R&P focuser recommendations?

Discuss any astro equipment that does not have its own forum, such as focusers, finders, chairs, etc.
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KathyNS Canada
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R&P focuser recommendations?

#1

Post by KathyNS »


My Orion 200mm f/4 Newtonian astrograph came with a GSO LF Crayford focuser. While it is a good unit, it doesn't quite have the traction to support the weight of my Atik 383L+ camera, EFW2 filter wheel, and Paracorr 2. At cold temperatures, the focuser has to rack out more than at warm temperatures. As the temperature drops and the focuser racks out more, it eventually loses traction and the camera load drops.

I'll try to dial in more tension on the Crayford mechanism, but the difference between too tight to move and too loose to hold is only about 10 degrees of rotation of the tension knob.

Perhaps the traction bar on the focuser tube is not flat enough, or perhaps the tube tilts as it extends, reducing the friction. I don't know. I have read about tuning up your Crayford, and I might give it a try.

But the more I think about it, the more I think the solution is a rack and pinion. Obviously there is a huge difference between the el-cheapo R&P focusers on toy scopes and quality units on AP scopes.

So I am looking for recommendations. It needs to take 2" eyepieces and accessories. It doesn't have to be particularly low-profile, since the Paracorr extends the focal point enough for AP. It does need to have a base for an 8" Newt. Being able to accept a Rigel focus motor would be a bonus.

Thanks for any suggestions.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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Lady Fraktor Slovakia
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Re: R&P focuser recommendations?

#2

Post by Lady Fraktor »


The Baader is supposed to be a solid unit and I think Agema Astro carries them: https://www.baader-planetarium.com/en/a ... track.html
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yobbo89 Australia
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Re: R&P focuser recommendations?

#3

Post by yobbo89 »


I can only recommend a moonlight ! or something 2.5'' with a 2'' adapter step down for heavy gear, i have about 2.7 kg - 3kg imaging gear (starlight 9x2''fw aog,cc,asi1600) no flex ,no slipping,on point every time
scopes :gso/bintel f4 12"truss tube, bresser messier ar127s /skywatcher 10'' dob,meade 12'' f10 lx200 sct
cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7,asi 290 mm
mounts : eq6 pro/eq8/mesu 200 v2
filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, chroma 3nm ha,sii,oiii,nii,rgb,lowglow,uv/ir,Thousand Oaks Solar Filter,1.25'' #47 violet,pro planet 742 ir,pro planet 807 ir,pro planet 642 bp ir.
extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII Coma Corrector,Orion Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel,tele vue 2x barlow .

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yobbo89 Australia
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Re: R&P focuser recommendations?

#4

Post by yobbo89 »


KathyNS wrote: Mon Sep 30, 2019 2:14 pm My Orion 200mm f/4 Newtonian astrograph came with a GSO LF Crayford focuser

Thanks for any suggestions.
I think you'll find it has rail bearing with a tongue/groove, all the support is being and is only done at one side of the focuser ie where the rolling pin is,i found this type of focuser gives me a lot of movement when drawn out, really need that extra roller bearing support on the other side of the focuser tube.

attached a pic of this monster focuser :Astronomer1:
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yiQeGq1.jpg
Last edited by yobbo89 on Tue Oct 01, 2019 5:56 pm, edited 1 time in total.
scopes :gso/bintel f4 12"truss tube, bresser messier ar127s /skywatcher 10'' dob,meade 12'' f10 lx200 sct
cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7,asi 290 mm
mounts : eq6 pro/eq8/mesu 200 v2
filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, chroma 3nm ha,sii,oiii,nii,rgb,lowglow,uv/ir,Thousand Oaks Solar Filter,1.25'' #47 violet,pro planet 742 ir,pro planet 807 ir,pro planet 642 bp ir.
extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII Coma Corrector,Orion Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel,tele vue 2x barlow .

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fatboy1271
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Re: R&P focuser recommendations?

#5

Post by fatboy1271 »


I've been using the ZWO EAF and while it's my first AF, I like it.
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
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mbenjaminz28 Canada
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Re: R&P focuser recommendations?

#6

Post by mbenjaminz28 »


I use a moonlight CSL2.5" on my meade 12" LX600 ota, works great. It held my Sbig STT-8300/FW8G/AO-8t with no problems.
William optics flt 132, WO 0.72 reducer, Sbig Aluma U694/FW8G/AO-8a, 36mm LRGB 3nm Ha Oiii Sii, Cem120 non ec, Celestron CGX, Meade 12"F8 ota, Meade 70mm astrograph, Meade 6sn, TSflat2
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