M33 17/11/12

Tzetze

I did some further tuning of my mount recently. I had been suffering from 'stiction' in the dec axis while guiding. This meant that if the guidestar was drifting South and a North pulse was sent to the mount - there was too much friction for the pulse to have an immediate effect, so another pulse would be sent, and so there would be an energy buildup until it overcame the friction. This buildup would then be enough to greatly overshoot the intended position. This would lead to a horrendous sawtoothing of the guide-graph and I'd end up discarding a lot of sub exposures.

So, I sanded all internal contact surfaces of the dec axis gear and housing progressively with wet/dry 1200, 1500 and 2500 grit paper and finally used a metal polish to get mirror like surfaces. I'm now getting a hugely improved oscillating dec graph. It can be further improved by replacing the internal bearings with a superior quality set - an upgrade for the future.

So, I was out on Sat night testing out the tuneup by revisiting M33 and managed to get 34x 600s subs. A further 3 subs were discarded - a much better discard ratio than before the tuneup!

I processed this image a lot differently to how I've previously processed by following Scott Rosen's excellent video tutorials on his DSLR LLRGB-Style Processing Workflow. It took about 6 hours to work through it and I'm very happy with the result. A much improved M33 than earlier visits.

5h40m data
34x 600s subs
60x darks
25x flats
50x bias
450D, CG5-GT, SW ED80, PHD-Guided,
Stacked in DSS, Tweaked in PS


M33 17/11/12 by .Tzetze., on Flickr

ZeRoY

Truly great results! The amount of detail on this is brilliant. Glad the tune up worked for you after all that work also

Tzetze

ZeRoY wrote: »

Truly great results! The amount of detail on this is brilliant. Glad the tune up worked for you after all that work also

Thanks Zeroy. Well, as you know, the tuneup worked after a very scary setback... *cough*

DubOnHoliday

That's an excellent photo, well done.