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)
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