Celestron PowerSeeker 127EQ Renovation

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Celestron PowerSeeker 127EQ Renovation

#1

Post by Sky Tinker » Fri Dec 27, 2019 11:55 am

"We’ve had it for months, couldn’t ever say anything through it."
"Might as well have thrown the money out the window."
"You'll never be able to collimate the primary mirror even if you are a magician..."

What might be greater than a magician? Ah, I know, a wizard...

https://media.giphy.com/media/u6tkwLGUL5nAA/giphy.gif

I had read all of the reviews on Amazon.com, but only after having received the kit...
box4.jpg
My own arrived mis-collimated; Polaris...
Polaris.jpg
Polaris.jpg (10.27 KiB) Viewed 505 times
But after its renovation, I saw Jupiter's Great Red Spot, and for the very first time in my life; with any of my telescopes. I can also attest that the bundled 4mm eyepiece, a symmetrical-Ramsden I think, is a treasure in its own right...
accessories.jpg
...the 20mm erect-image, not so much; nor the barlow. To make use of the finder-scope, its yoke should be shimmed...
accessories2.jpg
...not too tightly, nor too loosely, just right rather. It will then align nigh perfectly. True, it's only a 5x24, but not bad.

The kit also came with a CG-2(EQ-1) equatorial mount...
mount2.jpg
I had renovated that, too, with thin bronze-sheet and needle-thrust bearings, but for my smaller telescopes. The mount will never be used with this 127mm telescope, as it's much too small to support it properly. This thread, however, deals with the telescope itself, the OTA only...
catadioptric3.jpg
I got this kit on purpose, rather than unwittingly, for the OTA mainly, and the mount for those smaller. If this is to be your first, or your only telescope, get or have a separate, supportive mount for it; no ifs, ands, or buts.

Regrettably, this kit is most attractive to those first starting out. It's got the short tube -- easy to handle, store and travel with -- but most importantly, it's got that low, low price -- perfect all round, no?

Truth be told, I cannot and will not recommend nor suggest this kit for those first starting out, not ever. The telescope is a veritable Chinese finger-puzzle, and one that I have successfully unravelled. It is an economical alternative to a Celestron C5 Schmidt-Cassegrain. It is also, albeit incognito, a 127mm f/4 Newtonian, and all that that entails.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#2

Post by Sky Tinker » Fri Dec 27, 2019 1:24 pm

5" of aperture is nothing to sneeze at, particularly under Bortle-4 to -5 skies. That combined with a short tube makes for a delightful grab-and-go experience, with a supportive alt-azimuth mount. I found that the telescope combined with this Explore Scientific "Twilight Nano" alt-azimuth, an alt-azimuthal equivalent to an EQ-1, to be quite compact and tight; supportive and well-balanced...
1b.jpg
To transfer the OTA to another mount, I found that all that was needed was a dovetail-bar attached to the tube-rings...
Vixen style2.jpg
...and then, magic. At last, the telescope was free, and to attach to most any and every mount on the planet.

Yes, 5" of aperture is appreciable...
obstruction3.jpg
There are only two other telescopes, that I know of, with a four-stalk cowling like that: the Orion "SpaceProbe" 130, and the Sky-Watcher 130, both made by Synta, both being 130mm f/7 Newtonians, and both with spherical primary-mirrors. This 127mm f/8 catadioptric also has a spherical primary-mirror, and the telescope made by Synta, too.

All of the enhancements and modifications that I made to this telescope are optional, of course, and not really necessary to get good performance out of it. Still...

