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Royal Astro Optics 76/1200 restoration

classic equipment mount refractor tripod
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#1 Barnsey123

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Posted 31 August 2020 - 04:23 AM

Hi All,

Thought you might like to see some pics of an RAO 76/1200 I've recently acquired for restoration.  The previous owner has had it from new (purchased back in the 70's) but it has been knocked about a bit and badly stored for years.  Some bits look vandalized (a few of the metal pointers on the dials have been bent right back) and the focus wheel axle is bent.  Back in the day it was modernized to accept 1.25" EP's (there are no original .965 Ep's with it or the original diagonal).  Also no original box and the 'safety thing' from the end of the counterweight bar is missing.

 

The 6x finderscope is almost fine (quality of optics is brilliant except for the 'eye end' where there is some sort of damage like the coating has come off in parts) - mostly round the edge.  This doesn't seem to affect the view.  I had to clean the objective with Baader fluid and the microfibre cloth).

 

The objective of the main scope was COVERED in dust and dirt although the dust cap was present.  No dust cap had been placed on the rear of the scope so there was lots of dust INSIDE the scope.  I removed the lens cell with dew shield attached (cant see how to remove the dew shield on its own). And have cleaned it (very, very gently) using an air blower, a camel hair brush and finally used some baader cleaning fluid on cotton wool pads (better than cotton balls).  I've vaccumed the inside of the tube using a powerful vacuum cleaner with plastic attachments so as not to scratch the inside. 

 

I can't test the optics yet as I daren't put it on it's mount  (the felt has perished where the scope goes).  I think I also need to strip down the mount and re-lube as it hasn't been touched in decades and it all feels a bit stiff (smooth though). 

 

 

 

Questions: 

 

1.I'm thinking of sanding down the tripod legs and using a lighter color stain/varnish but really, should I stay with the original?

 

2. How best to tackle the rusting on the accessory tray (I've soaked the nuts and bolts/washers in vinegar and have cleaned in water/bicarb.).  Should I use a paint stripper and completely repaint it or just touch it up? Same applies to the metal mountings on the tripod legs.

 

3. There are scratches on the scopes white paintwork and parts where the black paint has flaked off from the mount.  Leave alone?

 

4. How do I tackle re-greasing of the mounts gears etc?  Some say use White Lithium Grease others not or should I leave it alone?

 

5. Finally (I think) I am missing the thing on the end of the counterweight bar (safety stop?).  Any thoughts on replacement.  I've tried every screw in my spares box but none fit (either too big or too small).  If I wanted one made what would be the specification (I know very little of such things)?

 

Original tripod
Accessory tray
Knocks and scratches
Counterweight Bar
Focus Wheel
Album: Royal Astro 76/1200
15 images
0 comments

 


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#2 macdonjh

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Posted 31 August 2020 - 07:52 AM

Welcome to Cloudy Nights.

 

There are three major "camps" regarding restoration.  One camp believes in leaving everything as original as possible (preservation).  One camp believes it is acceptable to refinish things in order to bring a scope and/or mount back to "like new" condition (restoration).  One camp believes anything is fair game, modify as you please (modification).

 

Your post makes it sound like you are in either the "restoration" or "preservation" camp.  You own the scope, so it really is up to you which path you follow.  You've posted in the right place.  There are people here who can help you find original parts if you're missing some, or get modern equivalents which will fit (like that screw for the end of your counter weight shaft).

 

My two cents: from the photos you've posted, I'd clean the tripod legs but not refinish them.  The black tripod parts I'd repaint.  I'd be tempted to strip and repaint the telescope as well.  But I'm not sentimental about old paint, and the scope would look good with a fresh black-and-white paint job.



#3 CharlieB

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Posted 31 August 2020 - 08:21 AM

I would repaint the leg hardware just to keep it from further rusting.  I've had good luck using Evaporust on rusted parts.  Here are a before & after.

