New from old 3 1/2"

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DeanD Australia
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New from old 3 1/2"

#1

Post by DeanD »


Hi All,

I am in the process of "refurbishing" an old 3 1/2" f10 scope that was owned by the late Bill Bradfield (comet hunter extraordinaire). I have got it to "proof of concept" stage, and now I need to improve the contrast by properly baffling the tube (it is unreal how much light scatter you have when the tube is only matt black!). At this stage the optics are looking good: it coped happily with a 120x view of Jupiter last night, but the seeing was atrocious.

I have included "before" and after images. As you will see, Bill never worried about aesthetics (check out his objective cover!!!), and used whatever came to hand, so I have tried to keep true to his memory by using what I could find lying around and a piece of 4" pvc down-pipe for the tube. The vixen-style dove plate attachment is made from a piece of wood I planed to shape, and with aluminium "L" section bent to fit. I had some old tube rings which I have lined to fit with bits of packing material from the cupboard. Cost so far is around $A20 (mainly for the paint!)...

This is Bill's original (and, yes folks, that is a piece of vacuum cleaner tube jammed into the focuser to act as the eyepiece holder, with a 1", 25mm fl Kellner packed with cardboard to fit!):
Bill Bradfield 90mm 1.jpg
From the front, complete with objective cover!
Bill Bradfield 90mm 2.jpg
Current refurbishment: The objective assembly is a solid brass tube, about 5" long (ex military, probably pre-WW11), so I have left the central bit of brass showing - the rest is ribbed and covered in military paint, so not worth polishing up).
Bill Bradfield 90mm refurbished1.jpg
Bill Bradfield 90mm refurbished2.jpg
Bill Bradfield 90mm refurbished3.jpg
It will be interesting to see how well it performs when I have added baffles.

Happy viewing,

Dean
Telescopes: 12" f5 dob, Celestron CPC800, 150mmf5 Celestron achro, Tak TSA102, TV76, ETX125...
Binos: Steiner Wildlife XP 10x26, Swarovski 8x30 Habicht, Zeiss SFL 8x40, Vanguard Endeavour 10.5x45, Fuji FMTR-SX 10x50, Tak 22x60, Orion Resolux 15x70
Eyepieces: way too many (is that possible?), but I do like my TV 32mm plossl, 13mm Nagler T6, 27mm Panoptic and 3-6mm Nagler zoom, plus Fujiyama 18mm and 25mm orthos and Tak 7.5mm LE
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AstroBee United States of America
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Re: New from old 3 1/2"

#2

Post by AstroBee »


That's quite the transformation! Congrats on a fine job.
Greg M.~ "Ad Astra per Aspera"
Scopes: Celestron EdgeHD14", Explore Scientific ED152CF & ED127 APO's, StellarVue SV70T, Classic Orange-Tube C-8, Lunt 80mm Ha double-stack solar scope.
Mounts: Astro-Physics Mach One, iOptron CEM70EC Mount, iOptron ZEQ25 Mount.
Cameras: ZWO ASI2600mm Pro, ZWO 2600MC Pro, ZWO ASI1600mm
Filters: 36mm Chroma LRGB & 3nm Ha, OIII, SII, L-Pro, L-eXtreme
Eyepieces: 27mm TeleVue Panoptic, 4mm TeleVue Radian, Explore Scientific 82° 30mm, 6.7mm , Baader 13mm Hyperion, Explore Scientific 70° 10mm, 15mm, 20mm, Meade 8.8mm UWA
Software: N.I.N.A., SharpCapPro, PixInsight, PhotoShop CC, Phd2, Stellarium
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WilliamPaolini United States of America
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Re: New from old 3 1/2"

#3

Post by WilliamPaolini »


Beautiful job! I love it when the dew shield is the same diameter as the OTA. Makes the lines so much cleaner looking. While IMO baffles are best, at f/10 I would expect just flocking the interior should be very effective as well. It's super easy if you can get the flocking that is on a stiff backing so it just slides in rolled smaller than the tube and opens to fit the tube staying in place by pressure.
-Bill

U.S.A.F. Veteran - Visual Amateur Astronomer since 1966 - Fully Retired since 2019
8" f/5 Newt - Lunt 152 f/7.9 - TSA 102 f/8 - Vixen 81S f/7.7 - P.S.T. - Pentax 65ED II - Nikon 12x50 AE
Pentax XWs - Baader Morpheus - Takahashi LEs - Edmund RKEs - BST Starguiders - 6ZAO-II/5XO/4Abbe
PM and Email communications always welcomed
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Re: New from old 3 1/2"

#4

Post by Bigzmey »


Looks great! Well done Dean!
Scopes: Stellarvue: SV102ED; Celestron: 9.25" EdgeHD, 8" SCT, 150ST, Onyx 80ED; iOptron: Hankmeister 6" Mak; SW: 7" Mak; Meade: 80ST.
Mounts: SW: SkyTee2, AzGTi; iOptron: AZMP; ES: Twilight I; Bresser: EXOS2; UA: MicroStar.
Binos: APM: 100-90 APO; Canon: IS 15x50; Orion: Binoviewer, LG II 15x70, WV 10x50, Nikon: AE 16x50, 10x50, 8x40.
EPs: Pentax: XWs & XFs; TeleVue: Delites, Panoptic & Plossls; ES: 68, 62; Vixen: SLVs; Baader: BCOs, Aspherics, Mark IV.
Diagonals: Baader: BBHS mirror, Zeiss Spec T2 prism, Clicklock dielectric; TeleVue: Evebrite dielectric; AltairAstro: 2" prism.
Filters: Lumicon: DeepSky, UHC, OIII, H-beta; Baader: Moon & SkyGlow, Contrast Booster, UHC-S, 6-color set; Astronomik: UHC.

