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Closed loop slew in TSX Pro using ASI 224MC

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#1 RunningMan

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Posted 17 June 2018 - 10:06 PM

Has anyone been successful using closed loop slew in TheSkyX Pro with a ZWO ASI 224 MC camera? I attempted several times to do so last night and received an error message indicating that there were saturated pixels.

 

I use the ASI 224MC with a C11 for planetary imaging (with 2X Powermate), and it would be amazing if the scope would find its way to my planet of choice, as myt red-dot finder gets me close, but the FOV is mighty small! The statistics about this optical & camera combination are as follows:

 

FOV: 3.00' x 2.25'

 

Resolution: 0.14"/pixel

 

Area: 6.74 sq'

 

Focal length: 5600mm

 

Focal ratio: f/20.0

 

Is there any hope that I may get this to work?

 

Thank you and clear skies!
Aaron



#2 iwannabswiss

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Posted 17 June 2018 - 10:10 PM

I have been using CLS successfully, but not with the camera you mentioned.  What is the exposure time that you're using?  Have you tried changed the CLS exposure settings to something smaller?

 

edit:  one more question that is relevant.  Are you trying to use CLS for the planets?  As far as I'm aware, that won't happen.


Edited by iwannabswiss, 17 June 2018 - 10:14 PM.


#3 RunningMan

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Posted 17 June 2018 - 10:39 PM

Hi IWBS,

I also use CLS with good success for DSO imaging. I cannot recall the exposure time that was used, could be 10 seconds (this is the exposure time I usually use with my other camera, an ATIK460, which has much lower noise), but I could try again using the ASI224MC with a shorter duration, as you suggest. With the ATIK, I have no problem using CLS for planets.

Clear skies!

Aaron

 

I have been using CLS successfully, but not with the camera you mentioned.  What is the exposure time that you're using?  Have you tried changed the CLS exposure settings to something smaller?

 

edit:  one more question that is relevant.  Are you trying to use CLS for the planets?  As far as I'm aware, that won't happen.


Edited by RunningMan, 17 June 2018 - 11:11 PM.


#4 APshooter

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Posted 18 June 2018 - 04:39 PM

I have tried it and I'm not sure it's possible.  TheSkyX needs so many arcminutes of sky to do a plate solve.  The 224MC chip is too small for it to plate solve correctly.  This was passed onto me at the SB forums.

 

Changing to a bigger chipped camera like my X694 chip will center planets just fine.


Edited by APshooter, 18 June 2018 - 04:40 PM.


#5 RedLionNJ

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Posted 18 June 2018 - 09:11 PM

With a good pointing model, you should be able to get within an arcminute of having the planet centered (just a regular [non-CL] slew).  As long a your AS224MC is still set to full-sensor (no ROI yet), that should put any planet on the sensor, allowing you to nudge it to the center and then reduce the ROI.

 

I'd be pretty sure CLS won't work on such a tiny field.



#6 RunningMan

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Posted 19 June 2018 - 09:29 PM

Thanks, APShooter, there's certainly not much real estate on the 224MC chip!

Clear skies!

 

I have tried it and I'm not sure it's possible.  TheSkyX needs so many arcminutes of sky to do a plate solve.  The 224MC chip is too small for it to plate solve correctly.  This was passed onto me at the SB forums.

 

Changing to a bigger chipped camera like my X694 chip will center planets just fine.



#7 RunningMan

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Posted 19 June 2018 - 09:40 PM

RedLion,

What you said about the pointing model could be true, however with the C11/ZWO ASI224MC, I am not sure I could effectively generate a pointing model. Perhaps without the 2X powermate in place I could. Furthermore, with my portable setup, I don't usually bother with a pointing model, as imaging time is of the essence. Instead, I use PoleMaster to polar align -> home the mount (it is an MX+) -> and then CLS to my target. I have two scopes, mounted side-by-side, in tandem: the C11 and a TSA120. The scope that I usually use for CLS is a TSA120 fitted with an ATIK460, so there's adequate FOV, and it can center pretty much any target. Unfortunately the C11 and TSA120 are not perfectly aligned with one another, and I don't see any easy way to align them, so my perfectly centered planet on the TSA120 results in an empty FOV on the C11.

