Doubles current PA angles

[mdstuart]

Out last night with the web cam on doubles..

Measured Almach using reduc and and I get a PA of 65.8deg but in the books in 2004 it says PA 63deg.

My question..Is there a database of current PA at 2011 or is there some software which has the orbits in it that shows the PA as of today etc...

Mark

[petek314]

Hi Mark,

I also use Reduc. I use the Washington Double Star catalogue which has a list of calibration stars :Sixth Orbit Catalog - Calibration Candidates

I think the web link is being moved so you may want to do a search on Washington Double stars and then drill down to calibration stars. I like reduc but for it to work accurately the webcam needs to in exactly the same orientation as when you image the calibration star. For me this means leaving the camera in place and attempting to line up the scope to the double star. With my scope I usually have to put an eyepiece in to centre the star and then fit the camera. Can i ask how you ensure the camera is in the same position as when you calibrated.

Pete

[mdstuart]

Pete

I have been using the synthetic drift method to get the angles and setting the E based on the split of the first star I did! So not very scientific but I can get the PA to with 2 deg and the seperation to with about 2" I think!

Mark

[petek314]

I have been using calibration stars but have been trying to find a way to ensure the imager is in precisely the same orientation when it is replaced. Perhaps this would mean that I only have to calibrate once. I hadn't noticed the drift method before yesterday and have been reading about it in reduc's help. I had mistakenly thought it was another way to setup the polar mount