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BB's Jaegers Classic Refractors Duo-Scope

Classic ATM DIY Equipment Optics Refractor
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#26 RichA

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Posted 11 April 2021 - 01:22 AM

Jaegers 50 is a Complete Kit.  All I gotta do is make sure all the parts fit; blacken the tube interior, and paint the exterior.  It'll have a 1.25" focuser.

 

Jaegers 89 will take longer to complete.  First, I gotta gather parts.  I already have that Edmund 2" rack & pinion focuser headed to The Swamp.  I have several ~ 90mm aluminum tubes in my shed.  I have an antique brass tube, too -- but I think it's too small diameter to use.  The Lens Cell... gonna try to find a Jaegers model first; or, modify a used one; or, have The Boys make one -- like they did for the JaegerMeister (and they did an Outstanding job!). 

Made back when 50mm might have actually showed someone something in suburbs, when you could see the Milky Way.  I had a 50mm f20, great lens, lost too much light before resolution lost detail on planets.


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#27 Bomber Bob

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Posted 11 April 2021 - 07:09 AM

Jaegers 50 - First Sky Test

 

Overall:  Performance equal to, and perhaps slightly better than, my Swift 838 F14.  I had this kludge OTA on the VG2, and I used my spectros .965" eyepieces.

 

Seeing was 7 to 8, variable (wrap-around high thin cirrus on the backside of a strong Low).  Capella:  At 62x (KE 10), at least 90% of the energy in the Disk, faint 1st Ring, very faint 2nd, but rings were not a perfect circle IF / OF.  My first thought was that the Jaegers lens cell wasn't on square with the 4348's, but it checked good indoors with the laser.  I pulled the NOS Nihon-Seiko diagonal, and replaced it with the new Tak .965" prism.  Boom!  Perfect Airy Disks at 62x & 124x (PL5).  Same results on Betelgeuse, Procyon, & Regulus.

 

Castor & Algieba:  Textbook Figure 8's at 62x with intersecting disks & 1st rings.  Took 165x (PL7.5 + 2x Barlow) to get clean splits.  Both views were beautiful.

 

Mars:  Tiny & low (in our Light Pollution Dome).  Its 5" disk was a featureless intense orange at 124x, but I could focus to a sharp edge.  I used the 2x AO Barlow from my 1964 Sears 6336 to go above 124x.  I did get a hint of a break in the orange at 165x, but I wouldn't call that a surface feature - too iffy.  The 4348 has a decent focuser, but at 248x, the view was soft.

 

Open Clusters:  41x (KE15) is best for the large clusters, 62x & 83x (PL7.5) for the smaller ones.  Faint stars are smaller than micro - nano (?).

 

I gave my Swift 838 to our youngest grandson.  The J50 is a worthy replacement, and I'll use it like I did the 838 -- Solar observing with the Lunt wedge, some lunar, and doubles & clusters.

 

As usual, I wound up with more 50mm fracs than intended:  Besides the 4348 & J50, I have my mint & complete Hy-Score 457 (50mm F10) on its AZ mount & tripod -- it's on display to the left of my Tinsley 6 (talk about David & Goliath!).  I may pull the baffles & peep-sight from the 4348, and use those on the Jaegers, since this lens is superior to the Towa.  But, I've already made 3 baffle frames for the J50; and, I the 4348 is a good example of a sub-60 -- it's just not quite as good as the Jaegers.  I had the 4348 mounted on my Edmund 4" F15 as a duo-scope & guide-scope.  I could adapt it to the tube rings on my C102 -- save my neck from its 6x30 straight-through...

 

For now, I had the TN5 + Edmund EQ on the Filo last night, and grabbed some fuzzies.  I'll replace it with my Tak FC-50 on its EQ for tonight, and see how the J50 stacks up against a fluorite APO.


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#28 Bomber Bob

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Posted 11 April 2021 - 11:43 AM

J50 & FC-50 - Side-By-Side Rig:

 

Jaegers 50 Restore S43 - M4348 OTA (FC-50 SxS).jpg Jaegers 50 Restore S46 - M4348 OTA (FC-50 SxS).jpg


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#29 Terra Nova

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Posted 11 April 2021 - 11:45 AM

How do you keep them collimated so that they are both spot-on the same target? I’ve always thought side by side setups worked better in theory than in practice.



