9694 replies to this topic

[jragsdale]

So.... basically take the human element out of it.

Yeah, that's hard to do as it requires a human to do it, but luckily we have a good community and when a vendor or manufacturer puts their thumb on the scale usually they're called out for it.

[Bomber Bob]

BORG K10-76AB restore done...

 

Lens Cell:

 

 

I had to use a chemical stripper to remove all the old glue.  Then, I tapped & threaded 3 holes for 3mm long #8-32 grub screws, spaced about 120* apart.  Finally, sanded & polished the bumps & such in the 2 plastic castings.

 

Reassembled OTA:

 

 

Harder than anticipated.  The dewshield has gray rubber inserts:  Sky End is a bit thicker & makes a snug fit with the dust cap;  Eye End is thinner, and has a lip that stops the dewshield at the lens cell.  Remember the grease ring?  Well, BORG used some brownish lube on the Eye End gasket, so the dewshield can slide back & forth.  No idea what they used, but I figured out pretty dang quick that I couldn't force the thing down the tube to install the lens cell.  I used clear machine oil, and worked it into the gasket until it would slide without King Kong arm strength.

 

So... BORG expects owners to have a greasy OTA?  I got it positioned, and won't be compacting it any time soon!

 

 

[Bomber Bob]

Daytime star test today for the BORG K10-76 a bust, even after getting the Turret on the focuser tube square:

 

 

So it's either the plastic lens cell, or the lens itself.  Glad I didn't stop my observing last night to troubleshoot it.

 

Odds are, all that yanking & pushing on the sliding dewshield bumped it enough to mess up alignment.

 

BIF:  On the Plus Side, I was reluctant to use my other (& heavier!) 1.25" eyepieces in the Turret.  But the combo plastic + synthetic rubber sleeve holds the barrel tightly -- even the hand-grenade sized Radians!  No slips, even hanging upside-down!

Edited by Bomber Bob, 18 September 2024 - 04:53 PM.

[Terra Nova]

the 3 DX8s I have all have very nice controls.  The focus knobs are nice and big and smooth.  I've gee whizzed with two of the scopes (the other isn't complete), and I see no image shift while focusing.  

 

Still, I predict you'll give it a C at best.  Them correctors are just too rough for a higher grade.

 

-Tim.

Just use it for a cool looking, low power, short 8” light bucket.

[Terra Nova]

Do you believe the 10kg capacity?  A Porta II can handle about 5kg at most, and then only if it's a short scope.  I can overload it easily with an FC-100 just by adding a few heavy accessories.

 

I'd like an inexpensive alt-az mount with slo-mo and more capacity than the Porta II....  so far everything suitable is too expensive to leave outside.

The Porta II, when it was in production, claimed it would handle a 10kg payload. I bought mine in 2010 and have used it a lot since, but I have to agree, the true payload threshold is much closer to 5 than to 10.

[jragsdale]

I recently picked up a nice orange C90 in great shape for $25 locally. Didn't really need it but it's one of those small scopes that's fun to have, doesn't take up much space and usually has good optics. And for that price, who could say no? So I 3D printed a small vixen dovetail to mount to the scope and a solar filter holder to mount some Thousand Oaks solar film. I mounted it in my new alt-az pedestal I made and it's certainly a very convenient grab and go; really light and nice and sharp optics. It'll be fun to have on hand for quick views to check on seeing or solar system viewing.

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[Cavs56]

My first telescope.

[norvegicus]

An excellent moon tool and terrestrial spotting scope.  Not too shabby for planetary.

[jragsdale]

An excellent moon tool and terrestrial spotting scope.  Not too shabby for planetary.

Yeah, should be nice for little things here and there. Also going to try it for birding. 

 

For fun I printed a little finder solar filter too, only 1.5g of filament and used the spare corner scraps from the thousand oaks solar film (have 12 square feet to use up, haha).

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[Cavs56]

I used mine in Yellowstone to watch a breading pair of wolves on their den. They were 1.5 miles away.

[Cavs56]

Bomber Bob gave me a 60mm SYW objective lens. I used a piece of a Sears Discover tube, a Meade lens cell and a finder from I don’t know what. Turned out nice. 420mm will make a nice companion scope.

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[Bomber Bob]

Carton ZO-101 ready for use:

 

 

Since the M64 threaded all the way in, I put a rubber ring around the 2" portion to help protect the Carton's thin wall.  I may have to add another 2" extender for some eyepieces... may get a chance to test it tonight. 

Edited by Bomber Bob, 23 September 2024 - 05:20 PM.

[clamchip]

I noticed a pinched primary when I star tested my new RV-6. Today I removed the mirror and cell to find

out why.

Defocusing a star presented a triangular shaped bull's eye. Hum I said, wow that's pretty bad. The scope

seemed to be working fine, saw 3-4 of Saturn's moons, Polaris B at only 50 power.

The 3 mirror clips were really tight to the mirror face and the mirror clip screws were missing washers so

the screws were too long pushing against the mirror side.

Everything is back together and I'll test again tomorrow night. I imagine having a pinched mirror must 

affect the views. If so this telescope will be super fantastic now. My old RV-6 still holds my personal

record for most Plato craterlets, these RV-6 can really perform.

