80 replies to this topic

[Astrobril]

Thanks! The cabinet has only wood, no signs of styrofoam in the past. The rubber/foam protections on the edges of the wood are completely petrified, so maybe 1962?

Well, if it is the original cabinet, I would say definitely 1962.
I have one from (I think) 1974 and the styrofoam is not very 'pleasant', to say the least. So you should examine if the cabinet is the original and might have been altered by the styrofoam being replaced. My box is dark brown, has a metal 'Royal Tokyo' shield on it and will hold the entire R-74, including the tripod. I always thought that the styrofoam was introduced around 1965/1966 so I guessed mine was from 1974. In a prospectus from 1975 the R-74 isn't listed anymore, so I guess mine is one of the last R-74's.

Edited by Astrobril, 05 January 2021 - 11:25 AM.

[Pete W]

slowly reaching the end :-)

 

After covering the wood with an oil-based stain, I finally applied a furniture restoration wax to even out and soften the shine a little, making it satin and velvety. I don't know if you can see it in the pictures, but I like the effect very much. I can't wait to put it all together ...

Wow, the legs are beautiful!     Excellent work.

[LukaszLu]

Well, if it is the original cabinet, I would say definitely 1962.
I have one from (I think) 1974 and the styrofoam is not very 'pleasant', to say the least. So you should examine if the cabinet is the original and might have been altered by the styrofoam being replaced. My box is dark brown, has a metal 'Royal Tokyo' shield on it and will hold the entire R-74, including the tripod. I always thought that the styrofoam was introduced around 1965/1966 so I guessed mine was from 1974. In a prospectus from 1975 the R-74 isn't listed anymore, so I guess mine is one of the last R-74's.

I think that the presence of wooden partitions and shelves precludes the use of styrofoam fittings. The style of the lettering on the box shield also points to the fifties rather than the seventies. The logo on the box is identical to that on the telescope and to the one on the company folder from the 1950s. Meanwhile, I came across a version of box shield logo which differs significantly from the one shown in the photo - perhaps it was a copy from the 1970s?

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Edited by LukaszLu, 05 January 2021 - 12:11 PM.

[LukaszLu]

Wow, the legs are beautiful!     Excellent work.

Thanks! Renewing the wood, especially in a way that exposes the wood structure, allows focusing attention on it, effectively diverting it from abrasions and losses of varnish on the OTA and mount. An easy way to improve the overall impression :-)

[Astrobril]

I think that the presence of wooden partitions and shelves precludes the use of styrofoam fittings. The style of the lettering on the box shield also points to the fifties rather than the seventies. The logo on the box is identical to that on the telescope and to the one on the company folder from the 1950s. Meanwhile, I came across a version of box shield logo which differs significantly from the one shown in the photo - perhaps it was a copy from the 1970s?

This is the shield from my 1974 R-74. It has the same logo that can be found in the Japanese RAO brochures from 1968 and later. 

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[LukaszLu]

Yes! This is exactly the logo I meant. The lettering under the logo is also much more correct in your version. The inscription 'ASTRONOMICAL TELESCOPE' is more clunky on the older version.

[semlin]

just subscribing to this thread so i can find it.  i have a tasco 10te-5 i found at the local garbage dump in the metal recycling pile which requires much attention so this is a solid gold resource.  

[LukaszLu]

Since people in your area throw the Tasco 10TE into the trash, I wonder what kind of equipment do they keep at home? Tak in every kitchen? ;-)

[Garyth64]

just subscribing to this thread so i can find it.  i have a tasco 10te-5 i found at the local garbage dump in the metal recycling pile which requires much attention so this is a solid gold resource.  

If you can't restore it, or if it's too far gone, it may only be worth parting out,  ,  and I'm sure there are many that may need parts.

[LukaszLu]

Finally, today I had a short moment of clear sky and a chance for First Light!

 

After disassembling and cleaning the lens, I've installed them back not even trying to play with collimation. I tightened the screws just to stabilize the lens - that's all.

 

Well... I must say that I did not expect what I saw today...

 

I had a look at Mars and the Pleiades. 120x magnification with the ortho Zeiss O-10 eyepiece. The planet disc is drawn like a razor blade. Beautiful, juicy colour "ball". The slight phase is visible. At this magnification and the current planet size, it is difficult to say that you can clearly see details on the surface, but I could clearly see there are darker patches on the surface. Aberration at a level that is difficult to distinguished from slight eyepiece aberration and the blurring caused by air movement.

