Quote:
Originally Posted by Exfso
Fred, I originally used the ED 80 as the guide scope which is the normal config, however in an attempt to get rid of any possible flexure, I removed it, the Tak guiding mount, the side by side and just left the Tak stand alone to test the guiding with.
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Although I dont know what the graph time scale is, differential flex wont be a problem at such short timescales, with the FL of your refractor, thats not the problem. Flex becomes a problem over say 1500mm at 15min or more, assuming the guide scope is well mounted and the guide cam is not waving in the breeze way out on the end of a dodgy ED80 focuser without being clamped.
Quote:
Originally Posted by desler
And Fred, guide scale of 1.8asp?? As I'm using a ed80 guide scope and qhy5, I'd like to know a little more on how you figure out the guide scale and how you use this number to improve your system or reduce guiding errors.
Darren
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Just plug the scope and cam into Ron Wodaskies CCD calculator (free) and it tells you the scale , get its very easy and fast to use.
The scale helps by knowing how just how big a problem is. A graph by itself is meaningless (to see how big the problem is anyway). If Peters graph has graduations at 1 arcsec then theres pretty much no problem, if its in pixels then you need to know the scale in arc/secs/pixel. If say the scale was 4 asp then there is a problem.
Watching how the graph proceeds is also very useful, you can tell PE, backlash, stiction, alignment, seeing, balance, and how stable guide control is (control settings). From my experience, Peters 1 st graph (and it may not be the case here) DEC curve is typical of iether DEC out of alignment with wrong correction settings (slow drift, and wrong/over correction), or a perfectly balanced DEC axis with backlash.
Quote:
Originally Posted by Exfso
Thanks Darren, yep it is great people are interested in helping, I really do appreciate it. Attached is a graph using Steve's Gemini and as you can see it it a real crappy graph. Balance was perfect, polar alignment was good.
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Perfect balance is not good generally, especially if you have backlash, both axis should be slightly out of balance so they always drive one way, this eliminates back lash.