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Goto'ing a Super Polaris mount

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#101 Dom543

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Posted 16 September 2012 - 11:41 AM

I have a Vixen SP with the old Skysensor II. The hand controller doesn't work any more. Does anyone have any experience or thoughts regarding an upgrade to a new hand controller while keeping the old motors and gears?

Thanks,
--Dom

#102 orlyandico

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Posted 16 September 2012 - 12:11 PM

if the original skysensor motors are bipolar steppers, use
a littlefoot Vpower. hard to find though - you'll have to troll ebay Germany. easier to find is the Littlefoot Elegance http://www.teleskopsteuerung.de/shop/ but it is rather pricey.

if it is using unipolar steppers would still work, some rewiring would need to be done (google - wiring unipolar as bipolar)

some assembly is required.

#103 Dom543

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Posted 20 September 2012 - 10:24 AM

Orlyandico,

Thank you for your reply and for calling my attention to the Littlefoot project. The Elegance is beyond my budget but some form of the Vpower kits may be feasible. But first I need to better understand the stepper based control systems.

My original hope was that one of the following approaches would be possible.

1. Use a stepper based commercial handcontroller, e.g. Sky-watcher and the corresponding motor board to control my exisiting motors.

2. Use a dual axis DMD handcontroller and add a computer interface to it. Hopefully something simple, similarly as people add autoguider ports to their dual axis controllers. In this case one could slew manually with the hand controller or use computer control for goto.

But, as said above, first I needed to learn more about stepper based systems. The motors that I have on my SP are the original versions with the DIN7+1 connector on the RA and DIN5+1 in the dec.

Thanks again for the input and any further suggestions or hints would be very much appreciated.

--Dom

#104 orlyandico

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Posted 20 September 2012 - 12:22 PM

Actually the easiest solution for you is to buy the Synscan upgrade unit for the EQ5 (which is a clone of the Vixen GP).

The gear ratios are all the same, it is essentially a drop-in replacement.

http://www.firstligh...it-for-eq5.html

sadly I don't think it's sold in the US. 300 UKP less 20% VAT = $400. You get the motors and everything. This is essentially your option 1.

Option 2 is unusable, because the DMD controller can only slew at 32X. Even if you could command it via autoguider, your hair would turn white and it still wouldn't finish slewing.

If you use a Littlefoot Vpower with your existing motors, your hair would still turn white :grin: because as I recall the original Sky Sensor could only slew at 64X which is still pretty slow.

Frankly for the price of the upgrade kit ($400) just buy a used Celestron CG-5 ASGT, which you can get for $400. Remove the motors and transfer them to your Vixen, and you get the advanced Nexstar GoTo with the mechanical niceness of the Vixen.

Then sell off the now driveless CG-5 for $150. Or not (the CG-5 tripod is quite sturdy and an improvement over the Vixen AL tripod).

#105 Dom543

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Posted 26 September 2012 - 12:54 PM

Orlyandico,

Thank you for your suggestions. I believe that the SkyView Pro goto upgrade kit that is available from Orion in the US for $500 is the same as what is sold as Synscan in the UK.

I also found a source for the iOptron Gotonova kit for $300 +shipping straight from China.

I am leaning towards your second suggestion of scrapping the motors and electronics from a used CG-5 mount. That way I would have the same system on my SP as on my CGEM. I particularly like and often use the All Star Polar Align feature available in the Celestron software.

So I am keeping an eye on the used markets to see, if a reasonably priced CG-5 comes up.

Thank you again for taking the time to help me.
--Dom






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