Date: 7/4/2010
Seeing 3/10 – Transparency 3/6
8″ Orion Newtonian Astrograph with Baader MPCC on Atlas mount
Autoguiding with Takahashi fs60-c and Orion auto-guider
Camera: Qhy8 with CLS CCD – 11 exposures of 360sec
Trifid is quite low on the horizon (about 30 degree) – and being right in the middle of the city with the SFO airport not very far, the sky glow and turbulence makes imaging quite challenging.
Especially the blue of the reflection nebula is quite hard to isolate from the overall noise – that’s why it is necessary to stack many images to improve the signal to noise ratio.
But thanks to the CLS CCD astronomik filter, and processing with Photoshop CS4 and Noise Ninja, the final image looks acceptable.
Having tested the Coma Corrector from Baader with the Orion 8″ astrograph, I can now tell that once the collimation is perfect (at f/d 4 collimation tolerances are very small), the Baader coma corrector does a great job to obtain round stars across the image, at least for an APS-C size sensor like the one the Qhy8 has.
Astrophotography in Urban Environment 