Deforking a Meade LX200gps

[roughy (Mark)]

Hi all

My 13 year old Meade fork mount appears to be dying a magnificently slow death. Thinks it is Hubble one moment and refuses to play the next. And the gps is inconsistent and probably also on the way out.

Therefore I’m thinking of getting a more modern, versatile and portable mount for the OTA, my Solarmax and my little refractor.

I’ve trolled YouTube looking for examples of removing the OTA but can only find examples of deforking the classic design which is a bit different to the more current design, to the best of my limited knowledge.

If anyone could point me in the direction of an example of how to get the tube off the mount, it would be greatly appreciated.

Cheers

Mark.

[Merlin66 (Ken)]

Over the years I've de-forked many Meade LX200 SCT's.

I think the method of attachment between the OTA and the Dec stub shafts remains the same.
I have a write up which explains my process.

[AndrewJ]

Gday Mark
If you do loosen the lower 4 bolts, it can make resetting them to the correct position ( orthogonality wise ) a lot harder.


Another trick you can try before removing the 4 large bolts that hold the fork to the boss is to use reversible G cramps as a spreader.
https://www.bunnings.com.au/irwin-30...clamp_p5860115

Using this/these, you can set up and spring the forks apart wide enough to allow the OTA to be slid out. ( not sure how springy an 8" is but the 10 and 12 inch forks are long enough to spring a fair way.)

Just tape cardboard strips on each side of the OTA to protect the paint when sliding the tube out. Cornflakes pack works well :-)
( as does a second set of hands )

Andrew

[Merlin66 (Ken)]

Andrew,
Yes, you need to mark the fork arm to minimize issues if re-used later.
It only requires the removal of one fork arm to safely remove the OTA.

[AndrewJ]

Gday Ken

Yes, you need to mark the fork arm to minimize issues if re-used later.

I found a simple mark wasnt all that good for reuse.
When you do the math on the angles involved, it doesnt take much error to end up with a few arcmins of orthogonality error
ie a 10" has say 388mm between bearings
1 arcmin at 380mm is only a differential height error of 0.11mm


Andrew

[Merlin66 (Ken)]

Having had to re-set forks on many occasions, I agree but they give a good starting point for the more rigorous ortho adjustments.

[AndrewJ]

Gday Ken
I found that by using the fork spreader trick, i could leave the OTA out.
Then i reset the forks first, using a long axle/bar through both bearings and a dial gauge, so i could adjust it relatively unloaded, then fit the OTA.
Much simpler than trying to adjust the older style forks with the OTA fitted. ( I wish they had fitted jacking bolts into the fork boss as well as the saddles )



Andrew

[roughy (Mark)]

Thank very much for the advice gents. Fortunately I don’t need to take any precautions with regard to putting it back in the forks. I’ll canabilise some of the electronics and the rest will be going to the tip.