#30 Bomber Bob

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Posted 11 April 2021 - 11:51 AM

In the past, I put both OTAs on the same 14" / 18" Vixen dovetail bar.

 

This Tak SC is supposed to be even easier to adjust, but it's my first time using it this way... so, we will see...


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#31 Terra Nova

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Posted 11 April 2021 - 11:58 AM

In the past, I put both OTAs on the same 14" / 18" Vixen dovetail bar.

 

This Tak SC is supposed to be even easier to adjust, but it's my first time using it this way... so, we will see...

I think if I were doing it, I would use adjustable guide-scope type rings on your ATM 50mm, then you could get the alignment of the two perfect. Just me tho... just a suggestion.



#32 Bomber Bob

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Posted 11 April 2021 - 03:33 PM

The J50 is on the EQ's Swing Arm:  I can tweak Altitude & Azimuth to align with the FC-50's optical axis -- according to Takahashi.  In theory, looks easy; in practice, I'll find out tonight.


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#33 Bomber Bob

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Posted 11 April 2021 - 11:10 PM

Splittin' Hairs - J50 vs. FC-50

 

BLUF:  A few of the faintest stars in the FC-50 eluded the J50; otherwise, the star tests, color tests, & double stars were very close - both 50's at the same magnifications.

 

Used TAK prism diagonals in both - 1.25" in the FC-50, .965" in the J50; spectros .965" eyepieces, except I had to use that 1950s ASC KE 30 to get the J50 to 20x.

 

Seeing tonight was 8 / 10; surface winds variable at 5 knots; some moisture at the mid-level.

 

Aligning the J50 OTA with the FC-50 OTA was tedious & annoying without motorized tracking.  The Swing Arm is like a crude AZ mount; and, you have to use an Allen wrench to adjust & lock the altitude, so naturally the star centered in the FC-50 drifts off...  I settled for the target just left / south of center for the FC-50, and just right / north for the J50 with both scopes at 80x.

 

Betelgeuse & Capella:  I expected the J50 to have more orange/red than the FC-50.  Nope.  AF / IF / OF at 80x made no difference.  Procyon:  White with a hint of yellow in both.  Regulus:  Brilliant blue-white in both.  As for fainter stars, both fracs showed the orange stars in M35 as orange - no observable difference.  Castor & Algieba:  Identical Figure 8s at 80x - though the stars appeared slightly brighter in the FC-50.  

 

So far, the J50's performance reminds me of the Swift 838.  I'll have to go back and read my SxS between the 838 & FC-50.  IIRC, the FC-50 pulled ahead with the Trapezium; and, significantly, with Jupiter & Saturn at 150x.

 

These tests have shown me that the J50 is worth building an OTA around; and, they give me a minimum standard to shoot for with that build.  If it does this well attached to the end of a Towa, the OTA I make should be even better!

 

** ------------------------------------------ **

 

Starting at 1030Z, the Duo delivered sharp views of the morning planets in 8 / 10 seeing.  C/V Turret on the FC-50, left the Tak .965" prism on the J50, and spectros .965" eyepieces.

 

Fair  /  49°F  (9°C)

Humidity 93%
Wind Speed Calm
Dewpoint 47°F (8°C)
Visibility 10.00 mi

 

Saturn & Jupiter:   A ringed planet in both at 40x; sharper at 80x in the FC-50, and the J50's disk has a very subtle hint of gold rather than pure white.  Ring shadow on the disk in both.  Both showed Callisto emerging from behind Jupiter - a dim but tight nano-dot.  Both showed 4 belts total, with the STB intermittent, and the NEB, NTB, & SEB persistent.  FC-50 showed the edge of the GRS notch in the SEB -- couldn't quite break it out with the J50.  I'll have to recheck this when the Jaegers is in its permanent OTA.  With Barlows:  FC-50 softened at 200x, J50 at 248x; both were sharp at 150x & 165x, respectively; though the J50 was dim, and took more effort to get the best focus.  Jupiter's disk is paper white in the Tak, and light wheat in the J50.  GSO 1.25" 2.5x APO in the Tak, and AO .965" 2x in the J50.  Both showed the 3 Galileans as fine Airy Disks -- I used these to get best focus.


Edited by Bomber Bob, 12 April 2021 - 08:09 AM.

