Motor drive kit for EQ5

[Grierson]

As a newcomer to astronomy and imaging I have just a few more naive questions which you folks may be able to answer for me!
 
I have bought the Skywatcher dual axis motor drive and fitted the RA motor to my EQ5 mount. Although it seems obvious that the left and right buttons on the controller control the RA motor the instructions open with the statement 'When control box is turned on and all buttons are depressed the RA motor will rotate at the proper speed ........' Pressing all the buttons appears to do nothing apart from changing the LED in the centre from red to green, reverting to red when the buttons are released. If I point the 'scope at the moon, for instance, I can stop it in it's track across my camera screen by pressing the right button but it is not clear if this should be pressed and released or pressed and held down. Does anyone use the kit or know where if anywhere a better set of instructions can be found?
 
Turning to the motor drive to the scope I assume this has a worm and tangent gear train. I am puzzling to make sense of what happens when the gear reaches the end of it's travel (albeit after a lengthy time). It would seem to this non engineering idiot like me that the gear would stall and potentially burn out the motor. I am sure that this is not likely to be the case but I would welcome a view on how it actually works.
 
The motor kit includes a port on the controller for guiding purposes. I have read a fair bit about guiding but the discussions invariably centre on laptops. My elderly laptop has very poor battery life from full charge and is not therefore suitable. I wonder if anyone runs guiding software on an Android tablet.
 
Many thanks to those who have taken the trouble to read this ramble. Any comments would be appreciated.   

be appreciated.

[DHEB]

Hi! I do not know if this will answer your question properly,  but may be it helps. I have a SW 200PDS, also on a EQ5 mount fitted with dual axis controller. As the manual says, when you switch it on, the controller will guide the RA axis at the speed of Earth rotation. If your scope is properly aligned you will then be able to center an object in the view and keep it there. There is a bolt on each axis, that you have to loosen to be able to slew manually, and tighten to allow the RA axis motor to drive the telescope (I do not know if "bolt" is the adequate English word). Reading your description, it appears to me that you possibly forgot to tighten this bolt. May be this is the problem?

Cheers and good luck!

[Cornelius Varley]

35 minutes ago, Grierson said:

Turning to the motor drive to the scope I assume this has a worm and tangent gear train. I am puzzling to make sense of what happens when the gear reaches the end of it's travel (albeit after a lengthy time). It would seem to this non engineering idiot like me that the gear would stall and potentially burn out the motor. I am sure that this is not likely to be the case but I would welcome a view on how it actually works.

The gears has no travel limit. The worm gear just rotates and drives the gear wheel around and around and around and...  The EQ mounts (EQ1, EQ2) have a limited amount of travel in the DEC axis, but these were not intended to be motorised so not a problem. All the larger mounts (EQ3, EQ5 etc) can be rotated through 360° and more.

[Bizibilder]

With the controller attached and all switched on the mount will be driven at "siderial rate".  This means that it will track the stars as they apparently move across the sky (actually it is the Earth rotating making the stars appear to move across the sky!).  So if you put a star (or Moon or Planet) in your field of view it will stay there (assuming your mount is correctly polar aligned).  These mounts and motors (and alignment) are not perfect so, over time, there will be some drift and you will see the target slowly move across the field of view.

The Buttons are there for you to do two tasks:  Firstly you can "nudge" the object back into the centre of the field of view by pushing and holding the appropriate button - relese it when you have the target centered.  This is done on 0.5x or possibly 2x setting of the slider switch.  Secondly "fast" ie 16x (8x on older boxes) allow you to move the mount rather more quickly.

However this is not "fast slew" as often mentioned for moving the mount across the sky to pick up a new target - it it still far too slow.  For that you have to release the clutch levers and move the mount manually, fasten the clutches and then use the buttons to "fine tune" the position of the object in the field of view.  Once aligned, you release all the buttons and only depress them again to re-centre the object - the RA motor will continue to operate until you switch the box off.

Hope that helps a bit - if not then ask and we will help you.

[Grierson]

Thank you very much for the comprehensive replies. Peter, that has put my mind at rest with regard to the gearing travel. Sinco Sauces thanks, I do understand the issue with what you have called a 'bolt' which I would term a small clutch {not the main clutches}  which surrounds the shaft on which the cog on the mount is located. (In fact the dealers advert {FLO} tells the reader that the mount can not be moved by hand once the motor is installed. This is not correct as unscrewing the 'clutch' away from the cog allows movement using a knob on the other end of the shaft on which the cog is mounted.)

My problem is understanding the use of the controller and thanks to Roger I have a better idea of how it should work. Last evening was the first opportunity I have had to try out the system. I am still a little confused as to how the controller should work given the explanation and I may not have remembered my actions exactly. Having centred the moon on my camera's screen the image began the natural move from left to right. Pressing the left button and holding it down intermittently did indeed keep nudging the image to the left. However without touching any buttons and although the system was powered up there appeared to be no control over the 'scope. The image just drifted to the right. If however I centred the moon's image and pressed the left button briefly (and not the right button as I think I mistakenly said above) the moon's image stopped moving which presumably meant the motor/'scope was apparently tracking the moon.

Sorry if there are too many lefts and rights, Roger, but I will have another attempt tonight with your explanation in mind. 

John    

[DHEB]

4 hours ago, Grierson said:

Thank you very much for the comprehensive replies. Peter, that has put my mind at rest with regard to the gearing travel. Sinco Sauces thanks, I do understand the issue with what you have called a 'bolt' which I would term a small clutch {not the main clutches}  which surrounds the shaft on which the cog on the mount is located. (In fact the dealers advert {FLO} tells the reader that the mount can not be moved by hand once the motor is installed. This is not correct as unscrewing the 'clutch' away from the cog allows movement using a knob on the other end of the shaft on which the cog is mounted.)

My problem is understanding the use of the controller and thanks to Roger I have a better idea of how it should work. Last evening was the first opportunity I have had to try out the system. I am still a little confused as to how the controller should work given the explanation and I may not have remembered my actions exactly. Having centred the moon on my camera's screen the image began the natural move from left to right. Pressing the left button and holding it down intermittently did indeed keep nudging the image to the left. However without touching any buttons and although the system was powered up there appeared to be no control over the 'scope. The image just drifted to the right. If however I centred the moon's image and pressed the left button briefly (and not the right button as I think I mistakenly said above) the moon's image stopped moving which presumably meant the motor/'scope was apparently tracking the moon.

Sorry if there are too many lefts and rights, Roger, but I will have another attempt tonight with your explanation in mind. 

John    

Thanks John for the word "clutch", I see we understood each other anyway and that the clutches, the small ones next to the knobs, arent the problem.

From your description, I would say that most probably the mount is not properly aligned. Then, if this is not a problem, may be you have not put the swith that controls the direction of the drive in the position for the Northen hemisphere?

If this is also not a problem, the I run out of options ?

Good luck!