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Very unusual Tasco Terrastro 50/600

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#26 CharlieB

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Posted 02 April 2013 - 09:50 AM

Yes. 50/700. It's a later scope from the early 80's, I think. The finder doesn't swing like the older 50mm.

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#27 terraclarke

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Posted 02 April 2013 - 10:55 AM

I love small, well made scopes. They are so cool. You got a beauty there Charlie.

#28 gelkin

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Posted 02 April 2013 - 12:13 PM

Very interesting little scope Charlie. Congrats on a wonderful buy. :bow:

#29 CharlieB

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Posted 02 April 2013 - 12:32 PM

Thanks. I hope I can find out more about it, but information is very thin.

#30 CharlieB

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Posted 07 April 2013 - 02:21 PM

Well, I had a chance to test our the optics of the Terrastro cemented doublet. With the rest of the scope so well made, one would expect a good objective, but this one was awful. No sharpness as all, regardless of which side was facing the sky. Couldn't even do a decent star test. Fortunately, I had a spare Tasco 50/600 objective that is very good, and the cell screwed right onto the tube. You have to wonder why so much attention was lavished on the scope mechanics and so little on the objective.

#31 CharlieB

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Posted 06 August 2013 - 12:31 PM

One last small chapter on this little Tasco. The objective had some major optical flaw and was worthless, so I decided to experiment with it just in case it had been cemented together incorrectly. I put it into a pot of water and heated it up slowly. After about ten minutes, I was able to slide the two elements apart. I cleaned off all the Canadian balsam with some alcohol and the flint & crown were clean as could be. I tried flipping the crown, but it was very obvious the surfaces didn't mate. I then tried the old rotating lens process and just stuck three very thin pieces of foil as spacers in lieu of glue. I stuck it back into its cell and screwed it back onto the tube. I was greeted with a sharp, contrasty image! I then rotated the two halves back into their original alignment and the image was even better. It had to have been the balsam that was causing the problem, or perhaps there was a bit of wedge between the glued halves. In any case, I am very happy with the end result. Has anyone else experienced this kind of problem before?

#32 terraclarke

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Posted 06 August 2013 - 01:19 PM

Great news Charlie. I'm glad it was a happy ending (and a happy beginning) for such a wonderful little scope.

#33 mikey cee

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Posted 06 August 2013 - 03:32 PM

Too bad the folks who put the instruction sheet together couldn't get it mounted properly for a photo. :foreheadslap: Oh well live and never learn. :smirk: Mike

#34 terraclarke

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Posted 06 August 2013 - 03:47 PM

Too bad the folks who put the instruction sheet together couldn't get it mounted properly for a photo. :foreheadslap: Oh well live and never learn. :smirk: Mike


Same people must have assembled the objective as well. :roflmao:

#35 CharlieB

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Posted 06 August 2013 - 04:06 PM

That's actually the model designed for below-the-horizon viewing.

#36 strdst

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Posted 23 August 2013 - 12:41 AM

Hi Charlie,

Mine arrived yesterday (eBay high bid) With it came thunder and lightning, clouds and rain. Always a good sign! :lol:

Here she is with my recently stripped of bad coatings Swift 839 on a Tasco 7te-5 mount... clouds and rain, lightning and thunder...

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#37 CharlieB

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Posted 23 August 2013 - 06:43 AM

Those a good looking pair of scopes you have there. That Terrastro sure is a solidly built scope, isn't it? And it packs up into as small, easily transportable case. Perfect grab & go. Let me know how the optics are. Was there any indication of the age of the scope?

#38 Glassthrower

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Posted 25 August 2013 - 02:47 PM

Nice find. This is a late 1950's, early 1960's Tasco scope. I think the maker is early Mizar, although they weren't called Mizar then. I had one similar to this several years back and it was built like a tank compared to later Tasco offerings. Optically it was very sharp. It's a keeper. :)

I later used mine as a piggyback guidescope on a larger 3" refractor. It served well and was eventually replaced by a 50mm early Asahi-Pentax refractor - one of the few small scopes of that period that could beat the little Tasco's optics.

Best regards and clear dark skies,

MikeG

#39 CharlieB

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Posted 25 August 2013 - 03:41 PM

Thanks for the great information. I thought it might be from around that vintage, but wasn't sure. Not only are they well built, but they are very portable in that little box. I would love to find one of the Asahi scopes (as well as a couple of other 50mm scopes).

#40 Glassthrower

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Posted 29 August 2013 - 05:09 PM

Hi Charlie,

Here are a couple of pics of my old Tasco of similar vintage.

I haven't looked at these in many years, so this will be a trip down memory lane. New relevant information might be revealed. :)

...

Ok, new info already. Scratch what I said about Mizar. I was completely wrong! :tonofbricks:

It was Towa, not Mizar that I was thinking of.

