Re: Requesting alignment tips for ROB...

[Stupendous Man <richmond@a188-l009.rit.edu>]

> I'm in the process of aligning ROB, and it's a painful process (for me at
> least).  So far, my best progress is when DEC is pointing at the pole and RA
> is stationary and level.  I've then been making mount adjustments based the
> gradients of the streaking stars (E-W and N-S), trying to get the stationary
> star in the middle of the frames.
> 
> Any other methods, pointers, hints that others may care to share?

  My method: aim the telescope due south (or north, for southern 
hemisphere observers), and tilt the Dec so that it is aimed roughly
at the celestial equator.  Adjust the camera so it is at the middle
of its range of motion in RA, and pointing roughly South.

  Using a magic marker or pen, mark the position of the front feet
of the Mark IV unit.  I just drew an outline around them.

  Now, take a 60-second image at night.  Stars will form long streaks
which slant "sideways" in the image if the camera isn't aligned properly.  
Note the amount of sideways motion in a streak -- say, 30 pixels from
top to bottom.

  Slide one of the camera's feet while keeping the other one fixed
in place.  Mark the new position with a pen.  Take another image,
and again measure the length of the streak.

  Repeat until you have bracketed the proper position -- in other 
words, until your streaks go from slanting down-and-left to slanting
down-and-right.  Figure out which positions gave the best results,
and interpolate between them.  Move the camera so that its feet
are somewhere between the marks for these two best positions.

  Done.

  I admit, I haven't tried to adjust the height of the feet.  I guess
I was just lucky.  Or, perhaps, I'm not too picky :-/

                                          Michael