I can't balance!

[Herzy]

When I try to balance my Newtonian reflector scope in declination I can't get it perfect because my camera pulls on it at a weird angle. I can get it perfectly balanced at one side of the axis but when flip to the other side of the declination axis it starts drifting from being unbalanced. The camera/focuser stick out, so on one side of the declination axis the camera/focuser is pointing up, while on the other side it's pointing west. Has anyone else run into this problem?

I really don't want to stress or damage my expensive mount so this is an issue that needs resolving! Thanks for any help! 

[DHEB]

Hi! This might sound obvious and you might already have tried this but, for what is worth, and depending on how your mount and telescope are built, you may try a combination of:

1. shifting the position of the tube relative to the axis, using the screws in the clamps for this

2. change the position of the counterweights until you find the right balance in both axes in the position you want to use it

My experience is that one might need to rebalance every time a significant change in equipment is made, as when taking out an eyepiece and setting up the camera, or when adding a Barlow to the optical trying for the camera; and when the general position of the telescope is changed.

My humble advice is to find the balance by experimenting, and recheck it every time you change your configuration.

Good luck!

Edited April 7, 2016 by Cinco Sauces
Rephrased answer a bit

[mikeyscope]

If imaging I think you are best to decide if your subject is rising in the East up to meridian ...or from the meridian to West, you can then balance the tube accordingly.

You will find the scope can be balanced as you say on one side of the mount or the other but not after going through the meridian due to the different position of the focuser & camera hence my first sentence.

You will find the tube can be balanced in RA & DEC quite easily on one side of the mount OR the other as with any other scope but only when  the RA is HORIZONTAL and the tube is HORIZONTAL but as soon as you try to turn the tube to vertical it will be out of balance again being heavier towards focuser ...you need to rotate the tube in the cradle until the tube balances in both vertical & horizontal .....then do a re-check of the RA axis. (When loosening the DEC clutch especially hold onto your tube at all times when checking balance!)

(Rotating the tube in the cradle perhaps 1/8th to 1/4 rotation at a time requires caution as you will need to return to horizontal preferably safe mode with the counterweights pointing to ground and tube horizontal then loosen rings very slightly to rotate tube in cradle ....tighten again return to vertical for check ...then repeat as required until balanced, this process is much easier and safer for your tube if it is mounted in rotating tube rings)

If you had a remote setup it's most likely counterweights would be required in order to do a flip through the meridian.

Mike

[ollypenrice]

Have a look at this image of Pieter Vandevelde's self built imaging Newt. He has the camera on the side of the counterweight bar, which has many advantages for dynamic balance. https://pietervandevelde.smugmug.com/Pics/Equipm/i-GM9mvHm/A

Olly

[andrew s]

And a considerably less elegant example! You need to balance an equatorial in 3 dimensions including with the Dec axis horizontal and the telescope both horizontal and vertical.

 I add lead as needed.

 

Regards Andrew 

[Herzy]

So I should add weight opposite of the focuser to balance out the "third dimension"?

[mikeyscope]

In theory yes ... but in practical use it may not be possible get balance equally on both the East & West side of your mount after a meridian flip, it would allow you to go through the meridian if required in order to complete an exposure but not recommended due to the risk of mirror slop distorting your images.

Some USA manufacturers such as Cave back in the good old 1970's to 1980's used to supply their telescopes with a sliding counterweight bar system opposite the focuser and sometimes a bar at mirror end too but I think this most mostly to satisfy the needs of the visual user. These days the imager has more individual requirements regarding equipment and setup options ....remote or attended that no manufacturer could easily cater for and generally resort to making, adding weights or making some compromises to suit their imaging needs.

Mike

[ollypenrice]

16 hours ago, andrew s said:

And a considerably less elegant example! You need to balance an equatorial in 3 dimensions including with the Dec axis horizontal and the telescope both horizontal and vertical.

 I add lead as needed.

 

Regards Andrew 

That's what you call a working telescoppe! Brilliant.

Olly

[andrew s]

15 hours ago, Herzy said:

So I should add weight opposite of the focuser to balance out the "third dimension"?

I have always balanced my telescopes exactly on all 3 dimensions. I know some recommend an in balance about the RA to even out drive issues but I have never found it to be an issue with the Paramount. 

Regards Andrew

Edited April 8, 2016 by andrew s