LNT-based scopes spinning???

[swood333]

I thought I'd post my findings on this matter on a seperate listing as I've listed them on other postings and others have seemed to post again the same similar situation.....

I was having the same issues as all the others... when trying to calc north the scope would just continue to spin... after some thoughts on it I came to the conclustion that the tube it's self might be magnetic. I work in a tool and die shop and the thin gage metals we get are magnetic UNLESS spec'd to be demag'd... I took all the electronics off the tube assembly. I.E. the drive mount and the LNT modual. then took it to work and passed it over our demagnatizer... I left the primarry and seconadry mirror and focuser attached.. it wouldn't hurt them in the process of doing this.. plus if they had metalic components it would demag them too...

Once I got the scope back home and reassembled.. I tried it...  it actually WORKED.. pointed north.. or at least a semblance of north... lol.  When I tried it that night in my open back yard it leveled and hit north and was on the alignment stars within a few degrees...  I don't think the LNT modual will ever point to TRUE north because of the effects of magnetic declination... it's where the earths magnetic field gives a false readig due to soil coposition and magma flows and such under the earths crust... here at my house a compass acctually is off by close to 5 degrees.. and from what I've read this can change over time even at the same location... but if you do the "calibrate sensors" item in your utilities menu it'll help.. it tells the control where true north is based on the location of Polaris (the NORTH star) in comparison to your LNT's reading of north...

So if you're having this issue and you replace the LNT a time to make sure it's not that.. I'd suggest taking your optical tube assembly (the scope tube, for the newbies), minus the electronic components to a tool and die shop or machine shop and have them demag it... if you can still remember how to make an electromagnet from you high schol science class maybe you could do it that way just leave the magnet on and pass it over in closs proximity to all the metalic parts...  just don't turn off the magnet while the scopes init's field or all you do is succeed in making it MORE magnetic..  but I'd suggest having it done somewhere there's prob alot less chance of elecricution that way...lol

if any one has questions about what I did.. feel free to shoot me an email... vwthing74@yahoo.com


I hope this helps out.. I know it did for me...

[MistrBadgr]

Thanks!  That is good information!  Do you think a TV degausing tool would work or is something stronger needed?

Bill Steen

[swood333]

HMMMMM.. good question...

might be..

but i think then the issue with that would be... to de-mag the metal you have to have the metal pass through the magnetic field un-interupted mening a constant field... if the metal is in the field while it goes out, as in with the pulse on a degause... the metal actually gains magnatisim...


making a electro magnet isn't diff... it's just a piece of metal that's been wound in wire that completes a circuit... cant remember if it has to be DC current or if AC will work... i'm sure someone with a little ingenuity can figure it out fairly easily on this wonderful world wide web...lol

i'd be glad to discuss it further if anyone needs....


-Sean

[liondogs]

I bought my son a DS2130-LNT for Christmas.  The first time we took it out the scope would not find north.  It just kept spinning in a circle during alignment.  I called Meade about it and they were of little help.  Something about light poles, cars, trees, or houses etc could make it malfunction.  Read some posts here on the "spinning" problem and discovered a lot of people having the same problem.  Read a post from someone on the position of the LNT in relation to the ground and did some experimenting.  I found for my scope for it to work right the scope must set in the holder with the eye piece pointing straight up to the sky when the scope is level to the ground.  Any other position and the scope will just spin when trying to find north during alignment.

This makes it a little less easy to see through the eyepiece but the scope aligns correctly now.

[MistrBadgr]

I have not used one of the LNT versions, only TC mounts.  Therefore, I cannot speak with any authority about what the programming will do.

In most versions of the scope, you normally point the scope North and level it.  The programming assumes you have done this at one point and takes off for its first star.  I believe that the LNT mount can still do this if the module is unplugged.  You will have to enter time and date each time you use the scope.

That way, you can turn the scope back around to a more comfortable viewing angle. 

Meade now makes an "atomic clock" that plugs into the LNT socket to give you time, since the mount does not have a time chip built into it.  This makes the mount function just like a TC version.

What you have found is good information.  It is another piece to the puzzle.

Thanks for sharing!

Bill Steen