Going H-alpha: Removing the Etalon from the PST body.

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WARNING: SOLAR OBSERVATION REQUIRES GREAT CARE AND SAFE FILTRATION.
INSTANT PERMANENT BLINDNESS CAN EASILY RESULT FROM SIMPLE MISTAKES.
NEVER LOOK AT THE SUN THROUGH ANY LENS, MIRROR OR INSTRUMENT UNLESS IT HAS BEEN FULLY TESTED AND APPROVED FOR SUCH USE. YOU FOLLOW MY EXAMPLE ENTIRELY AT YOUR OWN PERIL!

You would not believe the struggle I had to break the thread locking compound on the Etalon! It took an hour just to get the first, audible "crack." Even then it took a lot of force to keep it unscrewing. I was afraid the housing would break where it is slotted for the tuning. Or that the Boa's rubber strap would break because it was taking such a beating!

I added a length of PVC plumbing pipe to contain the rubber strap and provide a more comfortable handle. [See image right]  It also provided a little more leverage. The Boa strap is asymmetric to the handle. Which meant the Boa's body was hitting the PST's metal housing every time I tried to put some serious effort into it. It took two, well tightened, Bessey F-clamps just to hold the body still on the bench! I was very careful not to hit the sun finder prism in the corner of the casing.

Thankfully I had done my online homework and knew about the long, fine screw hidden under the concealing paper label beneath the knurled 'rubber band.'

The rubber band needs a fine screwdriver to lift it enough to start pushing it off sideways. Try not to scratch the finish. A cocktail stick might be a better tool.

If I hadn't removed the tuning screw it would have been forced against the internal tuning mechanism and bent.  Making it impossible to remove. The thin, rubber band sits on a thin metal sleeve. All these parts must be removed before the BOA strap wrench can possibly be used. I also removed the two narrow O-rings around the etalon body to save damaging them with the Boa. These O-rings provide smooth friction and even support for the tuning band.

Click on any image for an enlargement. 

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