[multiweb (Marc)]

Originally Posted by peter_4059

Cool shots Marc.

Thanks Peter.

Originally Posted by N1

Good to know the C14 works well at UV. I'll try our club's again when conditions are better.

When I had the 120MM on the 8" dob, I thought the SNR wasn't too bad actually. Image scale was the problem there, and to a degree, seeing. I'll have a 8" GSO CC here soon so will see what that might yield. Sick of doing hand tracked vids with the dob...

Actually I have a 8.5" TAK CC and I would love to start pushing a big dob.

Originally Posted by Merlin66

That's an interesting comment about AR coated windows...
I use the ASI 178 with the MiniSHG and have imaged in the CaK with no problems.
I should remove the window and see if the difference is measurable with the spectrograph.

Excellent. It'll be interesting to see the results.

Originally Posted by Merlin66

The ZWO data shows a 15% QE at 300nm which doesn't seem to match an issue with the coated window.
https://astronomy-imaging-camera.com.../asi178mm-mono
ZWO also push to use a UV-IR filter on colour camera with AR coated windows??!!
https://astronomy-imaging-camera.com...-ir-cut-filter
This infers to me that the AR coating is not equivalent to a UV reject coating.

I have a graph from C. Pellier that was sent to me recently about the AR window cut in the lower part of the spectrum. It's on my other PC. I'll post it.