Motorising a focuser (and connecting to the computer)

[lazjen]

I want to motorise the focuser connected to the SharpStar AL-107PH. And I'd like to control the focuser with the computer.

For my RC10, I just completely replaced the original focuser (as it was not good) with a Moonlite with motorised control and usb connection. And I've been happy enough with it.

However, the focuser on the SharpStar appears to be quite good, so it makes sense to keep it and add to it.

Could I get some thoughts on what would be good options for doing this? I have done some searching already, but it's not clear to me what's good, bad, etc. I did notice a specific unit for the SharpStar made by Avalon, but it's specifically for their mount system, so that's probably out.

While I'm asking about focusers, what about a rotator? Are there add on solutions possible?

[Atmos]

If you just wanted to go with a motorised focus on your current focuser there is the RoboFocus unit:
http://www.robofocus.com

A Sky Watcher might work:
http://www.bintel.com.au/Accessories/Focusers/Sky-Watcher-Electric-Focus/1319/productview.aspx

There is also the Sharp Sky:
http://www.sharpsky.net

[spiezzy]

I got one of these and it was easy to adapt to my GSO focuser on my 10 truss astrograph and with the FCusb from Shoe String it works a treat

http://www.teleskop-express.de/shop/product_info.php/info/p5218_TS-focus-motor-for-TS-UNCN2-Focuser-and-Baader-Steeltrack.html

http://www.bintel.com.au/Astrophotography/Focusing-Aids/Shoestring-Focus--br-Motor-Controller--Second-Motor-/761/productview.aspx

:thumbsup:

[lazjen]

Thanks. That SharpSky Pro looks good and I like the idea that I can also do dew heater control with it - since I don't have a solution in place for that yet either. I'll send off an email and ask for more details about it (mostly to check if I can attach to my scope).

Not cheap at >GBP300 (the RoboFocus is approx $US500), but I'm not willing to go back to manual focusing again. :)

[lazjen]

Nice, a belt driven system. Looks easier to install. Always get killed on postage from that place - extra 36 euro. Take off the tax that's included and it's still under 200 euro. Much cheaper overall, but no temperature monitor and no dew control.

[Atmos]

Realistically you don't need to worry about temperature detection, just set it up for automatic focus every hour.

[lazjen]

In most cases I'd probably switch to different filters in that time, so I could (and probably should) refocus after each change. And dew heater control can be a different solution if I really need it - I have not had many issues in the past with the RC10. I have no idea if a refractor will react differently.

Another option I'm checking out is the JMI Motofocus (http://www.jmitelescopes.com/)

[lazjen]

Found a rotator: http://www.optecinc.com/astronomy/catalog/pyxis/pyxis_le.htm

At $US695 it can go on the wish-list for now. :)

[acropolite]

The Sharpsky Pro is an exclellent unit, there are quite a few threads about it if you do a search. Dave is also easily reached for support.

[lazjen]

I've sent off a message, so I'll see what response I get.

I can cross the JMI Motofocus off the list - they got back to me and don't have a suitable connector for their system.

I've also sent a message to Avalon regarding their unit, since it's specifically made for SharpStar.

And sometime soon I'll probably send a message off to TE about their system as well.

[lazjen]

An update to this thread: After a good email thread with Dave on the SharpSky Pro, I'm going ahead with getting one.

Although it's expensive, especially with the lame AUD, at least I know it's being customised specifically for my scope. :thumbsup:

[Jussi]

I normally won't advertise any company but Seletek`s Armadillo and Platypus are bombproof stuff. And they are in my opinion very fairly priced for the quality and support you get for the money.

http://tienda.lunatico.es/epages/lunatico.sf/en_GB/?ObjectID=263810&ViewAction=ViewFaceted&FacetValue_CategoryID=263810&CurrencyID=EUR&CurrencyID=EUR&FacetRange_ListPrice=&FacetRange_ListPrice=

Been using Armadillo for years and never had any problems. Here in Finland we have very demanding weather conditions.

Also the support of Seletek is superior.

[lazjen]

That seems ok. In a similar price range to the SharpSky Pro setup.

Wish there were some more rotator choices...

[lazjen]

I got my SharpSky Pro a couple of weeks ago and have just recently started using it.

The build is excellent and was not difficult to add to the scope. The custom adapter plate supplied was near perfect.

Software installation for the driver was as easy as expected.

I've used it within APT to control the focus. Going from the 0 position (all the way in) to focus took over 130K steps of the motor - it has such fine tuning. :) I do have to tweak the settings in APT more to get its autofocus to perform perfectly, but it's been ok so far - the problems are in my configuration of the APT software, certainly not in hardware at all.

I have yet to have a good weather window to do a long session of imaging to see how it goes with holding the focus (it does have temperature compensation if desired). However I am not expecting any issues.

So, if you stumble across this thread because you've got a SharpStar AL-107PH (or some equivalent) and are wanting to motorise the focuser, I can recommend getting the SharpSky Pro unit.