TAL-M refurb

[DaveL59]

well I decided to be lazy this time around, bought some paint stripper and removed off the old paint layers, smoothed off and now primer coated

Will check in on these tomorrow now and tidy anything that's needed, then it'll be black hammerite smooth spray and hoping for a nice smooth finish. 

[DaveL59]

A few coats of black hammerite smooth spray and...

Looking good  That's the last of the major painting done, finally!

So tomorrow they'll move into the curing cupboard and I can start to think about looking at the mirror cell and spider vanes, clean up the mounting screw parts to remove any corrosion and decide what I want to do about darkening the OTA inner. Am thinking flock on acetate might be the easiest route as that'll also serve to cover over the base of the focuser which isn't matt blacked at all, as I mentioned earlier on.

[DaveL59]

wow it's been quite a while since I updated this one. Just ordered some circlips (e-clips) so I can replace the couple missing from the Alt-Az head controls, so the reassembly will have to wait on that. Thought I'd take a look at the OTA tho as I had been thinking to flock it, the original paint is more a grey than a dark matt black so doing this may improve things a little. So cut a piece of acetate, the flock I have is A4 sheets but this is a small tube and with the acetate it should work...

You can see the joins but that should be hidden once in the tube. Cut-outs for the focuser (saves having to matt black the underside of it, handy) and the 4 holes for the spider, the latter will need enlarging a little tho.

 

So just the bare OTA, no mirrors but what's the effect...?

View from the mirror end, actually pretty good it seems  

My one concern is on hot days will the flock come away from the acetate and decide to settle on the mirrors, which would be a disaster. Thinks I may add a few tack stitches along the joins just to be sure things stay put as far as I can ensure it. Bear in mind the conservatory where the scopes tend to live can hit 47C+ on sunny days, especially if I'm not home so can leave the doors open to help keep things cooler, hence thinking of ways to ensure things stay in place.

[DaveL59]

today this arrived, hopefully will be suitable to replace the 2 missing ones. Way OTT buying that many but ya never know when they might come in handy on something else  

So, started to look at the ALT-AZ head. Managed to free the locking screw so dismantled the AZ bearing...

It's a bit gritty in rotation as a result of the sanding most likely as can be seen above, so cleaned up with a degrease wipe and added some LM2

Refit in the reverse and tighten down the clamping ring so there's no rocking but the bearing moves freely, then lock in place with the locking screw.

I recall reading somewhere that one bearing was more than plain metal surfaces riding on each other but in my case both are the same. Seems to work fine, crude but effective if kept lubricated. Will pick up with the other bearing in the next day or so as I've a couple other things to sort too.

[DaveL59]

well, so much for picking it up again later, decided what the heck and reassembled the head

Then the OTA carrier - had to run a drill through the holes to clear the paint so the pins could be refitted, just twisting it by hand tho and then a tap for the threaded section. Added some felt on the inner of the rings and saddle which should be gentler on the OTA paint than the original plastic bumps that I removed earlier. Also a washer under the OTA securing thumbscrew so we don't chew the new paint. Will try find some nylon ones later on I think.

Then fit the carrier to the head and wipe down to get rid of the greasy finger marks  

Test fit the OTA which I've yet to finish assembly

Looks pretty good I think. So really it's just the OTA and focuser to complete now, almost there. Paint finish isn't perfect but considerably better than where it started and am quite pleased with how it's gone so far  

 

Edited July 9, 2020 by DaveL59

[markse68]

Looking great Dave   Such an interesting design too- I think i want one   Great to see you back at it

Mark

[Mick J]

Looking really nice,  'Way OTT buying that many but ya never know when they might come in handy on something else '   been there often and will visit again I expect🤩. 

[Kimboman]

A very good refurb job well done .

l find doing this type of work is very satisfying when the results turn out as good as yours

[DaveL59]

thanks all, I've enjoyed doing it, still a little bit to go but wanted to get the heavier bits out of the way before I go for an op, won't be able to punt stuff about for a while after that  It's looking pretty reasonable I think and way better than when I started. Really just the flocking, mirrors and focuser to go back I think, so mainly the OTA to finish up and it'll be done. How long the new finish lasts tho... time will tell  

[DaveL59]

On 10/07/2020 at 10:47, Mick J said:

Looking really nice,  'Way OTT buying that many but ya never know when they might come in handy on something else '   been there often and will visit again I expect🤩. 

ahh perhaps, but with a collection of binos and a couple of scopes... then the car and so on...

Will refurb the TAL-1 one day tho likely much later in the year or maybe next so may well need a couple more from that set. It's in fair shape really compared to how this one started, could do with a little work on the slo-mo controls is about all really, having already swapped to a TAL 1.25-in focuser and shifted the mirror so it's workable with regular eyepieces.

