Orion Optics 8” f8 - the repair job

[Stu]

Well, she lives!!! Lorna happy 😉

I got the scope assembled this evening, all quite straightforward I’m glad to say. I’ve collimated it using a Concenter and a Hotech laser. Seems to be good, but a star test will tell. I also backed the mirror off slightly so it was not gripped by the front clips as tightly.

Only thing remaining is to spray the top ring black but I don’t find it too offensive and would rather be using the scope.

1st light report later hopefully, sky looks good so far.

[JeremyS]

2 minutes ago, Stu said:

Well, she lives!!! Lorna happy 😉

Phew! Looking good, Stu!

[Captain Scarlet]

Wow can't think how I missed this! Fantastic result Stu, I look forward to 1st Light.

Re the retaining clips and side-grubs. I cleaned my 12" mirror about a year ago, and when I re-assembled I had precisely the same concerns about how much pressure/clearance between the mirror and its retaining clibs and side-grubs. Initially, my thinking was "well they wouldn't be there if they wren't necessary" so I had all 3 clips and 3 grubs slightly touching the mirror to keep it in place.

That night, I had my bro-in-law with me and naturally I needed to show off my (then) new 12" reflector, so we observed together. Quite literally his exact first reaction on looking through the eyepiece, being a total newcomer to astronomy and observing, was "Why are all the stars triangular?". They were indeed. That learned me, as they say.

So the lesson: ensure there's a tiny amount of fresh air between any retaining screws clips and grubs and the mirror, otherwise I can assure you it's highly noticeable!

Edited August 4, 2020 by Captain Magenta

[Moonshane]

Top result Stu 👍👍

[Stu]

Looking good so far. Just managed to get Jupiter in view before it went behind the house. GRS looking good, and another feature above it, almost looked like a pale shadow transit, will need to have another look to check what it was (defo not a shadow transit). More to follow...

[Stu]

37 minutes ago, Stu said:

Looking good so far. Just managed to get Jupiter in view before it went behind the house. GRS looking good, and another feature above it, almost looked like a pale shadow transit, will need to have another look to check what it was (defo not a shadow transit). More to follow...

Seeing is quite ropey, but it looks like some quite dark festoons. Nice. Collimation looks bang on👍👍

[DaveL59]

was just out with the rebuilt TAL-M too Stu, Jupiter and Saturn looking ok but thin cloud drifting by wasn't helping the view. Couple aircraft whizzed thru the FoV too. Was able to make out 4 moons with Jupiter but Saturn none in this scope. Pushed the mag with stacked x3 barlow on Jupiter just to see if it's usable, made it very soft and narrow FoV and eye placement was critical. Still the rebuild works fine for us both which is the main thing 🙂 

[faulksy]

nice one stu, glad all is good with your dob. just make sure your mirror floats properly and all will be good

[Stu]

Well, I think that counts as a successful first light! Chuffed that the collimation is spot on despite having to start from scratch.

Saturn had looked poor earlier on, got much better as it moved higher and I’m between the houses. The Cassini Division was showing itself in the moments of better seeing, and I counted five Moons; Titan, Rhea, Tethys, Dione and Iapetus. Light scatter seems well controlled, I reckon I would have got Enceladus with darker skies.

Vega was really tight, and the Double Double split at not much over x100 (using the zoom so hard to be accurate). M13 and M57 also well seen.

Happy chappy, bring on Mars!!