1200mm project: guide scope


August 14 I did the following:

Unwrapped the guide scope from Astromania.  

Early thoughts:

  • Small overall size for a 400mm guide scope.  Not much smaller than a strippled down ST80.  Given the small space inside the square tube, there was not enough room for the larger device.
  • Uncoated optics.  Not happy about this.  Will see how it performs.  It's mostly about controlling flare and keeping the stars from being too bloated.
  • The focuser has a thumbscrew that locks it down.  Will have to look at the rest of the body to ensure that I'm not missing grub screws.
  • The ring thumbscrews were not the best.  Two were missing the nylon inserts.  Glad that I won't be using them.

Did a trial fit of the guide scope inside the 6x4 box.  The scope fits but not the rings.  This was expected and I had ordered an extra finder foot holder to go with this project.

Removed the rings, marked the position of two holes on the body of the scope, drilled holes for the M5 screws, and then mounted the Synta foot dovetail on the scope body.  To access the inside of the scope, I needed to unscrew both the lens and the focuser.  This allowed my fingers to hold the nut that went inside the body.  These will stick out into the possible light path.  Not much that I can do.

Then, I marked the place where I could run two screws though the bottom of the box.  This needed to be drilled.  Did it freehand with the dovetail bar as a guide.  Was patient and the drill went well.

Then, I assembled the mounting bar and tightened it down with M6 bolts with a jam screw.  Looks good.

Unfortunately, my hand was not large enough to fit into the square tube and manuipulate the thumb screws.  I borrowed Abby to see if her hand was small enough.  She was not able to do it either.  The option now is to put the scope on the dovetail bar outside of the box, then assemble it.

To do this required attaching the bar with the nuts glued in place and run the screws up from the bottom.  This was done the next day as I had run out of time on the first effort.

See the above pictures on how it looks installed.  Pretty snazzy!

Eventually I put a red dot finder on the top of the main scope and it would be nice to put an RACI finder on it as well for precise centering.