Kev11
10-09-2019, 08:07 PM
Although city-based IIS members would regard my location as dark-field in fact I get relatively few nights of good transparency, possibly because we are at the Eastern edge of the South-West Slopes i.e. towards the high country and also only a few kms from the Murrumbidgee River. My observatory is in a valley which tends to fill with moisture-laden air in the right (or wrong!) atmospheric conditions. Autumn skies are frequently smoke-laden from hazard reduction or stubble fires.
On the other hand a clear and dry winter night is invariably magnificent. That happens to be the time of year when many Globular Clusters are high in the Eastern sky before midnight. Attached are some of my images from late June this year.
All were processed in DSS from five 30s RAW subs each at 1600 ISO taken with a Canon 1100 DSLR (unmodified) at the prime focus of a Skywatcher 8” f5 Newtonian on a HEQ5Pro mount on a permanent pier.
Darks and flats were included, however flats don’t seem to contribute much on this small number of lights. I used the DSS settings suggested by Startrek on this forum recently. On the final DSS image I superimposed the red, green and blue bell curves and moved them to the right along the S curve (whatever that is – I haven’t got my head around the technicalities yet) far enough to reveal all the resolution apparently available in each cluster. That seemed to simultaneously move the background from deep black to a shade of grey, albeit also unveiling many faint stars. I can live with that, not least because I haven’t yet calibrated the monitor on the computer I am now using.
DSS help is delightfully vague about the nature of the Luminance and Saturation adjustments offered, more-or-less saying “just try and see what happens”. As the possible combinations of settings are almost infinite, I would appreciate some guidance or explanation of the principles on that.
Cheers
On the other hand a clear and dry winter night is invariably magnificent. That happens to be the time of year when many Globular Clusters are high in the Eastern sky before midnight. Attached are some of my images from late June this year.
All were processed in DSS from five 30s RAW subs each at 1600 ISO taken with a Canon 1100 DSLR (unmodified) at the prime focus of a Skywatcher 8” f5 Newtonian on a HEQ5Pro mount on a permanent pier.
Darks and flats were included, however flats don’t seem to contribute much on this small number of lights. I used the DSS settings suggested by Startrek on this forum recently. On the final DSS image I superimposed the red, green and blue bell curves and moved them to the right along the S curve (whatever that is – I haven’t got my head around the technicalities yet) far enough to reveal all the resolution apparently available in each cluster. That seemed to simultaneously move the background from deep black to a shade of grey, albeit also unveiling many faint stars. I can live with that, not least because I haven’t yet calibrated the monitor on the computer I am now using.
DSS help is delightfully vague about the nature of the Luminance and Saturation adjustments offered, more-or-less saying “just try and see what happens”. As the possible combinations of settings are almost infinite, I would appreciate some guidance or explanation of the principles on that.
Cheers