Hi, When using my ST-8300 + ST8300 Off-axis guider on my Tak Epsilon 180 (F/2.8) I get a strange artefact as if the mirror in the off-axis guider sort of gets in the way. Anyone who has experience with that camera + off-axis guider with a fast scope? Thank you very much! Kind regards, Peter
Sounds reasonable. A pick off mirror or prism is usually at the edge of the field. The light cone that hits the main imager might be impacted by it. Perhaps you can post a FITS showing us what you mean.
The OAG-8300 mirror pick-off position is adjustable. Please refer to the user manual: http://diffractionlimited.com/wp-content/uploads/2016/04/oag-8300_manual.pdf Your f/2.8 optical system is extremely fast, and it might not be possible to completely eliminate the shadow. In that case flat-fielding will clean up your image.
Yes, that’s correct. It says that the outermost position equals F/5 - information I would have appreciated getting before buying the off-axis guider. A little late now, unfortunately. I’ve dismantled the off-axis guider after having tried to clean up the images with flats. It’s not possible - the stars are simply too distorted by the mirror getting in front of the sensor. Thanks for help and advice! Sent from my iPhone using Tapatalk