 

soligor before.jpg

 

soligor after.jpg

 

I've used several types of lubricant on this type of mount.  I have found a brand called "Red & Tacky" works well.  It doesn't seem to harden and is provides a similar damping effect on these older mounts, so there is less slop.

 

As for painting the OTA, that's a personal choice.  I used to paint mine, but found that when I did a good job and the scope looked great, I tended to leave it in the case for fear of scratching a nice finish.  Now, I only paint when a scope is meant for display or when it's very badly chipped & scratched.

 

I'll look around my parts for a toe-saver that fits your mount which you would be welcome to have.  Please post a photo of the mount so I can better judge which kind to look for.

 

Charlie

 


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#4 Barnsey123

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Posted 31 August 2020 - 09:00 AM

I would repaint the leg hardware just to keep it from further rusting.  I've had good luck using Evaporust on rusted parts. 

 

I've used several types of lubricant on this type of mount.  I have found a brand called "Red & Tacky" works well.  It doesn't seem to harden and is provides a similar damping effect on these older mounts, so there is less slop.

 

As for painting the OTA, that's a personal choice.  I used to paint mine, but found that when I did a good job and the scope looked great, I tended to leave it in the case for fear of scratching a nice finish.  Now, I only paint when a scope is meant for display or when it's very badly chipped & scratched.

 

I'll look around my parts for a toe-saver that fits your mount which you would be welcome to have.  Please post a photo of the mount so I can better judge which kind to look for.

 

Charlie

Hi Charlie, thanks for the info (nice result with your paint job)

 

Please see the mount pic.  There are no obvious model numbers or markings on this mount so I hope you can tell what it is from the picture.  I'm new to this game (restoration) and this is my first classic scope I've ever got my hands on so all advice appreciated.

 

If you have a compatible toe-saver I'll gladly pay the postage (I'm in UK)

 

Thanks

Barnsey

 

Attached Thumbnails

  • DSC00341_REDUCED.JPG

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#5 Pete W

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Posted 31 August 2020 - 09:15 AM

Barnsey, a fine looking scope you got there!    Your mount has some similarities to my Royal Astro - Sears 6339a version.  My counterweight shaft is 16mm in diam. and the counterweight safety washer is 17mm in diam. with the screw being an M4 with a 0.7 thread pitch.  The washer is beveled, but I don't think that's very important with regard to its function.  You might be able to grind down a fender washer or even cut out a piece of thick plastic to make a replacement.

 

20200831_085852.jpg   20200831_085816.jpg

 

Sorry for the blurry pics...I only notice their blur when posting them here!

 

Here's a link to a fine post on restoring a Sears 6339a version of the mount - this helped me out quite a bit: 

https://www.cloudyni...ount/?hl= sears

 

Good luck!


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#6 oldmanastro

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Posted 31 August 2020 - 09:22 AM

Congratulations on getting a RAO 76mm f/16. It is a fine telescope with great optics. I did some restoration work on mine some years ago and following your line of questions this is what I did:

 

1. On the tripos legs, I cleaned them very well using mineral spirits and a 00 steel wool pad. Then applied a 50/50 mix of tung oil and mineral spirits using a 0000 steel wool pad. Left it dry for two days. The legs looked as good as new with little if any change in original color. 

 

2. On the accessory tray I stripped all the old paint off, sanded the rust into bare shiny metal, applied a primer and then painted with Rust Oleum Satin Black. It is almost the same as the original. I did the same thing with the tripod legs metal hardware and replaced the corroded screws that hold the hardware with brass ones.

 

3. My tube had few scratches and I decided to leave it alone. In my case the color would have been difficult to match.

 

4. To disassemble, repaint and re-grease the equatorial mount follow the instructions in this link.

https://www.cloudyni...sco-3-eq-mount/

 

 

5. You can place an appropriate washer at the end of the counterweight bar to act as the toe saver.

 

 

 

It is a very nice project and the restored telescope will provide years of service. 

 

Guido


Edited by oldmanastro, 31 August 2020 - 09:31 AM.

