time for a new focuser

[Epicyclus Dave]

Hi there,

I have a skywatcher Evo 80ED ds (black & white one) and .85 reducer coupled to a canon 500d .

i've been saving up for a new focuser and im torn between choosing the moonlight or steeltrak model. hmmm

Also my sw .85 F/R screwed onto the stock focuser thread after taking off the 2" ring , on these fancier focusers, do i need to fit the reducer with an adaptor with 2" nosepiece or is there a step down thread ring available ?

Dave.

[Rustysplit]

Have you thought of the new revelation crayford/rack and pinion hybrids? Having had a good look at them in september, they seem very well engineered and beautifully smooth.

Telescope House have them on their site.

[Epicyclus Dave]

Hi , i must have missed those i'll have a look later , thanks.

When i do change the focuser , my old Helios 120 achro is eyeing up the synta dual speed that's on the 80ed

[Epicyclus Dave]

Had to get the exhaust fixed on the car , i'm gonna leave it till next month before choosing a new focuser , tho im drawen to the moonlite with it's 112mm drawtube compared to the others 80mm drawtubes , also give time to find user reviews of the revelation superfocus 2" hybrid focuser.

Dave.

[tea drinker]

Not to hijack the OP's thread, but did anyone get a chance to try one of these Superfocus yet? particularly interested in thoughts for an SCT focusser

[Uplooker]

I went for one of these Superfocus focusers:-

http://www.telescopehouse.com/acatalog/Revelation-Superfocus-2-inch-SCT-Rack-n-Pinion-Focuser.html

very pleased with it.

Ian

[laser_jock99]

Have you thought of the new revelation crayford/rack and pinion hybrids? Having had a good look at them in september, they seem very well engineered and beautifully smooth.

Telescope House have them on their site.

They do look interesting

http://www.telescopehouse.com/acatalog/Revelation-Rack-n-Pinion-Focusers.html

I have got some Revelation kit and it seems quite well engineered. The focusser on my Revelation Newtonian is solid and shift free.

[ollypenrice]

I didn't know about these new R and Ps but they do look the business. A Crayford is never going to appeal to me but an affordable R and P 2 speed s a potential winner.

Olly

[A McEwan]

Any more feedback on these Revelation Superfocus units? I'm considering an SCT model...

Ant

[nightfisher]

Any more feedback on these Revelation Superfocus units? I'm considering an SCT model...

Ant

I dont think they have been available long enough for many people to take up on them, if its any help i have the revelation crayfor for my 180, and its a pretty good unit, but only has 25mm of travel, this is okay as i rough focus with the original, then fine focus with the dual speed, has your 180 got the new style rear back, or the older style?

[A McEwan]

Not sure which is which, Jules. I do have an adapter that converts it to standard SCT thread though - and no, I couldn't care less about converting it to "wide field" use! (It's an f15 Mak after all!)

Ant

[Uplooker]

but only has 25mm of travel, this is okay as i rough focus with the original, then fine focus with the dual speed,

Agreed. It does feel lovely to focus with. i found that i had to adjust all the elements of the focuser to get it feeling just as i wanted it. Once done, its grand! I would recommend them - very well put together. Certainly eliminates mirror flop!!!

Ian

[A McEwan]

I decided to bite the bullet and order one of the Revelation Superfocus SCT focusers for my M603 and Orion 180. It will serve on both of them, depending on which is being used. I'm looking forward to seeing how good a modern R&P can be. Many GSO style Crayfords have been through my hands and all required tweaking out of the box to make them end up usable. Some ended up absolutely fine and dependable, others less so.

Pricey, I thought at £150, but maybe it will be worth it in the long run? I hope so...

Ant

[nightfisher]

Nice one ant, let us know your thoughts on it please

[Epicyclus Dave]

Telescope house are waiting for a selection of collar adaptors to fit different brands of refractor scopes , and i've just raided the piggybank for my first guide camera from Bernard , im saving again for a focuser in Jan or Feb , i've got the feeling guiding is more important than changing the dual speed ED80 just yet ,im soon to get more than 2mins exposures with round stars on the NEQ6 , im excited hehehe

[A McEwan]

Well my Revelation Superfocus SCT focuser arrived today - and I'm impressed! Attached it to the Orion 180 and took some quick snaps of it.

