ATM Project - 22" F4.54 Truss Tube

The grand telescope project of Ken Lester and Kurt Maurer

Updated October 17, 2000

22" f4.54 Primary mirror from Pegasus Optics
Spider and secondary holder are from Protostar
3.5" secondary mirror
Focuser - DX-2 focuser from JMI
18 pt mirror cell - by Ken Lester design by David Kriege
1.25" diameter truss tubes from Texas Towers
80mm finder scope by Orion, mounting fabricated by Kurt Maurer
Telrad pointer

FL test - Kurt 2.jpg (1878018 bytes)  

Kurt determining the length of the truss tubes.

Mirror Box and Cell 1.jpg (1828605 bytes)  

Eighteen point Cell mounted in the mirror box

Trunions on Mirror Box 2.jpg (1782324 bytes)

Adding the trunions

Lower Blocks.jpg (1805333 bytes)Bracket1.JPG (62677 bytes) Clampless truss tube blocks.  Truss tubes are held in place by tension.  The first picture shows the clampless blocks in the mirror box.

As it turns out, scope assembly and disassembly were a real chore with the clampless blocks.  I had originally ordered Malco machined aluminum lower blocks, but there was a substantial delay in delivery.  Kurt and I made the decision to try the clampless block technique.  It looked good, but assembling the upper cage was a real chore.  When the Malco blocks became available, I went ahead and took delivery.  Using the Malco blocks will result in an alteration of the truss tube lengths.  We took the opportunity to redesign the upper cage brackets as well.  The clampless block upper cage bracket design used a separate bolt for each tube.  The new design, uses one bolt for every two tubes.  This will give far greater rigidity to the scope.  The second picture shows an upside down view of the truss tube brackets on the upper cage.  Final metal work had not yet been completed.

Ken with Scope 1.jpg (1865623 bytes)  
Ken shows off the upper cage mounted on mirror box. Figure we need an 8' ladder.
Scope 3.jpg (1763379 bytes)  
After balancing, we did a star test on Polaris, it focuses. Next step, making the rocker box.
RockerBox.jpg (372536 bytes)  
Rocker Box....
Scope5.jpg (491805 bytes)  
Getting closer - Starting to look like a real scope!
Kurt installing fan2.jpg (1803004 bytes)  
Kurt installing the cooling fan.  Mounted on two strips of wood with a cushion made of an old mouse pad serving to absorb the vibrations from the fan.
Scope13.jpg (1839373 bytes)
Here is a fully functional telescope... All we need now is some finishing work and its done!

Star Testing.....

Looking at Venus.jpg (1897146 bytes)  
Low in the sky, the first object we found was Venus.  Venus provided us the opportunity to align the Telrad and finder scope.
M13 Bound.jpg (1800843 bytes) \
Testing the optics, Lisa looking for M13.  Notice that we've now mounted the Telrad on the 80mm finder scope.

Final Construction 
and Finishing

BoatTrailerBumperfeet.jpg (57888 bytes)Kurt had the idea of using the tapered rollers for a boat trailer for ground board feet.  I cut them in half and fastened them to the ground board with dry wall screws.  It is hoped that these will dampen vibrations quicker than the wooden feet we used initially.  They ended up a little tall...I may need to cut them down some.
PolyOnUpperCage.jpg (90549 bytes)KurtApplyingSparUrathane.jpg (85874 bytes)
Only 2 weeks till the JSCAS Ft. McKavett star party.  Our big debut of the new scope.  Kurt has been showing me the fine art of poly-urethaning.  I found a Minwax brand that is suppose to be resistant to UV rays and good for out door use.  It's called Spar Urethane.  After trying it out, Kurt says it applies very well with few bubbles or brush marks.  Here a a couple of pictures of the brush master at work...

TexasJSCAS.JPG (10417 bytes)
Typical of Kurt's creations, the State of Texas and a JSCAS plaque are proudly displayed on the back of the mirror box.  One more plate will be added....

Jscas.jpg (10059 bytes)
Close up of the JSCAS plaque.




FinishedScope.JPG (23758 bytes)
The finished scope...well, as Kurt'll never really be finished!
KenNscope.JPG (31560 bytes)
Here I am, Ken Lester, showing off the now completed scope.
KurtNScope.JPG (35218 bytes)
Here's Kurt Maurer, chief architect and master wood worker.  I'll be forever grateful for his patience and mentoring in the art of work working and telescope building.