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#7 Barnsey123

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Posted 31 August 2020 - 09:24 AM

Welcome to Cloudy Nights.

 

There are three major "camps" regarding restoration.  One camp believes in leaving everything as original as possible (preservation).  One camp believes it is acceptable to refinish things in order to bring a scope and/or mount back to "like new" condition (restoration).  One camp believes anything is fair game, modify as you please (modification).

 

Your post makes it sound like you are in either the "restoration" or "preservation" camp.  You own the scope, so it really is up to you which path you follow.  You've posted in the right place.  There are people here who can help you find original parts if you're missing some, or get modern equivalents which will fit (like that screw for the end of your counter weight shaft).

 

My two cents: from the photos you've posted, I'd clean the tripod legs but not refinish them.  The black tripod parts I'd repaint.  I'd be tempted to strip and repaint the telescope as well.  But I'm not sentimental about old paint, and the scope would look good with a fresh black-and-white paint job.

Hi,

yes, I'm between all those camps and can see the advantages of all.  As I haven't got all the original pieces - and the scope has already been modified - then IMO there isn't much mileage in complete preservation/restoration but I'm a bit of a traditionalist and I think that anything I do has to be at least 'sympathetic' with the original look (it wont get a purple paint job!).  This scope is going to get some use so I need to ensure the wooden legs are in tip-top condition (it wont be sitting in a museum). 

 

So much to do...but yes, I think I've come to the right place.

 

Thanks

 



#8 Barnsey123

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Posted 15 September 2020 - 11:09 AM

Progress.

 

Tripod legs sanded down to bare wood (last sanding was 400 grit) and has had several coats of Tung oil applied with very light 400 grit sandings in-between.  I believe the wood was Philipine White Mahogany. The metal fixings on the tripod including the accessory tray have been de-rusted and coated with smooth satin Hammerite spray paint.  I have to say I made a bit of a mess with that and it is absolutely evil stuff.  If I use it again it will be with great care (tip: Read the instructions FIRST and then start spraying....) mad.gif

 

I cobbled together a new toe-saver for the counterweight bar (original missing) and the slo-mo controls are new.  The scope as pictured has an Altair 1.25" diagonal and a TAL 25mm super-plossl EP (which is excellent BTW).  There was lots of dust and other crud both inside and outside the scope and one or two very slight marks on the objective.  It's been cleaned (gently) with a bulb-blower and Baader Optical cleaning fluid and its micro-fibre cloth. One mark maybe permanent but I'm really hoping it wont affect the image too much.

 

I've used it in the day (seems fine) and  - hopefully - I'll be using it tonight if the weather clears up...it's a bit cloudy...can't wait to see what it's like.  

 

Royal Astro 76/1200 cleaned up
 
Tripod and felt

 

 


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#9 Bomber Bob

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Posted 15 September 2020 - 11:40 AM

Barnsey, I found a tiny Astro Optical glyph / maker's mark stamped on this small part of the DEC Axis tangent arm:

 

Sears 6336 Restore S10L - Tangent Gearing (AO Stamp).jpg Sears 6336 Restore S11L - Tangent Gearing (AO Stamp).jpg

 

My AO is a 1964 Sears 6336 -- the standard 76mm F15 EQ, but on that tall pedestal.  IIRC, a couple of other AO owners found that marking on the same EQ mount part.  Why there?  Who knows!!


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#10 strdst

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Posted 15 September 2020 - 01:28 PM

Love the purple felt! Did you use a special glue?
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#11 Barnsey123

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Posted 16 September 2020 - 02:49 AM

Barnsey, I found a tiny Astro Optical glyph / maker's mark stamped on this small part of the DEC Axis tangent arm:

 

attachicon.gifSears 6336 Restore S10L - Tangent Gearing (AO Stamp).jpgattachicon.gifSears 6336 Restore S11L - Tangent Gearing (AO Stamp).jpgI

 

My AO is a 1964 Sears 6336 -- the standard 76mm F15 EQ, but on that tall pedestal.  IIRC, a couple of other AO owners found that marking on the same EQ mount part.  Why there?  Who knows!!