The "coarse" focus is nice and smooth, but weighty too. The fine-focus is just as smooth, if not more so, but with a lighter feel. Everything feels "true" and properly aligned so far.

Build quality is very nice and it's quite hefty too. All the components appear blemish-free, and the brass rack looks very stylish as well as being functional. The lock knob is a big chunky affair hidden underneath the body of the focuser. It has quite a range of travel, with only the very last little bit of it having the desired "lock" effect. Nevertheless, it is effective.

Very shiny, looks great. Haven't tried it on the M603 yet. No chance of first light - it's snowing!

Quick snaps to show it off a bit. Oh, and it IS rotatable, though the blurb on TH's website doesn't mention that fact.

Ant

[Stargazer33]

Any more news on this Ant?

I am currently in the market for one of these (birthday coming up this month ). I am currently trying to earn enough brownie points to ask for one of these as my present!

I've seen it for £145 somewhere which isn't that much more than the standard one.

Would love to hear if this thing is as good as it looks!

[memoryman]

What's the basic difference between a Crayford focuser and a rack & pinion design?

The Revelation rack & pinion Superfocuser is more expensive than the Crayford, is that due to quality, or another factor?

[Gina]

Quality I should think. A rack and pinion uses a small gear wheel called a pinion on the focuser shaft which engages with a toothed metal strip - the rack - which is attached to (or part of) the drwa tube. Like the rack and pinion railways that go up mountains. OTOH Crayfords use a friction drive. Clearly a rack and pinion can't slip but a Crayford can. I guess you could equate a Crayford with a standard railway engine running on plain rails - slipping can occur.

[Moonshane]

I recently 'tuned' someone else's Moonlite and this was a beautiful piece of kit. it was in several ways better than the Baader Steeltrack I have (mainly it was a lot lighter, the coarse focus was super smooth (although the fine focus about the same) and basically, more 'beautiful'). If I were choosing a Crayford going forward, it would be a Moonlite, preferably with dual speed but if not then single speed are lovely too. I think I'd prefer a single speed Moonlite to a dual speed Revelation.

all that said, the R&P Revelations do look rather good and I might be tempted sometime. it would currently be a tough choice between a single speed Moonlite and the Revelation R&P for the same approx price. I am visual only so tend to hang less weight off the focuser than the imagers amongst us.

[Gina]

The Moonlite focusers certainly look nice and I'm expecting to get one myself later on for the MN190. I have a Baader SteelTrack on my ED80 and that is very smooth and nicely engineered.

[A McEwan]

The Superfocus by Revelation is a keeper. I love the functionality of it. It performs perfectly in every way. It doesn't look as flashy as a Moonlite, but it's half the price and does everything that I ask for.

Note, this last statement does NOT apply to all "cheaper" replacement focusers. Some other replacement Crayford types in particular have definately been a compromise between performance and price. This Revelation Superfocus is Not A Compromise. Well worth every single penny of the asking price.

Ant

[memoryman]

The Superfocus by Revelation is a keeper. I love the functionality of it. It performs perfectly in every way. It doesn't look as flashy as a Moonlite, but it's half the price and does everything that I ask for.

Note, this last statement does NOT apply to all "cheaper" replacement focusers. Some other replacement Crayford types in particular have definately been a compromise between performance and price. This Revelation Superfocus is Not A Compromise. Well worth every single penny of the asking price.

Ant

Hi,

I have a Meade LXD55 SN10 scope and want to replace my stock focuser.

I'm interested in the Revelation Superfocuser and you seem to be impressed with it!

I can't seem to contact Revelation direct and so far Telescope House have failed to respond to the request for information I sent them on Saturday), so could you answer a few questions?

1) The stock Meade focuser has significant draw tube slop, which is one of the main reasons why I want to replace it as well as a course focusing action, especially when trying to fine tune! How tightly does the Revelation draw tube hold 1.25" & 2" eyepieces and collimators before tightening the screws up? Do you know what tolerance Revelation engineer them to? Moonlites CR2 2" draw tube is quoted as 2.001", where the competition, they say, more generally use 2.006".

