Crawford or Electric Focuser

[Missedapproach]

Hi guys,
I recently bought a skywatcher 102 f10 refractor. I was wanting to upgrade the focuser as it is difficult to fine focus without shaking the mount. The issue I have is I'm new to this and looking online Bintel had the best price for what I could afford. The problem was I called to ask for some advice on exact price and installation and was treated like a idiot and told to look at their website. So I now would rather pay double then give them a cent. After that I found that you can get a skywatcher motorised focuser that bolts to the standard rack and pinion for around the same price and it doesn't involve pulling the tube apart. What is everyone's thoughts?

[raymo]

The SW electric focuser works fine, and comes with fittings for
their refractors and reflectors. The early ones like mine used to drain the
battery quickly, even when switched off, so it took me 20mins to put an
on/off switch on the front of the control box, and I also use a rechargable
9v battery, although the battery lasts for weeks of use anyway. They are
great value, but if you're not much of a tinkerer, I would check with the retailer whether this problem has been fixed. Wouldn't be without mine.
cheers raymo

[Allan_L]

I agree with Raymo.
I too have the skywatcher electric focuser.
Pretty easy to install.
Reasonably priced.
And eliminates shaking when focus adjustments are needed.
(I must have the early model, drains battery if not removed :( )

[raymo]

There was a thread running on this battery drain issue several years ago.
Most owners installed a switch like I did. $5 for a small switch 20-30 mins
to install.
raymo

[Missedapproach]

Thanks guys I will be buying one based on your advice.

[MattT]

You should have a look at Andrews Communications as well. $10 cheaper than Bintel...actually most of what they sell is cheaper than Bintel.

http://www.andrewscom.com.au/optical-telescopes

[billdan]

I dumped the battery in my hand controller, and installed a phono socket to plug a 12V power adapter into it.

Best long term solution.

Bill

[raymo]

I have to respectfully disagree Bill. The rechargeable 9v battery lasts for
many sessions between charges, and I don't have yet another cable
hanging around waiting to be snagged.
raymo

[billdan]

I never did try using re-chargeable batteries, just got tired of replacing standard batteries.
Fair point about an extra cable hanging around, in my situation once I'm satisfied with the focus I unplug the cable from the focus motor.
Cheers Bill

[janoskiss]

The downside of mounting a motor controller on your existing focusser is that you'll still have the sloppy mechanics and backlash of a cheap R&P. You also have a dangling chord and hand controller to accommodate. A Crayford with 10:1 fine control is a lot simpler and IMO nicer to use. The fine control knob only requires very light touch that is unlikely to excessively shake the mount. (If it does then even a light breeze will make your scope unusable at mid to high powers and you really need to upgrade the mount.)

But either solution will work. If you want the cheapest option, the motor focusser is probably it.

[raymo]

When I have focus I remove the hand controller and cable. Only takes a second to put it back when I want to check focus.
raymo

[Allan_L]

You guys ought to get out more often. ;)
When at a group observing session, we enjoy sharing/comparing views through each others scopes, so the focus adjustment is always required to compensate for people's differing eyesight.

[billdan]

" You guys ought to get out more often. "

You're not wrong there Allen, last time I was in a group telescope session was in the 1970's when I lived in Canberra.

Hope to rectify that, now that I am retired.

Cheers
Bill

[raymo]

I did almost exclusively imaging, so removing the electric focuser was not
a nuisance for me. Unfortunately I don't know any other visual people in
my vicinity.
raymo

[Missedapproach]

Well here is a update. I received the focuser yesterday and installed it last night. I have a new 102/1000 skywatcher refractor so the focusing knobs were different to what i have seen. No grub screws or central screws so a quick call to tasco support and we had it sorted. (They hadnt seen one apart before either). The knobs actually screw onto the shafts so you just hold oneside and undo the other. I had to use the rubber joiner as the aluminium one was to small for the focuser shaft which is about 8mm. Once fitted it works perfectly and looks alot better than its pricetag. The fast setting is quite slow but sufficient and the slow focus is amazing. For $99 I couldn't be happier and the focuser has no backlash at all and is quite impressive for a so called cheap R&P.

