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Crayford: Dual Speed or single speed motorised?


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Hiya all,

I am not really impressed with a stock RP focuser on my SW200P, to say the least.. even with some added spacers, it is still wobbly and the slop is quite severe, especially annoying when collimating.. So I was/am contemplating getting a crayford, to hopefully eliminate/drastically diminish the slop. (of course, I will still try adding more teflon spacers etc, but me wanting to try some DSLR astro-work would probably still mean I'd need a lower profile focuser, so...).

As Moonlites etc. are way out of my league, I was looking at more budget type-ones such as SW dual crayford, Agena, GSO and all that family. Now I got to thinking.. Do I really need a dual speed one, as I already have a SW motor focuser with variable speed..? Wouldn't that be "same" or similar, as having 1:10 manual speed control? :) That could potentially save me some £££, as I have already spent too much this month(season!) :headbang: and my main requirements are slop elimination, and a lower profile. (though I really like the built-in extension tube on the SW dual crayford :)).

On the other hand though, not needing another battery to worry about going flat and not having another piece of wire hanging around here and there would also be quite tempting.. Though I am yet to test how this set-up copes with my shaky hands on the focuser :)

Your opinions please..:D

Cheers

Marius

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hi there

I presume you have tried tightening the little grub screws on the focuser? This eliminated the slop in the R&P focuser on my refractor (although I have swapped it for a 10:1 SW now). won't reduce the profile though.

I also have the SW 10:1 for my dob which I'll be fitting this weekend. I'll do a first light at some point after then.

cheers

Shane

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hi there

I presume you have tried tightening the little grub screws on the focuser?

Shane

Yeah, actually done that after I posted it yesterday :). It doesn't wobble that much with them slightly more tightened, but the motor focuser seams to be working quite a lot harder, and there's still that shift when changing directions, i.e. i have to defocus out and then return slightly back to focus, to level the focus tube angle.. This is even "bigger deal" when using my 2" EP which weights about 600g or working with higher magnification..

Marius

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Telescope House has their dual speed Newtonian crayford focuser at 10% off this weekend which would make it £90.00 and Scopes'n'Skies has a base plate in their AstroBoot section that will fit the hole spacing in the SkyWatcher OTA for £2.00 Just make sure you get the wider base plate that is half way down the page and not the narrow one at £3.00 that is near the top of the page.

http://www.telescopehouse.com/acatalog/Revelation_Newtonian_Crayford_Focuser_Dual_Speed.html

http://www.scopesnskies.com/AstroBoot

John

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Telescope House has their dual speed Newtonian crayford focuser at 10% off this weekend which would make it £90.00 and Scopes'n'Skies has a base plate in their AstroBoot section that will fit the hole spacing in the SkyWatcher OTA for £2.00 Just make sure you get the wider base plate that is half way down the page and not the narrow one at £3.00 that is near the top of the page.

http://www.telescopehouse.com/acatalog/Revelation_Newtonian_Crayford_Focuser_Dual_Speed.html

http://www.scopesnskies.com/AstroBoot

John

It's a cracking deal, one i've made use of in the past. And the Rev focuser works very well.

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This focuser is great, but you definitely need the Skywatcher-sized baseplate, and there are also focal length issues. Have a look at these two threads, wherein I chronicled the process of getting my Revelation to work on my 200P...

http://stargazerslounge.com/equipment-help/97658-revelation-focuser-skywatcher-200p.html

http://stargazerslounge.com/equipment-help/99455-help-focuser-woes.html

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Telescope House has their dual speed Newtonian crayford focuser at 10% off this weekend which would make it £90.00 and Scopes'n'Skies has a base plate in their AstroBoot section that will fit the hole spacing in the SkyWatcher OTA for £2.00 Just make sure you get the wider base plate that is half way down the page and not the narrow one at £3.00 that is near the top of the page.

http://www.telescopehouse.com/acatalog/Revelation_Newtonian_Crayford_Focuser_Dual_Speed.html

http://www.scopesnskies.com/AstroBoot

John

uuh, really tempting.. but the TH page shows it as £100.12 still..

Thanks for all the info guys! It's just the question in the thread title then, again, am I better off with dual speed, or single speed motorized? Even at this nice price, I reckon I could save another £35-ish if going for a single speed as I already have a remote.. :)

Marius

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If its the SW Autofocosuer you have, it might be problematic to attach it to a crayford. Mine certainly would not fit on the GSO or Antares Crayfords.

Stephen

Apparently Orion USA has another adapter plate available for the Autofocus/Accufocus that fits the dual speed crayford. Their dual speed is identical to the Skywatcher/Revelation. I'll see if i can find it.

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If its the SW Autofocosuer you have, it might be problematic to attach it to a crayford. Mine certainly would not fit on the GSO or Antares Crayfords.

Stephen

Good point.. though I think I remember a member here (euan?) selling his SW dual crayford with SW auto-focuser attached. Maybe some new hole drilling in the auto-focuser mounting plate is involved, but I'm fine with that :)

Apparently Orion USA has another adapter plate available for the Autofocus/Accufocus that fits the dual speed crayford. Their dual speed is identical to the Skywatcher/Revelation. I'll see if i can find it.

The thing is, as I said, I would be more inclined to buy a single speed crayford and attaching Autofocuser to save some ££ :D Though i Assume the holes for single/dual crayfords should be the same?

Marius

Edited by zhgutas
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Cheers Russ. Looks quite the same as the original adapter that comes with Autofocus.. maybe some measurements differ, though even then, I doubt it would be such a problem knocking out the adapter plate myself :)

Marius

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Cheers Helen, everyone's seams to be pushin' me towards this DS :)

Thanks everybody again for your input.

I'd like to reiterate my main question here, however, as I'm still undecided, even with such nice deals around..

Dual speed manual, or single speed motorized?

Cheers

Marius

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Sorry, i missed the original question. You don't mention any planetary imaging in your plans, so i would personally go with the dual speed.

Edited by russ
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I've used both, and I now just prefer a good dual speed focuser. With the motorised unit, having to disconnect the motor when you want to move the focuser manually gets really irritating, and then of course the battery can go flat.

John

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Sorry, i missed the original question. You don't mention any planetary imaging in your plans, so i would personally go with the dual speed.

Any notes on Why? Well I might just want to do that sometime :headbang: Thing is, as I said, I already have a speed regulated Autofocuser, so thought it would work as good/even better on single speed than DS crayford manually.. :) And is there a point in attaching Autofocus to a DS? ..:D

Excuse my ignorance..

Marius

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I went the single speed with autofocus route with my 200P. It made sense at the time because it was more important to have a vibration and image shift free setup for the planetary imaging. The single speed crayford with the Autofocus achieves this for only £100 which is amazing. But as John says, for normal visual observing you want to disengage the motor because it's easier to manual focus, especially if you have a lot of focus travel between different eyepieces. The Autofocus can seem painfully slow at times.

It's a shame Synta haven't modified the Autofocus with some sort of clutch system. It's been out a long time now, approx 6 years.

Edited by russ
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hi there

I actually bought Euan's DS SW focuser - it's packaged awaiting my wedding anniversary on Sunday (I buy everything well in advance if a good offer comes up!).

I had no use for the DC focuser so sold it.

the reason I mention this is that my for sale thread contained the pics below which might help you understand the mods that Euan made to the bracket to get it to work with the crayford.

hope this helps. I was lucky, I ended up getting an excellent DS SW crayford for my newt effectively for £70 after I sold the DC focuser.

good luck with the decision.

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