Balancing for different eyepieces with an SCT

[jonathan]

Just curious, I've read a few threads which eventually led me to this item at FLO -

First Light Optics - ADM Mini Dovetail Counterweight Kit

However I'm a bit confused as to how it would be fitted to my NexStar 8SE on NEQ6.

My set up is not terribly unbalanced, it's just that if I go from my 25mm to 38mm there is quite a difference in weight there, and I can't be pushing the scope backwards and forwards in the mount as there's a huge risk of it being dropped.

I thought maybe hanging a small bag from the diagonal would do it, but there again I don't want to risk the diagonal slipping out.

[Merlin66]

The ADM minirail is mounted onto the OTA; one screw at the cell end and one at the corrector.

The c'weight can then slide along the bar to achieve balance in Dec.

(I use an ADM to mount a 135mm electronic finder on my C11)

Re sliding the telescope in the holder..I have a "safety" clamp fitted which ensures the dovetail can't slide through.

HTH

[SaraG]

Can this fit onto a long focal length refractor?

[jonathan]

Hmm, but what about the dovetail bar that's already attached to my OTA? Wouldn't that be in the way? Also, if you'll excuse my newbieness, which is the cell end and which is the corrector end? Even more confused!

[Merlin66]

The cell end is where the eyepiece goes in (the "mirror cell") and the opposite end with the corrector plate faces the sky.

The dovetail is "on the bottom" of the OTA; the ADM minirail goes "on the top"

Sarag,

ADM range-

ADM Accessories

for a long refractor you may need to use additional tube rings to support the rail.

[SaraG]

I guess balance isn't an issue for me as I am not tracking, but it would be nice to have later, can this fit to one of those new dual mounts that are big for 2012?

THe Alt-Az and EQ combos that hold 2 scopes?

[michael8554]

Jonathan has an SCT on a NEQ6 equatorial mount.

These 3D counterweight kits are usually for SCT's on fork mounts, because the SCT can't be moved in the forks to get balance?

[SaraG]

Jonathan has an SCT on a NEQ6 equatorial mount.

These 3D counterweight kits are usually for SCT's on fork mounts, because the SCT can't be moved in the forks to get balance?

Because moving non SCT tubes up and down is lots of fun.

I suppose I could hang little weights off the front of my OTA's just to balance it but I am sure PETA will be onto me.

[Merlin66]

The ADM minirail can accept standard 1D c'weights and many other attachments.

(I have a piggy back camera mount and other stuff on mine..)

BTW 2D balance weights are NOT required on fork mounted SCT's to achieve balance! I used to balance my 12" Lx200 - first in Dec with sliding weights and then in RA by adding c'weight to the appropriate fork arm. worked 100%

[michael8554]

With my fork-mounted SCT with piggyback 80mm refractor I point to the horizon and run the weight along the rail until the SCT is balanced.

Then I point at the zenith and move the weight away from the rail on its threaded rod until the sct is balanced,

How do you get that range of balance with weights on the fork arm?

I use those to offset the finder on the left side of the SCT.

[Merlin66]

Micheal,

OK

With the forks vertical (ie on the meridian)

Set the tube vertically and add weights as necessary to give good Dec balance.

Set the tube horizontal and move the weights forward and/or back to achieve Dec balance.

Undo the RA clutch and add some weight say to the rh fork to get good balance in RA.

Job done.

[jonathan]

Thank you for the replies, it makes more sense now, I'll have to look at my SCT and see where it might fit as I don't remember seeing any extra holes. Am I safe to remove a screw from the front and back? Don't want the whole thing to fall apart!

[michael8554]

Merlin

Yes I see now.

I would guess the "meridian" balance would need a heavier weight in your case, without the threaded rod to add leverage?

[Merlin66]

Jonathan,

Yes, there are suitable screws on the outer surface of the cell and corrector plate surround...these can be removed safely.

Michael,

Probably, but it's much easier!

[earth titan]

Having seen this, I'm tempted to fit one to my dob to balance it.

Do they come with spare weights?

[Merlin66]

You can add weights and accessories as you need.