One-night M81

[discardedastro]

Definitely not the best seeing, and just one night of data, but at least a nice dark night.

200PDS, Baader Steeltrak + Sesto Senso, ASI183MM-PRO for imaging and ASI174MM guide camera with the ZWO OAG for guiding. Paracorr corrector. ZWO Mini EFW filter with Baader LRGB set.

40xL, 40xR, 36xG, 30xB. Stacked all for a superluminance, deconvolved, usual histogram/saturation stuff, photometric calibration, LRGB combined, etc.

[tooth_dr]

Very detailed despite the seeing. The 8” scope does a great job. 

[philhilo]

Very nice, and gives me a chance to ask a fellow 200PDS owner about vignetting. I am using the ASI1600MM Pro with 36mm filters and the vignetting is heavy and offset causing me headaches when processing.

Edited December 14, 2020 by philhilo

[tomato]

Nice job, plenty of detail and the Galaxy is beautifully framed in this sensor.

[discardedastro]

11 hours ago, philhilo said:

Very nice, and gives me a chance to ask a fellow 200PDS owner about vignetting. I am using the ASI1600MM Pro with 36mm filters and the vignetting is heavy and offset causing me headaches when processing.

I don't get much in the way of vignetting but the small sensor in the ASI183MM-PRO is pretty tiny, so makes all that much easier. I calibrate with a sketch panel for flats. Main issue I have at the moment is vignetting from the pick-off prism - I need to tear the optical train apart again and add a spacer to get the rotational offset spot on so the prism lands on the wide edge of the sensor. From memory, you may want to increase to an oversized secondary for the 1600MM-Pro - the 200PDS if I recall correctly has a larger secondary than the 200P but some early versions had the same secondary.

[philhilo]

Cheers, I had started to think I might need to get a bigger secondary ...... just after I rebuilt the dang thing.