Afocal M33 on alt-az mount

[dph1nm]

M33 - 40x16sec exposure with my Nexstar SLT 102. Afocal Olympus 2020Z digicam at ISO200 with 32mm eyepiece. Taken from my very light polluted back garden. Dark/background subtracted by using a median stack of 10 offset 'blank' sky fields.

NigelM

[SteelRat]

Decent result that Nigel 8)

[rawhead]

That's a great afocal

Lots of detail for 16 sec subs.What'sthe max you can get beforetrailing using the SLT?

Cheers

Jon

[LostNSpace]

Thats a good result Nigel considering its Afocal and only about 10mins of data overall......

Mark

[jgs001]

Excellent result Nigel.

[dph1nm]

Lots of detail for 16 sec subs. What's the max you can get before trailing using the SLT?

I don't know, 'cos 16sec is the maximum my camera will do. Being alt-az, field rotation will get you eventually of course, though this depends on where you are in the sky. I must say I am quite impressed with the mount and I hardly lose any16sec subs to tracking errors - although note that my setup does result in 6 arcsec pixels.

NigelM

[jgs001]

Oddly, I posted this a couple of days ago on the new SynScan mount thread . check here for info on max exposure length in AltAz before field rotation becomes an issue.

[dph1nm]

Yes, I think the bottom line is point E or W if you can, and whatever you do don't point at the zenith!

The M33 shot was taken pointing E by the way.

NigelM

[jgs001]

Yep, I'd agree Nigel, low down, east or west... I've managed 2 minutes without rotation and trailing on M31 a month or so ago using my NexStar SLT. I got 15 seconds on Polaris and 45/50 seconds on M52 about 2 weeks ago.

[CELESCOPE]

amazing that image ,for how it was taken , well done Nigel.

Rog

[Psychobilly]

well done for getting so much with short subs on afocally on alt/az

Billy...