[raymo]

Glad you're happy Ben. Did you check whether they still flatten the battery overnight, even when not in use? If it does it's easy to install an on/off switch.
raymo

[janoskiss]

Sounds like a winner, Ben! :thumbsup:

The SW unit appears to be the same as the Orion Accufocus. I don't think you'll have any issues with the battery. Mine lasts for ever on a single 9V.

[Terry B]

I've had one of these for at least 8 years (I don't exactly remember). I have changed the battery once in that time. No extra switch. It is on a vixen VC2000L with a CCD permanently attached. I only need to adjust it every few months hence why the battery lasts so long.

[Missedapproach]

Doesn't seem to flatten the battery but I would like to install a switch. What kind did you use?

[raymo]

As there is not much room on the front of the control box, I took it with me to my nearest Jaycar and got the largest rocker switch that would fit into the
space at the top left of the front of the box.
raymo

[guipago]

Do these units fit the Crayford style focusers or just the r&p type focuser, are they even needed on a Crayford focuser???

[OzEclipse]

I bought one of these Skywatcher Electric Focus in early-mid 2015. I put an alkaline battery in it but then put it on the shelf with battery installed and didn't get around to fit it to my focusser until a few weeks ago. I didn't know about the battery flattening issue. Battery has been in for more than a year and still working fine. I measured the no load current drain from the battery. It's 0.0 milliamps. If the buttons get pressed in your accessories box by contact with other items, with no motor attached, it will drain at 5mA.

I wouldn't both to install a switch unless you find it is actually flattening batteries.

Joe

[raymo]

They come with adaptors for both types of SW focusers.
Joe, there were quite a few of us early buyers of this electric focuser
that had this problem, a new battery would be dead within 12-24hrs.
As I have stated before, I have no idea whether this problem was ever
rectified. Mine is still the same if I forget to switch it off; luckily I now
use a rechargable battery. Yes, not much point in switch if focuser is o.k.

Mine is Crayford style, but I wouldn't be without my electric focuser.
You can override the electric focuser for very large focal adjustments by simply
pushing or pulling the focuser to an approximate focal position, and doing the final
adjustments electrically. Can't do that with r&p focuser of course.
raymo

[Allan_L]

Mine flattens a new battery overnight, (ie within 24 hours) even with the motor and cable disconnected.
Disconnecting the battery each night, the battery lasts for ages.
But, the wires are so flimsy, they are easy to pull right off the control board if you are not careful. [I hate 9 volt battery connections].
I hope they have fixed this issue.
But it wont take long to find out if not.

The switch sounds good Raymo, but as I said, the wires are so flimsy, and short, that I am not confident that I could attach a switch successfully.

[Missedapproach]

I went to Jaycar today and bought a small rocker switch and a meter of small wire. Totalled $3.40 so I think a cheap mod. Better than changing batteries. I will post a pic when done

[Missedapproach]

Well i got carried away last night and forgot to take photos but had a easy time fitting the switch. I used a low profile rocker switch and mounted it through the side between the in/out buttons and the top of the battery compartment. Simple job just cut the red wire with about 15mm from the battery connection. Soldered two wires to the switch then made the one from the board as short as possible and gave the one back to the battery a extra 20mm. Fits and works perfectly.

[raymo]

Yes, quite easy, saves messing about every time you use it. Allan, don't
you have a friend who likes doing this sort of thing?
raymo

[janoskiss]

That sounds about right. I'm pretty sure the battery is disconnected (or as good as) unless one of the buttons is being pressed. Mine's an older unit, approx 10 y.o. From what others are saying it sounds like it's some of the more recently made units that have an issue. I'm curious now. I'll have to have a look inside my controller.