Posts Made By: Charles Hakes

Hi all,

This is my first post on the DSLR forum. Although I have had the Canon 50D for a few months, I haven't taken it out for night shots until recently. This was shot a few minutes ago at f5.6 set at 1600 for ~4 minutes. I just used the JPG setting and shrunk the size for posting - no other processing yet. I am still playing around with whatever settings will give pleasing results, as far as ISO, and f-stop setting. The one feature I especially like with the Canon is the built in flat field feature. Next I need to research software for stacking and dark subtraction, so any suggestions along those lines would be most appreciated.

Thanks for looking - comments and suggestions most welcome.

Charlie

Another picture from last week. Canon 50D with 10-22mm zoom lens. Almost an hour - the camera battery died at ~50 minutes. Set at ISO 100, and f5.6. No processing. This was just saved as a JPG file by the camera. The glow in the trees at the bottom is the reflection from the lights in my house.

I am not sure why the circles appear to get dimmer near the end of the exposure. The sky looked very clear the whole time. If you have any ideas, please let me know.

Thanks for looking,
Charlie

This image was sort of for stamp collecting. I like M37 better visually, but that one got imaged last year sometime. 5x1min each RGB between sets of longer images of other things. Minimal processing. I am always trying to get the cluster that will show lots of star colors that look somewhat natural. I think this one is getting close.

Charlie

Supernova SN2009lb in the distant spiral galaxy UGC 2944 (PGC 14418). Note the many background galaxies. I suspect that many of the "stars" in this image are actually the cores of unresolved galaxies. The discovery magnitude of SN2009lb was 17.3, and I have not yet calculated this image.

This is somewhat of a "test" case to see the minimum number of files that can be used to get an image. Sigma Beta needs a minimum of 3 files, so this was three each in LRGB. The L files were 10 minutes, and the RGB were 3, so the entire image took less than an hour of open shutter.

(And I can see hints of the column discussed in the previous post near the bottom.)

Charlie

I have been looking at various timers and battery packs or combos for my Canon 50D. Looks like there are several options that might be much cheaper than Canon brand. (e.g. TR-A from Satechi,) Any comments on what is out there? Anything I am totally forgetting or should avoid? Any battery packs that use D cells? or adapters for 12V lead acid?

Thanks,
Charlie

I am also still tracking down possible mount flexture/guiding issues with the 16" LX200. I know that since I could not "see" the workings of the primary mirror lock, that it was not locking the way I thought (i.e. properly) for way too long.

Tweaking the secondary is about the biggest shift amplifier I can think of in the system. We have some Bob's Knobs installed, but generally don't tweak too often. Since I once again cannot really "see" what is going on inside there, does anyone know if there is room for flexing? Is the secondary mirror really locked with those screws?

Thanks,
Charlie

I started this image back in August. The most recent evening was almost a month ago now, but I never got around to processing it until this weekend. This is a total of 8 hours in 10 minute subs. L:R:G:B = 16:11:10:11. I was never very happy with the color ones - I am pretty sure the mount "knew" when one of the color filters was in and self-adjusted the tracking to be less good. :S I and am not sure I ever got a series as good as the first set - wish the scope could go longer on the subs, but not the way things are working right now. I tried processing the RGB with fewer, better, subs, but ended up using all that weren't awful.

Data acquisition with CCDSoft. Reduced and aligned in CCDStack. Subs combined in Sigma Beta. RGB combined in AstroArt at 1:1:1.5 ratio. Arcsine stretch import of L into Photoshop. Adjusted curves and levels. Slight blur on the dim areas and sharpening on non-star bright areas. ~25% minimum filter on the brighter stars. L was combined with RGB using three layers: Luminance on the bottom; RGB as a multiply(30%); and RGB as a color layer on top. Final stretch and tweak (including fixing "dripping" stars) in Photoshop.

I am curious about thoughts on processing choices. I could boost the color saturation and try to match the recent Hubble image, but I really don't want cartoon colors. Boost contrast? Or would I lose subtle detail? More sharpening? I set the black level for a more uniform sky, but made some of the background galaxies really dim now. I might be able to tweak all of the above for weeks, but I worry how it will appear elsewhere. Thanks for any suggestions.

Charlie

This is 8x4 minutes light with 10 darks. I just used all the defaults with DeepSkyStacker. There is something really funky going on in the upper right corner, as the individual sub-frames don't show the artifacts. This is at 10mm on my Canon 50D zoomed all the way out, but at f5.6. Next time I will try a mid-range focal length. That should clean up some of the chromatic "features". I easily detected a half-dozen galaxies, but only by comparing to charts - not enough resolution at this scale. I stretched and sharpened a tiny bit in photoshop. Any exposure and processing hints here would be most welcome. Thanks for looking.

Charlie

This was at the ~14mm setting on the 10-22 zoom. (Canon 50D) Still at f5.6, but at ISO 800 instead of 1600. Since it was much brighter in this direction this evening, (moon?) I cut it down from 1600 after looking at a couple of subs. I think the focus was off a bit, (?) but still hard to tell with this scale. Curve tweaking in Photoshop, but no sharpening.

These subs sure show up red - is this common with Canons?

Charlie

I finally got another night to play a little. This was with my other Canon zoom - their 18-200mm that came with the 50D. It was set at ~24mm and f5.6. This is a stack of 6 four minute exposures. (They came out 4'1", which I don't quite understand, but that may be a questions for another thread...) I did 10 darks. Everything shot raw this time, which sure increases the processing time, but does indeed improve things. I clicked on "auto color balance", since the raw stack looked a bit red for me. Slight curves and levels, and then I increased the saturation quite a bit. Finally, I used Carboni deep space noise reduction to even out the background.

Doing these shots makes me want to get a fiixed focal length for shooting constellations. Anyone have a preference in the ~24mm length?

Suggestions always welcome. Thanks for looking.

Charlie