After market focuser for refractors

[spaceboy]

This is probably curiosity more so than anything else. I notice a lot of people on SGL tend to go with moonlite focusers when upgrading their refractors. Given that a moonlite despite being a superbly engineered piece of kit is still basically at the end of the day a crayford focuser, how come most go with the moonlite over say a Baader diamond track? As far as I am aware they both rotate and are both collimateable. The only difference aside from the glitz of the moonlite is that in theory the Baader should offer a performance advantage due to the precission r&p design.

I will note that I haven't included feather touch focusers in the discussion as apparently these don't offer the option of rotating like the moonlit and Baader focusers do. This being a significant disadvantage when used on EQ mounts. Not only that they are considerably more expensive. I'm also aware that there are several other capable focusers available from revelation / gso but for some reason they don't seem as popular as Baader and moonlite for a stock substitute despite their affordability. Again I am purposely leaving out the budget end "upgrade" focusers from the discussion as while they offer some additional features over stock focusers I don't feel they offer the same level of engineering that moonlite and similar mid to high cost focusers offer. As far as WO focusers go this could be a muddy puddle as I'm aware they offer some truely superb focusers but also in a similar way to GSO have many comparable to the cheaper Chinese and quite poor offerings. 

I have also noticed that it appears to me anyway that we in the UK favor moonlite where the other side of the pond tend to have a larger following for Baader. 

I know a lot of member are happy buying used so I'm sure this also play its part and if something comes up that offers a significant advantage over stock at an affordable price then why not go for it. But if you had the choice which focuser would you go for if you had a realistic budget for new and what would your reasons be??

[Moonshane]

As a visual observer I fit in the whatever comes up first bracket. I have Moonlite and Baader Steeltrack and of the two I think on balance I prefer the Moonlite. I have never had any issues with either but there seems to be less fiddling required with the Moonlite and it's a tad smoother (softer touch). The Baader I had to tune ever so slightly. The one bane of the Moonlite is the apparently inevitable track lines on the drawtube, although they never seem to create any issues with smooth function. Given money no object, I'd buy new Feathertouch R&P as they are better again but for me Moonlite/Baader/Feathertouch are all fine and as I say whatever comes up used first is what I tend to go for. If buying new I think I'd still go for the Moonlite as costs are not that different.

[wookie1965]

I thought of a new focuser for my Tal but I have read that they are tricky if not impossible to change.

[Stu]

I've used all three of the main brands, FeatherTouch, Moonlite, and Baader SteelTrack.

Each have their merits. I like the small FeatherTouch units such as the FTF2025BCR I have fitted to my Tak. Lovely and smooth, there is nothing to match it really but the travel is short (2.5") and I do need to use extension tubes when not using binoviewers. I can easily rotate the tube in its rings if needed so a rotating focuser is not a big deal for me in that instance. The lack of a mounting point for a Finder is frustrating though, wish they would sort that out. I mount my Finder show on one of the tube rings, works well.

The Moonlites are lovely too, larger units which probably suit slight bigger scopes better (had them on ED120s a couple of times) but they do offer longer travel which is handy. Like Shane the marks left on top of the tube are a little annoying but is guess FT and Baader have the patents sorted to prevent them doing the same.

I fitted a nice Baader SteelTrack to the Vixen 150 which Kerry now has. Was very happy with that too, and particularly liked the motor kit, SteelDrive which was excellent. I had a similar setup fitted to my C8 Edge and would have another like a shot.

I've never had problems with any of them really, so I guess it is just down to personal preference, scope and budget.

[spaceboy]

8 minutes ago, wookie1965 said:

I thought of a new focuser for my Tal but I have read that they are tricky if not impossible to change.

I can't see why? You would at worst have to approach a local engineering shop to have an adapter made which I'm sure would cost not much more than buying a commercially available.

[swag72]

I have used a Moonlite, Feathertouch and Baader Stelltrack clone for imaging. I have to say that out of the bunch the Moonlite was the worse. It became very 'notchy' quick quickly and while it looked nice it was all mouth and no trousers in my experience. 

The Feathertouch is lovely - It was buttery smooth all the way through the focus and was a joy to use, inspiring total confidence.

The Baader Steeltrack clone was very good....... It was perhaps not quite as smooth as the FT, but worked well and held my camera without issue. 

[wookie1965]

6 minutes ago, spaceboy said:

I can't see why? You would at worst have to approach a local engineering shop to have an adapter made which I'm sure would cost not much more than buying a commercially available.

