238 replies to this topic

[tedbnh]

Cable scope pics.  Very similar to the JC Penney one in the above link, but without slow-motion Az control.  Also no thumbwheel on the altitude lock rod.

 

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[Kasmos]

Cable scope pics.  Very similar to the JC Penney one in the above link, but without slow-motion Az control.  Also no thumbwheel on the altitude lock rod.

It looks like the objective just presses into main tube. Is there another lens (possibly a image erector), at the other end of that assembly?

The closest scopes that look like the rest of it are the ones made by Diiachi Kogaku (DK). It's not exactly the same as the ones we've all seen but it looks like they use the same knobs. You might check the bottom of the focuser for a mark that looks like KD or pehaps there's another makers mark.

 

He're the closest example I found of a DK

 

https://www.cloudyni...bel/?p=10460395

Edited by Kasmos, 20 February 2024 - 08:04 PM.

[RichA]

Don't have it but I think design (novelty) wise these two would be worth it:

 

Takahashi Teegul 60

milk bottle 2.jpg

 

Skyline 60

post-50896-14074175896527.jpg

That mount with the Teegul refractor looks like a later Vixen which looks like the Chinese Sparta.

[photiost]

Impressed with the Pentax J60 objective and the mount is very smooth on both axis !!

.

 

 

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[Terra Nova]

Impressed with the Pentax J60 objective and the mount is very smooth on both axis !!

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Beautiful little scope Frank. I always loved those green J60s. Back when I was collecting I wanted one in the worst way. It just didn’t happen. They don’t come available very often. I think their owners like to hang onto them. That’s a good sign.

[Kasmos]

Beautiful little scope Frank. I always loved those green J60s. Back when I was collecting I wanted one in the worst way. It just didn’t happen. They don’t come available very often. I think their owners like to hang onto them. That’s a good sign.

Yes, it seems like only one or two pop up each year.

I believe it was (Kenko Fan) Bomber Bob who mentioned they were actually made by Kenko.

 

There are some small differences on some of the Kenkos I've seen,

but there are enough similarities to see a connection.

Note the focusers body and knobs

This KDS-609 has the same finder as the Pentax but with different knobs

The Circle K on the sticker is more obvious on the original photo.

 

The mount is embossed Kenko

 

All told, Kenkos are even rarer state side

[Kasmos]

I'm thinking of selling my Pennncrest 60/1000mm so I wanted to test it again by putting it up against a known good objective with comparable specs.

 

The best one for this test was the Soligor (white tube), which is also a 60/1000mm, which now has a Tasco 7TE-5 Objective.

 

The test subject was a transformer label on a power pole. The eyepieces used were a pair of 12.5mm and 9mms

The diagonals and EPs were switched back and forth so that they didn't affect the out come.

 

Considering the excellent views I had previously seen with the Soligor the results were very surprising.

The Soligor's 7TE-5 Objective was probably just a hair sharper but noticeably darker!

It seemed like the small data on the label was just as easy to read with the Penncrest,

but some very small defects (specks), on the label were just slightly more evident with the Soligor. 

Also, the Penncrest's image had a more obvious purple edge on dark shadows. 

 

The difference in brightness might be due to how each scope is baffled so I'll have to inspect them.

I also thought it could be due to the 7TE-5's coatings or lack of them, since I don't remember that objective looking like it had any.

So like the baffles that's another thing I need to look into.

 

I have to admit the results are making it harder to decide whether to sell the Penncrest or not.

I also may have to do this again and see if these results repeat?

 

I thought this was also of interest:

The construction of the OTAs couldn't be more different.

Soligor's OTA 5 lbs. 8 oz.

Penncrest (is half of that) at 2 lbs. 11 oz

 

Remember...

"This discussion is limited to Classic 60mm Japanese 'Achromats' that frequently come up for sale".

Edited by Kasmos, 09 May 2024 - 03:43 PM.

[deSitter]

I'm thinking of selling my Pennncrest 60/1000mm so I wanted to test it again by putting it up against a known good objective with comparable specs.

 

Sol-Pen-1.jpg

The best one for this test was the Soligor (white tube), which is also a 60/1000mm, which now has a Tasco 7TE-5 Objective.

 

Sol-Penn-72.jpg

The test subject was a transformer label on a power pole. The eyepieces used were a pair of 12.5mm and 9mms

The diagonals and EPs were switched back and forth so that they didn't affect the out come.

 

Considering the excellent views I had previously seen with the Soligor the results were very surprising.