Working from the front of the telescope to the back, from one end to the other, I began with the cowling...
cowling2.jpg
One thing that I noticed almost immediately is that not a single adjustment-screw for the secondary-stalk and -mirror lined up with the focusser...
hub misalignment.jpg
That's not good. You want one of them aligned, like this for example...
corrected2b.jpg
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I saw threads, and where the secondary-hub joins with the cowling there in the center...
hub threads.jpg
But that's not about to budge with all of that paint, not to mention that the hub was probably super-glued in to boot. There was only one thing to do: strip the cowling...
stripper3.jpg
stripper3.jpg (31.18 KiB) Viewed 498 times
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#3

Post by Sky Tinker » Fri Dec 27, 2019 1:45 pm

Before and after...
cowling5b.jpg
Why, that's a rather nice piece of hardware, and of solid aluminum throughout. After stripping, I still couldn't budge the hub in the center. I took the cowling outside, along with a mini butane-torch, and heated the area right good. I took it back in, and after grasping the edge of the hub along several points with pliers whilst pulling to the left, the hub finally broke free...
cowling7.jpg
Reinstalling the hub took place later. There was one more thing to do to the cowling. Have a look at this 114mm f/8 Newtonian...
kit3.jpg
See that? It has only a single stalk to support the secondary-assembly, and does so quite well being that it's a stalk and not a thin vane. "Why can't I have something like that with this telescope?", I asked myself. With the cowling of this "Bird Jones" telescope, who wants all of those diffraction effects whilst observing.

Hmm...
cowling3.jpg
How many would you remove? One?
cowling3a.jpg
Two?
cowling3b.jpg
What about these two?
cowling3d.jpg
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#4

Post by Sky Tinker » Fri Dec 27, 2019 7:19 pm

I would not have minded if the factory had shipped this telescope with a stripped cowling...
not a peep.jpg
...and with the hub un-glued and spinning round during transit. I would not have minded at all, in hindsight.

Out of the four stalks, which one to keep? That was determined easily enough, and where the hub stopped screwing inward...
hub orientation.jpg
The factory had gone beyond that point(at left), torquing it down, and at the stalk opposite the focusser. It turns out, also, that the cowling was installed at the factory upside-down; although I have seen it where two holes were lined up with the focusser's stalk or vane. I suppose either one or a set of two is acceptable, and to align with the focusser. I chose one, and per the configuration of my 6" f/5.

Opposite the favoured, lone stalk, I removed that stalk, and for a pattern of sorts...
cowling8.jpg
It is not enough to remove three of the stalks and be done with it. The lone-stalk must be strengthened, as this skimpy joint wouldn't hold up over time...
skimpy joint.jpg
From my local hardware, I got a hot-rolled steel flat, which I ground down to the shape desired and cut to length(top)...
splint2.jpg
I used the cut-out from the cowling to determine the curvature required for the underside of the steel splint...
splint3.jpg
...good enough.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#5

Post by Sky Tinker » Fri Dec 27, 2019 8:26 pm

The splint needed a hole cut out to feed it through...
splint4.jpg
The hole had to be slowly fashioned. You don't want the stalk to fit loosely nor snugly, just right rather; and you certainly don't want to hammer it into place and distort anything. Halfway there...
splint5.jpg
We're in...
splint7e.jpg
The top of the lone-stalk and the underside of the steel-splint were then roughened and scored...
splint8b.jpg
splint8b.jpg (18.89 KiB) Viewed 481 times
J-B Weld steel-reinforced epoxy, with the addition of steel dust made up from the steel-flat via my caring and loving hands, was used to join the two together...
splint10b.jpg
The bronze "key" there was used for the final alignment of the splint within its hole, and is permanent.

But no, it's not done yet...
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#6

Post by Sky Tinker » Fri Dec 27, 2019 9:02 pm

To complete what became the lone-stalk, it and the steel-splint must be as one.

