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YeeHaa! a clear night... Moon/Jupiter/Antares, M11, M16


SteveL

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A clear night, and I wasnt going to waste it. A few (predicted) clouds as the sky was darkening:

Jupiter top left, Antares below left, moon to right

20070724_moon_jupiter_antares.jpg

Once this band had passed, I powered on and did the usual alignment dance for 20 minutes or so.

First target, M11, the wild Duck Cluster.

OTA: NexStar 8 GPS @ f/10

Guiding: OAG + PHD + DSI-C

Images: Canon 350D, 10 x 60s @ ISO800 (+5 darks) via DSLRFocus

Processing: DeepSkyStacker, Photoshop CS + Noel's AstroTools

Note: Last time I tried imaging this, I also got "redish" background stars. No idea why, might be light pollution but not 100% sure

m11_20070724.jpg

Next, the tricky one, that went bad, but I learned a lot from it - M16, Eagle Nebula.

Being an emission neb meant that it has plenty of Ha... but my 350D is *UNMODDED* and so most of the Ha is blocked by the inbuilt Canon filter. Even so, I needed to have a go, "just to see" what I could manage. I knew I had to get as much data as possible because of the Canon filter issue, and so used my CLS filter to reduce the effect of LP.... but in the end I over did the exposure time, and the subs and darks started to show a lot of random hot pixels when processed, which destroyed the stacking process. Still, I managed to salvage a final image from it, and learned something new...

Here is a rescaled (but unprocess) RAW:

m16_20070724_raw.jpg

If I do a basic curves on it, you can start to see the hot pixels starting to create a lot of noise in the darker areas (well, everywhere actually)

m16_20070724_dss_curves.jpg

After imaging for nearly an hour (plus the darks), I just had to salvage something from the subs, so here is what I managed to retrieve (no darks, they just made things worse)

OTA: NexStar 8 GPS @ f/10

Guiding: OAG + PHD + DSI-C

Images: Canon 350D, 6 x 600s @ ISO800 (no darks) via DSLRFocus

Processing: DeepSkyStacker, Photoshop CS + Noel's AstroTools

Note: No Darks, so Amp glow quite prominant in lower right. Bright red "hot pixel" upper right quarter.

m16_20070724_cls.jpg

The clouds rolled in across the horizon as the last light was being taken, so it was time to pack up while I left the Canon taking the 10 minute darks. I will definitely be back for this fantastic Nebula, more subs, but (and a first for me) shorter exposures.

Things learned last night:

- Emission Nebs can be captured on unmodded Canons... just!

- 10 min subs is too much for ISO800

- The CLS filter effectively halves the amount of light coming through, but it does remove the LP

- My autoguiding works fine

- My polar align routine seems ok (no field rotation in the images that I can see)

- Need "smoother" darker subs that I can stretch, rather than "brighter" noisey subs that just get even more noisey as they get processed

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A great nights work there Steve. I think you are striving for perfection, but I don't see a lot wrong with any of them. I would make a poor critic anyway. One thing I do know, that Wild Duck cluster is magnifico.

Ron. :D

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What a session!!!

You'll probably disagree but the M16 version I like best is where the curves are very gentle just the point where the hot pixels are starting to show - very atmospheric.

Wild duck is really cool and the widefield moon etc is really nice.

Well done

Anthony

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