M101 again and again

[pfile]

i just keep shooting this thing...

the L for this image was collected from the dark skies of SRO with an AT10RC. it turns out the scope was badly out of collimation and i did not have the time to go out and fix it, so we replaced the telescope after only about a month and a half of service.

the RGB here was imaged with a 12" newt (lightbuckets-0005) before the L was collected, but there's only about an hour from that OTA. the balance was taken with an FSQ-106, drizzled, and then upscaled.

so the image is kind of a mess but it's almost presentable. i think maybe it got pushed a little too much to the purple.

rob

[ajbarr]

Looks great to me. Did you try using Excalibrator for the colors?

[pfile]

i used BackgroundNeutralization and ColorCalibration but the RGB data was pretty messed up with different FHWM in each channel and so there were a bunch of greenish halos that i had to take care of…

rob

[Geoff]

Hi Rob
I tried a standard colour calibration on your hi-res jpeg image from Astrobin using the galaxy as a white reference.  It enhanced the brownish centre and knocked down the purple outer regions to a bluer look.
I thought the result looked quite good.
Geoff

[pfile]

thanks... yeah i should have mentioned that i went thru a whole round of *a*b curves to get to the color that i thought i liked, but i agree it's a tad purple.

rob

[twade]

Rob,

Very nice and well processed image. Incredible detail.  It's funny how we just keep tweaking our images.  It seems like a never-ending process. 

Wade

[pfile]

thanks wade.

i have to admit the telescope had some very serious optical problems which are evident when you look at some of the stars. i have not had time to do the post-mortem but i am starting to think the sensor in my STT-8300M is tilted (i have heard of two other people with this problem), and since i collimated the telescope with that camera, when we switched to the camera on-site at SRO the collimation was just completely wrong. given my time constraints i never had the time to go fix it, and instead we just retired the telescope.

BTW i did the re-color balancing that geoff suggested and it does look better. i should upload that somewhere, but a screenshot preview is attached.

rob

[Zocky]

Yes, the second one is much better.
Nice work Rob.

[pfile]

thanks!

[RickS]

Nice repro, Rob!