BubbleTelescope
Active Member
Deep Sky Astrophotography on a Dob? You bet! Sort of. On rare occasions I have seen a 10 inch Newtonian or a C14 on a permanently installed EQ Mount. But by their nature Dob's operate exclusively on an alt-az axis, so very long exposures are not possible without star trails and other problems associated with Field Rotation. Maybe someday I'll be lucky enough to get an EQ Platform or a field rotator, which de-rotates the field at the focuser.
But for now I'm limited to 30 second unguided exposures, relying on the basic tracking of the Go-To system. Fortunately for very bright Deep Sky objects this is still more than sufficient. One of the first objects I targeted with my new 12" Dob was the Dumbbell Nebula. Thanks to the large mirror and sub 5 Focal Ratio, I was able to come away with, all things considered, a relatively clean and colorful image after just a single 30 second exposure.
The Dumbbell Nebula is a bright and easy target, being the first Nebula ever discovered by Charles Messier, in 1764. It's progenitor White Dwarf star visible directly in the center is among the largest white dwarfs ever discovered. It began shedding its outer layers 9,800 years ago.
But for now I'm limited to 30 second unguided exposures, relying on the basic tracking of the Go-To system. Fortunately for very bright Deep Sky objects this is still more than sufficient. One of the first objects I targeted with my new 12" Dob was the Dumbbell Nebula. Thanks to the large mirror and sub 5 Focal Ratio, I was able to come away with, all things considered, a relatively clean and colorful image after just a single 30 second exposure.
The Dumbbell Nebula is a bright and easy target, being the first Nebula ever discovered by Charles Messier, in 1764. It's progenitor White Dwarf star visible directly in the center is among the largest white dwarfs ever discovered. It began shedding its outer layers 9,800 years ago.
