Crayford Focusser Question

[NeilW]

Hi,

I'm looking at putting a 10:1 Crayford style micro-focusser on my 8" dob, and I'd like to know if there's any real benefit in getting the low profile version, other than it takes up space than the standard version. They're the same price.

Any comments?

Thanks

Neil

[Astrobserver99]

If you plan on doing imaging through your dob, then a low profile focuser is usually recommended...

[asimov]

I'd be tempted to go the low profile job. You can always get to focus by using an extension tube if needed.

[Benno18]

Just wondering where you were going to purchase the focuser from? Been looking around for the same thing for my 10 inch.

Thanks Ben

[middy]

I recently purchased a standard 10:1 Crayford for my 8" Dob. The reputable telescope shop where I purchased it told me that they no longer sold the low profile version as they had had some issues with it. I was told because the bearings were closer together in the low profile version that the drawtube was prone to a little sideways flex.

It is a good job I didn't get a low profile focuser as the standard size one I bought actually doesn't have enough OUTWARD travel for my eyepieces. It seems to be OK for my DSI camera though. I haven't had chance to test it with the Toucam yet due to all the bad weather in Qld lately.

[NeilW]

Ben, I was looking at the GS ones at Andrews:

http://www.andrewscom.com.au/site-section-10.htm (scroll about 3/4 of the way down).

Middy, I have the same problem. With the standard Crayford on my SW dob, there are some EPs that I can barely focus with the thing fully extended.

Thanks,

Neil

[bmitchell82]

If it where me ide stay well well clear of any focuser from gso, they might look and feel like they are built well but they are very very bad to the point where you standard SW focuser is better! I have been there and done it.

for skywatcher telescopes they have actually made them with sufficient back focus so a low profile varient is pointless and will just add to the leaver arm hanging off your focuser.

if money is a problem the standard Moonlight CR2 focuser is gold! good design and can lift a fair whack of gear (big eye pieces/cameras) if money isn't a problem a good feather touch from Starlight Instruments is beautiful!

Ill be posting some images of the install of a 3" feathertouch on my skywatcher dobsonian once it arrives. But for now another friend has one on his RC so i got to hold it upto the tube... wow it doesn't look small at all! :)

[multiweb]

Wow! Let me see... ED80, replaced the focuser by a 10:1 GSO. 5" Newt, replaced the focuser by a 10:1 GSO. C11, replaced the focuser by a 10:1 GSO... :confuse3:Damn! I'm screwed! :rofl:

[bmitchell82]

hahaha... well you have got lucky my dear friend. everybody i have seen with a GSO focuser just wanted to smash it with a ball pene hammer as hard as they could! I put mine on made special flanges and all to get it to fit it lasted a total of about 2 hrs on my OTA before i ripped it off in disgust!

[troypiggo]

+1 - I put one on my ED80 and had one on the C8. Both held focus well and worked a treat for a fraction of the price of Moonlites and FeatherTouches. I'm not "dissing" the Moonlites or FT's, I now have 2 Moonlites on other scopes, but still have the GSO one on the ED80 and it'll be there for as long as I own the scope.

[multiweb]

Brendan, I initially bought GSO based on other user's experience and they all recommended the product. I ended up converting all of my scopes focusers even replacing an old Moonlite in the C11 to a GSO :P. I have also used various adapters, mirrors, lenses, focusers and bits and pieces over the years from the GSO brand. I find them a very reputable mob. Hell, they even make RC clones that people are apparently happy with so go figure.... I find that saying GSO focusers are very very very bad is a bit misleading. They do the job IMO for what you pay for. Of course you won't hang an ST11K off one. I realise you had a bad experience and don't like them but that's you. Not bad luck. :)

[mithrandir]

+0.5 - I have a GSO 10:1 on the ST80 and a Moonlite (DC motor) on the C8.

No complaints with either one.

[bmitchell82]

Fair enough mark, my problem was that it couldn't hold a 40d and with massive axial slop no matter what adjustments i made. and if you get one of them big 2" eps they weigh just about the same as my 40d. once bitten 3 times shy. :) I guess for me if im going to spend 120-150 for a new focuser i want it to be a very big upgrade to standard. not just a intermediate upgrade that will only give you a feature not an improvement overall, its just the way i am.

Sure there is a point of deminishing returns but in the realm of low end focusers for less than 100 dollars more you can get yourself a base moonlight focuser that is superior in quality. Better 10:1 pinion gears, Better finish, Better fit, Better everything. and dont get me wrong, for light duty work the 10:1 focuser from GSO is reasonable and "gets the job done" but just like my skywatcher focuser... it too gets the job done and if i really wanted a bit better fine adjustment i should just make a 100mm leaver :) which would reduce the ratio of turn! :).

I have taken a path though astronomy where if i made a few different decisions i would have been better off and not ripped most of my hair out. If i can pass some of this information on then my job is done.