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#34 Terra Nova

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Posted 13 April 2021 - 08:59 AM

I found this to be true with my Mayflower 60mm x 700mm (APL, 1965) one night late last summer, when I watched a shadow transit on Jupiter with the Mayflower using premium 1.25” eyepieces and an excellent 1.25” diagonal. The image was just about as bright, sharp, well contrasted, and free of false color as with the excellent little Tak FC-60 that I just sold. I have often remarked as to just how good the Mayflower objective is and how perfectly collimated it’s rigid thread-in cell is in its heavy, thick-walled tube. This is the telescope that I watched the S-L 9 impact plumes with back in the mid-90s, and they were very distinct. As I have said before, an excellent longish (>F10) achromat in the 40mm to 60mm bracket will produce images that are hard to distinguish from a good apo. It’s when the aperture exceeds 60 to 65 mm, that the apo really begins to pull ahead and win the horse race. This is the principle reason that I decided to sell the little Tak. I could never part with my Mayflower; the lens is too good and the sentimental attachment too strong. 


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#35 rcwolpert

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Posted 13 April 2021 - 07:39 PM

I know that MAS . . . Mayflower Attachment Syndrome.  The 816 and 815 are with me till the end. I gave away the 814, but it’s just 3 miles away so I can still visit it. The Mayflowers are just too good optically.


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#36 Bomber Bob

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Posted 13 April 2021 - 09:36 PM

I feel that way about Monolux.  Pure dumb luck with my 1964 Model 4380 -- my 1st Classic.  However, both of my Mayflowers - 814 & 815 - were excellent 60mm refractors.


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#37 Bomber Bob

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Posted 18 April 2021 - 10:30 AM

https://alien-observatory.com/

 

this place will 3d print any baffle you want.

Johann, thanks for the link!  I've asked for a quote.  (Yeah, it's cheating - no 3D printers when this lens was new! - but I don't want to pull baffles from the 4348.)

 

Also, if y'all know of a Jaegers 3" F8 to F12 lens that's for sale, please let me know.  I'd still like to build both fracs for a Duo-Scope...



#38 Bomber Bob

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Posted 19 April 2021 - 05:51 PM

Fingers crossed that'll I'll finish the J50 OTA this weekend.

 

- 3D Baffles ordered.

- Put 2 coats of Flat Black on the tube interior yesterday.

- Finished all the hardware for the 1.25" Rotating Focuser today.

 

The aluminum tube is 24" long, so it's gotta be cut.  Y'all can check my math:

 

Focal Length = 24.5"

Focuser Height = 4.0"

Prism Diagonal = 2.5" (for 1.25")

Final Tube Length = 18.0"  

 

The Lens Cell slides over the tube, such that the back face of the flint is flush with the tube edge.

 

I'm most proud of the Rotating Focuser:  1st, I had to grind & polish the Jaegers casting to center it in the brass collar; next, I had to measure, cut, & polish the Outer & Inner vinyl collars; finally, I had to make a very smooth track for the moving parts...

 

Outer Vinyl Collar is fixed -- has a long tab that fits inside the tube, flush against the inner wall, and is held tightly in place by the 2 Finder Bracket bolts.  It has 3 screws that center the Inner Vinyl Collar, which holds the brass collar, and the Jaegers 1.25" focuser.  Its outer band uses 3 screws to center & level the Jaegers unit.  I rounded the ends of these, as they press against the brass collar.  Applied thin layers of white lithium grease to all the contact surfaces for smooth motions.

 

Since the lens cell is fixed, having dual-axis adjustments built into the focuser is very important.  Found that out when I built the 4" JaegerMeister.  The Jaegers 50 solution adds rotation.  Yes!


Edited by Bomber Bob, 19 April 2021 - 07:08 PM.

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#39 GreyDay

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Posted 20 April 2021 - 03:17 AM

Fingers crossed that'll I'll finish the J50 OTA this weekend.- Put 2 coats of Flat Black on the tube interior yesterday.

Who's (manufacturer) black paint do you use? Over the years I've tried all manner of automotive/DIY rattle cans brush paints, brush, roller, sponge, all kinds of black paper yet they're mostly shades of dark grey when dry. Flocking and baffling gets the best results for me, i've managed to cut costs by only flocking from the objective to the first baffle then paint to the focuser. I've got a few OTA's to do this summer unless i give them away first. Most of the time i'll use roller applied chalkboard paint coz it's cheap :)


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#40 Bomber Bob

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Posted 20 April 2021 - 05:38 AM

I use Rustoleum Chalkboard Black -- spray for long tubes, and brush for shorter areas.  I get the best results with the brush:  First coat is the base, and the final coat I rifle / make horizontal lines when the paint is almost dry.