.008"-thick bronze-sheet, bronze "veneer" if you will...
bronze plates3.jpg
Special clamps were created, of oak and the stiffer of red felt, to ensure that the plates would not lift up whilst the epoxy cured...
bronze plates4.jpg
The two were made as one...
bronze plates5.jpg
bronze plates7.jpg
At last, the other two stalks were removed...
for sale.JPG
for sale.JPG (25.49 KiB) Viewed 480 times
...and their remnants ground down...
cowling9.jpg
The hub was screwed into position, yet with 5-minute epoxy spread onto the threads of both surfaces; not too much, nor too little...
cowling11.jpg
At one point afterwards, I accidentally struck the hub, the brief sound reminiscent of that when a tuning-fork is struck; hence, very strong, that lone-stalk.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#7

Post by Sky Tinker » Fri Dec 27, 2019 9:38 pm

In reapplying the finish back onto the cowling, same was sanded throughout and primed first...
primed.jpg
The outside of the cowling was restored to its original, glossy, hammered-black finish...
hammered5.jpg
...then the inside was matte-blackened with chalkboard-black, including the forward-facing rim...
cowling12.jpg
Before...
before.jpg
After...
after.jpg
At long last, the primary-mirror was freed from its prison.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#8

Post by Sky Tinker » Sat Dec 28, 2019 12:59 am

Incidentally, renovating these entry-level telescopes, and pricier ones too, can be every bit just as fun and rewarding as when observing with them, for in so doing they become your very own, almost as though you had made them yourselves, nigh from scratch even. The junkier the sow's ear, the lovelier the silk purse.

The secondary-stalk and -mirror required attention as well...
secondary assembly.jpg
The mirror's clip doesn't even retain the mirror, as the mirror is glued into its black-plastic holder. I didn't like how high up the screw and washer of the clip rose up above the holder's surface...
secondary mirror4.jpg
I replaced the screw with one with a shallower head, and omitted the washer...
secondary mirror14d.jpg
secondary mirror14d.jpg (46.6 KiB) Viewed 469 times
I then matte-blackened the clip, its screw, the plastic holder, and the stoned edge all round of the secondary-mirror...
secondary mirror14c.jpg
secondary mirror14c.jpg (19.26 KiB) Viewed 469 times
secondary mirror14e.jpg
secondary mirror11b.jpg
A nylon-washer was epoxied to the bottom of the stalk, and for the tips of the three adjustment screws to bear against...
nylon washer3.jpg
The three set-screws were replaced with socket-head "thumbscrews"...
secondary set-screws.jpg
secondary set-screws.jpg (31.32 KiB) Viewed 469 times
...and for no-tool adjustments; well, almost, as a hex-key is required for the final tightening.

The cowling completed...
secondary mirror12.jpg
When fitting the cowling onto the tube, for a snug fit I had to apply four layers of aluminum-foil tape all round the inner flange, as shown.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#9

Post by Sky Tinker » Sat Dec 28, 2019 7:13 pm

Many, if not all entry-level Newtonians sold today come with this two-post solution for a finder...
finderscope3.jpg
I wanted more versatility than that...
finder base.jpg
Yes, a Vixen-type finder-base; that'll work.

But first things first, as the base would need a steel back-plate, similar to that that came with my 6" f/5...
flocking19b.jpg
back plate2.jpg
back plate3.jpg
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back plate4.jpg
back plate4.jpg (26.74 KiB) Viewed 443 times
back plate5.jpg
back plate7.jpg
back plate8.jpg
back plate8.jpg (19.45 KiB) Viewed 443 times
back plate9.jpg
back plate9.jpg (15.31 KiB) Viewed 443 times
finder base8.jpg
finder versatility.jpg
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#10

Post by Sky Tinker » Sun Dec 29, 2019 2:48 am

The wonky, plastic focusser...
focusser3.jpg
You can't get away from them, for small refractors and Newtonians up to 6" in aperture. But, you can and should renovate them to where they operate properly. Else, the collimation of the telescope, and therefore the images, will suffer. This particular focusser came with only one bearing for the draw-tube...
focusser3b.jpg
I like sweets once in a while, every single day actually, but I haven't had any of these for some time...
cinnamon rolls2.jpg
...and by that I mean, about a month. But there's another variety, that I like a little less: the cherry rolls, without cinnamon. It was when I was enjoying a package of those that it suddenly dawned upon me...
cherry rolls.jpg
The corrugated paper tray for the rolls bears an uncanny resemblance to the lone bearing for my focusser's draw-tube!
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#11

