TAL-120

[bambuko]

Thanks Andy, send me .rar - I can convert it , if you have a problem with it.

[AndyH]

All the older style manuals, incl the 120, can be found here......

http://old.astronomer.ru/telescope.php?action=14

[AndyH]

Does the following open and read okay? I take it nothing can be done about the sideyways aspect, due to it being a double page scan? Or at least it looks like it's been a scan of a manual.

Andy.

Tal 120 manual.pdf

[bambuko]

Thanks for the link - good one!

You can rotate all the pages, no problem.

Tal 120 manual-1.pdf

[AndyH]

Excellent.

Looks like this is a slightly later manual as the 15mm Kellner has been replaced with the 10mm plossl, which is what happened with the Tal 1 also.

edit: and the x3 barlow replaced with the x2.

[bambuko]

Which also points to "my" TAL-120 being older than 2001...

[AndyH]

Which also points to "my" TAL-120 being older than 2001...

Yup.

 I've got a Tal2m which is a yr2000 version and it came with the MKII 25mm plossl & 15mm Kellner.

Not sure when production first started on the 120's. But yours, I reckon, is in the second half of the 90's, maybe pushing to '00 at the latest.

But that's all a guesstimation.

Hope the skies clear soon for you to give it a good workout.

Andy.

[bambuko]

I was able to withdraw the whole focuser/spider assembly intact by removing secondary mirror first:

Corrective lens is in absolutely perfect condition (now that I can examine it).

The only thing to work out is how to remove eyepiece/rack tube for shimming... (hopefully without using mole grips and brute force )

[AndyH]

So the corrector(for want of a better term) assembly is tight in the base of the focuser? I was hoping it would be secure but easily removable. ie: once the focusers x2 screws were removed, it could be carefully jiggled off, leaving the corrector/diagonal assembly in the scope.

Andy.

[bambuko]

No it is "permanently" glued in, and I must admit I am baffled as to how is one supposed to take rack tube out without un-gluing the corrector...

[AndyH]

Without the plug at the lower back of the focuser, not sure. Can't remember if the pinion can be removed with the rack in place.

[bambuko]

There is a rectangular bit at the base of focuser (assuming we are talking about the same thing?), but removing it doesn't do anything, since afaik you have to withdraw rack/eyepiece tube downwards (ie towards the centre of the scope) and that is prevented by the corrector lens.

No, you cannot remove the pinion with the rack in place - at least afaik - I have tried but didn't succeed ...

[AndyH]

In the slightly more modern focusers, they have a small plastic plug, that lets you access the lower rack screw.....

[bambuko]

Corresponding view of my focuser:

The "puzzling" screws at the bottom appear to hold a block of metal (two large ones) and the third one (small grub screw in the middle) appears to be belt and braces screw to secure glued corrector/spider assembly.

[AndyH]

Great pic.

So this a specific focuser for the 120. Most interesting.

[bambuko]

I think, that for now I will put everything back together

If new ideas emerge it's easy to take it apart again...

[bambuko]

For now I have sorted out the problem with a piece of (plastic) shim material inserted between the eyepiece tube and focuser body:

It stays in place fine, everything works smoothly (no doubt helped by low friction of plastic shim material) and the only issue is long term longevity, but I am hoping it will be fine.

So, with secondary collimated, focuser sorted out, I only needed weather to test it...

However Metcheck.com was telling me NO chance tonight , so imagine my surprise when I looked out of the window around 5pm - clear sky (in between clouds) and perfectly visible moon.

Now was the chance for 120 to prove that it is "grab and go"   and so it was - five minutes later everything was out and given few minutes to rapidly cool down I was able to play at long last.

First 8mm, than 6mm, followed by 5mm and eventually 4mm eyepiece - all of them working great and better than I could have hoped for, including resolving a tiny star just on the edge of moon (which I couldn't even find in Stellarium, but perhaps it was me and my inability to use Stellarium?)

With 4mm giving x200 and working beautifully I was very happy customer - it was first time that I was able to use this eyepiece so successfully!

It was definitely a bonus evening

[AndyH]

Sounds like it's a good un !

Andy.