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Elongated stars

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#1 Mike1583

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Posted 08 April 2021 - 06:33 AM

Hello,

 

I have been following the forum for some time but this is the first topic I'm posting about. 

A number of months ago I switched from a DSLR to a ASI183MM-Pro since doing so I have been having issues with elongated stars and I'm not sure what's happening "images below." I did not have this issue while using the DSLR. I'm not sure if this is from sensor tilt, focuser sag or would guiding do this? Hopefully the images I attached will assist. I have a before and after Meridian flip images.

The scope I use is an AT60ED with a Astro-Tech .8x reducer/field flattener "ATRF60." I do have the 55mm of back focus suggested for the reducer. I am using ZWO filters and 5 position filter wheel.

Please let me know if any other info or images are needed and I appreciate the help.

 

Thank you!

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#2 asanmax

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Posted 08 April 2021 - 01:24 PM

To me it looks like a sensor tilt that may be caused by a lot of reasons.

 

Do you have an electronic Vernier caliper?

I'd start with measuring everything. Could be the focuser, adapters or the camera itself.

 

I once had a tilt problem with one of my APO scopes. It took me some time to figure out that the 2" compression ring had a slight manufacturing defect in it. One side was just a bit wider than the other.

Thankfully the manufacturer replaced it for free.

 

If you don't have the caliper, you can get one off amazon, the electronic stainless steel ones are not that expensive. It's a great tool that you will most likely use many many times.



#3 Mike1583

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Posted 08 April 2021 - 01:53 PM

To me it looks like a sensor tilt that may be caused by a lot of reasons.

 

Do you have an electronic Vernier caliper?

I'd start with measuring everything. Could be the focuser, adapters or the camera itself.

 

I once had a tilt problem with one of my APO scopes. It took me some time to figure out that the 2" compression ring had a slight manufacturing defect in it. One side was just a bit wider than the other.

Thankfully the manufacturer replaced it for free.

 

If you don't have the caliper, you can get one off amazon, the electronic stainless steel ones are not that expensive. It's a great tool that you will most likely use many many times.

Thank you for your suggestion and guidance. I currently do not have caliper but I will look into getting one. 


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