Next time I have mine apart I'll take a look.  It may be the only makers mark on the **** thing!  I couldn't get into the worm gear section as I couldn't loosen the bolt so will try again at some point (maybe need better tools!)  It's been fun though ;-)
 



#12 Barnsey123

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Posted 16 September 2020 - 03:02 AM

Love the purple felt! Did you use a special glue?

The purple does go well with the black doesn't it? I had a selection of colors which also looked good but I think the purple looks best - somehow more regal and so is in keeping with the 'Royal' in Royal Astro Optics!  Other colors considered: Orange, Red, Yellow, Green.  The original felt which had deteriorated and was detaching from the mount was a dull brown color. I don't like brown...the orange and yellow would be better in the dark though...

 

The glue I got is a no-name general purpose glue which smells and behaves EXACTLY like model-makers glue that I used to use as a kid when putting together plastic model airplane kits.  Unfortunately there is no useful information on the pack it came in.  I just put a generous dollop on in a grid fashion.   The felt was quite thin and some of the glue came through but now it's dried it's not too bad.  If I do it again I'll use less glue.  I have got some thicker felt but it might be too thick - the thin stuff gives a tight enough fit.  A thicker felt might be too much. 


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#13 Defenderslideguitar

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Posted 16 September 2020 - 01:48 PM

Re the spreader tray    I would make  a nice larger wooden one and put the metal one away and keep it for originality

 

I have a 1958 Tasco 10te   and I hate the little metal tray   I will be making a nice wooden one similar to the one on the 1959 Unitron

 

 

 Yes love the purple

Attached Thumbnails

  • unitron140traythumbnail.jpg

Edited by Defenderslideguitar, 16 September 2020 - 06:25 PM.

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#14 cavecollector

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Posted 16 September 2020 - 04:42 PM

What dimensions is your tray? Any chance you started a tray thread? Seriously dude, that's pretty awesome I would love to learn more.

 

Re the spreader tray    I would make  a nice larger wooden one and put the metal one away and keep it for originality

 

I have a 1958 Tasco 10te   and I hate the little metal tray   I will be making a nice wooden one similar to the one on the 1958 Unitron

 

 

 Yes love the purple



#15 Defenderslideguitar

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Posted 16 September 2020 - 06:01 PM

Barnsey123   possibly  make  a wooden tray?

 

Not to deviate to much from your   original thread   but  my suggestion about saving the metal tray and making a better one was inspired by another thread  link below

 

Cave collector        see the link below  I am not skilled at making tripods or tripod trays  but I am giving it a go.....

 

See the fine work skilled woodworkers  like Garyth64 and Roscoe and others  here in this thread

 

 

https://www.cloudyni...#entry8760814  

 

 

see trays like   Garyth64 and Roscoe's Red Molly  and others 

 

 for my 76mm Tasco10te  I just want to duplicate the wooden tray on my Unitron 142 mount

 

pic one Garyth64's tray

pic two  Roscoe's tray

pic three Roscoe's red Molly

pic four Rcwolpert  tripod

Attached Thumbnails

  • Gary64th traypost-243348-0-97970100-1503861856.jpg
  • Roscoe's tripodtraypost-66369-0-59310100-1530282762.jpg
  • Roscoepost-66369-0-98820200-1530315029.jpg
  • Rcwolbert.jpg

Edited by Defenderslideguitar, 16 September 2020 - 07:06 PM.

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#16 Defenderslideguitar

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Posted 16 September 2020 - 06:08 PM

Here's my 76mm Tasco 10te 1958  and the 1959 Unitron 140 on the 142 mount  compare the trays   this is why I suggest the OP save the little metal one and get a better one

 

pic one Unitron 140

pic two Unitron 142 tray

 

Pic three   Unitron and Tasco      

Attached Thumbnails

  • Unitron142mountpic5IMG_7487.jpg
  • Unitron142trayandchainIMG_7496 (1).jpg
  • UnitronTascothumbnail.jpg

Edited by Defenderslideguitar, 16 September 2020 - 06:12 PM.

