Quote:
Originally Posted by iborg
Hi Peter
I have even less knowledge than Ray about these things. 
But, I would be curious about the results of two things.
1: Change the camera angle through 90 degrees - does this change the axis with the main spikes?
2: Change the camera angle through another 90 degrees - does that reverse the direction of the spikes? (Can the spikes be reversed in direction?)
Good luck
Philip |
Thanks Philip. That sounds like quite a good suggestion. I will try it at first opprtunity!
Quote:
Originally Posted by Shiraz
Your mount is good enough that tracking a target low down in the west and then comparing with low down in the north should show if there actually is a turbulence pattern difference - I think that vertical turbulent flow should be aligned predominantly RA when west and DEC when north.
:.
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Ray, unfortunately I can't get low in the north or south from my location. Otherwise it would be quite a good test. I will try it getting as low as possible towards the south, and then as low as possible to the north west so as to get 90 degrees between the observations. Thanks for the suggestion!
Quote:
Originally Posted by gregbradley
When you callibrate using the Sky X or CCDsoft the guide camera angle is calculated and allowed for when it makes corrections so having the guide camera exactly square to the scope is not necessary. I prefer to have it close but I can't say I have noticed that it matters much so long as you do fresh callibrations if you change the guide cam in any way.
As far as sudden spikes are concerned that may also be an issue with the cam pin or belts shedding material onto the motor pulley.
Greg.
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Greg, I totally agree with what you are saying. My point, however is that with the guide camera pointed at pa=45 any crud or PE, or whatever on either axis would show up on the graph equally distributed between X and Y. It would only show up "more" on one axis than the other as the camera continued to be rotated towards the 4 cardinals (0,90, 180,270). On a cardinal all of the error of a particular axis would show on either X or Y, but not both. Calibration doesn't change at all what is seen on the graph (which is precisely why calibration is NOT required to perform PE measurement in TSX. With this in mind it is tricky to figure out why one should see any major differences between X and Y plots on average. How can one explain a strong spike in only one axis with the camera oriented at PA=45?
I really appreciate any and all input on this as my question at SB is being totally ignored.
Peter