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Synscan upgrade to Vixen GP - thoughts?

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#1 Astrojensen

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Posted 18 February 2018 - 10:21 AM

Hi all

 

I have a fine Vixen GP that I've bought new in 2001 and have been quite happy with. It's not motorized, but I'd like to change that. I have three options:

 

1: Basic dual motor drive from Teleskop-Service (same as Orion EQ-5 drive): https://www.teleskop...g-fuer-EQ5.html

 

2: Basic dual motor drive from Vixen: https://www.teleskop...ith-motors.html

 

3: Sky-Watcher SynScan GOTO upgrade: https://www.teleskop...-EQ-mounts.html

 

4: Something I have overlooked, but which you can point me to. 

 

 

Pros and cons:

 

1: Very cheap, but somewhat flimsy, according to some sources. Works well, though.

 

2: No issues with fitting it to the mount, but as expensive as the SynScan GOTO upgrade, but without GOTO. 

 

3: GOTO, if I so desire. More expensive than #1, but with many more options. 

 

4: ?

 

 

Before you all scream to me to get the GOTO, be aware that I am an incarnated starhopper, that would only occasionally need the GOTO, but that I am honest enough with myself that I've realized that there are situations, where it might be very useful, for example in our bright summer nights, where starhopping can be a little challenging. Thus I have some questions regarding the SynScan:

 

I know from the manual (freely downloadable) that I do not need to activate the GOTO align, but can skip it and just have RA tracking. This is just what I need. But the manual states that I need to move the scope with the motors, instead of by hand. Why? I can't see why this should be necessary, when I want to hop across large distances. The scope will obviously no longer know where it's pointing, but since I was not using the GOTO anyway, that doesn't matter. Or does it want to know where it is, so it can avoid bumping into the tripod? Might I get a false alarm, if the scope thinks it's somewhere, where it really isn't? 

 

Should I also not be able to get RA tracking and manual slewing, even if I've engaged the GOTO? Let's say I've aligned the mount and activated the GOTO function and let the scope aim automatically on an easy to find object, such as M31 (or a star or whatever). If I want to, I should now be able to aim manually on any object, by loosening the clutches and aiming manually, and still have tracking, as long as I don't change the object that the mount THINKS it's aimed at. This includes using the motorized slow motions. If I want to use the GOTO again, I can just turn back to the initial object manually, retighten the clutches, and ask it to aim at a new object. Alternatively, it should be possible to loosen the clutches, ask the mount to find a new object that is easily visible, let it turn to it, wait until the mount stops, then aim at the object manually and tighten the clutches. I should then be aligned again and GOTO should work as intended again. 

 

Thoughts? Experiences? I would also be very interested in knowing how the SynScan tracking performs at very high magnifications. I am specifically interested in knowing whether there are any stepper motor vibrations visible, because my first EQ-6 suffered badly from these. 

 

Thanks!
 

 

Clear skies!
Thomas, Denmark



#2 orlyandico

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Posted 18 February 2018 - 10:43 AM

I find that the real Vixen motors have better fit and finish and fit more securely than the generic EQ-5 style drives. So for this reason I would go for the Vixen motors and drive.

 

You can actually use OnStep to drive the stock Vixen motors. GoTo will be extremely slow, but it's cheap. I would only consider this type of GoTo if imaging (where a plate solve and short slew isn't too painful).

 

If you are a dedicated star hopper the GoTo may not be useful.  I don't know if the GP has working setting circles, but the SP does.



#3 KevH

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Posted 18 February 2018 - 10:54 AM

I've had the cheaper synta motors/hand control and the Vixen motors/hand control on a GP. While more expensive, the Vixen stuff was quite a bit more refined. As already stated, they mount much nicer than the cheaper motors. I found them to be much more responsive when changing direction as well. I thought the slop in the cheap motors was very annoying. With the Vixens, the mount moves immediately when a button is pressed and tracks the instant I let go. The Vixen hand control also has a faster slew rate which is nice.

#4 Astrojensen

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Posted 18 February 2018 - 12:14 PM

 

I don't know if the GP has working setting circles, but the SP does.

