Saturday, June 4, 2011

Bad Vibrations

Spent the night at SLKP (Secret Location- Kitt Peak) intending to image IC 4592 - "the Blue Horsehead" nebula in Scorpio with the 300mm and the 85mm lenses. When I arrived about 18:00 local - it was windy. Steady winds of 8 mph with gusts up to 25 mph swept the site from the east and south - though I believe this was a local phenomenon due to the high terrain all around. There seemed to be a degradation in sky transparency too - possibly from the dust kicked up by the winds and from smoke from the brush fires to the south and east of the site.

I considered bailing, but the engineer in me wanted to see how the mount would perform in the wind and how the cameras would perform at the increased ambient temperature (@ 67 degrees F). DSLR's are not cooled like CCD cameras designed for astrophotography and suffer from increased thermal induced noise as the ambient temperature increases. DSLR astrophotography in the summer in the desert southwest is hence extremely challenging.

I set up the mount and cameras and waited for twilight to deepen enough for sky flats - in the mean time I was treated to a beautiful moonset behind a nearby western hill.



After taking flats and darks I aligned the cameras on the region of scorpius with IC 4592. the autoguider was calibrated and I left the equipment to do the best it could in the poor conditions. All told I lost about 30 minutes worth of images from the 4 hour sequence due to wind vibrating the astrophotography setup. Below are the results - first the 300mm view of the "Blue Horsehead".



Second - the "widefield" view of the same region showing both IC4592 and the Rho Oph region.



Lastly, I stuck the fisheye on one of the cameras and acquired 55 minutes of data on the Milky Way.



Click on the images for a larger view.

3 comments:

Dean said...

Dave-
Spectacular results - as to be expected! I'd sure like to know your workflow on some of your images. There is certainly some unsharp masking in bright areas, but the zodiacal band is pulled nicely out of the southern airglow in the fisheye shot. How does one become one of your disciples, er students - does it take money, casting away of earthly possessions or something else? Great job!
-Dean

David A. Harvey said...

Thanks Dean. My workflow is pretty standard. Standard astronomical processing - darks, flats, median combination of stacked and registered images. the fun is in post - photoshop. It is more art then science for sure at that point. I would be happy to share my esoteric methods if you have the time. :-)

Paul said...

Cool pics, Dave. Now that we are in the "slow" time of year I might like to journey to the "secret location" with you on one of these shoots.