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Gem or Junk? Kenko SC125L SCT

Catadioptric Classic Equipment SCT
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#1 Bomber Bob

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Posted 25 November 2021 - 08:51 AM

Ole BB scores another oddball...

 

1980s Kenko SC125L F14.4 SCT:

 

Kenko SC125L A01 - Kit.jpg Kenko SC125L A03 - Label CU.jpg Kenko SC125L A05 - Optics Condition.jpg

 

Been through a lot of CATs, but those were generally faster -- F10 to F8.  What was Kenko thinking with this one?

 

It'll be at The Swamp soon, and we'll find out.  My First Thought:  More refractor-like than the C5 or Kenko 125C?

 

As I posted in the Finds thread, I've had that EQ before, on the B&L / Bushnell Banner 1000 (80mm EQ Kit), and with the quartz drive option.  IMO, it was the best part of that kit.  Will this Kenko be the same?


Edited by Bomber Bob, 25 November 2021 - 08:54 AM.

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#2 CHASLX200

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Posted 25 November 2021 - 08:56 AM

Never seen one.



#3 Bomber Bob

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Posted 25 November 2021 - 09:39 AM

Same here.  I think it's rarer than that Kenko 125C (Corrected Dall-Kirkham) that I had...

 

The 125C had some refractor-like views, and did very very well with my RKEs -- hoping this SCT is at least that good.


Edited by Bomber Bob, 25 November 2021 - 09:40 AM.

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#4 sdedalus83

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Posted 25 November 2021 - 10:53 AM

The CO looks like it’s around 33% and the tube is longer than a C5, so it might have better contrast, should have less coma, and will have less field curvature. Hopefully it performs like a nice Rumak.


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#5 Bomber Bob

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Posted 25 November 2021 - 12:02 PM

I'm thinking for its first SxS Test, I'll put it up against my same-era C102 F10 -- see how it does...

 

However, if does outstanding in its Solo Tests, I'll use the FC-100...  (Hey!  I can dream, right?)

 

BIF:  Seller informed me that the tripod was damaged, and not worth shipping:

 

Kenko SC125L AS07 - Tripod Legs and Tray.jpg

 

This is not the original wood tripod...  I told him to scrap it. 

 

This IS the correct wood tripod:

 

Bushnell80mmRefractor-S2.jpg

 

(Ain't that black Banner 80mm with its LONG dewshield a pretty scope?)

 

I have the Eagle Surveyor legs from my VG2.  And, I figured it would make for a smaller box.  ZEN packed both the SC125L & TS-50 together.  Fingers crossed that they took extra care with the corrector!  

 

-----------------------------------------

 

UPS says it'll be here by 2000L tomorrow (Friday).


Edited by Bomber Bob, 25 November 2021 - 07:36 PM.

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#6 Eric P

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Posted 25 November 2021 - 07:12 PM

I believe these were a result of Kenko acquiring JSO though this model has a longer fl vs the classic JSO 5 inch. Can’t wait to see the glamour shot on top of the Kenko NES.
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#7 Bomber Bob

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Posted 25 November 2021 - 07:35 PM

OOooooo... JSO optics?  That would be sweet.

 

Honestly, for what I paid, the EQ alone is worth the deal.


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#8 ccwemyss

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Posted 25 November 2021 - 11:17 PM

Having sold JSOs in the shop, I did notice a resemblance. But the rear cell of this one is more rounded at the edges, has a longer tailpiece, and the focuser housing isn't as pronounced. The JSO secondary holder had more of a rim. And all of the ones we sold were f10. Here's a nice article about them:

 

https://www.cloudyni...ptics-sct-r1527

 

So if Kenko produced these through their JSO acquisition, they must have done a substantial redesign. 

 

Chip W. 


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#9 Terra Nova

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Posted 26 November 2021 - 10:28 AM

I could forgo the scope and tripod but that mount is very nice! It really does deserve a set of nice wooden legs and tray.


