First go with narrowband imaging

[themos]

I managed a dozen 5min frames tonight just as the cloud was clearing up, M27 is quite bright in OIII so I used my Lumicon visual OIII filter (1.25") in the Xagyl filter wheel, sandwiched between the Meade 5000 80mm f/6 triplet (with SkyWatcher Flattener) and the Atik 16ic. Tracking by EQMOD/EQ6, capture by MaximDL and guided by PHD fed by a webcam and 300mm f/4.5 lens. Autofocus with FocusMax and homemade ASCOM stepper focuser. Thanks for looking, any comments welcome.

[JamesF]

Looks very nice. I wish I could get my guiding good enough for five minute subs. I really struggle to get the definition in the outer regions of the nebula.

James

[astrokoma]

Very nice image Themo......What are the light pollution condition at your area???

Kostas.

[themos]

Just about tolerable, Kosta. On the best night I can make out the little plough in Ursa Minor. A friend who lives nearby is affected a lot worse by the ornage glow and can only do narrowband imaging.

I used DSS with the 2x drizzle option and that's why the image came out at roughly twice the size of the actual sensor. I must say I wouldn't have noticed that, the guiding was robust. DSS also showed some drifting during the hour so either there's considerable field rotation (due to polar misalignment) or some differential flexure in the side-by-side rig.

[themos]

Last night I tried my "starter scope" on the same target. It's a Celestron Powerseeker Newtonian, 4.5-inch @f/8, which I've equipped with my own motorised focuser. One hour's worth of 5min frames, again. Side by side comparison, the 114mm f/8 Newtonian on the left, the 80mm f/6 triplet on the right. The Newtonian suffered from a lot more differential flexure (plastic focuser tube) but not bad after all.