The Soligor's 7TE-5 Objective was probably just a hair sharper but noticeably darker!

It seemed like the small data on the label was just as easy to read with the Penncrest,

but some very small defects (specks), on the label were just slightly more evident with the Soligor. 

Also, the Penncrest's image had a more obvious purple edge on dark shadows. 

 

The difference in brightness might be due to how each scope is baffled so I'll have to inspect them.

I also thought it could be due to the 7TE-5's coatings or lack of them, since I don't remember that objective looking like it had any.

So like the baffles that's another thing I need to look into.

 

I have to admit the results are making it harder to decide whether to sell the Penncrest or not.

I also may have to do this again and see if these results repeat?

 

I thought this was also of interest:

The construction of the OTAs couldn't be more different.

Soligor's OTA 5 lbs. 8 oz.

Penncrest (is half of that) at 2 lbs. 11 oz

 

Remember...

"This discussion is limited to Classic 60mm Japanese 'Achromats' that frequently come up for sale".

Is the Penncrest an SYW scope? Sure has that vibe, and they are light! My 3" SYW is MUCH lighter than the same spec AO scope.

 

-drl

[clamchip]

The Soligor is "Noticeably darker" it will be interesting to see what you discover.

I can rattle off a few thoughts but I know you are already thinking the same things I am.

Here's one you might miss, any chance the Penncrest's shorter dew shield may be letting in a little

stray light and making it appear brighter but reducing resolution, and maybe even bringing out more purple.

A restriction in the Soligor makes the most sense. Baffles, the focuser assy., less bright, less color, and

better resolution.

 

Robert 

[Kasmos]

Is the Penncrest an SYW scope? Sure has that vibe, and they are light! My 3" SYW is MUCH lighter than the same spec AO scope.

 

-drl

Nope, Towa.

[Kasmos]

The Soligor is "Noticeably darker" it will be interesting to see what you discover.

I can rattle off a few thoughts but I know you are already thinking the same things I am.

Here's one you might miss, any chance the Penncrest's shorter dew shield may be letting in a little

stray light and making it appear brighter but reducing resolution, and maybe even bringing out more purple.

A restriction in the Soligor makes the most sense. Baffles, the focuser assy., less bright, less color, and

better resolution.

 

Robert 

I wouldn't have thought so, but I could be wrong...

I have some temporay cardboard longer dewshields shields that I use at night so I could try one and see.

Also, even though the scopes were really close together, I wondered if the Sunlight was reflecting a bit more towards it than the other.

So I adjusted them even closer together, but maybe I should have completely switched their positions?

[jkmccarthy]

I expect the answer is yes but I'll ask anyway -- did you swap the prism diagonals + eyepieces between scopes during your testing (to confirm the darker view remained with the Soligor) ?

 

Inside one Vixen 60L refractor OTA I purchased from Japan I found a surprisingly long length of spider (silkworm?) web running axially between a pair of internal baffles (after first spotting it as uneven darkening in out-of-focus star images : - ).

 

Clear Skies,

 

         -- Jim

Edited by jkmccarthy, 09 May 2024 - 08:00 PM.

[Kasmos]

I went out and check both scopes

 

It's hard to completely capture in a photograph, but visually it was easy to see that the baffles were cutting off more of the aperture on the Soligor.

The illuminated exit aperture is football shaped in the photos as they get more clipped towards the edge of the lens.

You can see it getting clipped more and being cut off completely further from the edge of the lens on the Soligor.

In person, if I look where it's still completely round, it's much farther from the edge than with the Penncrest.

 

Both OTAs only have two baffles. One in the main tube and one in the pull tube.

The baffle in the Penncrest's main tube looks pretty far down from the objective and closer to the focuser.

Now that I mentioned it, I may try and get some rough measurements.

 

It might also be interesting to reposition them in the Soligor to see if it then matches the brightness of the Penncrest.

[Kasmos]

I expect the answer is yes but I'll ask anyway -- did you swap the prism diagonals + eyepieces between scopes during your testing (to confirm the darker view remained with the Soligor) ?

 

Inside one Vixen 60L refractor OTA I purchased from Japan I found a surprisingly long length of spider (silkworm?) web running axially between a pair of internal baffles (after first spotting it as uneven darkening in out-of-focus star images : - ).

 

Clear Skies,

 

         -- Jim

I guess you missed it. I mentioned switching both the diagonals and the eyepieces back and forth.