Skymax 180 focuser

[The Gray Man]

I've been looking and looking for a solution to this, but have been drawing a complete blank. I'm wanting to improve the focus on my Skywatcher Skymax 180 Pro - out the box it's just a knob to move the primary mirror (which I guess is standard for catadioptrics?), which is quick but coarse. So what do I mean by "improve"? I mean the following:

• Provide fine focus control
• Also provide coarse focus control for significant changes with (e.g.) new eyepiece
• Do so electrically to avoid shake by touching it
• Do so with as little extra weight as possible on the back of the scope
• Do so with as little extra physical space as possible taken up on the back of the scope, or else have it easily removable to store the tube
• In an ideal world, be able to control that from a PC or Smartphone, but that's just icing on the cake
• And naturally, do all that at as low a cost as possible!

Simple! Yet there just doesn't seem to be a solution ticking those boxes out there for the Skymax 180. I could add a Crayford, but they're either fairly expensive and very heavy, or outrageously expensive and still quite heavy. Other SCTs have the option for something like a JMI Motofocus, but they're not available for the Skymax 180 (and for what they are, they do appear IMHO to be quite pricey anyway). I could put a peanut butter jar lid or clothes peg over the focus knob, which is cheap and would certainly improve fine focus, but doesn't get away from the shaky touch problem.

Has anybody found the answer that I'm looking for?

Cheers,

Ian

[nightfisher]

Your going to have to make something using a motor and a controller rigged to the original focus knob, main problem is attaching to the scope, smallest system to work with is using 2 radio control servo`s

 http://homepage.ntlworld.com/telescope/Projects/ElectricFocuser.htm

using this set up and a rubber belt to the focus would work well

[r3i]

I knocked up a DIY focuser using a cheap motor like this one: http://www.ebay.co.uk/itm/-/361389342262?

This was connected to the focuser using a belt and pulley. The motor is controlled from a PC via a not so cheap Shoestring FCUSB interface  http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Imagers-Shoestring.asp?p=0_10_5_0_5_40 but there are probably cheaper options.

 

[Steve Ward]

Best bet would be to add an aftermarket focuser to the back end and fit a motor to this .

No need to go as far as Moonlite et al , the Skywatcher SCT focuser is a fine beast  for a modest outlay , handles a DSLR with ease , and the Skywatcher Autofocus motor can be fitted to it.

You can also add USB control to the motor (various options available) eliminating the need to touch the focuser by hand and control it from the laptop.

Coarse adjustment can still be achieved by using the original knob moving the mirror as before , independent of the rear focuser.

Yes it adds a little to the back end but nothing to worry about , my HEQ5Pro has no issues with the set-up.

The whole lot can be detached simply by unscrewing from the visual back if required.

http://www.opticalvision.co.uk/astronomical_accessories-focusers/dual_speed_2_crayford_focuser_for_sct_telescopes.html

http://www.opticalvision.co.uk/astronomical_accessories-focusers/skywatcher_auto-focuser.html

 

[Chrb1985]

i own a skymax 180 . https://www.ebay.com/itm/50-8mm-1-10-Dual-Speed-Focuser-For-Refractor-Telescope-New-Fully-Metal-Excellent/114211146574?hash=item1a9783cb4e:g:LnwAAOSwXedesECS can someone tell me if this fits straight one skymax180

[nfotis]

I think that the dual speed focusers for refractor telescopes are unsuitable for reflectors like the 180.

If you don't like the Skywatcher model, here's another option: https://www.teleskop-express.de/shop/product_info.php/info/p4299_TS-Optics-MONORAIL-2--Auszug---Mikrountersetzung---M90x1-Gewindeanschluss.html 

(got this one used, supposedly has a load limit of 4 kg, so it should easily accept an SLR and stuff)

N.F.