Balancing the telescope

[Jammy]

When I'm trying to balance my telescope for imaging does it matter that I can't get it balanced in declination?

I can get the right ascension to balance fine through the mount and counter weight.

With the telescope being relatively small (Evostar 80ED) with OAG guide cam, main cam, electronic focuser and filter wheel attached I can't physically move the scope forward enough within the tube rings to get it to balance.  It isn't greatly out of balance, but then I'm not sure how important this is.  If I helps to have this balanced, is there any way of adding counter weights to the front end of the scope?  Do i need to get different tube rings/dovetail?

I'm just wondering how others have managed to get around this.  All comments welcome 😀

[ollypenrice]

It's best to be as close as you can. 

If you move the tube rings forward on the dovetail you'll probably get it balanced. You'll probably need to drill new holes for this.

You can also use a longer dovetail and bolt a small weight to the front of it. Anything will do.

Olly

[joe aguiar]

maybe try to move the ota up or down inside the rings & move the vixen bar up or down the mount if theres not enough room you may need a 12" or 13" vixen bar instead of the smaller 8" bar

joejaguar

Edited January 8, 2020 by joe aguiar

[Louis D]

Or mount a longer dovetail bar with it sticking out the back below your imaging train.  You may need a riser to get the needed clearance.  As long as it's a solid, machined bar rather than an extruded one, it should be plenty rigid.

[Jammy]

Thanks for the comments.

I've moved the OTA as far forward as I can within the tube rings, but it's still not enough.

I do have a longer spare vixen dovetail bar which came with my NEQ6 mount, which I've never used.

I'll have a go at swapping the dovetail over and moving the OTA as far forward as possible.  See if that helps.

From your answers I gather that balancing in declination is just as important as it is for RA when imaging.  I thought it must be, but always best to ask.

[joe aguiar]

with goto in general if its not that will put more stress in either motor and prob make it die bit faster then normal. also goto are double the price of the same size manual mount

In a manual mount you don't have to worry as much since there no stress on the goto motors but u don't want to be too far off either as not to over stress the arms either.

in imaging being off even abit can lead to the motor over gearing so your star may not be pinpoint. I think we just answered kinda this on another tread last week where he had star trails and it could have been he setup wasn't balanced.

joejaguar

[SimM]

Like a see saw - if it's balanced with two adults at each end, a child can push it up/down with ease. Likewise the motors would struggle if it wasn't balanced.

Probably better to add weight to exactly balance it and best to  make it balanced by extending the rails without adding weight.

Some units work better with a loading so balanced and then a slight tweak to load it (probably best to consult the manual).

Simon

[Jammy]

Right!

I've tried fitting the dovetail bar that came with the NEQ6, but unfortunately the drilled holes are too small for the bolts that came with the Evostar 80ED.  Can anyone recommend a longer dovetail bar that will accept the 80ED tube rings and bolts?

I could try drilling out the holes on the bar which I have, but I'd rather not attempt it!

[TerryMcK]

If it were mine I would definitely open up the holes in the dovetail bar.

[geeklee]

50 minutes ago, Jammy said:

Right!

I've tried fitting the dovetail bar that came with the NEQ6, but unfortunately the drilled holes are too small for the bolts that came with the Evostar 80ED.  Can anyone recommend a longer dovetail bar that will accept the 80ED tube rings and bolts?

I could try drilling out the holes on the bar which I have, but I'd rather not attempt it!

I had a similar challenge with DEC balance and got the 11inch version of this:

https://www.firstlightoptics.com/adm-vixen-type-v-series/adm-vixen-style-universal-dovetail-bars.html

I had initially opted for the 14inch but FLO advised the 11inch was a better length for the 80ED... and they were right.  It came with a variety of bolts as well and allowed my green dovetail to mount on top - win-win.

If you're looking at cost alone, obviously drilling out the holes is attractive 🙂

[DaveS]

Ideally you should be balanced in three axes, RA, Dec, and around the OTA.

[Waldemar]

On 10/01/2020 at 15:39, DaveS said:

Ideally you should be balanced in three axes, RA, Dec, and around the OTA.

Absolutely correct, if your filterwheel sticks out on one side, or a focusmotor there will be a radial imbalance which needs to be corrected, to get rid of irregular imbalances. Not all mounts are equally sensitive to this, though.

Edited January 15, 2020 by Waldemar

[SimM]

My Newtonian OTA has an aluminium plate attached at the mirror end with three tapped holes in it. It is on the opposite side and opposite end to the eyepiece.

I never used the three weights that are each 500g to observe. If I tried them, the balance point moves 0.5" to 1" down the tube e.g. it's not significant.

With hindsight (and I never thought much about it until now) I realise this is to balance out around the OTA e.g. add a camera etc. and it can be balanced by using the weights.

Simon