Post by Sky Tinker » Sun Dec 29, 2019 5:00 am

This plastic focusser looks like most others...
focusser4b.jpg
...but with a twist. At the end of the draw-tube, there's a cell containing a cemented doublet-lens...
doublet 'corrector'3.jpg
doublet 'corrector'3.jpg (24.52 KiB) Viewed 408 times
That's what extends the focal-length of the telescope, from an f/4 to an f/8; a barlow if you will. It also, arguably, corrects errors associated with the spherical primary-mirror. More on that later, and during the collimation phase.

Right; let's now concentrate on how to enable the draw-tube to rack in and out, straight and true, along its entire length, with no binding nor slop whatsoever. You want the precision of the collimation achieved to enable sharp, pleasing images at the low, medium and high powers; all the way up to a theoretical 250x, and beyond even, particularly when observing the Moon.

You want to center the draw-tube nigh perfectly within the body of the focusser. That is accomplished by a triad of bearings...
drawtube integration2c.jpg
drawtube integration2c.jpg (15.09 KiB) Viewed 408 times
The bearings run the entire length on the inside of the focusser's housing...
focusser7e.jpg
focusser7e.jpg (16.22 KiB) Viewed 408 times
...top to bottom.

There are several solutions for DIY bearings for a draw-tube. The best solution, in my not-so-humble opinion, is the use of super-slippery PTFE(Teflon) sheets, cut into the three narrow strips required...
PTFE2b.jpg
PTFE2b.jpg (9.5 KiB) Viewed 408 times
I got my own sheets from this vendor...
PTFE2.jpg
...and economically.

For draw-tube bearings, I generally use the .015" and .020" in thickness, along with two other items...
focusser materials2.jpg
I also use scissors, single-edge blades, a #11 X-Acto knife, and 91% rubbing-alcohol to clean and de-grease the surfaces to be joined(very important).

You cannot glue PTFE to anything, or to itself, unless you first etch the surface of the PTFE with a dangerous acid. Instead of glues, I use Scotch-brand, double-sided, clear tape. The roll of aluminum-foil tape shown there is available from your local HVAC dealer. It's used to seal and secure joints for lengths of ducting, for heating and air. For our purposes, the aluminum tape, about .003" in thickness, is used to build up and adjust the thickness of the substrate for the PTFE-bearings...
drawtube integration4.jpg
After each bearing is installed, you then trim off the excess with a blade. Install however many layers of the aluminum tape required first, trim it, then place a longer length of double-sided tape onto that, then a longer length of the PTFE onto the tape, press them down hard all along the bearing's length, then trim.

Trial-and-error is the name of the game. Focussers and their draw-tubes can differ from telescope to telescope, hence this highly-adjustable method of installing bearings for the draw-tube. You may not need to build up the surface of the housing with the aluminum tape, or two per bearing may be required, or four. In any event, all the components are removable, and with the PTFE reusable, over and over until you get the thicknesses of each all round, just right. You do want all three bearings to be at the same thickness as much as possible. There have been times when I've had to make just one bearing slightly thicker, or thinner; again, trail-and-error. Also, the draw-tube's rack must come into close contact with the pinion-gear between the knob-assembly, but not too tightly meshed together. The thicknesses of the bearings will have an effect on that. The first thing I like to do is to insert the draw-tube loosely into the housing, without the pinion-gear installed, then insert the PTFE strips in between, loosely, and to get an idea of the thickness for each that will be required.

