multiweb
17-05-2009, 03:49 PM
Finally got to do a real test at Crago this saturday night. The scope's been in pieces most of the past few weeks and I couldn't wait to go imaging again. :)
I've attached a shot of the scope back cell. I added two handles, two fans, 3 mirror locking bolts and realigned/shimmed the whole thing.
The shot I took is 3.5 hours (10min subs) on the keyhole at f/10 with a QHY8 on a G11 guided with an OAG - QHY5/PHD. No filters. Should have used at least a UV/IR. Next time. :whistle: I did a similar shot prior to the mods as I wanted to shoot the same thing and compare.
The night at Crago was clear but a bit windy at times and the seeing was very average so I lost the guide star a couple of times and I had to guide quite aggressively. As a result the 10min subs are a bit soft but the field is much more uniform than pre-mods. It's as flat as an SCT will permit (salad bowl kind of flat :lol:) but hey, considering it was on an open field mobile set-up in the breeze :windy: I'm happy with the way the scope and the mount performed and the overall look of the pic. That's uncropped btw.
On a side note I was told there is an optimal distance from the mirror to the corrector plate for an SCT to perform at its best regardless of focus. Do you know anything about it or any resources/reading on this? Thanks in advance :thumbsup:
There's a higher-res shot quite soft though at: http://www.multiweb.com.au/astro/ngc3372_20090517_f.jpg [1MB]
I've attached a shot of the scope back cell. I added two handles, two fans, 3 mirror locking bolts and realigned/shimmed the whole thing.
The shot I took is 3.5 hours (10min subs) on the keyhole at f/10 with a QHY8 on a G11 guided with an OAG - QHY5/PHD. No filters. Should have used at least a UV/IR. Next time. :whistle: I did a similar shot prior to the mods as I wanted to shoot the same thing and compare.
The night at Crago was clear but a bit windy at times and the seeing was very average so I lost the guide star a couple of times and I had to guide quite aggressively. As a result the 10min subs are a bit soft but the field is much more uniform than pre-mods. It's as flat as an SCT will permit (salad bowl kind of flat :lol:) but hey, considering it was on an open field mobile set-up in the breeze :windy: I'm happy with the way the scope and the mount performed and the overall look of the pic. That's uncropped btw.
On a side note I was told there is an optimal distance from the mirror to the corrector plate for an SCT to perform at its best regardless of focus. Do you know anything about it or any resources/reading on this? Thanks in advance :thumbsup:
There's a higher-res shot quite soft though at: http://www.multiweb.com.au/astro/ngc3372_20090517_f.jpg [1MB]