LX70 GEM using 120mm LX70 Refractor Telescope

[Zyllos]

I have two quick, hopefully, minor questions (ya right!) about using the Meade LX70 GEM I got with my LX70 120mm refractor telescope. I purchased it about 4 weeks ago and I have only had a chance to use it three times (dang Oklahoma weather!). Either way, I digress...

On two of the nights that I have been using the telescope, when I use the fine motor control knobs, I notice that the telescope will only turn one way but not the other. If my memory serves me good, it happened when my telescope was in extreme declination and/or right ascension.

Is this due to the telescope/counter weight being out of balance, thus stressing the gears?

Also, I am having a VERY hard time using the right ascension and declination setting circles. Mainly, all three of my observation attempts have started with an hour of polar alignment (which is pretty easy), finding a good star (which I have been using Arcturus as is the first star that I observed) and dialing in the right ascension and declination, then attempt to go to another object's right ascension and declination coordinate. Every single attempt has lead to disaster (meaning just a complete failure of finding the object specified).

I have caught on to some things when using right ascension and declination, like that the 0h right ascension is actually moving constantly in the sky! Which actually now makes sense in why things in the sky keep the same coordinates even as they move. You know, mathematics and all. But a problem I keep running into is once you dial in the reference star, the star is constantly moving, thus your right ascension is going to be off (and the declination depending on how well your polar alignment was off of the NCP). I know there is a locking nob for the right ascension setting circle but it is pretty poor. If I lock it then move it, the dial will move a little bit with the telescope, thus losing it's precision. So one thing I tried was to ignore locking the setting circles, just look at the known star, dial it in, then immediately go to your object in mind. The right ascension will be off by the amount of time it took you do turn the telescope plus the miscalculated in the polar alignment and dialing it in. But to me, in a large eyepiece, like my 40mm Super Plossl, the object your trying to find should only be off by a bit.

But...this is usually what happens to me. I turn to the object and my telescope is hitting the mount or I am facing into the ground!!! I have no idea what I am doing wrong. It could be that I am dialing into what I thought was Arcturus but could be a different star. That would make a lot of sense but Arcturus is a pretty hard star to mistake as it is extremely bright. Maybe I keep viewing objects too close to right ascension coordinate that is the area of the sky that my mount will block. I don't know.

So, my two questions:

1) If the fine motor control knobs are not turning the telescope, is it out of balance?

2) Why can I not dial my right ascension and declination setting circles even close to the part of the sky I want to observe?

Thank you.

[Zyllos]

Oh, and how do you deal with changing eyepieces and balancing? Going from a 40mm to a 6.4mm has a significant weight difference, causing the entire thing to be out of balance. I have heard that I should loosen my OTA knobs and move the telescope forward/backwards in the clamps until it's balanced but is that the only way?

[triton1]

I tend to stick to 2inch ep,s and balance the scope to the one that,s the middle weight you don,t want to be mucking about rebalancing during a session.I might be a bit heavier obviously when using the Barlow as well but haven,t noticed any difference as yet.I did notice however when tracking in ra when observing as in Luna when reversing mine to did not go backwards so I listened to motor as I did it,the motor worked so tried again while looking thru ep and it was about a 4 second delay before it would start to move hence backlash.After slight adjustments managed to get it down to one.You don,t want to over do it,hope this helps

Jonn.

[triton1]

Ps forget the setting circles you might get within a light year

[michael8554]

First of all, if you are only observing, you don't need to spend an hour getting precise PA.

Once you have set PA, swing your scope to the approximate position of the object you are seeking, or Acturus if it is close to it. 

Then rotate the OTA in the rings so that the eyepiece and finder are in convenient positions.

Then balance the scope:

With the scope pointing to the south horizon, with the locks off and the weight arm horizontal, slide the weight along until balanced.

Now slide the OTA forwards or backwards in the rings so that it is balanced and remains pointing at the horizon.

Now might be a good time to put the locks on and try your fine motor control buttons in both directions. 

Remember the correction rate is very small, you won't see large movements unless you are looking at a star through an eyepiece.

And as triton1 says, there may be backlash to take up before movement occurs.

I don't know what the LX70 controller looks like, but I would imagine it has buttons, not knobs - are you trying to use the manual knobs on the bendy stalks?

If the motor is working, unlock and swing back to Arcturus and fine-tune the balance, maybe trying a compromise position that suits the 40mm and 6.4mm.

Now lock up and try the fine motor control buttons again.

Regarding using the RA and Dec scales, if you swing immediately to the new position then the time-lapse shouldn't matter, but you must start from a known star very close to your desired object, big swings across the sky won't work as the scales are so small.

Triton1 has a CG5 which is similar to your LX70, so his experience with the setting circles is probably what you'll find.

Michael 

[Zyllos]

About the experience with setting circles, I was afraid of that. The hour I spend is not just the polar alignment, it's the polar alignment, dialing into the reference object (Arcturus), trying to find a object in the sky. The polar alignment and reference takes like 30m or so.

But, I was wanting to be able to dial them in and then just go "I have these coordinates written down, now lets swing to them!". So maybe I need to have a reference star within every constellation and dial it in to that star then make the small move whatever I am looking at?

About eyepieces, I have the Meade 4000 Series (all 1.25"), and they seem solid so far. With a 2x Barlow along with 6 eyepieces, I can get various magnifications, field of views, ect. So I like them so far. But when I go from the 40mm to something smaller, I run into issues. So, according to you, triton1, I should maybe do a barlow lense and smallest eyepiece to get a good balance between the heaviest and the lightest?

I would LOVE to have all 2" eyepieces, but I was unaware that my telescope could handle them. But, I can easily get some in the future once I have more experience under my belt.