[DaveL59]

On 10/07/2020 at 10:28, markse68 said:

Looking great Dave   Such an interesting design too- I think i want one   Great to see you back at it

Mark

Came across this one, cambridge way but its the smaller Alcor (65mm) as Stu has (the peashooter). Even has the nice fully fitted wood case too tho the foam has had it and stuck to the tubes. Different design to the M but likely just as solid.

https://www.ebay.co.uk/itm/303623383926?ul_noapp=true

[markse68]

54 minutes ago, DaveL59 said:

Came across this one, cambridge way but its the smaller Alcor (65mm) as Stu has (the peashooter). Even has the nice fully fitted wood case too tho the foam has had it and stuck to the tubes. Different design to the M but likely just as solid.

https://www.ebay.co.uk/itm/303623383926?ul_noapp=true

😍 the Alcor was my first scope- bought new from telescope house in person way back when for iirc £150! I still have it 😉 But thanks Dave- I might bid on this to give to one of my nephews- bit more manageable than the Tal-1s i’ve been collecting for them. It’s a lovely little scope. So solid- not a toy at all. Mines probably in similar condition now- hasn’t seen the light of day for decades...

[DaveL59]

Does look ok Mark so long as the mirrors are still good, almost tempted but so can't do that trip at the moment, tho I am getting more tempted by the old refractor that's not so far from me lol

[sloz1664]

Hi Dave, great to see a Tal being refurbished and you are doing an exceptionally fine job on the old gal

Steve

[DaveL59]

thanks Steve, can't say the paint finish is perfect but it looks pretty reasonable and will be nice to get her back looking at the stars. Not so much left to do and it's been theraputic given the times and being stuck at home. Always good to keep the mind ticking along with a few little projects  

[DaveL59]

Finally reached the end. The other day I sorted some stitch loops thru the acetone and flock along the edges, I know, maybe not needed but am playing safe given temperatures where this can be sat during the day times. Don't want the flock breaking free and resting on the mirrors after all. Won't bore with a pic of a sheet of black flock tho there's one of those further up this thread 😉 

So today I cleaned the mirrors ready to go back and while they dried, reassembled the focuser and fitted back onto the OTA. Hopefully the alignment mark I made will have the finder still aligned with the main scope, will find out one day lol. With the mirrors clean and refitted I thought some vanity shots of it set up in the garden would be nice, tho only using a single pier section - less trips as I can't carry it assembled quite yet.

and back in the nice baltic pine case

I never did do a highlight of the latitude scale, I think there's not enough relief after the "baking the paint" experiment that turned the knuckle biscuit colour. I reckon I'd have to hard strip the paint with chemicals and start over on that part, another day maybe. Weird too how the pillar turned a slight off-white colour and they weren't baked other than sitting in the airing cupboard to cure the paint. Again, it'll wait

Funny how bright sunlight brings the eye sharply to any slight blemish in the finish 😢 but overall it's pretty good and am pleased with the final result. It can always be done again in the future should it need it and I'll have learned how not to do some of the bits, esp the part about patience and light coats and wait... and NOT TO BAKE the paint!! 😄 

I do think I'll need to sort some better felt for the case though as I can see some has lifted away. I'd like to better cover the sharp screw ends to protect the paint for a start, but it can wait for now. Also a place to stow the 32mm accessories (25+15 eyepiece and 3x barlow) that are dedicated to this scope, perhaps foam fit the wee box in the corner to hold them and the knuckle so they're safe and secure.

Anyways, hope you enjoyed a few laughs at the goofs and perhaps useful a reference if anyone else want to do the same 🙂 

edit: Oh yeah, still got to collimate and then set the finder aim but that can wait for another day too...

Edited July 30, 2020 by DaveL59

[markse68]

Looks great from here Dave  Nice feeling to finish a project like that- congrats

Mark

[DaveL59]

thanks Mark, it came out pretty good in the end, reassembly is pretty simple, literally reverse of dismantling and no odd bits left over at the end either, tho I was tempted to post a pic of some odds and ends and pose a question just for fun 😉 

Just need to collimate it now and tidy some of the felt in the box. Ordered another EC110 nitrile end cap so it has matching ends, tho it will mean the finder can't fully retract with the cap fitted. Still fits fine into the case tho but am thinking about how to make a dual-cap arrangement so the end of the OTA and the finder can be covered together. Perhaps glue a plate onto the larger cap to attach the smaller one after cutting that to suit. Will be nice to get it out under the stars and see how it performs after the overhaul, especially with Jupiter and Saturn showing in the evening and the moon leading them across too, just the timing after the op but with this little scope I reckon I can move it in bits easily enough.

Also ordered an EC120 for the 100RS, it's  a little too wide but some felt should see it fit over the objective with the dew shield removed for storage/transport. Was never comfortable with the objective exposed in the box so perhaps an original cap went walkies over the years under prev ownership.

[DaveL59]

one more thing to mention with this scope. With the finder being built-in to the main focuser, the intention is that the finder and main scope should be parafocal so you can seamlessly switch between the two and not have to fiddle with focus. Now having reassembled I find there is a focus shift needed which I'll adjust out. Basically loosen off the grub screw and adjust the finder objective in/out as needed, tighten the grub screw and you're all set.