The clear, double-sided tape, once pressed onto the PTFE, will lift off straight-up, perpendicular to the strip of PTFE, easily. However, when pulling the two components, forcefully, and parallel to a surface once pressed down, it will not budge in the slightest...
pulling PTFE.jpg
...and that suits our purposes admirably. In other words, the bearings will not slip out when racking. I suppose, over time, the adhesive of the double-sided tape may or may not fail. It may last for years, or decades even. If and when it does fail, simply replace the double-sided tape.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#12

Post by Sky Tinker » Sun Dec 29, 2019 7:01 am

Several tutorials for these "Bird Jones" reflectors instruct to remove the barlowing, corrective doublet-lens from the drawtube, and prior to collimating the telescope. DO NOT remove the lens from its cell. Instead, remove, unscrew, the cell with the lens still in place, from the drawtube...
doublet9.jpg
That way, you won't drop or lose the lens. You also don't have to worry about the orientation of the lens within its cell. It also makes the view of the scene wider when collimating. The lens is dropped into its cell only one way, and with the thinner lens of the doublet facing the eyepiece...
doublet10.jpg
...and the thicker lens facing the secondary-mirror.

I took my doublet-lens out, and to matte-blacken its edge all round, and for improved contrast. Contrast, that's what it's all about...
doublet3e.jpg
doublet3e.jpg (18.8 KiB) Viewed 398 times
The doublet's cell was matte-blackened where necessary...
doublet cell3.jpg
For the drawtube, I blackened that portion on the outside which juts into the light-path of the telescope...
drawtube7.jpg
...but with satin-black, not matte-black. That way, the tube will glide more easily along the PTFE bearings. I flocked the tip of the rack of the draw-tube...
drawtube5.jpg
drawtube5.jpg (18.22 KiB) Viewed 398 times
...as it faces directly at the secondary and primary mirrors. The forward-facing rim of the draw-tube, towards the mirrors, was matte-blackened.

The inside of the drawtube was flocked...
flocking8b.jpg
I simply matte-blacken the draw-tubes of my other telescopes, whether they need it or not. Then, the paint I use is generally blacker than what the factory applies.

A view to a kill...
doublet5.jpg
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#13

Post by Graeme1858 » Sun Dec 29, 2019 8:23 am

Really enjoying your thread Alan.

My first telescope was a 5" Bird Jones Newtonian.

Regards

Graeme
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#14

Post by mikemarotta » Sun Dec 29, 2019 1:46 pm

Sky Tinker wrote:
Sun Dec 29, 2019 7:01 am
Several tutorials for these "Bird Jones" reflectors...
Thanks for the fascinating shop talk. I would never do any of that, but I appreciate your skill and acumen. Nice work.
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#15

Post by Sky Tinker » Sun Dec 29, 2019 7:45 pm

The underside of the focusser's flange, the central perimeter, was matte-blackened...
focusser8b.jpg
focusser8b.jpg (26.92 KiB) Viewed 358 times
The focusser was installed, and its hardware matte-blackened. Lock-washers were added to secure...
focusser10b.jpg
focusser10b.jpg (55.04 KiB) Viewed 358 times
There, that's done, and for the life of the telescope.

Among my telescopes, the reflectors in particular, there can be only two reflective surfaces along the light-path: those aluminised of the secondary and primary mirrors. All other surfaces within are either flocked, or those that cannot be flocked, blackened instead; down to every, last, square millimeter.

Blackening...

I use deep matte-black paint, from rattle-cans; for examples...
blackening supplies3.jpg
The camouflage-black is of a warmer shade; brownish, yellowish. The chalkboard-black is cooler, bluer, and what I now prefer. Both are the deepest black of paints available, commercially.

I either spray it directly from the cans, or spray it into a plastic lid and apply it by hand with small artists' brushes. I never use ordinary, bog-standard, dead-common, flat-black paint...
flat-black.jpg
...and neither should you.

Flocking...
flocking2.jpg
flocking2.jpg (15.03 KiB) Viewed 358 times
Flocking is like very low pile carpeting, but for telescopes. Flocking absorbs, eats, light; stray light, from passing automobiles, porch and street lights, and the light from the silvery Moon whilst hunting for and observing the dimmer, deep-sky denizens of the night sky. Flocking is so very good for that sort of thing in fact that my cameras have a difficult time focussing upon a sheet or a piece of it, but eventually I do get a shot of it to illustrate.

