perfrej

Details? Motor, 18V DC, gearbox, total torque on 18V is 900 N, i.e. can lift around 90 kg. At 12V it is just right for roofs. Clutch, simple to operate, bicycle chain sprocket as final drive. The garage door opener as a complete product is called the Sommer Marathon 1100. I simply bought the motor carriage as a spare part. The part was SEK 1862 and the freight to Olly's was SEK 280. If you buy from them you may need to pay VAT, but we can probably fix that for you. The price given is as per May 8th this year. http://www.sommer.eu/en/marathon-sl.html As you see on that page, the unit is available in three different "strengths". With our four pier, 4 x 5 m observatory, I figured the biggest. You can get the medium one. Check it out. /per

I still say get the garage door motor with chain sprocket and clutch. It moves very slowly and works very well, and it is quite cheap. Also, no need to run the chain in a loop - one way will suffice. I'll ask Olly to shoot some images of our's when the weather clears. /per

2000 lbs of pull? DON'T do it! /p

Yes, they are 1.47 m each. So four of them would cost you in the neighborhood of £12-15. Are you sure you can live with that cost? /per

They last a long time when greased properly, that's for sure. I recall paying about £3.50 for the chains and we bought 3 or 4 of them. Maybe I should just source it for you... 116 links, standard 1/2" by 1/8" bicycle chain, SEK 39 according to the web site... /per

I'm in a bar right now, but I'll get you the motor details tomorrow morning [emoji12]

The drive I use has a clutch. Chain is standard bicycle chain available on every corner for close to nothing... Our's runs partly outside - no issies.

Gina, spooling is a difficult thing to tame! I strongly recommend a chain instead. If you stick with the winch, in whatever configuration, add a big low ohm resistor in series as a shunt so that you can measure the current and abort if it gets too high. A winch will rip the roof and everything off if left alone to do its thing... If you want I can help you get a 800 N 12V chain drive motor from a garage door opener as a spare part. I bought one here in Sweden and had the supplier direct ship it to Olly's. I think it was about £150 including UPS freight. /per

Exactly! I would use at least a five minute sliding average (and will in my own focuser design) - in the driver, naturally (hehe). /per

Good thinking [emoji4]

I an not sure that temp comp should be in the imaging app. It is better to have it in the driver as temperatures can change quite rapidly during a long sub. The amounts of change are small - in the microns - and a good focuser doesn't shift the image during focusing. /per

OK, I got the rowan and installed in an hour and a half - which I think is pretty good!

Frank, which mod are you talking about? Rowan?

Quick one: Having never seen the mount in question, does it not need counter-weights? /per