F/4 NB fun

[Meru (Michael)]

In the midst of having no focuser for my RC8,

A good friend of mine gave me his GSO 8" f/4 to have a play with last night. I was curious to see how of the difference f/4 makes to f/8, and what imaging at 800mm with the 8300 sensor was like. Spurred on by Peter M's work and processing technique I decided to give NGC 3576 & NGC3603 another go. I'd also like to add I had no coma corrector available!

General setup
Mount: NEQ6
Imaging Train: 8" f/4 newt - OAG - FW (Baader 2" NB set) - QHY9M
Guiding: Lodestar used with a TSOAG9, 0.5sec guiding
Image processing: Captured in Maxim 5, Dark subtracted and Stacking in DSS, Editing in Photoshop CS6
L:R:G:B -> Ha:Ha:OIII:SII -> 1200sec * (5:5:2:2) subs

I am quite happy with the outcome, given no coma corrector and no 10:1 knob on the focuser (Focusing at f/4 is REALLY tough). It was more just a test to see if I can improve my processing technique. The first image is the resultant, and the next 3 are the individual HA OIII SII subs used (In that order). For good measure I have added my old attempt at Tri-NB processing which was done on the same target with an un-collimated RC8 (http://www.iceinspace.com.au/forum/s...d.php?t=103466).

Just for fun I've uploaded another Bi-colour NB attempt (Gabriela Mistral, 3*900sec) and a Ha shot (4*1200sec) of NGC3576 with the RC8 when I had my focuser Same setup as above, taken with Ha & OIII (3*900sec each) and no darks.

Thanks for viewing!

[Peter.M]

Great work Meru, I am glad I have inspired you to get out and do it! I had lots of trouble with my gso 8 inch f4 scope, but with a corrector and careful collimation your camera setup would be a winner! I plan to move to one of the new STT cameras with the self guiding wheel to satisfy my love of newts (and thus correctors) but to guide with the telescope I have the camera on.

[Ross G]

Nice photos Meru.

Ross.

[Meru (Michael)]

Ross,
Thank you

Peter,
Your processing technique really helped me out! The 8" f/4 is great for widefields, and maybe in the future when I have some spare cash might get a CF version. I'll still stick to my RC8/0.67x reducer for now I didn’t know you have to have have sensor on to guide? I thought you can guide without having to image? Plus self guiding might be an issue with NB filters; I find OAG easier (In front of the FW), my current setup allows me to literally screw on and off my corrector(s) with no adjustment to the guidecam whatsoever on the OAG.