The GP has setting circles, and I know how to use them, but they're small and a pain to read, especially in the dark. The SP setting circles are at least 50% larger. 

 

 

You can actually use OnStep to drive the stock Vixen motors. GoTo will be extremely slow, but it's cheap. I would only consider this type of GoTo if imaging

No imaging planned. 

 

 

If you are a dedicated star hopper the GoTo may not be useful.

Some months of the year, we suffer from rather extreme, natural light pollution. Then the GOTO might be useful, but I don't know for sure whether I'll like it or not. 

 

 

Clear skies!
Thomas, Denmark



#5 Astrojensen

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Posted 18 February 2018 - 12:15 PM

I've had the cheaper synta motors/hand control and the Vixen motors/hand control on a GP. While more expensive, the Vixen stuff was quite a bit more refined. As already stated, they mount much nicer than the cheaper motors. I found them to be much more responsive when changing direction as well. I thought the slop in the cheap motors was very annoying. With the Vixens, the mount moves immediately when a button is pressed and tracks the instant I let go. The Vixen hand control also has a faster slew rate which is nice.

Very valuable information! Thanks.

 

 

Clear skies!
Thomas, Denmark



#6 andycknight

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Posted 18 February 2018 - 12:33 PM

Hi Thomas,

 

I have a non-Orion brand 'option 1' installed on my GP mount.

 

Although it was designed for the EQ5, it does fit my GP mount. The only modification required was to file about 0.5 to 1mm off the RA and DEC slow motion shafts. This allows the cogs to mesh fully (and also on the RA shaft allows to cog to fit inside the plastic box). One nice bonus is that the RA 'telephone connector' aligned nicely with the connector hole in the bottom of the RA plastic box.

 

gallery_135796_6581_4115.jpg

 

The DEC motor 'telephone connector' however is a bit flimsy, as it is mounted on a little PCB. This could break if the connector receives a blow, or the cable was yanked hard.

 

gallery_135796_6581_2206.jpg

 

Both axes come with 'slipper clutches', with knurled thumbscrews which must be done up tight to engage the motors without any slipping. If they are loosened then you can use the manual slow motion knobs as before. They also have a shaft fitted so you can fit the slow motion knob on either side of the mount.

 

Note a very minor niggle (and I am being very picky here grin.gif ) is that if you turn the slow motion knobs too quickly, the knurled ring can spin and sometimes tighten up by itself !

 

gallery_135796_6581_39012.jpg

 

I also agree about the backlash issue, that others are reporting. At the slowest speed (2x), it can take 10 seconds for the motor to change direction (at the highest speed it is about 1 second). This is only a problem with the DEC axis, since at the slowest speed, it only stops the RA motor when you reverse direction. To be fair though - I slightly offset my polar alignment such that adjustments are always in one direction.

 

It is powered by 4x D cells. Current consumption is about 250mA with one motor running and 500mA with both.

 

I would advise to get high capacity rechargeable D cells of about 6 to 8 Amp-hour rating. They will then easily last all night. As D cells can be rather expensive, another option (if you have lots of AA cells - like me) is to get some 3xAA to D cell adapters (4 off cost less than £2 on Ebay).

 

gallery_135796_6581_20223.jpg

 

In the centre of the buttons is a green LED (which turns red when you press a button). This is rather bright and can be a very annoying. A piece of tape has fixed this, but really I should change the resistor value inside the box!

 

It has slew speeds of 2x, 4x and 8x, these are fine for centring the object in the eyepiece (even in a wide field), but are too slow for slewing from one object to another. When locating objects, I leave the slipper clutches engaged and the tracking motor running. I unlock the clamps, manually align in the finder, lock clamps and then centre using the motors.

 

At 2x speed, the steppers pulse at about 5Hz. On a quiet night you can hear the 'ticking'. I have not noticed a loss of image sharpness, due the 'pulse tracking'. However, it must make some difference. I suspect the seeing limits its visibility. Perhaps on a really steady night I might spot some blurring in the 8", but I've not noticed any yet.