 

Flocking:  I've tried flocking paper, sand paper, sand (glued to the inner wall), and thin black foam sheets sold at craft stores like Hobby Lobby.  I prefer the foam sheets - it's easy to cut & shape, and takes just a bit of glue to stick to the inner wall & metal parts.  I buy only the dull black sheets (some have glitter in them!).  Once they're glued down, I can brush or wipe dust, pollen, etc. off of them.

 

For the J50, that spray layer is just the start.  As I place the baffles, I'll add brush layers & flocking between the lens, each baffle, and the focuser.  Then, I go back and brush on the black to cover any hardware - bolts, nuts, etc. & the faces of the lens cell, focuser, & baffle edges.  On a small scope like this, it doesn't take long to blacken everything.


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#41 Bomber Bob

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Posted 20 April 2021 - 06:27 AM

False Color Testing

 

Last night's waxing Quarter Moon was perfect for testing false color.  The Jaegers 50 lens is still on my Monolux 4348 OTA (which I improved / blackened during its restore), and makes a good baseline / comparison for the final OTA.  Seeing was 7 with thin mid-level clouds, 8 in the clear, and the Moon after sunset was close to the zenith.

 

I used only .965" accessories:  new TAK or 1960s Hy-Score 457 prism diagonals (the latter has larger faces than the TAK); and, my CZJ & spectros sets, my "bundles" from the H-S 457 (heavy, & similar quality to Goto) & Sears 6336, and hodge-podge Tani & Vixen units.

 

Typically with my achro refractors, CA is most obvious on the sunward faces of crater walls & peaks near the Terminator, and/or fringing at the bright limb...

 

The only combo that showed yellow-green at the Terminator was the H-S prism + Tani OR-4 (155x), but the resolution was excellent for a 2" refractor.  No Eye Relief, though!  Only saw blue fringing at the limb with the H-S prism + KE-22 (28x) from the 6336 bundle -- disappeared with the TAK prism.  Absolute Best Low Power View:  TAK prism + CZJ H-25 (25x) - took patience to nail focus, but it was worth it for the 3D hi-res view.  Best Mid-Power View:  TAK prism + spectros KE-10 (62x).  Complete & Bright! disk in the field, no CA, jet black sharp-edged shadows, subtle differences in & between the Mares.  Best High-Power View:  TAK prism + spectros PL-5 (124x).  Did Not look like 62x per inch at all.  Can't wait to see how my 1.25" TAK + Radian 4mm compares...

 

I had the J50 riding solo on the TAK SC EQ + Filo tripod, with those spikes pushed ~ 2" in the lawn.  Had to add a small c/w to the flexible arm for balance.  Zero vibrations at 124x.  Accurate polar alignment, so the only slo-mo I had to use was the RA knob.  (No motor drive test yet -- delivery of the last battery pack part now delayed until WEDS!)


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#42 Bomber Bob

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Posted 20 April 2021 - 07:17 AM

Odds & Ends - Finishing Touches:

 

Focuser Tube

 

The end of the chrome tube has no way to secure accessories -- 1.25" barrels slide in tightly, but not enough to trust at steeper angles.  Easiest solution for me is to fit a .965" to 1.25"  adapter -- it would fit inside the Jaegers tube, and I'd use 3 tiny chrome screws to lock it in place.  But, that limits the scope to .965" accessories.  Or, I can fit a 1.25" collar (from an old diagonal) to it -- press its short threaded end into the tube, and secure it with a couple of screws through the Jaegers tube.  Or, make a brushed aluminum collar that fits over the Jaegers tube -- like that adapter that I made for my Mogey 3.  Or, cut a short slot in the Jaegers tube, and use a clamp that fits over it -- like my Tinsley 6.  Or, limit my 1.25" accessories to the ultra-light Tani prism & UO HD Orthos & such.  Good Grief!  Is that how Jaegers intended it?