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#10 Bomber Bob

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Posted 26 November 2021 - 10:52 AM

Thanks for the info, chip.  I'm hoping there'll be some kind of markings on the primary to help assign a maker...

 

Terra, just wait till I get her all cleaned & polished -- make her PurrDee!

 

IIRC, the load capacity was similar to a Vixen Polaris.  IF it's good enough, I'll start casually shopping for the Quartz Drive -- talk about Hen's Teeth!!  It's been hard enough to track down Mizar MMD's.


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#11 Bomber Bob

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Posted 26 November 2021 - 06:33 PM

Dusty, Rusty, & Scratchy -- Delivery:

 

Kenko SC125L S01 - Delivery (OTA LS).jpg Kenko SC125L S02 - Delivery (OTA RS).jpg Kenko SC125L S03 - Delivery (OTA BTM).jpg Kenko SC125L S04 - Delivery (OTA Back Plate).jpg Kenko SC125L S10 - Delivery (OTA Focuser Tubes).jpg

 

I didn't clean anything before taking these pix.

 

Back Plate:  Uses a standard 42mm tube, a step down ring to 36.4mm, so a Vixen 1.25" adapter will fit.  I like that.


Edited by Bomber Bob, 26 November 2021 - 06:38 PM.

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#12 Bomber Bob

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Posted 26 November 2021 - 06:34 PM

Undamaged Corrector:

 

Kenko SC125L S06 - Delivery (OTA Corrector).jpg Kenko SC125L S07 - Delivery (OTA Corrector).jpg Kenko SC125L S08 - Delivery (OTA Corrector).jpg Kenko SC125L S09 - Delivery (OTA Corrector).jpg

 

It's not as dirty as the pix would suggest.

 

Both Mirrors look untouched, and coatings look new -- not bad after 40 years!


Edited by Bomber Bob, 26 November 2021 - 06:41 PM.

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#13 Bomber Bob

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Posted 26 November 2021 - 06:36 PM

Kenko NES EQ:

 

Kenko SC125L P12 - Delivery (EQ LS).jpg Kenko SC125L S15 - Delivery (EQ RS).jpg Kenko SC125L S14 - Delivery (EQ LS ZM).jpg

 

This IS the Banner 1000 EQ, but with a few differences:

 

- Vixen Dovetail Clamp rather the flat plate that the tube rings bolt to.

- Axis Clamps on the Banner are plastic, but on the NES are cast aluminum.  (My RA Clamp cracked on one side!)

- IIRC, the Banner didn't have the castings to attach a DEC Axis Drive on the right side.  So... there may be an NES Dual-Axis Drive System out there, somewhere...

 

This is a larger EQ than I remembered:  The diameter of the largest part of each axis housing is 89mm -- rather like its predecessor, the KES EQ.

 

No load on the mount yet, but each axis is slick-smooth.  If it's like the Banner, it'll be easy to use -- even in sweeping -- but the OTA will have to be balanced.


Edited by Bomber Bob, 26 November 2021 - 06:48 PM.

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#14 sdedalus83

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Posted 26 November 2021 - 07:58 PM

Kenko NES EQ:

- IIRC, the Banner didn't have the castings to attach a DEC Axis Drive on the right side.  So... there may be an NES Dual-Axis Drive System out there, somewhere....

I’m pretty sure I’ve seen them.



#15 Bomber Bob

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Posted 27 November 2021 - 01:02 PM

OTA Cleaning:

 

Kenko SC125L S01 - Restore (Disassembled Dirty).jpg Kenko SC125L S02 - Restore (Optics Dirty).jpg Kenko SC125L S03 - Restore (Primary Assembly).jpg Kenko SC125L S04 - Restore (Corrector).jpg Kenko SC125L S05 - Restore (Assembled Clean).jpg Kenko SC125L S06 - Restore (Assembled Clean).jpg

 

Taking a well-deserved break -- been at this pretty much since 7AM.

 

Here's some Specs...

