My first DSO (on my own) - Omega Centauri

cloud_cover · Post by **cloud_cover** » Sat Apr 09, 2011 4:50 am

The eastern/southern skies turned fantastically clear last night so I tried to take some non-moon and planetary pics

Taken using VMC200L with 0.6x focal reducer, Nikon D700, ISO 1600, 20s x 23subs, on Vixen SXD mount. Focus achieved with Bhatinov mask.

Unfortunately I had balance issues as I didn't account for the added weight of my new finder hence jerking in both RA and DEC was particularly severe leading to more than 60% of frames being discarded!

Please give your advice on improvements

Clifford60 · Post by **Clifford60** » Sat Apr 09, 2011 10:27 am

Very good shot, keep it up, the more you practice the better you will be.

Gary · Post by **Gary** » Sat Apr 09, 2011 12:45 pm

Wow. Nice!!! Clearer skies ahead, time to get back your return on your investments!

orly_andico · Post by **orly_andico** » Sat Apr 09, 2011 2:36 pm

Kevin, that's pretty good for a first shot!

There is some star elongation though.. need to work on that balance..

I assume you did not do any guiding?

Post by **weixing** » Sat Apr 09, 2011 2:49 pm

Hi,
I work late and miss the clear night and today weather don't look good... :-(

Anyway, very nice... million times better than my first DSO image... [smilie=admire.gif]

By the way, what happen to the colour?? I remember there are quite a few orange stars in it.

Happy imaging and have a nice day.

shirox · Post by **shirox** » Sat Apr 09, 2011 3:22 pm

Swee!

orly_andico · Post by **orly_andico** » Sat Apr 09, 2011 3:42 pm

i think the colour is DSS fault... for some reason DSS process RAW and colours disappear. haven't found time to explore why..

kingkong · Post by **kingkong** » Sat Apr 09, 2011 11:45 pm

very impressive for a "1st"

cloud_cover · Post by **cloud_cover** » Sun Apr 10, 2011 4:45 pm

Thanks for all the advice!

Orly --> nope, not guided. Figured I had enough on my plate (and I started out really late) so decided not to bring the Nexguide out. Maybe next time

I don't think guiding would have improved things though since the oscillations were really fast. You could see objects oscillating in the live-view finder by almost half the screen when centralized and zoomed to 300% (max zoom of a D700), with a period measured in seconds. Not sure if autoguiding at 2s intervals can smooth out that kind of movement! It markedly improved when I lowered the weight till it was halfway off the CW bar (previously sitting on the safety stopper, had to remove that and clamped the weight off the very end of the bar) so i assume its the balance.
My FWHM measurement according to DSS is about 5-5.5 generally so I guess that's a really bad value. Ah well......
Weixing --> I always thought OC was colorless! I tried bumping up the saturation in PS on some of the subs - no joy. Maybe I didn't expose long enough or the orange skyglow is washing out the color so my D700 thinks its white? Maybe I try next time with a UHC filter and longer exposure

orly_andico · Post by **orly_andico** » Sun Apr 10, 2011 6:40 pm

kevin, oscillations visible in Live View? did you balance it well in both RA and DEC? if both axes don't turn freely it will be difficult to get perfect balance, and imperfect balance will cause grinding/skipping of the gear teeth against the worm which will cause what you describe.