Narrowband Wizardry (NCG7380)

[physicus]

Three nights of relatively stable clearness allowed for some long(ish) exposures in narrowband this week, 8 hours of which went into this Hubble palette Wizard.  I could have stretched this further but, for the hours and the subject, I thought some black sky looked nice.   More hours and I'll re-visit.    Slightly odd thing during these sessions (there's always something odd): when the scope was on the West side of the mount the guiding/tracking was spot on, with dimmer stars coming out as perfect 4-pixel squares (as opposed to 6-pixel rectangles) over the 20 min subs, but when the scope was on the Eastern side of the mount (sinking if you like) I still have what can only be flex despite a perfect guide graph.  Maddening.  I suspect some compression vs tension thing going on somewhere.  Anyhow, none of those subs made it into this pic.  

Esprit 100/Atik460/AZEQ6/Baader filters.

Tim

 

[Yamez]

Beautiful, i love the green colours.

[alacant]

6 hours ago, physicus said:

I still have what can only be flex despite a perfect guide graph. 

Hi. Could it also be that east heavy thing about moving the counterweights to better mesh the gears? Cheers and clear skies.

[physicus]

8 hours ago, alacant said:

Hi. Could it also be that east heavy thing about moving the counterweights to better mesh the gears? Cheers and clear skies.

Thanks for the comment.  Yeah, I do watch for that.  But I slide the counterweights down when the scope flips, so it's still 'pulling' a weight around from east to west. Also, the guide graph is good, so it must be flex between the guide scope and tube.  We're only talking one pixel every 10 minutes - but when you're trying to play in this league!  I'm going to have a good look in daylight; could be something very subtle like felt on one side of the tube rings compressing one side and not the other?