 

Corrector Clear Aperture:  125mm
Corrector Diameter:  134mm
Primary Mirror Diameter:  130mm
Secondary Mirror Diameter:  44mm

Tube Length:  280mm

Tube Diameter:  140mm (outer)  /  132mm (inner)
Tube Thickness:  4mm 
Tube Weight:  3.2 lbs
OTA Weight:  6 lbs

 

Thank the Lord!  I didn't have to touch the mirrors -- puffer removed the dust & paint flecks.  Coatings look pristine.  The Corrector had 2 greasy finger prints on it...  Took a bunch of tissues + Nikon Lens Cleaner to get those off.

 

The Primary Mirror rides on a wide metal disk with an arm for the brass screw.  I saw no way to adjust tilt, but fully extended to the baffle ring, its distance from the base was consistent to sub-millimeter accuracy (about the best I can measure it).  No Maker's Mark on the Primary -- dang it!  The UP Arrow on the edge; and, there's what looks like an ink pattern stamped on the back -- it's a faded black circle with very faint something in the center.  Nothing definitive.

 

The Photo Tripod Plate & Finder (not included) bolt to the base.  The Tripod Plate has 3 x 1/4-20 threaded holes, but the Kenko dovetail has only 1 center hole, and it has rotated on it often in the past -- scraped-off paint down the metal.  Makes no sense, so I drilled 2 more holes in, and used 2 black anodized screws to lock it down.  No more swinging around.


Edited by Bomber Bob, 27 November 2021 - 02:58 PM.

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#16 davidc135

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Posted 27 November 2021 - 03:02 PM

Looking forward to the optical quality tests and seeing how well they tackled making the corrector.  David



#17 Bomber Bob

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Posted 27 November 2021 - 03:23 PM

Kenko NES EQ Cleaned:

 

Kenko SC125L S11 - Restore (NES EQ Clean LS FL.jpg Kenko SC125L S13 - Restore (NES EQ Clean RS FL.jpg

 

I really like the styling of this Kenko!

 

It was mostly dusty.  I did have to polish away small rust flecks on the counterweight shaft -- shiny now.  Ditto for the springy slow-motion cable.  Used the round metal brushes from my rifle cleaning kit to scrub all the rust inside the c/w bore.

 

Kenko SC125L S15 - Restore (NES EQ Clean Dovetail Clamp).jpg

 

Party Pooper!  Kenko's dovetail is about 3mm narrower than the Vixen standard.  OTOH, Kenko did something cool:  The dovetail that attaches to the scope's base plate has a small notch in the back; and, the clamp has a tiny Allen Head screw about in the middle of the clamp's track...  the scope cannot slide out of the clamp.  I like that security -- I get tired out there!


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#18 mikemarotta

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Posted 27 November 2021 - 04:03 PM

Ole BB scores another oddball...

 

1980s Kenko SC125L F14.4 SCT:

 

Thanks for the snapshots. I never heard of the brand, either, but that proves nothing. What counts is the view. You have a 5-inch telescope, f/14. What's not to like? I have heard that Schmidt-Cassegrains can be difficult to collimate, but I have no experience myself. You will have to let us know. You seem fairly adept at taking stuff apart. I trust that it goes back together well. Too bad about the not-Vixen mount, but I share your minor joy at the protecting Allen Head screw: nice touch.

 

Best Regards,

Mike M.


Edited by mikemarotta, 27 November 2021 - 04:07 PM.

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#19 Bomber Bob

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Posted 27 November 2021 - 04:32 PM

Assembled & Ready to Test:

 

Kenko SC125L S21 - Restore (Assembled Complete LS FL).jpg Kenko SC125L S23 - Restore (Assembled Complete RS FL).jpg

 

A white tube again!  Took a lot of Formula 409 + elbow grease to get all the dirt, grease, & grime off.

 

Collimation:  Straight-forward enough, and not quite as sensitive as the Meade 2045.  Fixed Primary, so all the adjustments are at the secondary.  First, I tried slowly rotating the corrector, which did get a slight correction towards center.  Had to use my smallest jeweler's Allen wrench on the 3 grubs.  Got the pattern in the exact center on my trusty old Orion laser, but I'm sure I'll have to make the final tweaks on a star.

