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Help choosing motors for EQ-5

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#1 kriss13

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Posted 09 January 2013 - 06:01 PM

Hi

Slowly I'm getting to AP...
The mount is next in line to to be prepared and cared for :).

I have several motorized/GOTO options but I don't know which is best (steeper motors, accuracy) and most compatible (gear ratio, nuts and bolts ..)

The list for my EQ-5 :) :
-Vixen DD-3
-DK-3
-iOptron GoToNova
-Skywatcher SkyScan GoTo

I don't care much about GOTO controller (if comes with the package that is it), but I really care about the motors and the way they are going to be installed (compatible)
I know stepper motors and bras gears are a must, but there are also some little things I'm not aware (tho I searched the hell out of google).

Any help will do,thank you.

PS.

Here is a token of gratitude :)...
my first AP, unguided.
http://d.pr/i/FG9C taken with this http://d.pr/i/rXID

#2 ccs_hello

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Posted 09 January 2013 - 09:44 PM

Hi,

Welcome to Cloudy Nights!
Since you seem to be only interested in tracking only (GOTO optional), I'd share my view:

1. the motor kit as the upgrade kit can be quite pricey, so try to find an inexpensive kit should be a very important factor.
Depend on which region you are in, some kits can be expensive. For tracking only, paying big $$$ just for tracking may be too high a price.

2. few inexpensive tracking-only kits use a simple stepper design. The accuracy is fine but if you use that for astrophotography or high magnification viewing (e.g., planet), you'll find motor is jittering a lot and disturb the viewing or astrophotography.

3. very inexpensive DC perm-mag motor based tracking-only kit cut the design too much thus can be quite inaccurate for tracking (hit-n-miss).

4. a bit more expensive DC perm-mag motor based tracking-only design has speed feedback loop (which form a servo) which is good on tracking and no jitter.

5. If it's from a GOTO kit, either DC perm-mag or micro-stepping motor based, the tracking accuracy is good and no jitter. But the price is high and sometimes hard to find depend on regions.

These are general guidelines and without knowing your budget, expectation, and local price/product availability, it's very hard to get a definite answer.

Clear Skies!

ccs_hello

#3 jrcrilly

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Posted 09 January 2013 - 09:55 PM

I know stepper motors and bras gears are a must


Not really. The motors and controller must be of good quality (as has been pointed out in this thread) but if there's a general preference it is for servos (at the top tier of imaging mounts, two [AP and Bisque] use servos and only one [Tak] uses steppers. All of the above work VERY well.

The only gears that have much effect on tracking are those already installed inside your mount; the transfer gears from the motor don't matter much.

#4 kriss13

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Posted 10 January 2013 - 05:58 AM

Thanks for replies.

The budget can be shaped out from the items in the list (+/- 20% maybe).

Could anyone tell me a few words about these, which to avoid, which is better and maybe why.
Or even another kit I missed during my research (GOTO or not)

I mean specific info abut them.

-Vixen DD-3
-DK-3
-iOptron GoToNova
-Skywatcher SkyScan GoTo

I live in Europe.

thank you

#5 andysea

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Posted 10 January 2013 - 09:01 AM

John is right. MY Tak uses Steppers while my AP uses servos and I can't really tell any difference in tracking. They both seem to track equally well.

Any

#6 ccs_hello

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Posted 10 January 2013 - 06:27 PM

-Vixen DD3 (max 32x sidereal), still need to buy MT1 motor (which looks like the inexpensive 48 step/rev stepper). This probably match the (2) I mentioned. I checked the US price and certainly "very Vixen". Hint, hint!

- DK3: similar to Vixen DD3. Cloned version. Price just slightly lower, motors included.

- ioptron Gotonova kit: 5(a) DC perm-mag servo based, also pricey. For tracking only, kind of waste.

- Synscan GOTO kit: 5(B) microstepping based. It's very good but pricey. For tracking only, kind of waste.


My take: none of the above. Way to expensive than what you just want to do (tracking only). Suggest sell your mount and buy a mount that come with the motor already. <--see my point (1).

Clear Skies!

ccs_hello

#7 kriss13

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Posted 12 January 2013 - 05:00 AM

Great info thank you all.

I think I will use GOTO for those nights when I feel to do just observing :).

I am using my scope to both observing and AP.
I find a sweet spot in between :)... I am no Hubble :)






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