5838 replies to this topic

[icomet]

Oh yeah, forgot. It has rotating rings, also.

 

Clear Skies.

[Garyth64]

My tube is 60" long.

[Bomber Bob]

(Too Many!)  Focuser Options:

 

I recently bought 2 vintage focusers...

 

1960s Tinsley 8 Cassegrain and 1980s Vixen NA140:

 

 

Both focusers are robust, and have very smooth & precise rack & pinion gearing.  But... the Tinsley is a 1.25" format, while the Vixen is 2" format.

 

2 of my fracs could use a better focuser:  Dakin 4" F10 and ATM 5" F5  Of the 2 scopes, the Dakin would require the least re-tooling, and could accept either focuser.  And, I use the Dakin at high powers, so of the 2, it needs the more precise focuser...

 

 

The original has 3 main parts:  A 110mm tube flange, a 90mm threaded disk, and the Japan-made flat base focuser (that was trimmed at the corners to fit) attached with 4 brass screws.  The 2 ATM parts are thick machined aluminum -- built to last.  The current focuser is 2" format, and I kinda hate downgrading to the smaller Tinsley.  And... by unscrewing that 90mm disk, the excellent NA140 will thread right in -- Easy Peasy!! 

 

Or, if I want to preserve things as-is, I could have my local machinists (The Boys) make a new 110mm flange that the NA140 would thread into.  The Dakin's lens cell has no collimation, so they'd have to make sure that the 90mm threaded hole is dead-center...

 

Or, I could cannibalize the 390:  Its lens cell will fit the tube interior, and it would accept the NA140 on the eye side.  But I like the 390, so this is my least-favored option.

 

Naturally, when I restored the Dakin, I painted the focuser as a whole, so I'd have to break the seal just to unscrew that 90mm disk. 

 

What would y'all do?  All I've done so far is measure the parts, and confirm which could fit what...

 

[clamchip]

Lately I've had a real craving for some serious purple.

I mean electric neon purple so strong it looks like the moon

is being terraformed as I watch.

I owned a scope that would do this, years ago, a 5" f/5 unknown

in a plastic cell. I sold it.

Looking over my pile of clamchipped instruments it occurred to 

me I have nothing that qualifies.

Why purple, why the ugliest aberration? because it's awesome when

you have gobs of it.

I'll bet everyone secretly thinks it's cool too.

Funny, my wife and I as a test we bring frosted animal cookies

and Twinkie's to our community potlucks once in a while and

guess what, they are the first to get eaten ! heaven forbid ! no

one likes those !

I do have this scope, I put it together this afternoon.

It has a cemented Jaegers 3-1/16" f/5. I've never looked thru it.

Unfortunately in the Jaegers catalog it is listed as a,

"Top notch telescope objective as demanded by  astronomical

telescopes."

It will still do I think, at f/5 and a little magnification I should see

lots of glorious purple.

Robert

 

Edited by clamchip, 12 January 2021 - 07:52 PM.

[Garyth64]

I really like the looks of that 3" finder, even if it did show lots of purple.

[Kasmos]

Lately I've had a real craving for some serious purple.

I mean electric neon purple so strong it looks like the moon

is being terraformed as I watch.

I owned a scope that would do this, years ago, a 5" f/5 unknown

in a plastic cell. I sold it.

Looking over my pile of clamchipped instruments it occurred to 

me I have nothing that qualifies.

Why purple, why the ugliest aberration? because it's awesome when

you have gobs of it.

I'll bet everyone secretly thinks it's cool too.

Funny, my wife and I as a test we bring frosted animal cookies

and Twinkie's to our community potlucks once in a while and

guess what, they are the first to get eaten ! heaven forbid ! no

one likes those !

I do have this scope, I put it together this afternoon.

It has a cemented Jaegers 3-1/16" f/5. I've never looked thru it.

Unfortunately in the Jaegers catalog it is listed as a,

"Top notch telescope objective as demanded by  astronomical

telescopes."

It will still do I think, at f/5 and a little magnification I should see

lots of glorious purple.

Robert

 

post-50896-0-13926100-1475105882_thumb.jpg

post-50896-0-57934400-1475105903_thumb.jpg

If anyone's gonna to have fun like that.... it's gonna to be you!

 

[Bomber Bob]

It was brutal:  Got another Meade cast aluminum accessory tray for my 2nd vintage StarFinder mount -- the short pedestal version.  I had to remove 3 bolts, lift that EQ up & away from the pipe, slide the new tray (with felt-lined ring) down the pipe, position it, tighten 1 screw to hold it fast, then reattach the mount...  I'm exhausted.

 

Now ALL of my EQ platforms have accessory trays.  These Meade rectangular trays are large enough to set my Panasonic ToughBook on for if / when I attempt digital imaging again...

[icomet]

OTA work today.

 

Clear Skies.

Attached Thumbnails

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[icomet]

"Beck Optics" got a remake this last week.

 

Bad photo. Sorry.

 

Clear Skies.

Attached Thumbnails

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Edited by icomet, 17 January 2021 - 07:34 PM.

[icomet]

The tube pictured above this scope wasn't for this scope.

 

Different one being worked on.

 

Clear Skies.

[clamchip]

I've been collecting parts to build a Jaegers 5 inch f/15 and to double the fun I'm going to

build both a 5 inch f/15 and a 5 inch f/5.

I have only one cell to share between the two but I'll drill the cell for set screws that don't

go through the tube so it will be easy to swap between the two tubes.

The Jaegers 'Super Focuser' is correct for the f/5, standard focuser for the f/15.

I did the flock paper treatment on the small focuser, the big one has baffles.

The Super Focuser body is Teflon lined and butter smooth, I'm not sure if Jaegers did this

or a very skilled amateur.

Tubing is on it's way from Hastings.

Robert

 

[clamchip]

I forgot about the clock.

This clock motor has a sealed rotor, I run it upside down for a week once in a while to

redistribute the lube in the sealed rotor.

 

Robert

[Bomber Bob]

Yet another gut-wrenching, nail-biting, gallon-of-cold-sweat project...  Converting a Celestron (V) SCT Rotary Eyepiece Turret to conventional 1.25" format:

 

 

After removing the SCT coupler hardware, I noticed that the threaded hole looked like it might be standard.  I confirmed it with my new fancy-schmancy digital Calipers --> 30.51 mm . . .  Well, not 1 of my 1980s Japanese 1.25" barrels matched the thread.  Dang It!!  Then I remembered my 2 Celestron (V) prism diagonals...  Bingo!  The chrome barrel from the uglier one is a perfect fit:

 

 

I smeared a thin bead of Tacky Glue into the turret threads so it won't twist loose with all the rotating.  All 4 eyepiece slots are .965" format, but I generally use my spectros or CZJ .965" eyepieces in the old Unihex for zooming in / out on the traditional long refractor targets.  These turrets were NOS (like those Nihon-Seiko diagonals I bought), and the prism faces are pristine and a bit larger than the Unihex...

 

Whew!  After all that, I need a Scotch or two.

[icomet]

I'm presently dismantling 3 scopes to remake 2 scopes from them.

 

Retiring 1 mirror, with the results being 1 Newtonian and 1 dobsonian.

 

My "mystery project" warranted this, which will continue after this ATM project is completed.

 

Clear Skies.