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#17 Kokatha man

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Posted 16 September 2020 - 08:06 PM

A person here in Oz (pretty sure it was Melbourne) posted a long thread here last year chronicling the complete strip-down & restoration of one of these scopes...it might be worthwhile as a reference for anything further you might wish to do...

 

Do a search here on CN in this forum using the scope & model/specs to find out more, it was a very thorough article. ;)


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#18 Barnsey123

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Posted 21 September 2020 - 07:44 AM

Like the idea of a wooden accessory tray. The ones in this thread look dead cool.  I really don't like the original metal one.  I might have a stab at that.

 

In meantime, I've mounted the R77 on an HEQ5/Pro using the following gear (purchased from 365astronomy.com in UK)

 

SkyWatcher 76mm Tube Mounting Rings
SkyWatcher MEDIUM 21cm Dovetail Mounting Bar

 

I maybe should have gone for a longer bar but it works OK.  I found the screws supplied with the mounting rings a little short so I may replace with slightly longer ones in future.

These skywatcher rings are VERY snug but I couldn't find anything else (affordable anyway).

 

The scope is optically fine (tested on Jupiter/Saturn last night which were very low in the sky ~15 degrees from UK) no problems.  Was hoping to image Mars last night but was way too tired.  Hopefully tonight.  Will be sticking in my Altair GPCAM 327C cam and - if time allows - my GtVision GXCAM 3EY5.   Really need to test on on the Moon but not visible yet.

 

 

On a Skywatcher HEQ5/Pro
 
RAO R77 on a HEQ5/Pro

 


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#19 Barnsey123

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Posted 22 September 2020 - 05:23 AM

OK, used it last night to image Mars. Blown away by the detail captured with this 3" scope.  Wanted to wait until about 03:00 when MArs would have been at it's highest but just had to goto bed.

 

Imaging using RAO R77 76/1200 on a SQ HEQ5/Pro (with Altair 2x Tele-Extender and Altair 1.25" dialectric diagonal)

 

Rao R77 imaging mars

 

Mars at 22:58

 

mars 20200921 2258

 

Mars at 23:50

 

mars 20200921 2350

 

 

I now need to change the focuser....it was altered back in the day to change it from a .965" focuser to a 1.25" focuser.  The axle is bent and I can't straighten it 100% which means it's all over the place when focusing.  Any ideas? Has anyone ever changed the focuser on on of these?

 

Recommendations appreciated.


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#20 Senex Bibax

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Posted 22 September 2020 - 11:40 AM

A person here in Oz (pretty sure it was Melbourne) posted a long thread here last year chronicling the complete strip-down & restoration of one of these scopes...it might be worthwhile as a reference for anything further you might wish to do...

 

Do a search here on CN in this forum using the scope & model/specs to find out more, it was a very thorough article. wink.gif

I took that thread and cobbled it into a PDF file so i could more easily print it and follow along as I stripped and rebuilt a similar mount for my Sears 6339A (also an RAO 76/1200). I can send it via a PM if you like. The rebuild isn't too difficult, but there are a couple of gotchas.

 

Beautiful images of Mars! I had mine out on Sunday and checked out Saturn and Jupiter, but didn't wait for Mars to rise. Too cold.

 

BTW I can't look at your avatar without picturing Father Jack looking through a telescope and swearing.
 


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#21 Barnsey123

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Posted 23 September 2020 - 04:02 AM


Beautiful images of Mars! I had mine out on Sunday and checked out Saturn and Jupiter, but didn't wait for Mars to rise. Too cold.

 

BTW I can't look at your avatar without picturing Father Jack looking through a telescope and swearing.
 

Feck! Drink! Gobshite! lol.gif


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