Subject: AOAS 13" F4.5 DOB Rebuild Status Report

Well, I got the OTA rebuilt.

Looks Great. I will wait till I have the DOB Components together before I try to cullimate the OTA.

After I got the mirrors cleaned up, I found that the "thin" mirror and secondary was the "Good" mirror set. Except for the 1/2" diameter black blotch near the center, the rest of the primary mirror is in real good shape. (Being near the center, most of the blotch will be covered by the seconary reflection.) I estimate the mirror is about 95% as good as original. The other plus is that the mirror mount on this mirror fits the tube with no modifications.

The "Thick " mirror and secondary have a white glaze that no amount of cleanning can remove. This reduces the reflected light by greater than 50%. I assume that this is from exposure the elements and summer heat for a long time in the old observatory storage building. This is the one that I will send and have recoated and use for my scope.

I had to rebuild the secondary holder and spider to fit the tube. First I had to replace the glazed secondary mirror with the good one in the holder........... Perfect fit. Next I had to remove the spider tube connecters, cut 1/4" from each spider arm and reattach the tube connecters. The tube this spider came from, evidently, was 1/2" bigger in diameter that the one I am using.

I recoated the tube interior and spider with a rubberized flat black spray paint. This stuff is what I used on my DOB, and works & looks great.

Finally, the exterior of the Main Tube is no longer red, but I didn't paint it.........."Thinking-Outside-Of-The-Box", this is an idea that I came up with for my 10" SN10 DOB but never did. I won't go into detail, but it is one of the purdiest tubes I ever did see...Looks nothing like the original..................I will leave this for a surprise............

I have all the materials to build the DOB components.

The plan is to have the telescope completed by Friday of this week and have "first light" at the Star Party at the Nature Center or at the latest, the next Saturday at the Lake Ft. Smith Sar Party.

Re: AOAS 13" F4.5 DOB Rebuild Status Report

You da man!
Mike

Re: AOAS 13" F4.5 DOB Rebuild Status Report

To use an old 70's expression - Faarrr out, man!

I'm looking forward not only to seeing it, but to having a look through it. I think this will be a great scope for club members to use at our new facility!

Re: AOAS 13" F4.5 DOB Rebuild Status Report

"Woody" is finished (When you see it, you will understand the name).............and it is really purty.

It is also heavy........It is a chore to carry it very far.

After redoing the mirror mount and the spider, everything lined up and collimated perfectly.

It hasn't had "first light" yet..........real soon!!!!!!!!!

I will post pictures in the next few days...............

Re: AOAS 13" F4.5 DOB Rebuild Status Report

I took "Woody" to the Booneville Girl Scout Camp for a Star Party for group of 4H kids, but had a problem.

The eye piece wouldn't come to focus.............Didn't have enough "Infocus".

I had used the original 3" focuser hole in the tube to mount the focuser, but with the new focuser being thicker, I need to move it and the secondary about 1" toward the Primary mirror for the eye piece to come to focus. I think this would be easier than cutting 1" from the end of the tube and moving the primary (I don't have a way to cut it "Square").

Back to the grindstone..............

I really should have tried it out before taking it to a star party...............I live and learn by my mistakes.

Re: AOAS 13" F4.5 DOB Rebuild Status Report

I finished the scope again.

I move the focuser and secondary 1" down the tube, towards the primary.

This should give me apple focus range.

I will try it out tonight on the moon and jupiter.

Re: AOAS 13" F4.5 DOB Rebuild Status Report

I uploaded pictures of the scope to my gallery.

As soon as Dave posts them, they will be avialable to view.

Re: AOAS 13" F4.5 DOB Rebuild Status Report

"First Light" after latest modifications.......................Comes to perfect focus. Wide field of view (4 degrees with 30mm 80 degree U. O. Eyepiece @ 50X).

Veiwed the moon.............Blinding Bright. Great contrast on mountains and craters.

Viewed Jupiter - Moons and surface features visible. View with a 6mm TMB eyepiece (250x) shows a moon shadow and GRS.........

AOAS.ORG - Forum
http://www.aoas.org/forum/viewtopic.php?showtopic=2348