|
Martin, one you have the line on the ground how do you align the RA axis along that line? Do you just sight it or is there a less subjective way to make sure they are parallel?
David,
I just use geometry to align the tripod to the true south line then set home position on the mount.
See below and attached
Setting up a Tripod to Align to True Celestial South
NB: This procedure is based on having your True South line already marked on the ground from a previous procedure ( length of true south line marked on ground approximately 500mm long or alternatively 2 fixed points marked on the ground 500mm apart)
1/ Open your tripod fully out and extend all 3 legs out by about 100mm then lock them
2/ Place foot of front tripod leg marked “N” directly on True South line and roughly line up the 2 rear tripod legs equally spaced in respect to the True South line
3/ Level the base platform of your tripod by adjusting the legs in or out as required .Check level of the tripod base in both north/south and east/west directions using a good quality builders aluminium bubble float level.Level the base as accurate as you can then lock the tripod leg adjusters nice and tight.
4/ Extend out your True South Line along the ground just past the intersection of the 2 rear tripod legs using a string line, aluminium angle or a straight edge. The feet of both rear tripod legs must be equidistant from the intersection of the extended True South Line. When adjusting make sure you only move the 2 rear tripod legs left or right whilst keeping the front tripod leg “N” stationary or pivoting but not moving off the True South Line
5/ Once the 2 rear tripod legs are equidistant from the true south line , the tripod is now set up level and pointing to Celestial True South
6/ Ensure you take care in setting up the tripod and measuring accurately to the nearest millimetre.This will assist the accuracy of your polar alignment procedure.
Cheers
Martin
|