I cleaned the primary, it has a few permanent freckles but still nice and bright. I found a serial number on

the mirror side, 1113. I also removed and cleaned the finder objective.

I previously cleaned and lubed the cast iron focuser and it sure is sweet. It gives the scope an old school 

feel and sound I like very much.

Robert

 

 

 

[Bomber Bob]

Good views last night -- extenders didn't slip...

 

 

Despite the crazy shape, it's a good 100mm F5 achromat.   Lots of Red, but at 20x, not a show-stopper.

[clamchip]

My RV-6 is ready to go for tonight, I'm so excited I feel like a kid again.

Today I did a close collimation with a glint from a powerline insulator and while I was "on the pole" I found

a thumb nut with some knurl on it and pushed the power up to 254X with good sharp resolution of that knurl.

I'll say it's ready to go!

I'm going to start off with a serious star test, I want to see exactly what I have here. I was cut short at first

light because of the pinched primary, well that's fixed now, I could see that today. Isn't it amazing those thin

little mirror clips can distort the figure of this thick slab of Pyrex.

I'm running out of pictures. Here's the drive box. I have a feeling this telescope was stored in a open carport

where moisture could get at it, it has the ear marks, I know because I have an open carport!

I will eventually remove the rust from and re-blue all the fasteners like I have done in the past on Criterion scopes.

Robert

 

 

 

 

Edited by clamchip, 24 September 2024 - 06:51 PM.

[clamchip]

The RV-6 was fabulous last night.

Great conditions with a bit of high haze, I was able to collimate to perfection and really enjoy the sky.

I can't believe this level of performance for $200, it's no wonder it was a great seller for Criterion for so many years.

Not only high points in optical but an A+ in the fun to operate category too.

You know what's next, what every equipment junkie does, a comparison!

I've been thinking about it all morning, a little like Ford vs Ferrari, RV-6 vs my Jaegers (LOMO) 6 inch Mak.

Robert

 

 

[CHASLX200]

Getting some OTA's and mounts off the flow before the surge from the cane comes in late Thurs in the dark when ya can't see anything,

Edited by CHASLX200, 26 September 2024 - 06:01 AM.

[Bomber Bob]

We got the first arm of rain from Helene at lunch time, so I sat down with the BORG K10-76, and got it as square as possible, given all the flexible plastic parts.  The upper half of the lens cell still shifts, even with 3 grub screws...  add to that, the focuser tube & turret, and I think I know why it was on sale so cheap.  OTOH, if I'm reading the parts chart correctly, I could replace the achro with the 76ED...

[CHASLX200]

Got the scopes up off the floor. Guess it won't won't matter if we get 5ft of water in the house. Show time comes once the storm center goes abeam of me and a wall of water comes in fast once the wind comes around.  

[Terra Nova]

An excellent moon tool and terrestrial spotting scope.  Not too shabby for planetary.

I wouldn’t be quite so generous based on my own experience with one. I was never too impressed. It was fine for a spotter and also worked well for the sun with a front filter, but I didn’t think it was good for much else.

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[Bomber Bob]

Finally!  After all the previous tinkering, I got the Plastic Fantastic BORG 76 collimated, using the daylight tower stars.  Should be able to use it tonight, and verify.  I don't see violet fringe on the shady side of tree limbs & such until about 100x (Radian 7, UO OR 6).  But... I'll let the Summer Triangle be the final judge!

[Kasmos]

I wouldn’t be quite so generous based on my own experience with one. I was never too impressed. It was fine for a spotter and also worked well for the sun with a front filter, but I didn’t think it was good for much else.

Way back in 1979 my C90 Astro was one of my first 3 scopes. My only other choices were to use my 60mm Mayflower 814 or set up the Jaegers/Cave 4", so it got used a lot. Considering it's size I remember it giving me really good views of the planets. Nowdays having too many others to choose from (plus it needs to be serviced), I haven't used it for astronomy for years. I really want and need to test and see what I think of it now. Having said that, I kind of miss the simplicity of only having those 3 scopes. I don't think I'd be happy whittle it down to only three, but 6 or 7 might be a good compromise. 

[norvegicus]

I wouldn’t be quite so generous based on my own experience with one. I was never too impressed. It was fine for a spotter and also worked well for the sun with a front filter, but I didn’t think it was good for much else.

. Yeah I think I got lucky. Mine was a bit more modern than that one.

[norvegicus]

Way back in 1979 my C90 Astro was one of my first 3 scopes. My only other choices were to use my 60mm Mayflower 814 or set up the Jaegers/Cave 4", so it got used a lot. Considering it's size I remember it giving me really good views of the planets. Nowdays having too many others to choose from (plus it needs to be serviced), I haven't used it for astronomy for years. I really want and need to test and see what I think of it now. Having said that, I kind of miss the simplicity of only having those 3 scopes. I don't think I'd be happy whittle it down to only three, but 6 or 7 might be a good compromise.

My Mayflower 814 blew away my C90 for every task. Such a nice scope.

[Steve Allison]

I used to own an orange C90 that was quite sharp- similar to the ETX90 I also had at the time. But every C90 I owned or looked through thereafter was decidedly inferior. Luck of the draw, or some change by Celestron?