Focusser choice

AstralTraveller (David) · #1 12-04-2010, 04:44 PM

I have finally got the pip with the focusser on my Celestron 6" refractor. It started out poor and has gone downhill since. It has reached the piont where image shift is just impossible. It isn't adjustment its wear.

So ..... which aftermarket focusser should I get? Feathertouch is out of my league but MoonLite, JMI and WO all make suitable units and all are reputable brands. Any advice, feedback or reviews would be most welcome.

sadia · #2 12-04-2010, 04:59 PM

My preference among the 4 you mentioned would be

1. Feathertouch
2. MoonLite
3. WO

* I havent used JMI focuser so can't realy comment on JMI

wavelandscott (Scott) · #3 12-04-2010, 10:16 PM

I can't speak to their refractor focusers (I assume they are just as good) but if you eliminate the FeatherTouch (which I think is the Top of the Class), the MoonLite is the next in line...although it is close...

I'd rank them (note my gaps):
FeatherTouch
MoonLite
(gap)
(gap)
JMI
WO
(gap)
Everything else...

marki · #4 13-04-2010, 03:15 PM

I own all four of the focusers you have listed. My preferred order is;

1. Moonlite - tough as nails, solid as a brick, smooth as a babies bottom, excellent for AP. You will not go wrong with a moonlite, I own 2 and they are a great focuser (I prefer them to the FT but I have a ton of weight hanging of the back). Just make sure you get the drawtube with the 2" compression ring (3 thumbscrews) as the single thumbscrew version is hard on your diagonals and camera nose pieces. They are super smooth as and pretty to look at as well.

2. feather touch - okay I guess but not worth the extra money over the moonlite. For visual work they are excellent being very smooth in operation but for AP I have found they do not cope with heavy loads as well as the moonlite - note IMO dont want to start a war here.

3. Williams Optics - Nice and smooth but does not cope with heavy loads too well. Are well priced but the draw tube is too short for the refractor they fitted it to.

4.(massive gap)
5.(massive gap)
6.(massive gap)- 3 lucky bands and a paper clip.
7.(massive gap)
8.(massive gap)
9.(massive gap) - by now we are down to a bucket full of pond water and stick.......

10. JMI- worst focuser I have ever owned and has a manual action akin to being dragged through gravel in your undies. It is a motorised EV1 with smart focus and cost a heap to buy. It never could reposition itself after focus changes, continually slipped and autofocus routines were a joke. The motor was way to weak for the job it had and in all was an absolute waste of my hard earned money. It is so bad that I will not sell it on as I fear my good character would take a bashing from the poor buyer so it sits on the shelf gathering dust.

Mark

AstralTraveller (David) · #5 13-04-2010, 05:08 PM

Thanks for the replies. It looks like Moonlite is the go. Now I have to chose the colour. Red because it reflects red light or something else because it doesn't? I see pro and cons for both. Then whether to get the standard compression ring tube or the low position version in case I ever get a WO diagonal or similar. I have to be careful because some of my eyepieces (eg the great Zeiss 10mm ortho) focus very close to all the way in and the low position version stands about 0.5" higher.

Paul Haese · #6 13-04-2010, 07:42 PM

I have owned both the Moonlite and the a Feather Touch. The Moonlite can drag heaps of weight but is not as good in quality as the Feather Touch (its just the tiny things that make the difference). The Feather Touch is very slick in operation but cannot move as much weight in the 1.5" class. Maybe the 2" is better. Feather touch is superbly engineered and constructed and is very classy looking.

Both lovely focusors and both made to very high standards. You will be hard pressed to find better equipment anywhere. So either is fine really.

AstralTraveller (David) · #7 13-04-2010, 08:51 PM

OK, now I thought I knew exactly what I wanted but I've started having doubts. I've decided the stepper-motor focus control is beyond what I need (and more importantly can afford). So the choice is between the DC motor focus and the 2-speed manual (with focus lock). I've used both. On the refractor the motofocus was great, but mostly because it eliminated tube shake. On the dobs even the GSO 2-speed is nice to use and the manual operation is more intuitive than pushing buttons.

So, it seems to be an argument between intuitive operation vs. stability. I expect stability will win but I'm wondering how much a smooth manual focusser will decrease shake?

TrevorW · #8 13-04-2010, 08:57 PM

Buy Moonlite

marki · #9 14-04-2010, 12:21 AM

Quote:

Originally Posted by AstralTraveller

OK, now I thought I knew exactly what I wanted but I've started having doubts. I've decided the stepper-motor focus control is beyond what I need (and more importantly can afford). So the choice is between the DC motor focus and the 2-speed manual (with focus lock). I've used both. On the refractor the motofocus was great, but mostly because it eliminated tube shake. On the dobs even the GSO 2-speed is nice to use and the manual operation is more intuitive than pushing buttons.

