Guide sensor alignment with main sensor

Hi, I have an AC4040 and Starchaser guider. I'm setting up ACP, and one of the questions asked is whether the internal guide chip is 'aligned' with the main imaging chip. I'm not exactly sure what this means in practice. I have an accurate FOV set up in TheSkyX, and know from using it that the long axis of the guide chip is parallel with the main chip side. It would be easy for me to decide what ACP is asking if the main imager chip was a non-square, but since it is square, I'm not sure whether it is, for ACP purposes, considered to be aligned or at 90 degrees. Anyone with this setup use ACP? If so what are you using for this parameter? It may be obvious once I try the ACP setup under the stars tonight, but I'm trying to get everything I can out of the way before dealing with what I'm sure will be a series of other issues

EDIT: Is it as simple as looking at the 'accurate' FOV in TheSkyX and noting that when the main chip PA is o/360, the guide chip is not on the 'top' when 0/360 FOV is displayed with 0/360 up?
Thanks,
Mark

 

I will answer this, I think correctly. When going through ACP setup tonight, I tried initially the 90 degree offset, given my observation of the FOV. That appears to be correct. ACP adjusted it to 89.5 after calibration, and it seem to work well. In case anyone else is working on ACP with this setup.
Best,
Mark

 

Mark — That does seem confusing. Can you point me to the place where it says that? The CalibrateGuider script in ACP does calculate and set the rotation angle of the guider with respect to the main imager, automatically, and ACP always knows the difference vbvetween the mechanical and sky PA so you don’t have to align your main imager to 0 on the rotator. If you go through the ACP guider setup for rotated off-axis, and you start out with a good FOVI like you have, the process should be fast and easy. If you have more questions, please post to the DC-3 Dreams Communication Center. I am not in the office due to being a Memorial Day Weekend… I just thought I would look in here after being away for AIC and so busy last week after getting back.

 

Hi Bob, the reference in the ACP help files is under "Calibrating the Guider" where it talks about determining the guide sensor angle manually. That note mentions some SBIG cameras have a 90 degree internal guide chip sensor angle rather than 0, and I suspected that applied to my off-axis guide chip too when I noticed in my FOV setup that when oriented with 0/360 up, the off-axis guider was off to the side. When I ran the CalibrateGuider script, it confirmed that (89.5). All good, and your documentation was clear about how to go about it.
Nice to see you the other day, and congratulations again on the Hubble Award. Overdue!
Best,
Mark

 

Ah, the confusion is between the orientation of the guide sensor, rather than the location with respect to the main sensor.

I’ll be so happy when it becomes the norm to take short images and stack (CMOS) eliminating the need for guiding. A rotated off-axis pickoff is a beast to install and configure, and after that it is inconvenient as heck to use.

 

I agree!!