Globular Cluster M12

Astrophotography by David Gares

Globular Cluster M12

M12 might be a beautiful globular cluster, but you wouldn't know it from this lousy image. I used my Hartmann mask (see Antonio Fernández's site), but still didn't get the focus right. The homemade mask has irregularly cut openings to produce diffraction spikes, and when you line up the spikes very carefully during focusing it is truly reliable. But when the sun goes down you get stupid immediately. At least I remembered to remove the mask . . . (I often forget, no kidding).

Globular Cluster M12
(Click image to enlarge)

Object Details:

Type: Globular star cluster
Constellation:  Ophiuchus
Distance: 16,000 light-years
Diameter:  75 light-years

Image Details:

Date: May 23, 2004
Site: Harahan, LA
Exposure: CCD, 7 x 5 min.
Filters: Orion SkyGlow LPR
Processing: MSB Astroart 3.0
Telescope: 10" Meade LX200
Reducer: Meade, f/4.3
CCD: Starlight Express MX7C
Autoguider: S.T.A.R. 2000