Got this from another post I dont want to mess the scope up.

[spaceboy]

9 minutes ago, wookie1965 said:

Got this from another post I dont want to mess the scope up.

From what I gather an external adapter will be the solution. As I previously mentioned an adapter will have to be made so this can be took in to consideration when approaching an engineer. If anything this may be a good thing as it seems the seam on Tal100RS aren't the best as I too can confirm. Personally I found the crayford on my RS to be fine. I'm aware the older R version R&P focuser were poor though but ironically had far better optics.

[wookie1965]

Thank you Spaceboy I will look into that the focuser in it is smooth but when I rotate it the object im looking at moves quite a bit sometimes even out of the FOV. I thought a different focuser may stop this.

[spaceboy]

Sounds more like the end of the ota isn't 100% square and so the focuser isn't aligned with the objective. Have you ever checked collimation? 

[nightfisher]

I dont see the point of a rotating focuser, its no harder to rotate the diagonal if needed 

A decent rack and pinion focuser is always going to be hard to beat, the Mk1 RS 2" R&P that was fitted to the TAL 125r i owned was one of the best focusers i have ever used.

If i was to be in the market for a new focuser and could not get a decent R&P i would look at the Baader

[John]

My scopes have Moonlites apart from the Tak which has the stock R&P and the TMB / LZOS which has a Feathertouch. For my visual observing needs they all seem to do the job pretty well. I'm sure I'd be happy with a Baader as well. 

 

[alan potts]

Like John I have Moonlite and Feathertouch though I have owned a Baader before and a TS version, I still have a TS focuser on the back of the 70mm ED piggybacked on my Meade SC. In my humble opinion the two main player Moonlite and Feather are better than the others but also cost a good deal more, I was happy with the Baader on the SC to, it was only a case of money burning a hole in my pocket that made me change it to the one where you can fit the focal reducer, which I never have done, not even sure where it is.

Alan

[spaceboy]

3 hours ago, nightfisher said:

I dont see the point of a rotating focuser, its no harder to rotate the diagonal if needed 

I'm sure most can live with fixed focuser and just rotating the diagonal or the ota (not always easy with out risking the ota slipping) but I for one have gotten used to rotating focusers and appreciate the advantages of using them. The most notable advantage IMO is not flapping my hand about trying to land your hand on the focuser knob. If you use a DS focuser this can become even more frustrating depending which side of the meridian the scope is pointing. There is also the convenience that some allow you to attach finders to the focuser so there no need to crick your neck aligning objects. If you only use AZ mounts its not so much an advantage of course.

[ollypenrice]

How frank should I be? Very? Then the Moonlite is a joke, albeit a pretty joke. It has one nice design feature, which is that there is no need to align the drive shaft to the drawtube. It is the interaction between the two which defines the rotational angle of the drawtube. This is good. What is dismal is that the roller drives the smooth anodized surface of the drawtube. This is fine on a Dob, where the focuser is always horizontal and carries no weight. It may also be OK on Cats and refractors for visual when it only has to resist the pull of an eyepiece. But hang a camera on it and it is soooo likely to slip. Sorry, it doesn't make the grade.

We did heavy camera CCD imaging with a Baader Steeltrack without difficulty here for two years but one of our robotic Baader Steeltracks cracked a ballbearing.

Feathertouch rack and pinion? That would be my choice. I have all three so have no axe to grind.

Olly

[Dave In Vermont]

I have Crayford 10:1 Dual Focus units made by GSO in Taiwan on 4 of my telescopes. These cost just about 1/3rd the price of a Moonlite and - though these don't come in some pretty golden colour - they work the same way. I really don't see how people can shell out the £££'s when you can have a 10:1 Crayford that focuses 'scalpel-sharp' in basic-black. To the original question in this thread, my guess for a reason hinges on having that "Bling!" that a golden-metallic colour is supposed to cause in the local star-parties the owners' bring their scope to.

If they'd had the opportunity to try a GSO 10:1 Crayford before shelling out their cash on a Moonlite (or the other aforementioned brands), they likely would realize that there is really no way or purpose to improving on these. They work beautifully. But to each there own. I, persoally, would prefer to stick to the GSO models. The money I'd save could buy me something with an even better resolution and clarity - like a TeleVue® Nagler or such - or even a nice 'grab & go' telescope like an ST80.

Speaking of Crayford 10:1 dual-focuser by GSO & ST80's.....

