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Skywatcher autofocuser


IvanT
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Hi,

Am I correct in saying that the skywatcher autofocuser http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Imagers-Shoestring.asp?p=0_10_5_1_3_10 is compatible with the stock focused that comes with the 200P and that the cable is just 4 core bell wire that could be extended to around 9 Mtrs?

After my notebook iced up quite badly one night I now remote control everything from indoors, having to run in and out to focus is a right pain.

Cheers

Sent from my iPhone using Tapatalk

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I think it is definitely worth it. I only have a single speed crayford but with this I don't need to upgrade to a dual speed one now. I always found it hard at high power as touching the focusser made the telescope vibrate and the image shift. This gets rid of all that and fine focus is so much easier. I love it!

Mark

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I have found my Auto focuser to be great at keeping the image steady while focusing. I doubt the cable would stretch to much of a length with out pulling on the focuser but you could easily knock up your own cable with some supplies from Maplin's

SPACEBOY

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Just one thing to remember: with the auto focusser installed you can't focus manually very easily - at least not without damaging the gearing. You have to use the auto focusser all the time - which can be a bit slow if you're going from one extreme of focus to the other.

Still easily worth it IMHO.

Mark

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The cable terminates in a RJ-11 plug at each end. The four wires are Y,G,R,B. They are commoned up as Y+G and R+B. The fast speed (10s/rev) is +7.7V and the slow speed (30s/rev) is 2.9V. I did a mod in the box by putting a 100 ohm resistor across the 265 ohm resistor to slow it down. It now goes at 75s/rev at the slow speed. I now have it on my C8 SCT:

http://stargazerslounge.com/diy-astronomer/125767-c8-sct-motor-focusser.html

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I have the focuser set up on my 200p and it is great. I have also set it up to be used from inside by extending the cable over 5m.

To highjack the thread can the watcher focussed be fitted to the c80ed. I have seen that the Orion accufocus can but are these the same?.

Cheers

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The cable terminates in a RJ-11 plug at each end. The four wires are Y,G,R,B. They are commoned up as Y+G and R+B. The fast speed (10s/rev) is +7.7V and the slow speed (30s/rev) is 2.9V. I did a mod in the box by putting a 100 ohm resistor across the 265 ohm resistor to slow it down. It now goes at 75s/rev at the slow speed. I now have it on my C8 SCT:

http://stargazerslounge.com/diy-astronomer/125767-c8-sct-motor-focusser.html

I had seen another thread mentioning they felt it was a little quick on the slowest speed but I found it OK. If I want to get it bang on I just give the button a quick tap. I would be interested to see how you did the mod but what is the fast speed like now?? The "fast" is the big let down IMO, as Mark says it can be a pain between some EP changes.

SPACEBOY

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To slow the motor down I examined the circuit and noticed it was controlled by a LM317AZ regulator. The output voltage range of this regulator can be controlled by changing the 265ohm resistor. By soldering a 100ohm resistor in parallel with the 265ohm, the original voltage output range (2.9-7.7v) was changed to (1.7-7.1v). This avoids removing components and lets you use the original potentiometer and has little effect on the original 'fast' speed. The slow rotation rate is reduced from 30s/rev to about 75s/rev.

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To slow the motor down I examined the circuit and noticed it was controlled by a LM317AZ regulator. The output voltage range of this regulator can be controlled by changing the 265ohm resistor. By soldering a 100ohm resistor in parallel with the 265ohm, the original voltage output range (2.9-7.7v) was changed to (1.7-7.1v). This avoids removing components and lets you use the original potentiometer and has little effect on the original 'fast' speed. The slow rotation rate is reduced from 30s/rev to about 75s/rev.

Sorry for hijacking the thread!

You will have to forgive me do you have a picture of the mod ? I havn't found it a problem but the extra control would be a nice touch if it dosn't slow the fast speed. Would be the best of both worlds.

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To highjack the thread can the watcher focussed be fitted to the c80ed. I have seen that the Orion accufocus can but are these the same?.

Cheers

Yes. The C80ED focus knobs unscrew (no grub screws). They are quite tight and you will think that it is not going to unscrew...but it does.

Steve

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Just another +1 on the benefits of the original post question, I have one on my skywatcher 150 and it has solved all my focus wobble problems at a stroke.

Dont let the unit hang down as that introduces its own wobble, velcro it to something.

It is very annoying not being able to manually quickly shoot from one end of focus to another (as mentioned), its very slow to do this using the motors and for imaging I often need to go from almost full in to out when I switch from one setup to another. I am working on a quick release/clutch of some sort.

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Placed my order with FLO last night while stuck in Liverpool airport. I'll make the extender cable this weekend. Nothing like a little impulse buying to alleviate the boredom.

Now surely there is nothing else I could possibly need to complete my imaging setup, oooo, what's that, look, it's a shiny thing......

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Yeah, they do look cool, but for now I think I'll settle for the auto-focuser with extended cable and Nebulosity fine-focus to get it as close as I can. If my wife new exactly how much I've really spent from I started Aug last year & now, she'd have a cow!

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