 

Finder Scope Bracket

 

The "kit" came with that Yuge! cast metal bracket -- same as the one on my 1950s Edmund 4" F15; and, on my Dakin 4, where its size looks appropriate.  It's a lot of metal for a 30mm or smaller finder scope!  I don't have any age-appropriate small finders.  I have several 5x24 & 6x30 finders from the 1970s that'll fit; and, I have the parts on hand to make a 1960s style small finder.  OTOH, the J50 doesn't really need a finder.  With the RKE 28mm (22x), pointing in the general area of most objects will work for sighting them...

 

OTA Color Scheme

 

I can blame this on Robert (clamchip):  He pointed out that the ivory (?) focuser knobs are an unusual & old style...  so, I've ditched the bright yellow (for a Sun Scope), and I'm inclined towards a vintage US Army OD Green -- but in satin or flat rather than gloss finish.  Jaegers parts stay textured black.  All the visible hardware in chrome or stainless steel.


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#43 Bomber Bob

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Posted 20 April 2021 - 05:27 PM

I solved the Focuser Tube problem:  Made an extension tube from a 2" length of 32mm chrome pipe (from experiments to replace the Sears 6336's manual / coarse focus tube) + the 1.25" sleeve from an old diagonal.  It slides into the Jaegers tube for a very tight fit -- no mods required to the Jaegers hardware.  I'll post some pix later.


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#44 Bomber Bob

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Posted 23 April 2021 - 01:03 PM

J50 Rotating Focuser - Pre-Paint:

 

Jaegers 50 Restore S33 - Focuser COMPLETE (Pre Paint).jpg

 

NOTE:  This is a How the Sausage is Made!  photo.  ALL of the cheap "steel" hardware is temporary -- got an order of high-quality stainless steel grub screws & such headed to The Swamp from Mc-Carr...

 

The pix is right before I dis-assembled and applied thin layers of Satin Black to all the kinda/sorta black parts.  They'll all match.

 

From left to right:

 

- Scope Tube (which I haven't cut yet)

- Fixed / Outer Ring bolts to the tube (finder bracket screws on one side); grub screws press against...

- Brass Collar that's attached to the Rotating Ring (a nice chrome thumbscrew on the Outer Ring presses against the Collar to lock it)

- Rotating Ring uses 3 grub screws to hold both the Brass Collar and the...

- Jaegers cast metal Focuser (pot metal?)

- Jaegers Chrome Tube

- BB's Chrome Extender Tube

- BB's 1.25" Accessory Holder w/ Thumbscrew

- Sample 1.25" chrome eyepiece barrel

 

Grub Screws on the 2 Vinyl Rings allow centering the Jaegers Focuser.  Once assembled, the Brass Collar won't show - the inner rotation is brass against a vinyl band (normally used to help vinyl couplings grip PVC pipes).  Outer rotation is vinyl against vinyl.  I polished all the contact surfaces, and with just a bit of Lithium grease, the rotation is smooth.  I can adjust the tension, too.

 

The Jaegers cast focuser... gotta be honest, it's poor quality compared to even the oldest / cheapest Japanese imports.  There's a flaw on the right side.  I considered stripping the paint, then trying to make it prettier with filing & sanding, but since it's cosmetic, and would remove the crinkled black, I left it as-is.

 

Okay Y'all...  BEFORE I CUT THE TUBE, here's my calculations:

 

- Focal Length = 24.5"

- Focuser Length = 8" (with Extender)

- Diagonal Light Path Length = 2.5"  (Baader 1.25" Prism)

 

So...  Tube Length14"

 

Does that pass a sanity check??

 

 


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#45 Bomber Bob

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Posted 24 April 2021 - 03:24 PM

J50 - First OTA Assembly (Pre Paint):

 

Jaegers 50 Restore S52 - OTA Complete LS (Pre Paint).jpg Jaegers 50 Restore S55 - OTA Complete RS (Pre Paint).jpg

 

All the external hardware fits & functions.  Still waiting on the Baffles, the OD Green spray paint, and stainless steel grub screws.

 

Tube Length:  I used Sean Cunneen's method of putting the focal plane 1/4" above the top of a prism diagonal; than add that distance to the racked-in length of the focuser.  Since I know I'm gonna use a Barlow; and, I may want to use my binoviewer, I gave myself an additional 20mm of in-focus.  For the Diagonal length, I averaged my Baader, Tani, & Takahashi prisms.  Thus:

 

- Rotating Focuser + Extender Length = 145 mm
- Prism Diagonal Length + 5 mm FPC = 65 mm
- OTA Tube Length = 415 mm / 16.33"  

 

That leaves plenty of back-focus -- pretty much the full rack on the Jaegers.