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#41 Glassthrower

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Posted 29 August 2013 - 05:11 PM

Another - mounted on a vintage Towa small EQ mount. I purchased the mount and OTA seperately. When I bought the OTA, the only included accessories were the finder, diagonal, and an eyepiece or two.

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#42 Glassthrower

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Posted 29 August 2013 - 05:20 PM

Here is a shot of the Tasco OTA. As you can see, it was part of a lot of small refractors that I had at the time. Yes, it is a sickness, I am aware of that. :lol:

Notice, it had the same Alt-Az mounting brackets as your 50mm Terrestrial-Astro tube. I removed those, covered the holes and repainted the tube. I mounted it on a small EQ using a clamshell.

The top two scopes were junkers. Later Taiwan and China-made scopes with dubious optics and lots of plastic parts. The top one was branded "Simmons" and the second one from the top was branded "Meade Polaris". The third, green, scope is a vintage Sears 60mm that had really good optics and few plastic parts. That one ended up with another CN member. I don't recall where the others are now.

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#43 Glassthrower

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Posted 29 August 2013 - 05:22 PM

Another shot of the Tasco rig, showing the tripod.

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#44 Glassthrower

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Posted 29 August 2013 - 05:26 PM

The same Tasco, showing a close-up of the mounting arrangement.

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#45 CharlieB

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Posted 29 August 2013 - 06:09 PM

The best part about that mount is the 60mm clamshell. It's easy to mount onto a Vixen dovetail and use it on many other mounts. Now if I could just find one just like it that fits a 50mm scope...

#46 Glassthrower

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Posted 30 August 2013 - 11:40 AM

The best part about that mount is the 60mm clamshell. It's easy to mount onto a Vixen dovetail and use it on many other mounts. Now if I could just find one just like it that fits a 50mm scope...


I had this same problem because I also owned a few 50mm scopes that I was particularly fond of, especially the Asahi-Pentax (which you also see branded as "Jupiter" occasionally). I wanted to use it with my old Japanese GEM mounts, but couldn't find a ready-made solution to fit the configuration. I found two ways to work around this :

1) simply put a shim the inside of the OTA into the clamshell. You can make a rubber o-ring to build up the diameter of the tube and put that around the tube and then clamp the clamshell around the entire thing. This works, but might have a little play in it.

2) Or, scrap the idea of a clamshell and put generic 50mm split rings (the Scope Stuff used to sell for super-finders) on a Vixen-compatible accessory bar. I'm not sure if Scope Stuff still sells those - this was many years ago.

See this photo. It shows a similar arrangement of split rings, accessory bar, and Vixen SP mount. If there is any play in the diameter of the split rings, just use shims to snug-up the difference. :)

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#47 Glassthrower

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Posted 30 August 2013 - 11:47 AM

The bottom Vixen tube is mounted to the SP head using split rings bolted directly to the head with no dovetail bar involved.

The piggyback Pentax tube is mounted to the larger Vixen via a generic Vixen-compatible accessory bar and 60mm superfinder split-rings with nylon adjustment bolts. Once I had the 50mm Pentax tube centered and locked into the split finder-rings, I'd leave it there and just use the generic accessory bar as an adhoc dovetail. I could mount it directly to the SP mount head without using the larger Vixen scope underneath it, if needed.

Total cost wasn't much either. There are 50mm vintage clamshells of the same type, from the same period. But they are a little harder to find, because most smaller tubes like that were mounted onto Alt-Az mounts, and the brackets mounted onto the sides of the OTA were more popular (and cheaper to make) than the clamshell arrangement.

Best regards and clear skies,

MikeG

#48 strdst

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Posted 04 September 2013 - 10:43 PM

As I posted in page 2 of this thread, (by synchronicity), while CharlieB's thread was active, another same vintage terra/astro Tasco 50X600 scope appeared on eBay. I bought it primarily for the mount and tripod in the event the optics were less than advertised back in the day. As found, they are good but certainly not crazy good.

I have a few 50 mm scopes. A Swift 838 which is fine to crazy good and the others. The others mostly came on tabletop tripods and optically have been surprisingly poor quality. The older scopes are quite well made mechanically. very heavy OTA construction... and will fit the Tasco yoke quite well. Except the Sears which is of a much more recent vintage and doesn't conform hardwarily.

Only one objective stands out as pretty darn good. Anyone wanna guess which scope it is attached to?

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#49 mgwhittle

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Posted 05 September 2013 - 09:15 AM

I say the Stellar. Those focus knobs are a beautiful piece of machining. You would think if that much work went into the focus knobs, then the lens got some serious attention during polishing.

#50 CharlieB

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Posted 05 September 2013 - 09:24 AM

My guess, too. Looks like it might be a Asahi-Pentax rebrand, although I've seen some very nice Orbits, too.






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