M11 (Wild Duck Cluster), M16 (Eagle Nebula)
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
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
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:
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)
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.
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
Posted by Steve under Astro | Comments Off on M11 (Wild Duck Cluster), M16 (Eagle Nebula)
