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Contains:  Gear
C8EHD - AO+ONAG, 





    
        

            Daniel.P

C8EHD - AO+ONAG

Description

This is the set up I am using now with my C8EHD at FD=10 :
- C8EHD
- SVX-AO-LF (without the OAG)
- ONAG -SC from Innovative Foresight
- QHY8L imager
- SVX Loadstar X2 guiding camera
- Micro Touch focuser
- PoleMaster from QHYCCD for polar alignement
- AZEQ6 mount

I am not achieving the theoretical Back Focus of 133mm for the C8EHD at FD=10, mainly due to the significant optical path of the ONAG (+35 mm). This is resulting in slight field curvature on the outside of the image, 2.15" at the center and 2.25" at the corners (see picture E : analysis of my NGC7217 final image).
I was first surprised that the difference was so small, but after a second thought I realize the autofocus routine in SGP is using all the stars in the field to decide best focus. This is likely to result in deteriorating the focus at the center to get better focus on average.

I plan anyway to correct this BF adjustment.

Comments

Author

Daniel.P
Daniel.P
License: None (All rights reserved)
2830
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Revisions

  • C8EHD - AO+ONAG, 





    
        

            Daniel.P
    Original
  • C8EHD - AO+ONAG, 





    
        

            Daniel.P
    B
  • C8EHD - AO+ONAG, 





    
        

            Daniel.P
    C
  • Final
    C8EHD - AO+ONAG, 





    
        

            Daniel.P
    D
  • C8EHD - AO+ONAG, 





    
        

            Daniel.P
    E

Histogram

C8EHD - AO+ONAG, 





    
        

            Daniel.P