Hi,
Experimenting with the O-III filter last night on the Orion Nebula yielded a nice result.
M42 certainly pumps out a lot of O-III light around its core. Some other shots that I took of the Eta Carina, Tarantula and the Freak Nebulas turned out well with each one being large, bright O-III sources and the camera picking out some nice detail.
With O-III imaging I think that collecting 60 mins total exposure would be best. The image attached here is the result of 22mins, and it was taken with the big white thing in the sky (66% moon).
Being able to take detailed pics with a rampant moon is definitely a plus for O-III photography!
The main hassle I had was framing and focusing, but using the software in MaxDSLR to check starsize it worked out okay. The same result could be achieved by taking repeated test exposures 10 seconds @ISO1600 and tweaking your focus to get the minimum starsize. All you'd need is some way to view the focus-test pics (eg. on a TV monitor or a PC). [For info: the 350D has a video output on the side of the case that can go straight into a TV, and there's buttons on the case that let you zoom and move around the image.]
Looks like the Canon 350D (unmodified) is very well suited for O-III narrowband imaging
(but too bad about the H-alpha though...
)
Based on the result of this test if I had a modded (H-alpha sensitive) camera I'd definitely try creating some Hubble-color narrowband pics. Maybe a new camera for Xmas next year...
Anyhow, I'm just happy that La-Nina finally let me see some clear sky for a while...
Scope: Orion ED80, O-III filter;
Exposure: 11x2 mins, 800 ISO;
Mount: Meade LXD-75 guided;
Guidescope: Meade SN-8 (with x2 barlow and Mintron video camera);
Processing: Stacked in MaxDSLR. Stretched and the core composite in Photoshop.
