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Camera just for plate solving

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#1 rockethead26

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Posted 06 July 2020 - 04:14 PM

We have a 14" Planewave CDK that we use with a Mallincam for public viewing. We also have mounted on the 14" an Optec instrument selector with extra ports available. I usually steal the ATIK 314L camera from the LISA spectro on the 17" CDK when I need to redo a pointing model on the 14", but I'm getting tired of doing that.

 

I just need a monochrome camera good enough for plate solving.

 

Any recommendations?

 

Thanks,

Jim

 

 



#2 descott12

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Posted 06 July 2020 - 04:18 PM

I just got an ASI120MM mini that I use with an Orion 50 mm guide scope. I bought it just for plate solving and it works great.



#3 gionk

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Posted 06 July 2020 - 04:25 PM

If you platesolve through the 14" CDK with your instrument selector, I'd go with a small, low-noise CMOS like the recommended ASI120MM. Only issue with that narrow FoV plate-solving could take forever. If money is not an issue, I'd go for the ASI290MM (Using that for guiding and with QE of 80% and low noise, it's really awesome!) or even with the ASI174MM Mini. An additional benefit of using those 1.25" mini cameras is that your instrument selector wont even feel the additional weight.



#4 rockethead26

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Posted 06 July 2020 - 04:25 PM

I just got an ASI120MM mini that I use with an Orion 50 mm guide scope. I bought it just for plate solving and it works great.

Thanks, Dave. The CDK has a 70mm image circle, do I need to take advantage of that to get the best plate solves in the fewest exposures? I admit that most of these kinds of details are over my head. The ASI120mm mini has a relatively small chip, does that matter?



#5 rockethead26

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Posted 06 July 2020 - 04:29 PM

Hi,

 

I posted a question back to Dave while you were posting about the small chip in the ASI120 and wheter or not that mattered. Thanks for your answer, evidently it does. Looks like the 1290 is only $300 which is quite doable.

 

If you platesolve through the 14" CDK with your instrument selector, I'd go with a small, low-noise CMOS like the recommended ASI120MM. Only issue with that narrow FoV plate-solving could take forever. If money is not an issue, I'd go for the ASI290MM (Using that for guiding and with QE of 80% and low noise, it's really awesome!) or even with the ASI174MM Mini. An additional benefit of using those 1.25" mini cameras is that your instrument selector wont even feel the additional weight.

 



#6 scadvice

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Posted 06 July 2020 - 04:48 PM

I'm using the ASI174MM Mini for OAG with it's larger still fov sensor than the 290 it might be the ideal one if the cost isn't prohibitive. 


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#7 descott12

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Posted 06 July 2020 - 04:56 PM

I don't think the image circle comes into play. The resulting FOV is 3436 X D / L where D is the size of the sensor and L is your focal length.  So yes, the 120 is a very small sensor and that can result in a small FOV  but at short focal lengths like my guide scope, the FOV is really quite nice (about 90 arc-minutes).

 

I am guessing your CDK has a much longer FL so the FOV will be very small and smaller FOV's take alot longer to plate solve. It is a balance for sure. But actually most people that use ASTAP say they plate solve in literally a few seconds so maybe that doesn't matter. I tried ASTAP and was never able to get it to work. So I use ASPS and it works well but it is slow and a smaller FOV would make it pretty difficult to use.


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#8 scadvice

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Posted 06 July 2020 - 05:36 PM

+1 for ASTAP



#9 rockethead26

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Posted 06 July 2020 - 05:47 PM

I don't think the image circle comes into play. The resulting FOV is 3436 X D / L where D is the size of the sensor and L is your focal length.  So yes, the 120 is a very small sensor and that can result in a small FOV  but at short focal lengths like my guide scope, the FOV is really quite nice (about 90 arc-minutes).

 

I am guessing your CDK has a much longer FL so the FOV will be very small and smaller FOV's take alot longer to plate solve. It is a balance for sure. But actually most people that use ASTAP say they plate solve in literally a few seconds so maybe that doesn't matter. I tried ASTAP and was never able to get it to work. So I use ASPS and it works well but it is slow and a smaller FOV would make it pretty difficult to use.

Thanks for the followup, it helped. We use Planewave's own pointing model software which is pretty much automatic except for picking the number of targets wanted. It's just waiting while it does it's thing. The FL on the CDK14 is 2563mm, so a bit longer than your guidescope. I think a larger chip might be beneficial.

 

The 120 on the CDK will yield a 6.4 arc min FOV,

the 290 7.5 arc min and

the 174 a whopping 15 arc min°.

The ATIK that I use now provides about 13.7 arc min.

 

I may have to see if I have the budget for the $500 174 model.


Edited by rockethead26, 06 July 2020 - 06:59 PM.


#10 descott12

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Posted 06 July 2020 - 06:56 PM

Thanks for the followup, it helped. We use Planewave's own pointing model software which is pretty much automatic except for picking the number of targets wanted. It's just waiting while it does it's thing. The FL on the CDK14 is 2563mm, so a bit longer than your guidescope. I think a larger chip might be beneficial.

 

The 120 on the CDK will yield a 6.4° FOV,

the 290 7.5° and

the 174 a whopping 15°.

The ATIK that I use now provides about 13.7°

 

I may have to see if I have the budget for the $500 174 model.

Actually, the FOV is in arc-minutes, not degrees. You definitely wouldn't want something as big as 6 or more degrees.



#11 rockethead26

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Posted 06 July 2020 - 06:58 PM

Actually, the FOV is in arc-minutes, not degrees. You definitely wouldn't want something as big as 6 or more degrees.

Oops, my bad. Thanks for catching that. I'll edit that post.



#12 TelescopeGreg

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Posted 07 July 2020 - 12:42 PM

For what it's worth, I plate solve using the guider, since my main imaging camera is a DSLR that does not have good USB support.  The guider is a ZWO 60mm f/4.6 scope with an ASI174mm Mini camera.  I've got it aligned with the main scope, and solve with CCDciel + ASTAP.  Works very well.


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#13 AhBok

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Posted 07 July 2020 - 01:28 PM

The 174 is a big step up in FOV from the 120, but the 290 really has no practical advantage over the 120 for just platesolving. I have both and both have similar size FOVs. The 290 is more sensitive which makes it a better guide cam for an OAG, but platesolving is much less demanding.
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#14 rockethead26

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Posted 07 July 2020 - 01:46 PM

Thanks for the additional info Randy and Greg. I'm working on seeing if we have the budget for the 174 as I agree that's the way to go.

 

Jim



#15 rockethead26

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Posted 14 July 2020 - 08:35 AM

Just and update and a thank you to all that helped.

 

We have a 174 on the way from Agena Astro.




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