M42 - Heart of Orion Nebula - NB HST + CFHT

Amaranthus (Barry) · #1 11-10-2014, 09:24 PM

The heart of the Great Nebula in Orion, M42, imaged in narrowband with HST palette (Red = SII, Green = Ha, Blue = OIII). I also tried the CFHT palette (Red = Ha, Green = OIII, Blue = SII -- the more pinkish image). Which do you prefer?

A synthetic luminance was created by separate post-processing of each channel and then normalized blending (first, greyscale image).

Imaged with a fast (f/4) 120mm achromat refractor, with 25 x 2 min subs per channel. Camera was a drizzled Orion Starshoot G3, with Astronomik 12nm NB filters.

Full capture and processing details, and high rez image here: http://www.astrobin.com/127280/B/

Slawomir (Suavi) · #2 12-10-2014, 07:39 AM

Very good result and because taken with the little G3, that is impressive.

I like the mono version the most :-)

Amaranthus (Barry) · #3 12-10-2014, 11:37 AM

Thanks Slawomir! Yes, the G3, with only 752 x 584 pixels and a low-performance Peltier (-10C below ambient, max), needs a bit of gentle coaxing to get satisfactory results out of it - but it is possible, with careful dithering/drizzling and, ideally, shooting on cooler nights!

cometcatcher (Kevin) · #4 12-10-2014, 02:48 PM

That combination works really well Barry. The stars are so tiny.

Did you upgrade the focuser on the SW120? The stock focuser is pretty horrible.

Amaranthus (Barry) · #5 12-10-2014, 05:00 PM

Thanks Kevin. I'm actually using the stock focuser (figuring that it's a false economy to upgrade the focuser on a $550 OTA). It's not ideal, but with practice I've gotten quite used to 'tweaking' it slightly, and so can still use it relatively effectively with a bahtinov. As you can see from the stars, it works! (albeit rather fiddly).

Basically, I've concluded that this scope is a pretty darned useful narrowband imager at f/4. I tried the RGB experiment with it and was really dissatisfied (blue bloats, red swells, green is small), so I won't be revisiting that setup. But for NB, it'll probably see a lot more use, as I can keep the subs relatively short. At least until I purchase that WO FLT132 that I've got my eye on...