 

Here's how the 625mm J50 OTA compares with the 600mm Monolux 4348 (without accessories / with accessories focused at infinity):

 

Jaegers 50 Restore S60 - OTA vs Monolux 4348 (Pre Paint).jpg Jaegers 50 Restore S62 - OTA vs Monolux 4348 (Pre Paint).jpg

 

Like many Towas, the 4348 uses a slender manual-pull / coarse-focus tube.  In the pix, its using a NOS Nihon-Seiko prism + Tani OR 12mm.  The J50 has my 40+ year old Tani prism + Jaegers ER 16mm eyepiece.

 

BIF:  If I don't want / need the Rotating Focuser feature, I can remove the whole thing, discard the Fixed Ring, and slide the Brass Collar back into the OTA -- center & secure it with 4 bolts such that its flush with the tube end.  Also, if I'm not happy with the OD Green paint, I noticed in polishing the tube that the aluminum looks pretty good by itself.  I'd have to clear-coat, or the Swamp Air would turn it into corroded mush!


Edited by Bomber Bob, 24 April 2021 - 05:23 PM.

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#46 Bomber Bob

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Posted 25 April 2021 - 08:02 AM

For positioning the baffles, I'm gonna use it in Fixed Focuser Mode:

 

Jaegers 50 Restore S73 - OTA Fixed Focuser (Pre Paint).jpg

 

But I was itching to try it out yesterday - between severe storms - on the cellphone tower artificial star, but too much glare!

 

It's tough to get it to show, but the Jaegers focuser casting is wonky:  It has a DIP on the top of the casting.  It doesn't affect the focuser tube - thank goodness!  I went through 2 belts on my sander shaping the casting base to get it symmetrical enough to really center it.  Kinda disappointing that Jaegers sold this thing in this shape.  If you just plugged it in a tube unmodified, the focuser would be about 2 mm south / below the final portion of the light cone:

 

Jaegers 50 Restore S74 - OTA Fixed Focuser (Pre Paint).jpg

 

The Finder is one of the best vintage 6x30s that I have:  1980s Celestron (Vixen JP) LER (Long Eye Relief) with a real (not stopped down) doublet objective, and very bright views.  I've swapped it around on at least a half-dozen scopes -- so far...

 

ALL of the Frankenstein Bolts sticking out will be replaced by #10-32, #10-24, & #8-32 grub screws.


Edited by Bomber Bob, 25 April 2021 - 08:57 AM.


#47 Bomber Bob

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Posted 26 April 2021 - 04:55 PM

Baffles - COMPLETE:

 

Jaegers 50 Restore S23 - Brass Baffles COMPLETE (Painted).jpg

 

Paint is still drying!  The 3 x 3D Printed Apertures came in the mail today.  I crimped 4 spots on the edge of each brass collar to get a snug fit, and get each one level.  The material is a satin plastic.  Apertures are:  40mm, 32mm, & 24mm.  But BB, 24mm is smaller than the 32mm focuser tube!  Yep, but the light cone won't be that wide that close to focus. [Based on my calculations, the light cone will be 13.1mm wide -- less than half the tube diameter.]  And, this isn't an RFT, where I want 0% vignetting.  The J50 is a moderately long F12, and I want max contrast -- wring every last detail out of it at 75x per inch!

 

Y'all remember graph paper?  I sketched this out on a sheet, with a scale of 1mm = 3.125mm, and gave the lens its full width of 53.65mm to create a very skinny triangle.  I invite y'all to check my work -- and remember, these baffles have felt strips on the exteriors, so they can slide as needed...

 

BAFFLE APERTURE :: DISTANCE FROM LENS FACE L4

 

40mm :: 168.75mm

32mm :: 258.75mm

24mm :: 374.38mm

 

FOCAL TUBE APERTURE = 32mm :: DISTANCE FROM FOCAL POINT = 145mm :: LIGHT CONE DIAMETER = 13.1mm


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#48 Bomber Bob

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Posted 27 April 2021 - 04:14 PM

Had to hustle to get the baffles & flocking installed early this morning.  Used the artificial star(s) on the tower boxes & hardware (2.5 miles away) to align the finder, and to test the OTA with a UO OR 12.5mm (50x) & Brandon 8mm (78x), straight-through.  VG results (I mainly look for symmetry).  But... with the Baader prism, rings weren't circular:  Jaegers Focuser Tube has about 1mm slop in its casting channel.  I may be able to correct that with pressure from 3 sides with thin vinyl -- milk jug scraps.  Or, tap 3 grub screws in the top, left, & right -- side screws at about 35* to the top one -- and press in on the tube.