 

It not an expensive system, hence I can live with its faults. What I like is that you can simply undo the clutches and the slow motion knobs can still be used (i.e. if stuck without any power).

 

Regards

 

Andy.


Edited by andycknight, 18 February 2018 - 01:06 PM.


#7 Reid W

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Posted 19 February 2018 - 01:28 PM

ED103S

 

Thomas- I have installed the SynScan Go-To upgrade on my GP mount.  

 

With my install, I removed the components from the upgrade kit RA housing and set those components in my Vixen RA housing.  It took a little time, but you can see the outcome looks pretty good.

 

If you do move forward with the install, dremel a flat on the shafts for a better setscrew "bind". 

 

Yes, there is the option to have the mount advance in RA only.  I use this setting for solar as well as those evenings when I'm concentrating on those objects that are "easy" to find.  Any yes, just loosen the clutches and swing to where you want to go.

 

As far as power, I've used a 12v "jump type" battery, but recently I picked up one of those TalentCell li-ion 12v batteries on Amazon for $30 or so (for my lightweight SLT) and I found the 12V talent cell works great on the SynScan system.



#8 Astrojensen

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Posted 19 February 2018 - 02:48 PM

 

 

 

Thomas- I have installed the SynScan Go-To upgrade on my GP mount.  

 

With my install, I removed the components from the upgrade kit RA housing and set those components in my Vixen RA housing.  It took a little time, but you can see the outcome looks pretty good.

 

If you do move forward with the install, dremel a flat on the shafts for a better setscrew "bind". 

 

Yes, there is the option to have the mount advance in RA only.  I use this setting for solar as well as those evenings when I'm concentrating on those objects that are "easy" to find.  Any yes, just loosen the clutches and swing to where you want to go.

 

As far as power, I've used a 12v "jump type" battery, but recently I picked up one of those TalentCell li-ion 12v batteries on Amazon for $30 or so (for my lightweight SLT) and I found the 12V talent cell works great on the SynScan system.

 

Fantastic! Just the info I needed. A few more questions: How is the tracking at high magnification? Any vibrations or butter smooth? Does the motors react immediately, without backlash, when you press a button?

 

The fact that you can rehouse the electronics in the Vixen motor cover is highly valuable information as well. I definitely looks pretty. The Gibraltar legs on your GP mount looks very snazzy as well, I must say. 

 

 

Clear skies!

Thomas, Denmark 



#9 brisdob

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Posted 19 February 2018 - 04:26 PM

IMG_0163.jpg

 

Thomas, here's another photo of the GP RA motor cover with the synscan components inside.  You just need to be careful where you drill the holes so that it all fits in and can be out on the mount without snagging on anything.



#10 Reid W

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Posted 19 February 2018 - 05:44 PM

Regarding the backlash.  If there is- it is minimal.  My backlash compensation settings are at zero.  Both Vixen and Syn Scan gears are are brass and the mesh is very good.  

 

The tracking:  here I am going to say that the original Vixen dual drives *might* have provided a bit smoother tracking at high mags.  That said, when using the Syn Scan and observing tight doubles at 200X and up, I see no jumpiness and the tracking is smooth enough.  It's a subjective determination.  I think that if you set the speed to its lowest (1) and then press the left arrow, tracking will just pause, like the old DMD units...but I have had not felt the need to pause tracking.    

 

The legs- yes.  The legs transformed the mount.  Prior to finding the Gibralter legs, I was using the 1/2 pier option and the standard tripod.  That setup was cumbersome-heavy too.



#11 dUbeni

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Posted 20 February 2018 - 05:40 PM

