Conditions: aquired July 9, 2005 in Barraba, a small town in New South Wales, Australia; no moon, incoming clouds permitted just two 600 sec frames in luminance
Setup: Borg 100ED F6.4, DF-2 focusser, CFW-8, L(IR reject) filter, ST10XE, Takahashi EM-10 mount (here's a picture of this setup). The RGB color data is from Brian Coote taken with a Tak CN212 and ST11000M camera
Exposure time: L: 2x600 sec; R,G,B: 6x300 sec
Processing (Mira, MaximDL, Registar, Photoshop): dark subtracted, flat fielded, de-bloomed, registered, median/avr combined, DDP filter, combined as LLRGB, softened stars, selective noise reduction/sharpening
M83 is a beautiful face-on spiral at declination -30 degrees. It subtends a rather large angle on the sky and is therefore a good target for my short focal length refractor. The weather on my Australia trip was really bad for the whole week I was there, affecting nearly all images, this one included. I had planned to do eight 600 sec. exposures on luminance to get a decent S/N ratio, but clouds came in and permitted just two good exposures. I didn't even get any color data. Instead of abandoning these few good data I borrowed some RGB frames taken by my good friend Brian Coote and combined them them with my two 600 s exposures as an LLRGB image. (click here to see Brians image of this object)
Click here for my earlier version of this image, where I have not paid so much attention to star hardness, star colors, galaxy
colors and noise reduction. I have written up a small tutorial on the method of selective noise reduction used in the above image.
Here's my main page where you can see more of the pictures I have taken so far.
Comments greatly appreciated! (mikael@leif.org)
