TwinStar 4.5" Reflector Scope/ Problem with EQ Mount

[dtumacde]

I recently purchased a TwinStar 4.5" Reflector Telescope for my family for Christmas and it is our first telescope. I followed the Assembly directions perfectly and was able to view Jupiter on on the first night!!!

My problem is with the EQ mount. The declination axis only seems to turn in one direction when using the flex tube knob. The only way for me to adjust the scope is to turn it manually and it was a real pain trying to zero in on anything. Did I do something wrong? Is there something I can do to fix this?

In addition, I noticed that if I just let the scope sit still for 10 minutes the planet would drift to the side and I would have to recenter it. Could this just be a novice issue? If I move the counter weight up the rod will that help with this problem? Is there something I can tighten to prevent this kind of drifting?

Thanks for your help.

[AstroTux]

I am not familiar with this 'scope but did dig out the instructions after a brief trawl through t'interweb. Your problem with disappearing planets is that you will need to use the RA control knob to keep the planet centred ( unless you have a motor drive to do this for you ). The position of the counter weight should be so that the 'scope is properly balanced on the mount. There are many web pages about that will explain balancing for you.

As far as your problem with the declination control is concerned, I would go over your set-up with a fine-toothed comb to see if either you are at the top ( or bottom ) limit of travel. If your mount uses a worm gear to control this it may be that you need to centre it first so that it will work in both directions. Also check that the slow-motion cable is properly fastened, as it may be that it is slipping in one direction, but not the other.

Hope all this helps, and enjoy your new 'scope......

[brantuk]

"if I just let the scope sit still for 10 minutes the planet would drift to the side"

If the scope is sitting still for ten mins then you will find that the object drift in the eyepiece is due to the Earth spinning round and carrying you and the scope with it

[dtumacde]

The cable is fastened correctly, I can see and feel the metal piece turning but the scope does not move.

Can you explain centering? I have tried turning the dec. control a lot in the direction it will turn to see if that fixes the problem. Is there something i need to do to center it?

I realize that the earth rotates and that planets move but I didnt think they moved fast enough to see a drift with the naked eye while looking through a telescope.

Edit: Im going to try and switch the dec. and ra cables when I get home from work to see if this solves the problem. Keep you all updated.

[assasincz]

AS far as this "drift away planet" is concerned, this is where the equatorial mount you have comes in handy, because, after you set it up right (takes a bit of study and practise) you just turn the R/A knob and the obect that drifted away from the field of view should be there again - very handy indeed. It might be worth to get a R/A motor, then, there would be no need for recentering objects again, provied you have set the mount up right

[brantuk]

Yup - ten mins is enough to detect drift in the eyepiece of a stationary scope. Have you actually polar aligned the scope? If you can do that then you will only need to track in RA (with the odd tweak in Dec).

For visual use a rough polar alignment will suffice. Just point the mount due north using a compass, then set the altitude scale to your lattitude on Earth. Then loosen the RA and Dec clutches to find an object - center it in the eyepiece and lock the clutches up. Center the finder too so it's looking at the same object as the main tube.

You'll then find it much easier to find stuff using the finder scope, and much easier to track in RA only

[Cornelius Varley]

There is nothing wrong with the dec axis on the mount. The small EQ1 and probably the EQ2 aswell have only a small amount of angular movement on the dec axis when using the slo-mo cable. If you need to slew the mount you have to disengage the dec axis by slackening the dec axis thumbscrew and then move the telescope by hand to the new target and then retighten the thumbscrew. The target should remain in the fov by slowly adjusting the RA slo-mo cable.

You can recentre the dec axis by counting the number of turns required to rotate the dec axis from one limit to the other and then turning the cable half the number.

Peter

[dtumacde]

Cornelius - When turning the dec. cable counter clockwise there is a small amount of movement. When turning the dec cable clockwise there is absolutely no movement.

I have only taken the scope out once due to incliment weather but tonight we will have clear skies so I will tinker around with it. I need to polar align the scope and I also need to align the sight scope properly. Perhaps when I do that I wont need to mess with the dec. too much.

The plan tonight is to look at Venus and to explore the moon.

[brantuk]

Venus is allmost set and the moon is following rapidly - Jupiter is high in the sky though right now

[Cornelius Varley]

Cornelius - When turning the dec. cable counter clockwise there is a small amount of movement. When turning the dec cable clockwise there is absolutely no movement.

I have only taken the scope out once due to incliment weather but tonight we will have clear skies so I will tinker around with it. I need to polar align the scope and I also need to align the sight scope properly. Perhaps when I do that I wont need to mess with the dec. too much.

The plan tonight is to look at Venus and to explore the moon.

How much is a small amount ?

Peter

[dtumacde]

I have turned the scope at least 15 degrees counter clockwise in less than a minute, I probably could have turned it more counterclockwise but I never bothered to try. I could turn it clockwise for 15 minutes and get no movement.

[Cornelius Varley]

I have turned the scope at least 15 degrees counter clockwise in less than a minute, I probably could have turned it more counterclockwise but I never bothered to try. I could turn it clockwise for 15 minutes and get no movement.

I think thats about as much rotation there is in the dec axis. The slo-mo control of the dec axis is intended for small adjustments, just to get the target in the fov after the telescope has been slewed by hand with the clutches released. After the target has been centred in the finder the clutches can be reengaged and fine adjustments can be made using the cable. The dec axis slo-mo on the EQ1 doesn't have the full rotation that is available with the EQ3 and above.

Peter

[Perpetualbug]

I fixed the problem with the declimation axis. The manual release bolt was not tighted fully. After I tightened the bolt the cable control works perfectly in both directions.

My DC control allows for a full 360 degree rotation so I guess I have one of the newer model mounts.

Of course we had clear skies all day and it looked promising when I got home from work. 30 minutes after I get home we have complete cloud cover I was able to algn the sight scope with a barn light that is about a mile away but I still need to align my scope to polar the polar north.

Thank you all for helping