Astronomy Search:

Live Star Chart -- Messier Slide Collection -- NGC Slide Series

Click here, to see latest weather radar Vail, AZ from Weather Underground

Get Polaris transit times at the U.S. Naval Oceanography Portal

Monday, March 24, 2008

My first astrophotograph in 25 years

Captured finally on a night with successful alignment, clear skies, and perfect focus. Full moon didn't appear to degrade my ability to capture this shot.

The lovely Great Globular Cluster M13 in the constellation Hercules.

My setup includes a heavy duty Atlas EQ-G mount with a brand new Orion 6" fast f/5 Newtonian reflector OTA. After a few months of struggling to learn digital astrophotography with a DSLR, I finally achieved success!

My recipe:

- Reasonably accurate polar alignment (a little better than aiming it at the North Star, dude)

- Automatic dark frame (noise) subtraction, as provided for by the most excellent Canon Digital Rebel XT

- 1600 ASA (high gain, mo' power)...a lot of folks online tell others to use 400...this is somewhat misleading given the latest DSLR technology. If you can subtract out the noise levels, get as much gain as you can. You don't need to triple or quadruple your exposure times for fun!

- Short exposure sequences (40+ 15 to 30 second exposures)

- 2" wide focuser and 30% larger secondary mirror to fully illuminate 100% of the DSLRs CMOS detector (this is a big deal)

- Hartmann mask for rough focus and 11:1 fine focus control to dial it in (most important last step to taking the shots)

Have always been interested in astronomy, and now I can begin again with something started in my youth. Will begin my survey of the Messier objects...see how far I get. This is going to take a while...

No comments: