(2023-04-18, 11:15 PM)PMSchu Wrote: Dennis, it's odd that the quasar is a 'ghost'. Did you find additional 'ghost' objects on the image too? Is the Aladin image also an IR band image? At least we know that the quasar hasn't moved.
Would you have been able to get better sensitivity without the IR filter or would the light pollution have overwhelmed the quasar's signal?
Still a nice effort.
Phil S.
Hi Pil
SkyTools showed a magnitude of "19.4 I" and I took the "I" to be Infrared, so fitted my IR742 Filter.
Some of the professional resources I browsed were imaging at between 800nm and 1200 nm which are longer wavelengths than my 742nm.
I'm not very familiar with the various aspects of Photometric Analysis, my only previous experience was in hunting down Star cluster Westerlund 1 using an IR807 IR Pass Filter which really made the stars pop, whereas in LRGB imaging the cluster was less conspicuous.
I sometimes use the IR642 for lunar imaging in poor seeing as the longer wavelengths of light are less affected.
Cheers
Dennis
(2023-04-18, 10:11 PM)theskyhound Wrote: That's cool. It seems to me that 60s is a really short sub exposure time. I know that systems vary, but still... did SkyTools recommend that? Or are you limited by tracking or something?
Hi Greg
I’m still in the process of commissioning the mount, which is taking so much longer than anticipated due to the effects of La Nina generating much more cloud cover than usual. Thankfully we are now exiting this cycle.
The mount is a SB Paramount MX+ and I am imaging at around 2100mm and provided I use the mount control SW to calibrate the mount, I can usually image for 30 secs and enjoy round stars at this FL.
60 secs is still good, but I begin to get some trailing, so these exposures are currently mount-limited at the moment (with no auto guiding) and the effects of having to set up and tear down each night.
The mount can be set up and configured with some one-time permanent SW settings and session-by-session calibration results that need to be refreshed each time I set up and tear down. If I had a permanent set up I could probably exceed 60 secs.
I will probably have to revert to auto guiding so I can dither the exposures as I am seeing a lot of fixed pattern noise which requires dithering to reduce its effects when stacking.
The whole commissioning process is taking longer as there is a Southern Hemisphere anomaly with the HW/SW system when trying to implement the mount’s PEC routine, and I have had to resort to 3rd party SW for an interim solution. More stuff to learn.
So, to cut a long story short, once I have mastered the nightly set up and tear down process, obtained a good PEC recording and fitted a guide scope, I’ll be able to make more use of the planning and exposure tools in ST4 and go much longer, notwithstanding my Bortle6/7 skies (I am on the borderline).
Cheers
Dennis