Observing: DSOs: 3106 (Completed: Messier, Herschel 1, 2, 3. In progress: H2,500: 2180, S110: 77). Doubles: 2382, Comets: 34, Asteroids: 255
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DeanD Australia
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Re: New from old 3 1/2"

#5

Post by DeanD »


WilliamPaolini wrote: Fri Nov 26, 2021 8:02 pm Beautiful job! I love it when the dew shield is the same diameter as the OTA. Makes the lines so much cleaner looking. While IMO baffles are best, at f/10 I would expect just flocking the interior should be very effective as well. It's super easy if you can get the flocking that is on a stiff backing so it just slides in rolled smaller than the tube and opens to fit the tube staying in place by pressure.
Thanks Bill: I wanted to do that, but I can't find anything suitable locally. I am trialling a "cage" made up of 3 baffles of appropriate diameter and separation connected by 4 fibreglass skewers that were once ribs from a dead umbrella. Waste not, want not: following (the other) Bill's example! I will push the cage in from the focuser end and fix it in position if it works... The main problem with this is getting nice clean-edged internal holes.

All the best,

Dean

(BTW, fun fact: I was talking to Bill Bradfield about his comet hunting one day (I think he found 18 visually!), and he commented that he lived in the wrong century- he calculated that if he had got the prizes offered in the 19th century for discoveries he could have had enough to buy a house! ;) )
Telescopes: 12" f5 dob, Celestron CPC800, 150mmf5 Celestron achro, Tak TSA102, TV76, ETX125...
Binos: Steiner Wildlife XP 10x26, Swarovski 8x30 Habicht, Zeiss SFL 8x40, Vanguard Endeavour 10.5x45, Fuji FMTR-SX 10x50, Tak 22x60, Orion Resolux 15x70
Eyepieces: way too many (is that possible?), but I do like my TV 32mm plossl, 13mm Nagler T6, 27mm Panoptic and 3-6mm Nagler zoom, plus Fujiyama 18mm and 25mm orthos and Tak 7.5mm LE
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WilliamPaolini United States of America
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Re: New from old 3 1/2"

#6

Post by WilliamPaolini »


Love what Bill Brandfield told you!! An idea for you on the flocking should the baffles not work as you want, if you can find flexible plastic sheeting that can be rolled then will unroll when let go, you could always glue the conventional un-backed flocking to that, then just roll it up and put it in the focuser end.
-Bill

U.S.A.F. Veteran - Visual Amateur Astronomer since 1966 - Fully Retired since 2019
8" f/5 Newt - Lunt 152 f/7.9 - TSA 102 f/8 - Vixen 81S f/7.7 - P.S.T. - Pentax 65ED II - Nikon 12x50 AE
Pentax XWs - Baader Morpheus - Takahashi LEs - Edmund RKEs - BST Starguiders - 6ZAO-II/5XO/4Abbe
PM and Email communications always welcomed
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DeanD Australia
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Re: New from old 3 1/2"

#7

Post by DeanD »


Follow-up post: the baffles are working well, and the view is very good with nice contrast and sharpness. It is very slightly out of alignment so it needs a bit of tweaking, but I could see the 6 stars in the "trapezium" in a recent test of the optics (number 6 was pretty difficult, but popped in and out), so I am happy with it.
I hope to have a bit of a play with it tomorrow night from a dark site.
My only problem now is what to do with it: I would like to give it to a worthy home because while it is great for what it is, realistically I have more than enough telescopes (yes, I know that is heresy!)...
(... and before anyone asks: sorry, but I am not posting it to the US or Europe!)
Telescopes: 12" f5 dob, Celestron CPC800, 150mmf5 Celestron achro, Tak TSA102, TV76, ETX125...
Binos: Steiner Wildlife XP 10x26, Swarovski 8x30 Habicht, Zeiss SFL 8x40, Vanguard Endeavour 10.5x45, Fuji FMTR-SX 10x50, Tak 22x60, Orion Resolux 15x70
Eyepieces: way too many (is that possible?), but I do like my TV 32mm plossl, 13mm Nagler T6, 27mm Panoptic and 3-6mm Nagler zoom, plus Fujiyama 18mm and 25mm orthos and Tak 7.5mm LE
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Re: New from old 3 1/2"

#8

Post by Lady Fraktor »


So much for that thought... :)
A wonderful job with this Dean, hopefully you can find a good home for it.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
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