Rick, you need to buy an SDM and a pair of denk binos
I'm happy to look through an SDM or two every year at Astrofest, Chris
Quote:
Originally Posted by Retrograde
Great first light Rick. looking forward to seeing what you can produce with this combo.
I have this lens for my DSLR. It works really well but I tend to get flaring around bright stars.
Thanks, Pete. I have seen some halos in blue and Oiii but I'm assuming that's the filters. Bright stars, and ever Saturn haven't come out too badly so far.
Given the playing you've done with spacing Rick, when you were achieving infinity focus at lets say, 10m, did you need to increase or decrease spacing?
I have a Zeiss 135mm that I've used with a QHY163M and I can focus but it isn't quite at the correct spacing so I was curious as to whether I needed to increase or decrease where I am at.
Given the playing you've done with spacing Rick, when you were achieving infinity focus at lets say, 10m, did you need to increase or decrease spacing?
I have a Zeiss 135mm that I've used with a QHY163M and I can focus but it isn't quite at the correct spacing so I was curious as to whether I needed to increase or decrease where I am at.
Hi Colin,
Increasing the spacing pushes the focal point further towards infinity on the lens scale for all the lenses I have tested. I'm working on the assumption that I'll get the flattest field when the lens scale matches the actual distance and that seems mostly correct. Adding filters seems to complicate things. Spacing that works well for the Ha filter doesn't always do so well with the other filters. Things get tricky at the focal ratios where I have been playing!
Increasing the spacing pushes the focal point further towards infinity on the lens scale for all the lenses I have tested. I'm working on the assumption that I'll get the flattest field when the lens scale matches the actual distance and that seems mostly correct. Adding filters seems to complicate things. Spacing that works well for the Ha filter doesn't always do so well with the other filters. Things get tricky at the focal ratios where I have been playing!
Cheers,
Rick.
Thanks Rick. I think I have another 0.5-2mm that I need to add then. I'm pretty close but I'd like to get it as close as possible. As my Astrodons are all 3mm thick I wouldn't have thought that different filters would cause issues. I have done some RGB imaging and my only "issue" seemed to be blue bloat at F/4... Along with tilt caused by my mounting
Might get a clear night on Wednesday night to do some playing.
Thanks Rick. I think I have another 0.5-2mm that I need to add then. I'm pretty close but I'd like to get it as close as possible. As my Astrodons are all 3mm thick I wouldn't have thought that different filters would cause issues. I have done some RGB imaging and my only "issue" seemed to be blue bloat at F/4... Along with tilt caused by my mounting
Might get a clear night on Wednesday night to do some playing.
I'm using Baader filters that are purportedly all 2mm thick but I'm not sure that's the only consideration. Purportedly "parfocal" filters never focus at the same place for me and I have found the differences are quite large in fast systems.
I’ve tried RGB from “the Far East” with all its streetlights and found it a bit lacklustre...at the sluggish f/5.5 will have to look into the IDAS.
Should be a ripper out at a dark site...
Thanks, Dunk. I don't plan to do much RGB imaging from home but it's good to know that it isn't completely impossible. I am really looking forward to the next opportunity for some dark sky imaging time.
That looks promising. I am fan of lens imaging and that's a very modern setup you have there.
Dipping your toe in short exposure multiple subs stacking eh?
The results show.
Hi Greg,
Thanks, I thought I'd try something altogether new for me. So far it has been quite challenging but I think there's a big payoff if I can get it all working well. I have some large targets and also some very faint ones in mind...
I have been experimenting with Nikon 180mm and 300 mm lenses with the asi1600 and getting mixed results.
The quality of the lens to camera adapter seems to be the biggest problem.