Celestron Omni XLT 150 Mount problems

[Legin (Nigel)]

Hello,

I have recently purchased a Celestron Omni XLT 150. The mount is pretty good but it seems to have problem. On of the screws on one of the axis seems to not tighten enough (declination). I have looked at the screw and it seems to just be a normal brass screw that fits onto a clamp like clip thing that you turn to tighten and losen it. I have attached a picture to show you what I mean. Basically if you tighten the screw to a point where it is as tight as you can make it without going to tight. I try not to over tighten it as I am afraid it might dethread the screw or even dmage the mounting thread itself. Either of these things would be a pain to fix. Basically when the screw is tightened the telescope often still moves in the declination motion. This makes it near impossible to keep the scope pointed at things and downright annoying as suddenly the scope will fall due to gravity and swing through the declination. Anyway I was wondering what I could do to help reduce the problem here. I usually get the scope to stay pretty much pointed in the right direction but this issue can be a bit annoying.

[dannat (Daniel)]

have you balanced the scope and counter weights as best you can? sometimes the mounts you buy with a scope aren't quite up to the job.

Does it happen when the scope is flat, at 45 and 90? ooh sorry did you mention was it the dec axis?

You could try some magnets to add mass to the lighter end

[AlexN]

did you balance the dec axis so that it doesnt rotate when unlocked with the RA @ 90 degrees? I have seen this happen with my 6" before I realised that to balance the mount, its payload had to in fact be 'balanced'

[Ian Robinson]

Originally Posted by Legin

Hello,

I have recently purchased a Celestron Omni XLT 150. The mount is pretty good but it seems to have problem. On of the screws on one of the axis seems to not tighten enough (declination). I have looked at the screw and it seems to just be a normal brass screw that fits onto a clamp like clip thing that you turn to tighten and losen it. I have attached a picture to show you what I mean. Basically if you tighten the screw to a point where it is as tight as you can make it without going to tight. I try not to over tighten it as I am afraid it might dethread the screw or even dmage the mounting thread itself. Either of these things would be a pain to fix. Basically when the screw is tightened the telescope often still moves in the declination motion. This makes it near impossible to keep the scope pointed at things and downright annoying as suddenly the scope will fall due to gravity and swing through the declination. Anyway I was wondering what I could do to help reduce the problem here. I usually get the scope to stay pretty much pointed in the right direction but this issue can be a bit annoying.

The GEM (a CG4) looks like a rebadged GP or GPE.

The plastic part pops off , might take a little coaxing with a pair of pliers, or a bit of a jimmy with a big flat ended screwdriver under the (as close as possible to the bolt body) and when it comes off it will reveal a square shaped or similar top (that's what my old CG5 has) , you can then screw it in with a shifter or spanner until tight enough and attach the plastic cover on top , and that should fix the problem, (you've only got a part turn between tight and loose). Careful not to tighten too much as the casting (aluminium is not very strong and you risk stripping the thread).

Hope that helps.

[Legin (Nigel)]

Yeah the scope needs to be balanced for the best results but then when I view the eyepiece sometimes ends up at rediculously difficult angles. I often rotate the tube of the scpe to move the eyepiece around to get the best angle for viewing. However this tends to ruin the balance of the tube on the mount (if that makes sense). I think that is why I get that movement throught the declination axis.

Just for the record I tried bigger screws but they don't seem to make much difference.

Hmmm I guess I will just need to keep the scope a bit balanced at least partially. Though I do wish there was a way to lock the mount in place without risk of threading the screws or the mount. I could probably replace the screw itself, as I have used other ones with the same thread, but the mount would be more trouble to fix.

Anyway it isn't really a major problem and I am sorry if it is a really simple question *shrug*. However this is my first decent scope. My last scope was a cheap 75mm refractor. You know the ones you purchase at the local discount store. Sure it was kind of ok and it showed the moon and Jupiters moons but it was not the best first scope to have when I look back on it. Now I have 6 inches of lovely aperutre if I can ever get it collimated right (arrrghhh another trial for me to stumble through).

[csb (Craig)]

There have been 2 other IIS members who have bought that setup recently - they have posted in these forums about it, no issues just noobie questions.

I suggest you change your post header to include your scope package name ie 'Omni 150XL mount problems'.

This may attract Omni owners attention.

Your pic is of a 'lock screw' as it is called in many manuals

Try swapping the declination lock screw with the ascension lock screw and see what happens.

Also contact the retailer if they are likely to be telescope savvy or send Celestron an email - it may be particular to those mounts.

[Legin (Nigel)]

Just for the record it turned out to simply be a balancing issue. Nothing to dramatic. The screws tighten fairly well, though they could be improved a bit. If nothing else this little scope has got me thinking and learning about telescopes in general. I really wish I could get a bigger one though. But unfortunately I live in a unit and I need to cart it in and outside each time I use it. This scope is about as far as I could carry on my own and I don't have any friends to help me 99% of my observing time.

Anyway thanks for your help folks.

[andyman]

Hi m8....I to have xlt 150..no probs like you m8 i think its your weights
as i had same issue unti i ballenced it correct.
m8 im a nooB but thought i would post as i have same scope

if you like pm me and i will send a pic of my scope mounted and weighted
to fix the issue.(worked for me)

btw...to be honest m8 i think its a great scope but do see my self upgrading
to a much larger one one day

[Legin (Nigel)]

Yep...

Just for the record I have balanced the scope and everything works fine with it. If anyone else gets a scope like this and has the same problem try balancing the scope. The actual tube assembly needs to be balanced or it will not lock properly as the weight will pull it on one side or the other and the lock will often come undone.

The mount on this telescope is actually pretty good.

In any case I will definately be upgrading one day alas this little scope is good but it is just a bit to small in aperture.

Anyway everything works fine now and it was so easy to fix. Alas it is my first scope and I am entitled to not know simple stuff at first .