Back to the drawing board!!

Clear skies!

With a good pointing model, you should be able to get within an arcminute of having the planet centered (just a regular [non-CL] slew).  As long a your AS224MC is still set to full-sensor (no ROI yet), that should put any planet on the sensor, allowing you to nudge it to the center and then reduce the ROI.

 

I'd be pretty sure CLS won't work on such a tiny field.



#8 RedLionNJ

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Posted 20 June 2018 - 05:47 AM

RedLion,

What you said about the pointing model could be true, however with the C11/ZWO ASI224MC, I am not sure I could effectively generate a pointing model. Perhaps without the 2X powermate in place I could. Furthermore, with my portable setup, I don't usually bother with a pointing model, as imaging time is of the essence. Instead, I use PoleMaster to polar align -> home the mount (it is an MX+) -> and then CLS to my target. I have two scopes, mounted side-by-side, in tandem: the C11 and a TSA120. The scope that I usually use for CLS is a TSA120 fitted with an ATIK460, so there's adequate FOV, and it can center pretty much any target. Unfortunately the C11 and TSA120 are not perfectly aligned with one another, and I don't see any easy way to align them, so my perfectly centered planet on the TSA120 results in an empty FOV on the C11.

Back to the drawing board!!

Clear skies!

Bummer - I see your predicament.  I also have an MX+, but I have an 80mm f/4.9 on top of my SCT (with an APS-C DSLR) so I had plenty of FOV to build a pointing model (and yes, I made sure to very carefully align the APO's optical axis with the SCT's). I'm also permanently-situated, so I have that advantage, too. I did a 34-point TPoint model via the 80mm and have never had reason to look back.

 

I will have to redo it soon, though - I find I need to raise my pier about 20 inches to get a good view of Mars this summer. Not looking forward to that, but afterward I'll be building a bigger pointing model anyway.

 

Good seeing!



#9 RunningMan

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Posted 20 June 2018 - 08:16 AM

May I ask how you managed to align the two optical axes?

 

With my side-by-side setup, the saddle bolts that enable me to adjust the x-axis are inaccessible while the scope is in the cradle, and there's no "official" adjustment for the y-axis (meaning that I think the only option is to shim it?).   

 

Bummer - I see your predicament.  I also have an MX+, but I have an 80mm f/4.9 on top of my SCT (with an APS-C DSLR) so I had plenty of FOV to build a pointing model (and yes, I made sure to very carefully align the APO's optical axis with the SCT's). I'm also permanently-situated, so I have that advantage, too. I did a 34-point TPoint model via the 80mm and have never had reason to look back.

 

I will have to redo it soon, though - I find I need to raise my pier about 20 inches to get a good view of Mars this summer. Not looking forward to that, but afterward I'll be building a bigger pointing model anyway.

 

Good seeing!



#10 RedLionNJ

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Posted 20 June 2018 - 09:03 AM

May I ask how you managed to align the two optical axes?

 

With my side-by-side setup, the saddle bolts that enable me to adjust the x-axis are inaccessible while the scope is in the cradle, and there's no "official" adjustment for the y-axis (meaning that I think the only option is to shim it?).   

My APO rides atop my 12-inch SCT. The APO tube rings are bolted directly to the top Losmandy rail on my SCT. "Horizontal" alignment has always been good between the two. "Vertical" required a cardboard shim inside one of the tube rings, achieved via trial and error (ended up being a LOT thinner than I first suspected). Is it perfect? No.  Is it good enough within all the other tolerances (mirror shift, flexure)?  Yes.



#11 RunningMan

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Posted 20 June 2018 - 10:26 PM

I think that nailing the alignment is my best bet... It won't be any fun, though.

Thanks for the inspiration!

 

My APO rides atop my 12-inch SCT. The APO tube rings are bolted directly to the top Losmandy rail on my SCT. "Horizontal" alignment has always been good between the two. "Vertical" required a cardboard shim inside one of the tube rings, achieved via trial and error (ended up being a LOT thinner than I first suspected). Is it perfect? No.  Is it good enough within all the other tolerances (mirror shift, flexure)?  Yes.




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