m focal length range.

I am looking for a camera that will give me an imagine ratio around 2

My existing cameras all work out to be over sampling

Any recommendations from people with a similar setup?

 

thanks

 

Cameras

ASI294MC-cool

ASI1600mm-cool

 

[michael8554]

You need a camera with 10um pixels, not sure that exists, or one with 5um pixels Binned 2 x 2.

Michael

[tooth_dr]

I use a 1200mm scope with a KAF8300. This gives a native resolution of 0.93”/px with 5.4um pixels, and could be binned to give 1.86”. That would be close?

[iapa]

Thanks folks, binning didn't occur to me duh.

I'll try playing with 1X1 binning at camera, with 2x2 being done at processing

Then compare 2x2 at camera and no binning are processing

 

 

Edited May 1, 2020 by iapa

[tooth_dr]

38 minutes ago, iapa said:

Thanks folks, binning didn't occur to me duh.

I'll try playing with 1X1 binning at camera, with 2x2 being done at processing

Then compare 2x2 at camera and no binning are processing

 

 

I wonder is there an advantage to capturing at 2x2.  I find it takes less exposure to get the same signal, so would that mean x2 as much SNR?

[Davey-T]

Atik 314L, second hand come up regularly, I use one on 10"SCT generally binned 2 X 2.

Dave

PS: CCDs do " proper " binning, CMOS do their own thing 😁

Edited May 1, 2020 by Davey-T

[iapa]

Good point.

Although, I'm forgetting the reasons I asked in the first place which was 

a. improve guiding,

with a 1x1 imaging, my PDH2 dither scale is 3.11, 2x2 binning gives 6.23. My understanding is that it would be easier with a cheap mount like my CGEM-DX to get t to move 6 pixels rather than 3

b. increase imaging pixel scale (which impacts a.)

 

[michael8554]

Those aren't very good reasons for your choice of camera. 

Do you mean Image Scale or Dither Scale, very different properties?

If you do mean Dither, those are large motions that any mount will manage, it's the fine motions involved in guiding that some mounts will struggle with.

Are you Off Axis Guiding, because you seem to be talking about Imaging and software binning one one hand, and then the impact on guiding???? 

Michael 

[iapa]

I haven't decided on whether I need to change my camera yet.

imaging camera is currently siting at an image scale* of 0.78"/s (over sampling somewhat*) with the guide camera at 3.02"/s.

Guiding scale is 3.86 (there was an article in SGL suggesting this should be <4 that I noted, but not the specific article)

from the above a guiding scale is derived giving me 3.11 dithering in PHD2 based on my image camera moving 12 pixels.

This being, I think, the number of pixels the guide camera needs to move.

With my not so wonderful CGEM-DX, my line of thinking was to increase guide camera pixel movement to some the mount would more readily hand.

So, there's two things on the go

• dealing with under sampling - by binning at camera or processing software
• increasing guide camera movement - by binning at camera or replacing guide camera/OTA

 

* image scale seems to be agreed to be between 1 & 3.

* that's just around 1/3 of estimated "seeing" around 2.5 in Bortle 5 skies, but binning is also increasing required exposure times ,