All in all, it amounts to nothing more really than simple arts-and-crafts.

In the end, you want the interior of the telescope as dead to stray-light sources as possible; darker than the darkest of dark-nebulae, blacker than the blackest of black-holes, and for levels of contrast beyond your wildest dreams.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#16

Post by Sky Tinker » Sun Dec 29, 2019 8:46 pm

Before I detail the rather lengthy process of renovating the primary-mirror's cell, the optical-tube should be addressed...
paint comparison.jpg
That's the chalkboard-black of the cowling, arrowed in green; and the factory-black of the manufacturer, arrowed in red. I call the factory-black "Synta grey"...

no center-spot.jpg

I use the self-adhesive flocking. Another type is available, and to where you just pop it in and snap the whole sheet into place; so much for that.

Flocking adheres best to a glossy, shiny, smooth surface. Never install flocking onto a flat-black finish. The use of satin or semi-gloss clear-coat can be used to prepare the inside of the optical-tube, but in the end high-gloss enamel is best...
tube glossing2.jpg
Imagine observing the Moon with the tube's interior like that. :Astronomer1:

The tube was then flocked...
flocking26.jpg
flocking24.jpg
flocking25.jpg
There is an alternative, if not wanting to get down-and-dirty, and in using the original black surfaces of the telescope's components. Simply clean the surfaces and apply a matte clear-coat, which can be of enamel, or acrylic even.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#17

Post by Sky Tinker » Sun Dec 29, 2019 9:57 pm

The heart of any and every telescope is the objective; and of primary importance, above all else.

The hind end of the telescope, the primary assembly. I'm almost afraid to look...
hind end2.jpg
hind end2.jpg (33.25 KiB) Viewed 350 times
Note how it seems to arrive locked up tighter than Fort Knox. In the beginning, before I cracked it open, I thought that that center, recessed portion was a circle of naugahyde, or leatherette, and in keeping with the low price of the kit.

How is the primary-mirror within supposed to "breathe"; to acclimate?

That portion of the cell to which the mirror is secured is easy enough to remove...
primary cell2.jpg
primary cell3.jpg
What is that gunk? Why, it's black-silicone. Why did they glue the mirror to the rubber retaining-clips? All of that was removed in the end.

I then de-clipped the mirror and lifted it out...
naugahyde.jpg
It turned out that it was not a circle of naugahyde, or leatherette, after all. It's a steel plate, and painted with that ubiquitous, glossy hammered-black paint, the kind used for mail-boxes. Let's have a look at it from the side...
naugahyde2.jpg
It turned out that those rubber stand-offs were self-adhesive, on both sides; one side to grip the mirror, and the other side to grip the steel plate. The plate and the stand-offs became history, and upon the very sight of them. I did make use of the plate later on, for bits and bobs for other telescopes.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#18

Post by JayTee » Sun Dec 29, 2019 11:09 pm

This is a wonderful thread to follow. Thank you for posting this.

Your disassembly and discovery of the different manufacturing processes is fascinating. Having a background in manufacturing Hi-Tech objects and devices, I have some knowledge of the engineering process from cradle to grave. In the past I have worked with industrial, systems, materials, mechanical, and electrical engineers. All of these disciplines are necessary when designing the build, the materials, and the use of a newly manufactured device.

With this in mind I often wonder if the engineers at the major telescope manufacturers actually own and use a telescope. If this were the case would their knowledge of the use/care of a telescope change how they would manufacture this device even if it meant greater expense? I do not have the answer to this question.

Over the years that I have asked this question I have yet to see a primary engineer from the major telescope makers weigh in on this subject. The vast majority of them hold their manufacturing processes quite close to the vest, and probably with good reason.

Thanks again for posting your endeavors,
JT
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#19

Post by Sky Tinker » Mon Dec 30, 2019 2:04 am

JayTee wrote:
Sun Dec 29, 2019 11:09 pm
This is a wonderful thread to follow. Thank you for posting this.