So, it seems to be an argument between intuitive operation vs. stability. I expect stability will win but I'm wondering how much a smooth manual focusser will decrease shake?

If your mount is stable the two speed manual will be fine (the fine adjustment is like butter). Motorised versions are always good if your mount is a little unstable and is handy for AP. The stepper motor versions add considerable expense to the focuser as you also need a controller but are fantastic for AP as they have great lifting power and brilliant accuracy. The problem with the stepper is they are very slow unless you use the moonlite controller (fast and slow speeds) over the other options (cercis and james lacy controllers) and are an absolute pain to use in visual applications.

Mark

Louwai (Bryan) · #10 14-04-2010, 10:23 AM

I've only owned WO & Feathertouch.
WO & FT (2") were both on my C8
My 20" SDM also has a FT on it.

The WO was the most disgusting piece of junk I've ever had the misfortune to own.
The movement was harsh, & the optical path was not aligned. If I rotated the entire unit (as it was designed to do) everything was thrown WAY out of alignment.
The draw tube was far from well supported.

On top of that, it wouldn't support a WO28mm UWAN without side flop.

The FT, on the other hand, is absolutely the finest focuser I've used. Very well made, & well worth the money.

mbaddah (Mo) · #11 14-04-2010, 11:08 AM

Now where would the GSO 10:1 crayford focuser sit in these charts

?

erick (Eric) · #12 14-04-2010, 12:14 PM

Better than no focusser at all! But if you want to attach a motor drive to the main shaft, it is better to use the single speed GSO in my experience.

JethroB76 (Jeff) · #13 14-04-2010, 01:53 PM

Make a great sales slogan, wonder if Bintel will take it up?

"GSO Focusers: Better than nothing!"

mithrandir (Andrew) · #14 14-04-2010, 02:00 PM

Quote:

Originally Posted by marki

If your mount is stable the two speed manual will be fine (the fine adjustment is like butter). Motorised versions are always good if your mount is a little unstable and is handy for AP.

The Moonlite DC motor focuser has variable speed. I run it fast to get close and slow it down for fine focus.

Since the CG5 is not the most stable mount in existence, I also have a Motofocus on the C8 mirror to do the rough focus. The Moonlite only has a very short focal adjustment range compared to the mirror.

mithrandir (Andrew) · #15 14-04-2010, 02:02 PM

Quote:

Originally Posted by mbaddah

Now where would the GSO 10:1 crayford focuser sit in these charts

?

I have one on my guide scope, where critical focus is not that important. It is definitely better than the rack/pinion the scope came with.

bmitchell82 (Brendan) · #16 14-04-2010, 06:48 PM

... to be honest i think using 2 pieces of polly pipe and duct tape would be better than a GSO focuser! just my opinion!

I was looking at the specs for my new focuser inbound which is a FTF3015B-A, and they rate is for 7kgs.... so i dunno if because its so big they make it carry a hell of alot more.
but i can tell you now if i have 7kgs of gear hanging off it ill have some MINT gear!

marki · #17 14-04-2010, 07:01 PM

Brenden the larger the draw tube the greater the weight carrying capacity in general....I think it has to do with the larger surface area presented to the roller pin distributing the weight across the friction surfaces better allowing greater weight to be lifted. Not too sure if that will help with flexure issues though.

Andrew my comments were aimed at the stepper motor version not the DC motor on which I cannot make a valid comment simply because I have never owned one. Having sampled a number of Rons products I can only guess that they will do the job well.

Mark

AstralTraveller (David) · #18 15-04-2010, 07:55 PM

Moonlite 2" focusser with DC motor drive and a gold finish ordered!!

Bassnut (Fred) · #19 15-04-2010, 08:05 PM

Is this all about just visual, or manual focus?. Not a mention of proper focusers if imaging is in mind?, eg Optec, Robofocus (with Moonlight or Feathertouch)?.

marki · #20 15-04-2010, 08:54 PM

Fred budget was an issue here. I have used the manual 8:1 two speed (still do) on my refractor to good effect for AP. If you are going to buy a moonlite dedicated to AP then it's best to buy the version fitted with the stepper motor and moonlite controller. Unfortunately this more than doubles the price of the focuser. I have one on my LX200R and they are very good indeed.

Mark