Small Astonomy Project

We've done a lot of walking over the past week which has resulted in my ankle and knee swelling up again so I'm laying a bit low lately.  To recap, back in January, I first sprained my ankle badly enough that I could not put any weight on my left leg at all.  That required about four months to heal well enough to do some things again.  However, the four months of hobbling around with all my weight on my right leg only resulted in a sprained MCL (medial collateral ligament) on the side of my right knee.  The knee injury was mostly better until we did miles and miles of walking this past week.  Now my knee is painful and swollen again so I am now back to ice and elevation for a good chunk of each day.  My left ankle is a bit painful too but nothing like my right knee.

Putting my health problems aside, I always try to accomplish something, anything, each day.  Mostly, I've spent my time at the piano lately but I have managed to squeeze in a few other little things too.  Time at the piano is limited because of my extensive spinal injuries.  I can only sit at the piano for short spurts at a time before the spinal pain is so bad that it makes breathing painful (thoracic spinal injuries).  This morning, like most mornings, I sat at the piano for a little while and then I managed to accomplish a small astronomy gear project.  

I have an old Celestron CG-2 telescope mount that needed some work.  While I was adding ball bearings to both axes a year or so ago, I managed to break the saddle.  The saddle is where you place the telescope and then clamp it in place using the saddle.  Unfortunately, this old cast aluminum part was brittle and it cracked while I was clamping down a telescope to test the new bearings.  It seems that this is the way my luck has been lately...  I did all that work to add bearings to this old mount and then the saddle cracks apart in my hands as I'm clamping the very first telescope into its saddle!  That didn't please me at all.  

In the photo, above, you can see that I have a dovetail bar (the gold part) bolted in place in the original saddle and then a small saddle bolted to that new gold dovetail.  Then the telescope is clamped up above in the silver saddle.  The telescope should really be placed where the gold dovetail bar is located but the clamps on the old saddle broke and I couldn't drill new holes spaced correctly for this particular new saddle so I had to add that gold dovetail bar into the mix as a place to space the bolts correctly.  Now the telescope is requiring more counterweight because all the weight of the telescope is up higher than it should be.  That is bad news which is why I found a different and more permanent solution.

What we see in the photo, above, was just a temporary fix.  I bolted a dovetail bar to that broken saddle and then bolted a new small saddle on top of the dovetail bar.  Unfortunately, these extra parts added extra weight that the mount needs to carry (which is a bad thing... mounts are rated for only a limited amount of weight and this is a very lightweight mount with absolutely no weight capacity to spare) and it also raised the center of gravity (which is also a bad thing).  As I said, this was only a temporary fix though.  I would still be able to use the mount in this condition with this temporary fix.  It wouldn't be ideal but it would be usable.  

In the meantime, I ordered a new replacement saddle that had hole spacing that would work for my broken mount.  I drilled two holes in the broken saddle 60mm apart (see photo below).  I then used a hacksaw to cut off all the protruding brackets that once held the telescope in place.  The main protruding part of the saddle is is the part that had cracked so there was no loss in cutting off all the protruding parts this old saddle.  This left me with a relatively flat mounting plate where I could mount a new saddle.

I used a belt sander to smooth out the surface of this old saddle so the new saddle would sit perfectly flat on top of it.  Cutting and sanding this part was easy since cast aluminum is so soft.  Now I was ready to bolt a new saddle onto the old saddle which is now just a mounting plate.

This morning, I bolted the new saddle to this old plate on top of the mount.  Now the mount is as good as new.  Actually, it is far better than new now!  I have added bearings to both axes and now I have a far better saddle for mounting telescopes too.  This particular saddle has two clamps for holding the telescope which is much safer and secure.

In the photo above, you can see the Phillips head bolts I used to mount the new saddle onto this old mount.  Those relatively small bolts are spaced 60mm apart.  I think the bolts are 1/4-20 thread.  I also used flat washers and locking nuts to secure this saddle.  This plate was too thin and brittle to tap threaded holes for bolting so I used nuts on the bottom side of the newly flattened plate.

In the photo above, you can see that this new saddle now sits flat on top of what was left of the old saddle after I cut and sanded it to be flat and smooth.

If I hadn't said anything about this small project, I don't think anyone would notice the difference in this mount.  Well, regular astronomers would likely notice the better saddle but the average person would have no idea that this old Celestron CG-2 mount was significantly upgraded.  In use, this mount is significantly improved now with the added bearings and this new saddle.

So, although I am laid up for a bit again, I managed to accomplish something this morning!