Your disassembly and discovery of the different manufacturing processes is fascinating. Having a background in manufacturing Hi-Tech objects and devices, I have some knowledge of the engineering process from cradle to grave. In the past I have worked with industrial, systems, materials, mechanical, and electrical engineers. All of these disciplines are necessary when designing the build, the materials, and the use of a newly manufactured device.

With this in mind I often wonder if the engineers at the major telescope manufacturers actually own and use a telescope. If this were the case would their knowledge of the use/care of a telescope change how they would manufacture this device even if it meant greater expense? I do not have the answer to this question.

Over the years that I have asked this question I have yet to see a primary engineer from the major telescope makers weigh in on this subject. The vast majority of them hold their manufacturing processes quite close to the vest, and probably with good reason.

Thanks again for posting your endeavors,
JT

Thanks!

Nowadays, as I see it, China merely clones what Japan and the U.S.A. produced in the way of astronomical equipment, other than perhaps the electronic aspects. Here's a dreadful, modern feat of "engineering"...
focusser9b.jpg
focusser9b.jpg (30.55 KiB) Viewed 336 times
That's the draw-tube housing of a Celestron(Synta) "AstroMaster" 70mm f/13 achromat. I hope to replace it with a conventional unit someday.
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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#20

Post by Sky Tinker » Mon Dec 30, 2019 3:52 am

The primary-cell consists of two components, and most generously coated with hammered-black paint...
primary cell5.jpg
Some reviewers were saying that this telescope was junk; cheaply-made. Other than the plastic focusser, I've found the opposite to be true.

The first order of business was to sort out the tension when adjusting the primary-mirror, and most important when collimating. These simply were not going to get it...
rubber grommets.jpg
rubber grommets.jpg (24.18 KiB) Viewed 328 times
...rubber...grommets, which will fail over time. Then, they're not that great in the beginning.

I set out to find some heavy-duty metal-springs for replacements. I finally found this, at my local Home Depot, and for $5...
springs5.jpg
Out of all of the likely candidates, I chose this type, and the only ones of stainless-steel...
springs2g.jpg
I took two of those and cut them to size, for a total of the three required...
springs-stainless.jpg
A comparison of the two types...
spring types.jpg
spring types.jpg (17.66 KiB) Viewed 328 times
The metal-springs make it so much easier to control the tilt of the primary-mirror, and therefore so much easier to collimate the telescope, that opting not to replace the rubber-grommets would be a tragedy. The grommets were not too happy upon the event...
rubber grommets2.jpg
rubber grommets2.jpg (26.53 KiB) Viewed 328 times
In addition, the slippery Phillips-head screws were replaced with socket-caps which act as thumbscrews to a point, then to torque them down with a hex-key in the hopes of preserving the level of collimation...
primary cell2b.jpg
"Look, son! Up there!" His son shouted back, "I see it! What is it?" The father regaled, "The galaxy! Andromeda! Our origin, our destiny!" And so the boy was hooked, and for the rest of his natural life.

Alan

Apochromat: Takahashi FS-102 f/8 - Achromats: Meade "Polaris" 90mm f/10(flocked & blackened), Antares(GSO) 805 80mm f/6(flocked & blackened), Celestron(Synta) "AstroMaster" 70mm f/13(flocked & blackened), Sears(Towa) #4-6340 50mm f/12(flocked & blackened) - Newtonians: Orion(Synta) 6" f/5(flocked & blackened), Meade "Polaris" 114mm f/8, Zhumell(GSO) Z100 100mm f/4 - Catadioptrics: Explore Scientific(JOC) 127mm f/15 Maksutov-Cassegrain, Celestron "PowerSeeker" 127mm f/8 "Bird Jones" reflector(modified, flocked, blackened...& collimated!)...and mounts, eyepieces, barlows and diagonals.
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