Nicely thought out design on this little scope 🙂 

That finder is quite good too, I've even forgotten to pull it outward in the past and was looking at Venus via the finder instead of thru the OTA, even barlowed up and still getting a pretty good image which was a surprise!

[markse68]

11 hours ago, DaveL59 said:

That finder is quite good too, I've even forgotten to pull it outward in the past and was looking at Venus via the finder instead of thru the OTA, even barlowed up and still getting a pretty good image which was a surprise!

What diameter is the objective Dave? Same optics as the Tal-1 finder? I like my Tal-1 finder very much

Mark

[DaveL59]

hmm I never checked, turns out it is 25mm according to this site:

http://rus.telescopes.ru/product.html?cat=1&prod=10

 

[DaveL59]

decided to set up the TAL-M so its ready to pop out in the garden later if the clouds co-operate. Modified a lens cap by trimming away a small section of the edge such that it will sit on the finder objective end and not snag the nitrile cap. Holds fine and a snug fit so I guess that'll do as a solution and no real need to rig a plate to fix the 2 caps together and look tacky (excuse the pun).

Then I pondered - the OTA on this baby scope is 110mm and the TAL100RS is about the same, hmmm so I decided to see what happens...

Not exactly well balanced tho felt quite stable and most likely way too big a load for the mount, but a mod to rig an extra counterweight under the Alt-AZ head and it might almost make an easy transport mount for the big frac. The feet may be a little short to trust tho, wonder if the TAL-1 feet would fit the pier to improve that...?

Wow the wide-angle on this phone and parallax from the angle taken sure makes the old vintage scope look long compared to the TAL, they are in fact around the same at 96-100mm long.

As you can probably tell, the conservatory is the scope store and cats' room 😉 Well the kitties vacate when it gets too hot on sunny days, thankfully as 45-52C is a bit much for anyone.

Of course now I've done all this I see the cloud gods have decided to lob some more cotton wool into the skies, typical huh!

Edited August 1, 2020 by DaveL59

[DaveL59]

Well after clouds earlier when things were better placed, I popped the scope out just a few mins back and could just get Saturn above the fence, Jupiter and moon behind the oak tree so obscured. Tweaked the finder focus and aim which is fun in the dark finding the tiny grub screws, but now they act as expected. Saturn looked as lovely as ever so was a nice target to test against, tho I stayed with the 25mm plossl as time was limited before the oak was again in the way.

So I think I'm now all finished on the refurb, mirrors collimated and finder focus and aim set. Easily able to just pick up and pop out into the garden and enjoy the views, happy days 🙂 

[DaveL59]

was thinking last night about the one missing component (well apart from the spanner) for the optical train on this scope - the "mount" or focuser extension tube (top left) which allows you to reach a higher magnification. Browsing another thread here I found some information as per pic below

Now being 32mm non-standard it's not quite as simple as buying a standard extension tube and possibly modifying it as while it may fit in the focuser the other components won't fit into the 1.25-inch tube without boring it out a little, not simple without a lathe. The spec arrangement is the extension sits before the barlow as below.

Then I remembered, when I bought the TAL-1 for the 32mm eyepiece set it also has a barlow, but I can't use it in the M as it is wider at the nose. Now since I've modded the TAL-1 for 1.25-inch eyepieces and focuser this 32mm x3 barlow is redundant and I wonder if I can modify that to become the missing extension piece.

It'd be a touch longer than the original "mount" tube but if I can remove the nose end carrying the lens it might just work. Problem seems to be that it seems to be machined as a single piece rather than the nose end screwed into the barrel. Even the lenses look to be cemented in place, no regular rings to be able to remove them:

TAL-M barlow internal

TAL-1 barlow internal

Looking like the only way to fettle this from what I have would be to hack the nose end off the TAL-1 32mm barlow and sacrifice a part that is now rare to find, which would be a real shame I think. I was hoping that nose end and taper back to the main body would have just unscrewed but seems not. Anyone have any ideas on how this might dismantle, if at all?

An alternative would be to try make something up. I can find Acrylic tube that has 32mm OD and another OD 38mm & ID 32mm that I guess I could make a stepped tube, flock the internals and it might work ok. Would feel tacky compared to the nice solid metal of the rest of the scope but preserve rather than sacrifice an original barlow at least.

I recall a couple months back using the TAL-1 barlow inserted into the TAL-M barlow and got good views of Venus thru that crazy combo, will have to check that this works or if memory fails me but if it does then perhaps that's a better solution than knocking up a plastic tube solution...?

Edited August 3, 2020 by DaveL59

[Stu]

On 15/07/2020 at 15:45, DaveL59 said:

the smaller Alcor (65mm) as Stu has (the peashooter)

Err hmmm, it’s actually a light thimble, the Telementor is the peashooter 🤣🤣