Hello all, I've been following Steve's technique on removing stars and I think I've produced some pretty good starless images (surprised myself). This is from 60.4 hours of data. However, when I put the stars back, things are uncertain and not sure how I should go. The lion shape has come out really well - there's an eye, mouth, etc. It really looks good I think. There is some faint background nebulosity also. But then with the stars, the question is whether to emphasise the lion or background or find a balance or what. Steve processed my image and he managed to do it using only HOO data with stars and I think my starless image looks good but with stars is tricky.
There has minimal processing done on the SHO combined images, so I recognise some artifacts still exist, etc. but I've been able to clean them before in the mono images at least. Again, it has to do with where the stars come from and how you add them.
Perhaps I've been doing this too much---staring at the same target for a long time. So I thought I'd post where I am and then get your thoughts/suggestions on where to go. I have two starless and four starred versions to decide from as to the direction I wish to go. The starless images (the one posted here, the second one is linked below) were created after removing the stars for each filter, processing the starless images, and then putting them back to create a SHO image.
The stars only were created in two ways, which led to four choices for the final images since I started with two starless versions: either I used the stars from combining the individual filter stars (so a SHO image in colour) or I just used the stars from the
Ha master light. In addition to this, there's also the choice of whether to get the stars (either SHO or
Ha) from the starless image closest to it or furthest away from it, and whether to add these stars straight at 1:1 or at some other combination.
Starless image, with S2 data emphasised is the first image below. Starless image with S2 data slightly darker is here (second link is same as attached image):
http://ram.org/images/space/downloads/s ... arless.jpg
http://ram.org/images/space/downloads/s ... arless.jpg
The two starless images are reasonably similar but when you combine them with either the SHO stars or
Ha only stars, we get four images. The combination of the above image with the
Ha only stars is what is shown below. All the four are here (this is the third link):
http://ram.org/images/space/downloads/s ... o.v0.1.jpg
http://ram.org/images/space/downloads/s ... o.v1.1.jpg
http://ram.org/images/space/downloads/s ... .v00.1.jpg
http://ram.org/images/space/downloads/s ... .v10.1.jpg
Thoughts? Which of these do you like the best? Do you like the pure lion focus or the background or both?
Finally, I want to give out a huge thanks to Steve and others who helped in creating this starless technique. It has really helped make the data stand out. Now I need to figure out how to put the stars back properly to continue to make it shine. Thanks everyone!
--Ram
PS: Also if you look at the top left corner, I had a hard time getting the framing right from last fall when things were upside down - should I crop that or is that not a big deal?
Tubes: Celestron 9.25" 235mm f/10 XLT EdgeHD SCT; Meade ETX 80mm f/5 achromat; Coronado SolarMax II 60mm f/6.6 Hα <0.7Å BF10 solar; Stellarvue 70mm f/6 triplet apochromat; Obsession UC18 457mm f/4.2 with Argo Navis & ServoCAT; Takahashi FS128 5" f/8.1 and FC100DF 4" f/7.4 fluorite doublet apochromats.
Mounts: AVX; LXD75; Paramount MyT. Eyepieces: 2" Tele Vue Ethos 4.7/13/21mm, Paracorr, 2,4x Powermate; Stellarvue 0.8x, Takahashi 0.7x, 0.66x reducer/corrector.
Cameras: ZWO ASI120MC-S; Lodestar X2c; X2m; Canon T7i; QHY163M; QHY247C; QHY294M-Pro.
Filters: 1.25" Astrodon 5nm Ha, 3nm O3 and S2; Chroma LRGB.