 

Daylight Tests:  Colors are as vivid as the FC-50 with both scopes at ~ 80x & 125x; BUT, fringing on the sharp bright edges of boxes, buildings, etc. that's NOT visible in the Tak Fluorite.  However, no glare shield on the J50 -- yet.  These comparisons were straight-through for the J50, Tak diagonal on the FC-50.  Lunt Wedge:  Excellent Solar Scope!  I pushed the magnification up to 195x with the Radian 8mm + GSO 2.5x APO Barlow, and it did not go soft on the spots (limb was a bit hazy, though!).  Best views at 125x with the Nagler 5 (the Wedge is so heavy that it presses the rack down into the channel!).

 

Mounting Issues:  J50 tube is too wide for the 4348's hinged ring, so I had to make a pad for the 60mm Hefty Cradle that came with the Tak SC EQ.  That combo weighs more than the FC-50, and is much longer, so I moved it to the SC's fixed platform, and put the FC on the swing arm for today's tests.  The combined CG was wacky enough to make the SC's stepper motor louder than usual, so I dropped back to manual tracking.  (For night tests, the J50 is heavy enough to ride the SC solo - & properly aligned!)

 

Initial Impressions:  Now in its own OTA, the J50 is far superior to the Towa 50 F12.  I'd have to beg my Swift 838 back from Nolan for a SxS, but once the final hardware issues are fixed, I think it'll be a contender.  It should have less CA than the SYW 60 F7, and better contrast on bright objects.  It is DARK inside the OTA, with no vignetting.  The Brandons are as good as the spectros for showing any glare in the optics, and I saw none today on the very bright tower, windows in the tallest buildings, etc.  Full Moon test tonight IF the weather cooperates -- that'll settle the issue.

 

Jaegers 50 Restore S29 - Baffles Installed LS-Z (Pre-Paint).jpg

 

M-C hardware due by Friday.  Paint due by the end of next week.  CV-19 has made for some of the delays.


Edited by Bomber Bob, 27 April 2021 - 05:00 PM.

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#49 Bomber Bob

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Posted 29 April 2021 - 03:26 PM

I'm Calling It:  Jaegers 50 F12 DONE

 

Jaegers 50 Restore S75 - OTA Fixed Focuser RS (Polished).jpg Jaegers 50 Restore S76 - OTA Fixed Focuser BR (Polished).jpg Jaegers 50 Restore S77 - OTA Fixed Focuser BL (Polished).jpg

 

I had to drive in to the office early this morning.  When I got back home, 2 packages were waiting for me:  the Mc-Carr grubs & the OD Green paint...  Well, at least the M-C order was correct.  The paint vendor sent the Wrong Color -- Gloss Flame Red.  I got an RMA, so it's going back.

 

After I swapped out the bolts, I sanded & polished the aluminum tube; and, at this point, I've leaving it that way -- looks nice!


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#50 Terra Nova

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Posted 29 April 2021 - 04:12 PM

I like bare aluminum tube ATM scopes. I’ve had a couple of them that I really liked! I loved this one. It’s a 102mm with an F6.5 Fujinon objective that was a wonderful lens. I’m not sure that one of the elements didn’t use exotic glass as the color was quite well controlled for a fastish achromat? Not an apo but still, very good! I gave it to a dear friend after I got the Vixen ED102SS, (also a 102mm F6.5).

 

The little one here is a 70mm F 4.5 with a Carton objective. It’s gone too. The TV Pronto fills that gap now. I also gave away the fairly rare,1940s Professional Jr. newsreel camera tripod they’re sitting on. Idiosyncrasies associated with its age and design made it less capable for telescopes than for its intended movie cameras. Anway, brushed bare aluminum tubes are quite attractive for ATM refractors in my book.

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Edited by Terra Nova, 29 April 2021 - 04:17 PM.

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