 

Vixen 1.25" adapter installed.  And, I was able to attach a standard finder dovetail foot, so I have an RDF on it now for testing. 


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#20 Bomber Bob

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Posted 27 November 2021 - 08:06 PM

Functional Test:

 

GOES 20211127.jpg

 

Star Test?  Are you kidding me?  Jupiter and maybe a half-dozen stars were able to peek through the broken cloud deck.  I tried for it, anyway.  At 64x (RKE 28), Jupiter was all alone -- no moons.  I kept chasing focus, then got very close in a better cloud gap.  Plainly saw the 2 EQ belts, and a hint of the NTB.  Upped it to 86x (RKE 21), and got 4 belts.  Gotta say, the disk was brighter than expected for an F14.4 CAT.  The Galileans made a brief appearance, then... Poof! they were gone.

 

IOW:  Inconclusive first test.  I can tell that collimation is very slightly off, but will have to wait for a better night to do proper star tests & tweaking.

 

NES EQ:  Smooth!  Man, I wish it had that drive, though!  Small fields in this old scope.  Some of the controls are opposite the Mizars, but I'll re-learn it.  Clutches locked, no slips, no jerks, just some vibrations from that springy DEC slo-mo cable.

 

Needs some kind of dewshield:  When I brought it back in the shed, faint haze around the secondary cell...

 

For the first serious star tests, I'll adapt the base plate to a Vixen dovetail, and put it on the Mizar AR-1.


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#21 Bomber Bob

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Posted 28 November 2021 - 01:14 PM

Daytime "Star" Testing...

 

For the New Folks:  There's a microwave tower about 2 miles from my back yard.  It has boxes & hardware on it that -- in a pinch -- can serve as artificial stars.

 

Well, no Sun yesterday by the time I finished cleaning & collimating the SC125.  Today we are (so far) overcast.

 

However, yesterday the SC125 was able to resolve the boxes, lines, and junctions; plus, the frame of the tower.  Resolution looked good at 90x with a UO HD OR 20mm.  My neighborhood is mostly 100+ year old oaks, and they're pretty much bare now; but, there are pines between me and the tower, about 4-5 blocks away.  Green needles, gray-black trunks, black shadows.  Not bad.

 

On a positive note:  The SC125 is as good / better with my RKEs than the Kenko 125C, which in turn was better than both C5s that I had at that time.

 

IME, SCT collimation that's close gets you a low-medium power fuzzy scope.  If you want decent high-power planetary, you have to do that last little bit of alignment towards ideal.  But... I haven't used an 8" or larger SCT, so maybe those overcome ideal with raw aperture.



#22 CHASLX200

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Posted 28 November 2021 - 04:11 PM

All SCT's gotta be dead on with collimation.



#23 Terra Nova

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Posted Today, 07:28 PM

Daytime "Star" Testing...

 

For the New Folks:  There's a microwave tower about 2 miles from my back yard.  It has boxes & hardware on it that -- in a pinch -- can serve as artificial stars.

 

Well, no Sun yesterday by the time I finished cleaning & collimating the SC125.  Today we are (so far) overcast.

 

However, yesterday the SC125 was able to resolve the boxes, lines, and junctions; plus, the frame of the tower.  Resolution looked good at 90x with a UO HD OR 20mm.  My neighborhood is mostly 100+ year old oaks, and they're pretty much bare now; but, there are pines between me and the tower, about 4-5 blocks away.  Green needles, gray-black trunks, black shadows.  Not bad.

 

On a positive note:  The SC125 is as good / better with my RKEs than the Kenko 125C, which in turn was better than both C5s that I had at that time.

 

IME, SCT collimation that's close gets you a low-medium power fuzzy scope.  If you want decent high-power planetary, you have to do that last little bit of alignment towards idealBut... I haven't used an 8" or larger SCT, so maybe those overcome ideal with raw aperture.

You’re forgetting your long gone DX8! ;)




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