Hello Thomas

  1. I can only speak of my experience with the Vixen motors and controller DD2 on my GP. I got them 10 years ago and are still tracking beautifully and in silence, you will hear a low buzz when adjusting at 32x (max.), obviously good tracking at high magnification require good polar alignment. I do experience some backlash but is on the worm itself, it's short but there, I fear the thought of playing with the worm adjustment screws, the motors and cog wheels respond at the touch of the button. I do adjust cog wheels once in a while, they must not be over tighten or they will stick. The shafts have flats. The weakest link I found on this set is the DIN connector on the DEC motor, part of the socket comes off when pulling the plug. The only Alert is that the minus pole is at the center of the power plug, as explained on mount manual, if you still have it cool.gif . I only noticed it when trying to use a common cable, fortunately DD2 and DD3 are protected against this simple mistake.
  2. Power: the 8 D size battery pack lasted me around three long sessions depending on how much I used 32x slew, it becomes expensive so after a couple of years I got a car jump-starter battery witch require some care to keep'em alive, and more recently a bought a 12V LiFePO4 battery that works seamlessly with less care.
  3. I'm a visual observer 99% of the time, never used the setting circles and love star hopping, I also have the clutches and find them very useful when power fails or to center an object manually, at least I know that a full turn is 2.5º grin.gif , the controller doesn't tell me that... unless I put my fingers on the knob.

I do consider getting a go to system once in a while for the same reason you stated -"Light pollution"- but I'm looking at something a bit more expensive: Avalon StarGo goto wifi controler with belt driven motors for GP.  https://www.unitroni...otti.asp?cod=AV  The reasoning behind this option is that if I go go to I would like it to be wireless and Sky Safari driven, truly modern, add a Pole Master and no more kneeling, all on the tablet or phone. But... but I would like to hear your experience if you go the SynScan route.

 

Some pictures of the Vixen setup

36 Vixen GPE
Vixen GPE with MT1 motors and DD2 controller
37 Vixen GPE(MT1 DEC)
Dec motor with a nicely fitted dust-cap . a - holding screw it also adjusts the cogwheels mesh.
38 Vixen GPE tight Cog wheel meshing
The cogwheels mesh is a bit to tight in the picture
39 Vixen GPE worm adjust screws
I fear touching that trio
31 12V 16A LiFePO4
The power case

 

Bernardo

 

 



#12 Astrojensen

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Posted 23 February 2018 - 11:58 AM

Highly valuable and informative posts all around. Can't thank you guys enough.

 

 

Clear skies!
Thomas, Denmark



#13 brisdob

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Posted 23 February 2018 - 04:51 PM

Hi Thomas, just a few more observations, I apologise if I accidentally repeat what other people have said. 

 

When I said "out on the mount" in my earlier post, what I meant was when you install the Synscan components in the green RA cover you need to take care that the holes you drill allow the wiring and connectors to fit inside without snagging on the mount when you reinstall the cover.  If you simply use the supplied synscan black cover you will need to shave a few bits of plastic off so that it fits correctly.

 

I have used the Vixen MT-1 motor kit in the past, it is efficient and easy to fit.  The newer controllers are robust, the early DD-1 controller I had failed fairly quickly due to voltage issues on the RA motor chip.  I believe Vixen resolved this issue.  Vixen have manual clutches that fit on the worm shafts (one of the photos above shows this - post 11) these enable you to still use the mounts slow motion controls when you disengage the manual clutch, very useful.  My memory may be wrong, but I'm not sure these will fit with the Syn Scan motors because of the slightly different position of the spur gear on the worm shaft, I may well be wrong on this however, the clutches in post 6 above seem fine on the Orion kit.  As you say though, you can still simply loosen the mount clutches and swing the mount to where you want.

 

I must admit I have gone back to using my Sky Sensor 2000PC system because I have been using it for nearly 20 years on and off and am used to it, also it does not care as much as Synscan does about the initial rough polar alignment of the mount - useful for me in Australia! but possibly not a consideration for you.  It will eventually break I know, but I have a spare complete kit in the cupboard.

 

I was not aware of the Avalon kit, looks to be a great modern solution if you want Go To, but expensive!

 

Clear Skies

 

Richard


Edited by brisdob, 23 February 2018 - 04:54 PM.


#14 skycamper

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Posted 24 February 2018 - 03:31 AM

You can't beat the original vixen green motors and clutches. I have two sets of the skysensor 2000, a set of green non-goto motors, and a MTS-3SLP controller no longer made.  I've also had two sets of meade LXD 75 motors with autostar that worked out fine which is another option.

 

If I were a star hopper I'd stick to the green MT-1 units.

 

 

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