Difficulty in getting proper guide camera image

[John robertson]

I believe setup is correct. See pic attached. Distance appears to be the same from guide camera to prism as imaging camera to prism.

Imaging camera is in focus. See pic attached. 

Guide camera appears grossly vignetted & slightly out of focus both in Sharpcap and PHD2. See attached pic. 

Both cameras are accessible via Sharpcap for testing purposes. 

Celestron cpc 8” HD Edge 

Imaging camera- asi183MC

Guide camera- asi174MM

OAG-  ZWO 16.5mm

Is there an issue of this OAG with the asi174MM (smaller prism with larger sensor?)

I need help. Any assistance is strongly appreciated. 

(Sorry for the multiple postings)

[thinkstraight689]

My guide camera mount is adjustable to allow focusing the guide camera independently from the imaging camera (within a small range)  I first focus t he imaging camera then adjust the guide camera focus.  Have you done it this way?

John 

Sent from my Verizon, Samsung Galaxy smartphone

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[mj.w...@gmail.com]

Hi John

Looks like you're 99% there.

" Guide camera appears grossly vignetted"

Prism is 8x8mm, size of the "tunnel" may be smaller, sensor is bigger at 11.3x 7.1mm, so there will be vignetting,.

Not a problem.

"Guide camera .......slightly out of focus"

Setting up an OAG on a distant landmark is a good idea.

But needs fine tuning on stars.

Focus the ASI 183MC.

Without altering the ASI 183MC focus, now focus the ASI 174MM.

Looks like to do that you lower/raise the camera in the holder.

Once that's done, whenever you adjust the Edge focus, the guidecam will be in focus too.

Michael

Wiltshire UK

[Wes Atchison]

Looking at the specification for distance the CMOS sensor to the front of the camera there appears to be about 2mm difference between the two cameras.  I would suggest you review the spacing for both cameras to insure it is correct to bring them both to focus. Then I would verify that the spacers are all threads are bottomed out so you are actually getting the spacing distance you think you are.  Not all spacers will bottom out the threads when mated thus distance is longer than you think it is.  It is best to measure the actual distance you actual get. 

Wes

WA5TKU

[George Shoup]

I also suggest getting a set of calipers on Amazon to make a direct measurement of your spacer lengths when

all bolted up.

George

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