 

 

Best Wishes -

Dave

[AlistairW]

I have a question. If you attach an electronic focuser such as a Lakeside to the Moonlite, shouldn't the Lakeside hold it (the focuser) in position, by the nature of the motor drive. Would this not then eliviate the slippage ? - (if you use Bhatinov only and manual focus - this obviously still would have the potential to slip I guess?)

[Moonshane]

I forgot that my 102mm f7 has a Feathertouch focuser, albeit the FT upgrade which is a FT spindle and speed reducer but the Synta style drawtube etc. It's very smooth but has 'Moonlite lines' on he drawtube. I did wonder if I could get the FT bits and send to USA for adding to other FT parts but probably cheaper to just buy one.

[John]

1 hour ago, Dave In Vermont said:

... I really don't see how people can shell out the £££'s when you can have a 10:1 Crayford that focuses 'scalpel-sharp' in basic-black. To the original question in this thread, my guess for a reason hinges on having that "Bling!" that a golden-metallic colour is supposed to cause in the local star-parties the owners' bring their scope to.

If they'd had the opportunity to try a GSO 10:1 Crayford before shelling out their cash on a Moonlite (or the other aforementioned brands), they likely would realize that there is really no way or purpose to improving on these. They work beautifully. But to each there own. I, persoally, would prefer to stick to the GSO models. The money I'd save could buy me something with an even better resolution and clarity - like a TeleVue® Nagler or such - or even a nice 'grab & go' telescope like an ST80.

 

I have used a number the lower cost GSO type crayfords Dave. The Moonlites are better engineered and take heavier loads in my experience and the Feathertouch even more so. Not just "bling" and anyway some of mine are in the all black finish.

If the GSO's work well for you, thats great. Each to their own, as you say

 

Edited July 7, 2017 by John

[wookie1965]

10 hours ago, spaceboy said:

Sounds more like the end of the ota isn't 100% square and so the focuser isn't aligned with the objective. Have you ever checked collimation? 

No I have not and not sure how to on a Frac. Reflector easy now.

[AlistairW]

26 minutes ago, wookie1965 said:

No I have not and not sure how to on a Frac. Reflector easy now.

Checking the focuser is square with the Objective can be done by making a paper mask for the aperture and inserting a collimated laser ( like a Howie Glatter ) in the drawtube. Spin the collimator, and if the laser spot on the paper mask stays dead central - then your focuser is square to the Objective. However, this does not necessarily mean the Objective is collimated. This can be checked by inserting a Cheshire eyepice in the drawtube and looking at the reflection patterns ( that should overlap one another - like a donut ). If they do not, then the idea is to adjust the Objective - which on a triplet is not easy, and quite frankly a lot of fracs today are fixed Objective and can not be adjusted by push/pull screws on the Objective.

[wookie1965]

1 minute ago, AlistairW said:

Checking the focuser is square with the Objective can be done by making a paper mask for the aperture and inserting a collimated laser ( like a Howie Glatter ) in the drawtube. Spin the collimator, and if the laser spot on the paper mask stays dead central - then your focuser is square to the Objective. However, this does not necessarily mean the Objective is collimated. This can be checked by inserting a Cheshire eyepice in the drawtube and looking at the reflection patterns ( that should overlap one another - like a donut ). If they do not, then the idea is to adjust the Objective - which on a triplet is not easy, and quite frankly a lot of fracs today are fixed Objective and can not be adjusted by push/pull screws on the Objective.

Thank you I will have ago tomorrow. Can I do the same thing to check collimation of the diagonal?

[Joe G]

Dave

I  realise the GSO focuser is not one of the original focusers  mentioned by Spaceboy  but  do " track lines" similar to the Moonlite  eventually appear on the  drawtubes after a certain amount of use? Thanks in advance Joe

[John]

31 minutes ago, wookie1965 said:

Thank you I will have ago tomorrow. Can I do the same thing to check collimation of the diagonal?

Yes, but you need to do the refractor first and confirm that the optical axis of the focuser is aligned with that of the objective ie: with no diagonal in place, a well collimated laser in the focuser should exit the objective lens pretty much bang in the centre. If you then put the diagonal in, put the laser in the diagonal, and find that the beam now exits the objective lens off centre, that is a diagonal collimation issue.

Once the focuser axis is aligned with the objective lens, you check the tilt of the objective using the cheshire method described by AlisairW.

 

[wookie1965]

Thank you very much John much appreciated.