Old 23-10-2010, 01:55 AM
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Tandum (Robin)
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Is Robofocus Worth the Money?

I'm thinking I want to robofocus the tak scopes. Are these units worth the dollars or would a cheaper unit make me just as happy? I'm guessing one control box can only control one scope.
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Old 23-10-2010, 07:20 AM
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Hard to say Robin, depends on the individual, his/her expectations, and equally importantly, the wallet.
I think so though. In my case I already had a Feather Touch or two, and the digital drive system was a natural albeit expensive, extension of that. I have a single hub and cabling all set up on the rollout pier, and whatever imaging scope is attached to the mount has a F/T on it, with the motor already attached to the focuser. The motor cable is in a loom which also has the power and USB cables for the camera, as all three are in the same area. Plug the cables in and away I go.
Maxim, AstroArt, and many others support the focus, and for a while I went auto all the time. For some reason I now just focus with the hand controller, go figure, but auto can be good too, especially if you are remote imaging (I'm not).
Buy one used, and try it.
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Old 23-10-2010, 02:44 PM
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Hi robin

The cercis controllers can operate two focusers from the one box and I think they are compatable with Robo focus units. I have one of these sitting around doing nothing so you are welcome to try it if you want. Looks like the pic on the page below but does not have all the DSLR stuff, that must be new. It is a focuser control unit only with two outputs and can be used for temp compensation if the sensors are plugged into it.




Last edited by marki; 23-10-2010 at 02:55 PM.
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Old 23-10-2010, 04:07 PM
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I have 3 robofocus units, one on each of my refractors. I also have a FLI PDF digital focuser.

The FLI unit is very good but it takes up backfocus and needs adapters in the imaging train.

The Robofocus are good as they don't take up any room in the imaging train, don't require an extra adapter and are very accurate. I love them. Simple, easy to use.

I didn't get the temperature compensation going though. You have to callibrate the focuser with various temperatures so the software can form a scale of how much the focus shifts with different temps.

One minor bug with Robofocus is it uses RS232 ports instead of USB so its a bit old fashioned that way. Most laptops either don't have an RS232
port or only one.

You can get RS232 to USB adapters and software. I use one with my Planewave CDK17. That one worked. I bought another one for the Robofocus and it did not appear to work. So get a good one.

Oh and make sure you get a specific connector for the shaft of the Robofocus to your specific scopes focuser. The shaft diameters vary and if you get the standard shaft connector it will be too large causing a wobble in the focuser as it spins the shaft. This can lead to it being easier to focus on one side of the focal point than the other.

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Old 23-10-2010, 04:09 PM
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Tandum (Robin)
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Cheers guys, I guess it depends on if it's necessary or not and right now it's not essential for me, maybe once the obs goes up.

Thanks for the offer Mark but I'll bypass the whole remote focus issue for the time being and spend elsewhere
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Old 24-10-2010, 08:02 PM
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bokglob (Darrell)

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Hi Robin. I find being able to sit behind my laptop away from the scope and do my focusing really helpful,much quicker and less painful than fiddling around in the dark. Steps in, steps out, memorized or pre-pro, love it. I use and recommend Keyspan usb serial adapt, got it from Technical innovations in Sydney. As Greg says, temp comp looks awkward, in Maxim anyway.
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Old 26-10-2010, 09:18 AM
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Robin, I have one on my TSA102 and it works a treat. Just order it specifying your type of scope and everything fits.
Once you calibrate it your away. The algorithms used for focus are super accurate and like someone has already mentioned, it remembers the focus position from last use. I could quite safely say that if you go the robofocus way you wont be disappointed. Also greg pointed out that its a serial interface and so a usb to serial converter is required. There are builds of these that are not reliable, sometimes the hardware requires physical CTS RTS lines. http://www.dontronics-shop.com/easys...0cm-cable.html I use this brand of converter with 1m and 10m versions available its handy.
Good Luck
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