|
Thank you Martin,
The Astrobin version shows the issue with the stars in more detail. I recently baffled my OTA which although has helped my contrast no end, I think I’ve got light just catching the edges. They’re not knife edged as would be ideal and as such are giving me artifacts. Not a major issue as all I need to do is make a small knife edged mask for the edge of my primary. Just enough to cover the mirror clips so no big deal.
I’ve also found with interest that the maximum angle of incidence with the ZWO dual band filter is 8deg. Although I can’t find the figures for the STC, I figured it may be similar. Given my F/L I calculated my light angle is about 13 degrees. I moved my filter to the camera side of my MPCC and although the FWHM only changed slightly, I felt like my focus shot was considerably sharper. Another thing to address. ZWO filter draw coming in Jan.
Thirdly my MPCC is the series 1 which is only quoted down to F/4.5. At F/4, I’m pushing it. The series 3 is quoted to f/3.5 so I think I’ll invest in one of those too.
All of these things are going to be contributing to a less than perfect image. Step by step I’ll work through them.
As far as collimation goes. I’ve spent a lot of time and effort improving my scope to make it easier and hold better. Soft wedges in the mirror cell to hold the primary from moving around, better springs on the adjusters both primary and secondary and drilling, threading and fitting grub screws in my focuser to adjust the bearing plate to hold the draw tube dead center and not tilt when I use the focuser lock. It gets and holds collimation really really well now.
Thank you again for your nice comments
Cheers
Ryan
|