testing 2" focuser adapted to fit an orion ST80

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realflow100 United States of America
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testing 2" focuser adapted to fit an orion ST80

#1

Post by realflow100 »


testing 2" focuser adapted to fit an orion ST80
I got it as a gift someone sent me in the mail for free. took some tuning up and needs to be re-greased thoroughly. but it works.
I had to modify the focuser with a hacksaw as the focuser tube was far too long. I shortened it by slightly more than 3 inches. to remove the excess and minimize vignetting as much as possible. to get maximum open aperture.
Adjusted telescope baffle position
I'm planning on flocking my telescope fully as well. to maximize contrast as much as possible and reduce internal glares flares and reflections. from the focuser. to the lens hood.
vignetting test and image of it assembled (eyepiece and diagonal are not used with my camera. I just happened to have that in it at the time of taking the picture)

Focuser is just stuck on with a tight friction-fit. it just barely fits. Need something to cover the screw holes up with. and also clamp the focuser on tight to make sure it doesnt budge in use. (its on there pretty darn tight already. doesnt come off easily)

Image
Image
Image
It was cloudy when taking this photo so thats what those streaks are and why its so much brighter at the top.
but the corners dont seem too bad. its mostly even.
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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Frankskywatcher United States of America
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Re: testing 2" focuser adapted to fit an orion ST80

#2

Post by Frankskywatcher »


That’s very interesting that you were able to cut down the focuser tube.
Bravo for getting it together,abet a really snug fit !

I recently did what you did ( yesterday ) but I could not cut down my tube as the toothed rack also goes right to the end of the tube.
I wish I could have because the tube is all the way out of the focuser to focus.
Did your toothed rack go alll the way to the end of the tube too and or did you just cut it off and re screw it back on ?
I’m really curious about how you modified the tube, thanks in advance Frank
Attachments
65D24791-1096-4818-895A-947C83EAB5BF.jpeg
Gee if I had known there was so much to see I would have started decades ago ! :Astronomer1:

Equipment :
Apertura AD10” Dobsonian

Polaris 4” Dobsonian

7x50 binoculars
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realflow100 United States of America
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Re: testing 2" focuser adapted to fit an orion ST80

#3

Post by realflow100 »


I cut the saw tooth rack as well and drilled new holes in it as well as the tube for a screw (Used a different screw with a wider and sharper thread pitch to bite into the aluminum better. with a tapered tip)

I did it by unscrewing the rack flipping it upside down and re-attaching it with one screw near the eyepiece side. then marking and drilling a hole in it at the other end where I want to attach it to. and through the focuser at the same time. so the holes both line up.
Then unscrewed it flipped it right-side-up and simply screwed both screws down. worked fantastic! though you do need a hacksaw and an appropriate sized drill bit
I left a gap at the end of the focuser so it doesnt rack out too far and get super wobbly. (you can adjust for focus range distance by changing where you cut the toothed rack part)

You can tape it down or something so it doesnt "move around" while drilling the hole and for alignment.
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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Frankskywatcher United States of America
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Re: testing 2" focuser adapted to fit an orion ST80

#4

Post by Frankskywatcher »


Thank you for taking the time to respond.
You are a braver man than I Gunga din because I was afraid to cut that rack but thank you for explaining that to me in terms of how you did it .
I think I’ll be doing that down the road at some point.
Congratulations on a successful operation Dr.😁
Gee if I had known there was so much to see I would have started decades ago ! :Astronomer1:

Equipment :
Apertura AD10” Dobsonian

Polaris 4” Dobsonian

7x50 binoculars
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Bigzmey United States of America
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Re: testing 2" focuser adapted to fit an orion ST80

#5

Post by Bigzmey »


Nice mod! Since you are comfortable with saw and drill, you could drill and tap new holes to secure the focuser.
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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realflow100 United States of America
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Re: testing 2" focuser adapted to fit an orion ST80

#6

Post by realflow100 »


Dont have a tap and most of my drill bits are missing or broken lol.

also the focuser doesnt slot on far enough for screws to hold. its blocked by protruded surfaces underneath each screw hole. which only gives a tiny tiny surface to hold onto the edge of the telescope tube.
I would need very small screws. and a lot of them. all precisely drilled like a machine. probably at least 6 for it to fit securely enough.
but I dont have the skill to do that. or a drill press for precision.
I used an actual cordless drill for the focuser (I did a couple test-holes on the cut-off piece to make sure im doing it right)
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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Bigzmey United States of America
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Re: testing 2" focuser adapted to fit an orion ST80

#7

Post by Bigzmey »


realflow100 wrote: Fri Apr 08, 2022 10:51 pm also the focuser doesnt slot on far enough for screws to hold. its blocked by protruded surfaces underneath each screw hole. which only gives a tiny tiny surface to hold onto the edge of the telescope tube.
It did look from photo that way. You could file off those protruded surfaces to push the focuser deeper.
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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realflow100 United States of America
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Re: testing 2" focuser adapted to fit an orion ST80

#8

Post by realflow100 »


That might take several hours unless I had some kind of motorized file or a sanding device. but even then it might still take a long time.
Also it seems to hold fairly well enough as it is. not sure I want to ruin it. Doesn't seem like its coming loose on its own without a BIG bump or bonk. its hard to get off on purpose.

I could probably just put 3 small spots of superglue if I want to ensure it doesnt shift or tilt slightly.
Svbony SV503 70mm ED F6 420mm FL refractor telescope (New)
Canon EOS 100D/SL1
Tamron 18-200mm F3.5-F6.3 II VC lens
canon 50mm STM F1.8
svbony 8-24mm zoom eyepiece
svbony goldline 66 degree 9mm and 6mm + 40mm plossl + 2x barlow.
svbony UHC 1.25 filter + astromania 1.25" O-3 filter + also an svbony H-B filter.
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