Jump to content

stargazine_ep38_banner.thumb.jpg.6fe20536a22b28c17b2ee1818650993c.jpg

EQ3-2 Motor Drives


Recommended Posts

Hi Guys,

My first post here, although I have been visiting the site a lot to gather much needed info. I am very new to all this and I would like to be able to take some astro pics.

So I have just purchased the dual axis motor drives for my 150 SW Newtonian on EQ3-2 mount. The Dec axis has a nice thumbwheel clutch so that you can engage and disengage as required. However, the Ra axis has a silly little allen-key hex screw that needs to be loosened to disengage the drive. I can see that being a right faf in pitch darkness.

Has anyone managed to source an alternative thumbwheel screw or similar to make this a little easier in the field?

Any suggestions much appreciated. Many thanks.

Bill

Link to post
Share on other sites

I'm no expert so what I am about to say may well be tosh, but I would imagine you wouldn't want to disengage the RA drive as this is what is required to counteract the Earths rotation and keep your object in your field of view?

As I said, might be complete tosh but someone will know for sure.

Link to post
Share on other sites

Thank you for your reply. Sorry, I didnt make myself clear. I meant that, when you are doing your initial setup (ie polar alignment then slewing to taget) you need to have the RA axis diengaged from the motor drive. Then, when you have the target locked, you need to tighten up this fiddly little grub screw in the pitch dark, using an allen key. I wondered if a small thumbscrew or similar would fit in place of this small screw and/or if any members had a good way of dealing with this.

Thanks

Bill

Link to post
Share on other sites

I have the same mount (or CG4), as for polar aligning, I haven't undone either clutches? The motors won't work if they are 'loose' When I unlock the clutches it lets me manually move the scope, but motor use they need to be tight. Maybe i'm doing it wrong lol....but so far all is good. As for the screw, try a scope shop :rolleyes:

Link to post
Share on other sites
Thank you for your reply. Sorry, I didnt make myself clear. I meant that, when you are doing your initial setup (ie polar alignment then slewing to taget) you need to have the RA axis diengaged from the motor drive. Then, when you have the target locked, you need to tighten up this fiddly little grub screw in the pitch dark, using an allen key. I wondered if a small thumbscrew or similar would fit in place of this small screw and/or if any members had a good way of dealing with this.

Thanks

Bill

No worries Bill. Just a thought though if the axis (axii?) is disengaged from the motors then it will not slew, unless you are doing it by hand?

It sounds like you are manually slewing to a target? If so, why not use the motor drive to get you there as this sounds like the way it should be done given the fiddly allen key arrangement?

Link to post
Share on other sites

Thanks for all of your replies.

Celeste, I will try a scope screw and see if the thread is the same. How do you unlock the clutch on the RA axis as this is the one with the allen key?

Digz, as for using the motor drives to slew to your target, after polar aligning I would have thought it would take an age to slew using the motors, especially if the target is to the south, even using the 8x speed setting. I have only just bought the motors so have not had a chance to test this so I could be wrong.

Link to post
Share on other sites
Hi Guys,

My first post here, although I have been visiting the site a lot to gather much needed info. I am very new to all this and I would like to be able to take some astro pics.

So I have just purchased the dual axis motor drives for my 150 SW Newtonian on EQ3-2 mount. The Dec axis has a nice thumbwheel clutch so that you can engage and disengage as required. However, the Ra axis has a silly little allen-key hex screw that needs to be loosened to disengage the drive. I can see that being a right faf in pitch darkness.

Has anyone managed to source an alternative thumbwheel screw or similar to make this a little easier in the field?

Any suggestions much appreciated. Many thanks.

Bill

1. Polar align before switching on the drives.

2. To point the telescope in a new direction disengage the RA and DEC clutches, then slew the telescope by hand to the new direction and re-engage the clutches once the new target is found. The EQ3-2 drives are used for tracking and small adjustments to the mount only. The small grub screws on the RA drive connector should not be loosened to adjust the telescope in RA.

Peter

Link to post
Share on other sites

Peter,

Thats the problem. Only the Dec motor has a clutch. The RA motor is connected with the grub screw and there is a lot of resistance from the RA motor if I try to slew by hand without undoing the grub screw and I dont want to force it. If the RA motor also had a clutch there woud be no problem. I appreciate your help. Thanks.

Bill

Link to post
Share on other sites

The RA axis has a clutch, the locking lever is located on the body of the mount just above the RA drive shaft. The drive is connected directly to the RA drive shaft on the side of the the mount. To slew the mount disengage the clutch and the re-engage the clutch once you have repositioned the mounted. There is absolutely no need to loosen the grub screws on the RA drive shaft once the motors are installed.

Peter

Edited by Cornelius Varley
Link to post
Share on other sites

Peter,

I have check and double-checked and there is no clutch lever on this drive. This is what the manual says: "To use the R.A. fine-adjust cable, the set screw in the rubber shaft of the R.A. motor drive must be loosened to allow the R.A. worm gear to rotate."

I was hoping there might be a more practical and elegant solution that didnt involve using an allen key in the dark. Again, thanks for your assistance.

Bill

Link to post
Share on other sites

You are right the drive shaft doesn't have a clutch - use the RA clutch lever on the top of the mount to disengage the RA axis to slew the mount over large angles. There is no neat solution for the problem, I went through this a few years ago with my own CG4, simply loosening a grub screw to adjust the RA axis isn't ideal and is difficult at night and the grubs screw may not locate onto the flat on the drive shaft when retightened. The ultimate solution is to upgrade the mount with the Synscan kit.

Peter

Link to post
Share on other sites

Peter is exactly right with this.

Loosen the locking levers on the mount (not the motors), point the scope where you want it by hand, tighten the locking levers on the mount, then switch on the motors to start tracking, and centre the target in the eyepiece using the handset.

I use a 2" LV 30mm EP as a finder to get in the right place, then switch to my DSLR for imaging.

Link to post
Share on other sites

Even if I loosen the the locking levers on the mount, the resistance from the RA motor prevents me slewing unless I also loosen the grub screw. It looks as if I will have to live with it or find something better than the grub screw - maybe a thumbscrew or similar.

EDIT: I tried Celeste's earlier suggestion of using a scope screw - it fits perfecly, its the same thread. Nice one!

Thanks for all your suggestions and help.

Edited by A320Flyer
Link to post
Share on other sites

Hmmm

How are you "slewing" the mount???

Are you loosening the clutch knobs and physically moving the tube WITHOUT using the slo-mo cables???

I can accept if you want to use the Slo-Mo cables to slew you'll have the problem you describe....just don't use them to slew.

Link to post
Share on other sites

Yes, that's right. You need to loosen the locking levers and then push the scope about 'Dob style'. Forget about the manual slow-mo controls. BTW, I have a Rigel Quickfinder set next to the finder scope, so it's quite easy to manualy get the scope pointing 'close enough' to where you want it.

Link to post
Share on other sites

Doh! and double-Doh!.

Its obvious now that you dont use the slo-mo control on the RA axis - push the scope Dob-style then use the RA motor for fine tuning. What confused me was that, with a clutch supplied on the Dec axis, I thought there should also be a clutch on the RA motor.

Everyone, please feel free to whip me with a long whippy thing.

Bill

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.