We were very inspired by Louie's (Atalas's) recent M4. We had half an hour to fill in (in our freezer suits at -1C) while our main target appeared above the scope slew limit, so we thought we'd get as close as we could to Louie's shot.
Rattled off 30 one-minute subs on M4. Both seeing and, ominously, guiding and even focus seemed to vary a lot from sub to sub. We threw out ten dodgy frames and kept the remaining twenty.
Cracked record: We have very much in mind that globular clusters are extremely ancient objects, and therefore most of the stars must be very cool and hence reddish in order to have lived that long. Only a few are hot and bright as a result of recent collisions increasing their mass, and therefore only a few very salient ones are bluish.
Mindful of recent discussions on saturation, we've tried to set the colour balance and saturation at the point where we can clearly see the different colours (which is kinda the main message after all), but no further.
We've also pushed the contrast to the point where M4 is the subject, not the Milky Way behind it.
North is on the left, because that way an Aussie farmer will immediately recognize the face of a Merino sheep looking straight at the camera.
Presumably by luck, there are several interesting streamers of faint and pinpoint stars forming apparent straight lines (from our point of view) heading toward the bottom of the image.
Aspen CG16M on 20" Planewave on MI-750 fork. Seeing fair at about 2.2 sec arc. New moon, very clear, no wind. Field 36 min arc, 0.55 sec arc per pixel.
Big image here
Cheers,
Mike and Trish