I have to concur with Mike's comments. The stars just overwhelm this image, but I understand the challenge of getting them just right.
You are also right about the Planewave CDK.....tough to find images. Its outside of the mainstream telescope lines and while I have not investigated it thoroughly, I do not see a TCC comparable item to control secondary temperature, fans, and focus. I thought you sold your RC?
Martin
I'll have another go at the processing trying to tame the stars more.
Planewave has a lot going for it with what appears to be a superior
optical design. As far as a TCC goes are they that important anyway? I never had one with my 12.5 before I sold it and figured it was more for remote imagers.
Without going too OT, I consider the TCC and its functions absolutely critical to acquiring the highest quality of hi-res images. By optimising both the primary and secondary mirror temps such that they were within 1 degree of ambient meant that I could image all night long, every night, without focussing in between filter changes. This took some experimenting of course i.e calibrating the secondary heater, calibrating the fans and altering the fan aggressiveness, but the output was a single focus run at evening start, then an entire nights imaging, multitple filter changes without focussing. And then there's dew...did not get any at all.
Of course, without the TCC, I presume you had used a third party focussing mechanism for the secondary, like a Robofocus.
Finally, without a TCC, you cannot use a rotator...and you know how small that guide window is on a scope that has 3m focal length.
Interesting. I used the Robofocus on the secondary that was built in. Mine was a closed tube and I didn't get dew either. I also found focus did not shift throughout the night (my dark site has fairly stable temps though where it falls for the first 3-4 hours then a slow fall from there until dawn). My BRC hasn't dewed either and temp changes don't affect focus much at all (very slight, I would refocus if I got a 3C change but usually I see only about 1-2C change).
Your images showed higher res than mine so perhaps going this extra mile paid off. With filters they tend to be slightly different focal points as well despite the marketing although I find they are very close and at this point don't make any allowance for the slight difference as it would mean sitting with the scope all night or setting up some automation software.
greg
Quote:
Originally Posted by Martin Pugh
Without going too OT, I consider the TCC and its functions absolutely critical to acquiring the highest quality of hi-res images. By optimising both the primary and secondary mirror temps such that they were within 1 degree of ambient meant that I could image all night long, every night, without focussing in between filter changes. This took some experimenting of course i.e calibrating the secondary heater, calibrating the fans and altering the fan aggressiveness, but the output was a single focus run at evening start, then an entire nights imaging, multitple filter changes without focussing. And then there's dew...did not get any at all.
Of course, without the TCC, I presume you had used a third party focussing mechanism for the secondary, like a Robofocus.
Finally, without a TCC, you cannot use a rotator...and you know how small that guide window is on a scope that has 3m focal length.
Greg that's a gorgeous image to be sure.
I know how hard it is to tame the stars, I wouldn't know where to begin if I were imaging this object.
The overall image is fascinating though and you've done a great job with it.
I never get tired of drooling over your setups, thanks for sharing those too and congrats on the Paramount !!
The quest for the ideal scope is somewhat of an ongoing pursuit.
The TEC180 is close to the top, the BRC is great but as Mike points out the star shapes sometimes aren't so good. If I were game I'd get the spider changed over to something more suitable for astrophotography. ASA had the same problem with theirs and went to a double spider arrangement. S shaped spiders also don't give diffraction spikes.
The Paramount will be fun to use and a new learning curve.
wow now thats a starry pic i like it Greg 
