Placidus
08-09-2016, 10:16 PM
NGC 7205 in Indus, on a night of for us exceptional seeing, approaching 1.5 sec arc around midnight.
The main galaxy itself is pretty, but we've counted at least 180 other galaxies in the field, definitely our personal best.
We inspected the image visually, and classified anything with very clear galactic morphology - e.g. an edge-on spiral or visible spiral arms, as a galaxy. A handful of big salmon blobs that were too big and too faint to be stars (compared with nearby stars) were classed as almost certain ellipticals.
We kinda get the feeling that extra hours won't find so many more. It was the good seeing allowing the identification of the morphology that did the trick. A longer exposure on a night with poor seeing would reveal fewer, not more.
We collected 6hrs of colour on a separate night. The colour helped confirm the galaxies previously identified based on the luminance image, because the smaller ones tended to be strikingly orange. There is an obvious cluster of orange ellipticals about two thirds of the way toward top right, and another about one third of the way toward 9 o'clock. We've only marked some of these, as the rest are only inferred from context and not counted in the tally.
Hope you enjoy hunting around the original image (www.photos.smugmug.com/Category/Astrophotography-at-Placidus/i-zKmsFR3/0/O/Indus%20NGC%207205%20and%20180%20fr iends%20Lum%207%20hrs%20RGB%202hrs% 20each.jpg), where the shape of the smallest edge-on spirals is more obvious.
Aspen CG16M on 20" PlaneWave. Processing using our GoodLook 64.
Best,
MnT
The main galaxy itself is pretty, but we've counted at least 180 other galaxies in the field, definitely our personal best.
We inspected the image visually, and classified anything with very clear galactic morphology - e.g. an edge-on spiral or visible spiral arms, as a galaxy. A handful of big salmon blobs that were too big and too faint to be stars (compared with nearby stars) were classed as almost certain ellipticals.
We kinda get the feeling that extra hours won't find so many more. It was the good seeing allowing the identification of the morphology that did the trick. A longer exposure on a night with poor seeing would reveal fewer, not more.
We collected 6hrs of colour on a separate night. The colour helped confirm the galaxies previously identified based on the luminance image, because the smaller ones tended to be strikingly orange. There is an obvious cluster of orange ellipticals about two thirds of the way toward top right, and another about one third of the way toward 9 o'clock. We've only marked some of these, as the rest are only inferred from context and not counted in the tally.
Hope you enjoy hunting around the original image (www.photos.smugmug.com/Category/Astrophotography-at-Placidus/i-zKmsFR3/0/O/Indus%20NGC%207205%20and%20180%20fr iends%20Lum%207%20hrs%20RGB%202hrs% 20each.jpg), where the shape of the smallest edge-on spirals is more obvious.
Aspen CG16M on 20" PlaneWave. Processing using our GoodLook 64.
Best,
MnT