 

Unfortunately, before I managed to setup my SW 120ED to compare the picture, the sky was overcast again. But I had the impression that the aberration was not clearly much worse than on ED. Even with the ordinary H-6mm eyepiece, the image has not suffered much from aberration while maintaining precision and contrast.

 

Then I managed to get a look at the Pleiades using the wide-angle Polarex MONOCHRO 40mm eyepiece. What a Beauty! Perfect stars, blueish sharp points...

 

My shortest summary of the first impression: YOU DO NOT FEEL THIS INSTRUMENT! You don't feel the optics, the glass, lenses that are between you and the stars - you are just THERE! :-) Honestly, I haven't felt it for years. And now, unexpectedly I've found it again! Maybe just for a moment, until I get used to this incredible instrument?

 

I hope not :-)

Edited by LukaszLu, 08 January 2021 - 05:06 PM.

[CharlieB]

You have now joined the ranks of the classic scope aficionados.  Great post!

 

Charlie

[LukaszLu]

Thank you. It is true that this is the merit of the telescope and not mine - but I am happy to accept this honor! :-)

Edited by LukaszLu, 08 January 2021 - 05:53 PM.

[semlin]

If you can't restore it, or if it's too far gone, it may only be worth parting out,  ,  and I'm sure there are many that may need parts.

 

i am optimistic she will fly again.  i have by dumb luck finagled a pintle shaft for the focusser from another generous member which was up until now my biggest single hurdle.  i also found another scope in closer to ready shape which gave me an excuse to buy the eyepieces and diagonal.

[LukaszLu]

Since I have the opportunity to relax a bit after working on the renovation of this telescope, I thought it would be worth sharing a few tips that I came up with while working.

 

For example, the problem of recreating the black logo on the shield of the tilt adjustment screw. I am not quite sure if the original logo was black, but in later copies (with a quarter of the scale) it was black for sure. Similarly, in the later copies signed with the Tasco brand. It certainly looks much better in this version than the unreadable relief that remained in my case.

 

I used ordinary acrylic paint, the advantage of which is that until it dries, it is water-thinnable. It's easy to remove excess paint, correct mistakes, and finally wash your hands and brush without using smelly solvents. I was surprised how easy it was to get a great effect. I applied a large excess of paint with a small brush, without even trying to be precise. Then I picked up the excess paint with a cotton ball, wiping the face of the shield clean. The acrylic paint remained in the grooves, and when it set, it became waterproof.

 

Hope it will last the next 58 years - until the next renovation!

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Edited by LukaszLu, 09 January 2021 - 07:55 PM.

[LukaszLu]

My next tip will be about the RA brake knob. It turned out that under full load the brake is pressed too lightly to hold the rotation in the RA axis. The length of the threaded pin in the lock knob turned out to be too short.

 

Initially I threw a plain steel nut between the brake plunger and the knob, but since it is much harder than the plunger, it began to destroy its top surface.

 

Eventually, I replaced it with a BB intended for the ASG rifle. Yes - I know, inserting plastic into such a mechanism looks bad, but the same problem applies to the rifle, in which the BB could also get damaged and get stuck in complicated mechanisms if it was made of non-resistant plastic.

 

I will not give anyone a guarantee that such a procedure will not end with crushing the ball and cleaning the entire mechanism - but for me it works very well, additionally preventing some flexibility and allowing for more convenient operation of the knob, which has moved away from the cover surface. Of course, it would be best to insert a pin made of soft metal - brass, for example.

 

Finally, one more note - initially I also applied unnecessary grease to the plunger and its seat in the rim which it is supposed to spread. It turned out that this made it impossible to unlock the brake, which remained "stuck" in its position even after loosening the knob. Apparently this element shouldn't be greased.

 

If you see any mistakes in my comments, please criticize!

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[LukaszLu]

Today I had the opportunity to have another observing session. This time the weather was good and I could easily compare the image of Mars in RAO and the modern 120mm ED. This time I used one 10mm/0,96'' vintage eyepiece (Zeiss O-10) and one modern 9mm/1,25'' wide-angle eyepiece of average quality (Svbony). What can I say ... Maybe something like this:

 

I, the undersigned, declare that I do not see any clear difference in the chromatic aberration between the RAO R-74 and the SW 120ED. :-)

 

Well - maybe mini-mini-mini-mini-slightly larger than on ED? However, it is difficult to assess it quite reliably, because the significant difference in diameter.  120 vs 76 mm means 2.5 times more light! Such a difference also influences the intensity of the aberration effects. Perhaps with a diameter of 76 mm the ED lens would have produced significantly less aberration. My impression however is that the traces of aberration that I see come mainly from the eyepiece, they intensify, for example, with non-axial viewing.

