Scope Balance

[NovaTJ]

Just wondering what you all are having to do to keep your scope balanced. Case in point...I balance my C80, eq mount with a diagonal and ep and it's fine. Then I put my 40D on the scope either on the diagonal or straight through prime, and I know if I don't do a quick re-balance, I risk putting undo strain on the drive motors or gears. Any insight is appreciated.

Greg

[Nighthound]

Hey Greg. It's important to balance your rig with all items in place for imaging. Failing to do so will add stress to the gears but will also make long exposures much more difficult if not impossible. Even the priciest and robust mounts require proper balance.

Proper alignment, balance and alignment fine tune are essential if your goal is to get extended exposures. I'm assuming you're not autoguiding but even if you are the same is required to minimize difficulty that an unbalanced rig puts on that process as well.

You'll find that there are quite a few checkpoints to cover in the imaging process. Each one checked puts you closer to success.

[Catanonia]

I really need to put all these checkpoints together as a check list to be printed out each time I start a session. Sometimes I forget one.

Believe it or not, I spent 2 hours on M57 Ring and forgot to focus the picture :)

[NovaTJ]

So, I have to do a complete re-balance everytime I make the switch over from viewing to imaging. Which is what I'm doing now. There are no quick methods any of you use. Ideally, a separate scope used for imaging would be nice as I see most of the steller imagers in this group have. Sounds like my next step-up. Thanks Nighthound and Catanonia for your insight.

Greg

[Nighthound]

So, I have to do a complete re-balance everytime I make the switch over from viewing to imaging. Thanks Nighthound and Catanonia for your insight.

Greg

You're very welcome.

Not necessarily. Since you're not overloading your mount it wouldn't be terrible to do a little viewing after balancing with your camera in place for imaging. But if your mount is a bit old or if you just don't want to stress the mount then I'd say take the time to rebalance before imaging if for no other reason than peace of mind.

Another option would be to balance with your camera in place. Then once the camera is removed and you place your eyepiece and diagonal in, simply attach a weight just forward of the focuser that is close to the weight of your camera. An ankle weight or any appropriate weight with a small piece of velcro or a strap would do the trick. Just be sure it's secured and doesn't fall where you don't want it to. And don't forget to remove it after inserting your camera.

[NovaTJ]

Another option would be to balance with your camera in place. Then once the camera is removed and you place your eyepiece and diagonal in, simply attach a weight just forward of the focuser that is close to the weight of your camera. An ankle weight or any appropriate weight with a small piece of velcro or a strap would do the trick. Just be sure it's secured and doesn't fall where you don't want it to. And don't forget to remove it after inserting your camera.

That's what I was looking for...a quick tip that would work in a pinch! If setup before hand, it would save some time in the field. Thanks.

Greg

[chris.bailey]

For the most part you tend to use the same items when imaging. a couple of small scores on the dovetail plates with you imaging train in place lets you get fore and aft balance pretty quickly and a ring of tape or two on the counterbalance shaft sorts that one.

[Jeff]

For the most part you tend to use the same items when imaging. a couple of small scores on the dovetail plates with you imaging train in place lets you get fore and aft balance pretty quickly and a ring of tape or two on the counterbalance shaft sorts that one.

+1 for that. I marked my weight rail with blue painters tape in two places one for visual and one for imaging. I just slide the weight to the right place for what I want to do. The setup is the normally the same or at least close enough for both.

[Adrena1in]

Sounds a little picky, but it's best to even set the focus and then do your balance. Racking the pinion out with a heavy camera on the end can upset the balance quite a lot also.

I have to adjust my balance several times during a session, and even if I adjust from shooting in the east to shooting in the west I need to do a slight adjustment.

[NovaTJ]

All good advice! Thanks for the insight guys! The painters tape mark was what I was using and it helps for the rough guess. I do find that when using the camera in prime mode, I do have to rack out the focuser quite a bit and it does affect balance. In fact, there is not enough tube weight with my scope to achieve balance in the focused position so I think I will work on the velco and ankle weight idea. I have some old magnets from an electric motor that have about the same curvature as my scope...any thoughts on using the magnets on the front end to add weight? I wouldn't want to throw off anyone's compass or affect the magnetic field around the north pole....:rolleyes:

Greg

[chris.bailey]

It is also possible to be too well balanced. All the gears have a little "slop" in them and being slightly out of balance keeps them meshed. I tend to unbalance very slightly in favour of the east and forwards.

[Nighthound]

Lots of great input guys.

Chris brings up an important point. If you are able to achieve perfect balance this puts you in a position to add a slight amount of bias on the east side of the mount. How much bias has to be determined by trial and error and will vary depending on the position of the scope at any given time. I use an ankle weight that I can hang on the shaft and move it up toward the scope as less weight is needed. Once I have imaged as far as the mount will go with the counterweight in the east, I'll do the meridian flip and then take the ankle weight and drape/attach it on the scope which is now on the east side of the rig. It's best to keep an eye on star shapes and decide if any bias is needed as you go, there are times when I don't need it and it can actually be a negative. Other times it brings the stars to round right away. This is where having gears adjusted well really comes into play. Finding the sweet spot in the gear meshing tension is very important.