2) Do the compression ring and screws consistently hold eyepieces and collimators at dead centre? ie:- is there much slack to take account of (thereby introducing a variable) when collimatiing and fitting eyepieces? If so would it be advisable to buy a Revelation Self Centering Eyepiece Adaptor?

3) Is the 22mm focus travel a limitation if you are visually *observing (I'm a relative newbie and don't understand as much as I think I do! Or in other words, I don't know enough to ask the right questions!)? If so do they sell spacers, longer draw tubes (I almost sound like I know what I'm talking about!) etc?

4) How easy was it to install and adjust (what kind of adjustments might be needed?)? And is it easy to centre in the OTA accurately?

* My range of eyepieces runs from a William Optics SPL 3mm to a Meade Super Plossyll 40mm.

Sorry for all the questions, but the quest for answers leaves you feeling brain dead after a few hours!

Thanks in advance for any info you can give me. Eventually, I will make an informed decision .... !

Paul B

East Midlands UK

[A McEwan]

Hi Paul.

I'll try to answer as fully as I can...

1) There is no tube slop. None. Zip. Nada. The compression ring has a single thumb-knob which holds the 2" adapter or eyepiece in position. From fully open (slack) to holding firmly takes about a 6th of a rotation of the knob. Once at that level of grip it is very firm and nothing moves. Please note, I only have experience of the SCT version and am not sure if it's the Newt version you would need? I'm sure the tolerances etc are the same across the range though. Tolerance figures? No idea but I know when something's right!

2) I cannot imagine it would be "Dead Centre" simply becaue it has only a single thumb knob, which will only apply pressure from one side of the compression ring. However, see answer 1 above. The diffrence between the knob being "slack" and "tightened" (holding eyepiece or diagonal in place for example) is very very small amount. I would say that certainly for visual the centering would be fine, but for a high precision laser collimator? Personally I'd go with it, but I'm not going to say "exactly" centred.

Please note, that with my two inch barrel eyepieces, to slide them into the focuser directly they are actually pushin against the inner edge of the drawtube, such is the lack of space for movement in there! My diagonal on the other hand has a ever so slightly less tight fit. I'm going to replace the nosepiece of the diagonal with one that doesn't have a safety cut too as that does interfere with the compression ring holding position.

3) No it's not an issue when used with SCT or Mak scopes. The main focus is done with the telescopes own native focus control. Then, when in a "near focus" position the mirror is locked (if the scope has that function) and then the Revelation focuser is used to fine-tune. The coarse and fine focus knobs have plenty of sensitivity and there's plenty of room in that scenario to achieve great focus. If you were switching from say a 31mm Nagler to a 4mm Ortho, you may then need to adjust the main focus using the scope's own focuser first, but for my own eyepieces I've not had any problems at all.

For use with a SN scope though, I suspect the situation may be different as the Revelation will be the only focus mechanism on the scope. Yes, you may well need spacers or extension tubes, but until you try it you probably won't know. Although, what you could do it set your scope up and focus on a star using every single eyepiece you own and measure the position of focus on your current focuser. That will give you the distance from the secondary mirror where focus is achieved. You could then get the measurements of the new focuser (body depth, drawtube travel, etc) and work out if the focus positions would be achievable with the new focuser in situ without extensions. If needed they can be bought cheaply enough.

I'm using it with Intes M603 and Orion US 180mm Maksutovs. The scopes own focus knobs are plenty usable on both scopes, but both do not have the sensitivity required for critical high power focus adjustment with zero mirror slop. The mirror slop is completyely removed when using the add-on Revelation focuser (or for that matter any other add-on focuser that's well-engineered) and so you can focus totally on achieving best focus rather than worrying about where ther target is going to wander off to!

4) When sticking it on a SCT or Mak it just screws onto the rear port. Simples. Some Maks may need an adapter ring to provide the correct thread, but that's it. Nothing further required. If your scope's collimated already the new focuser shouldn't affect it. again, for a SN scope it may be different. I'd imagine it would be simple enough to centre the focuser drawtube hole over the secondary, just as if you were collimating. I'd imagine that little if any adjustment would be needed though.

Hope this helps,

Ant

[Tinker1947]

If its going to be used for AP, check out the motorized options some can be some can't.....