 

I am waiting impatiently for the Moon, which - as a very bright object - should tell the whole truth about the chromatic aberration of this lens!

Edited by LukaszLu, 10 January 2021 - 02:59 PM.

[LukaszLu]

It's no secret that the passion for classic telescopes does not always go hand in hand with the interests of other household members. This simple idea will show them that we care about them too :-)

 

It often happens that the legs of old Japanese tripods are shod with sharp spikes that cut the parquet. The worst case I had was old Unitron / Polarex 114 tripod. It's legs were fitted with a pointed caps made of galvanized sheet.

 

In the case of the R-74 it is a bit better, but the hardware is still very sharp and can leave a mark on the wooden floor every time the telescope is moved.

 

A simple and effective solution turned out to be the use of ordinary children's wooden blocks with a hole of such a size that the angled leg wedges in the hole without reaching the floor.

 

This is previous owner's idea, not mine - the pads came together with the telescope. My contribution was to add felt pads from the bottom. This allows the telescope to be easily pulled across the floor near the exit door. I think it is a great help as the tripod is large and unstable and the telescope is heavy. Moving it is quite a challenge. An additional advantage of the solution for people with pets: the pads collect all the hair on their way very effectively :-)

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Edited by LukaszLu, 13 January 2021 - 10:01 AM.

[Piggyback]

Putting finishing touches to my Royal Astro R74 serial 870976. Thanks to this thread I was able to avoid pitfalls. Great time saver! I was dealing with frozen mechanics, a flipped front lens and general neglect. Love the presence of this scope. Serial No, gold sticker, wooden box, styro inlets indicating 1968 build. First light watching shingles on a rooftop a harsh disappointment. Image nicely focusable yet lots of straylight. Looking down the optical train just one field stop visible halfway down the tube. Asking for advise as to size and position of additional field stops if present in other units. Thanks!

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[Garyth64]

In my ATCO 1254, there are 3 baffles in the main tube and two in the focuser.

 

I'll dig out the 10TE, and take a look. . .

 

In the 10TE, there is only one baffle in the main tube, and none in the focuser.

Edited by Garyth64, 13 January 2021 - 12:14 PM.

[LukaszLu]

Congratulations! Such a beautiful copy is a real decoration of any interior, allowing to enjoy the equipment also on Cloudy Nights :-) I am very glad that this thread turned out to be helpful!

 

In my copy, I found a rolled-up sheet of dark grey sandpaper inserted into the eyepiece sleeve. I took it out for fear that its particles would fall off the surface reaching the lens. However, it's presence was probably no coincidence. The sleeve is blackened but not mat enough. With its exceptionally long length, this is enough to generate strong reflections.

 

I haven't tried to fix it myself yet, but maybe you'll be the first to find a simple (and safe!) way to do it? Maybe plain black paper?

Edited by LukaszLu, 13 January 2021 - 01:00 PM.

[Piggyback]

Actually this is great news as I was pondering the idea that the previous owner may have altered the inner tube. I will think about a solution to this. Now I'm curious if other 76/1200mm specimen suffer from this problem?

[CharlieB]

I've flocked the interior of most all my classic scopes.  The difference in contrast is quite noticeable.  It's usually done in two pieces, each slides up to the baffle.  I also flock the draw tubes.

 

I've also used 120 grit sandpaper painted flat black.  The keeps the particles on the paper.  The results are very good. 

 

Charlie

[LukaszLu]

I've also used 120 grit sandpaper painted flat black.  The keeps the particles on the paper.  The results are very good.

Great idea! Painting the sandpaper did not occur to me...

[Astrobril]

I've flocked the interior of most all my classic scopes.

+1 - great improvement.

[LukaszLu]

It might seem that this hack is well known, but as the example of my copy showed, its rules are not quite understandable for everyone... :-)

 

 

In order to avoid damage to the viewfinder's paintwork, the previous owner decided to protect it from the fixing screws with ... adhesive tape. Not only did this have no effect, but it also led to a permanent yellowish discoloration of the paintwork, that had been absorbing the adhesive over the years.

 

 

Instead of sticking anything to the surface, just wrap it with a strip of plastic, cut off from ordinary packaging! I guarantee that after tightening the screws it will not fall out ;-)

 

Edited by LukaszLu, 15 January 2021 - 08:12 AM.