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My Meade telescope sometimes points too far up


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#1 chase172

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Posted 30 April 2015 - 11:27 AM

Hello, my StarNavigator 90mm Altazimuth Refractor with AutoStar (White Tube) Telescope sometimes points too far up when locating planets or stars. It touches the tripod and keeps slewing, is this okay? Will this break the telescope? Also, the servos are still on after slewing so it makes a weird mechanical sound. And is it okay to shut off the Telescope when it's slewing so that it doesn't break and touch the tripod but keep point up? Thanks. -Chase



#2 MistrBadgr

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Posted 30 April 2015 - 02:52 PM

Hi Chase,

Welcome to the Forum!

Normally, when the scope hits something, there is a spring mechanism inside that will cause the worm gear that meshes with what I call the bull gear and allows the worm gear to rise out of the teeth of the bull gear. Normally, you will hear a thumping sound when the worm gear pops back into the bull gear.

It is really not a good idea to have the mount do that. There is a place in the programming menus where you can limit how far up the scope can go to keep it from hitting the tripod legs. That takes some objects out of your capacity to view, but you can wait a few hours and those objects will descend back into your viewing space.

Whenever the scope does hit a tripod leg or some other item and either stalls or keeps driving and makes the popping sound, your alignment is now off. You need to reset the scope to level and North, then go through an alignment procedure again.

If your scope ever seems to argue with you about final placement of an object in the view, or the object seems to move across the field for a while before the scope starts tracking, the drives need to be calibrated. What this amounts to is going through the calibrating routine to let the scope know how much backlash (slop) there is in each drive train from the time the motor starts turning until the scope moves. All gear trains have to have some of this or the gears will not move. The scope just needs to know how much there is.

Hope this helps. If not, let me know where I got off base and I will try again.

Best Regards,

Bill Steen
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#3 chase172

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Posted 30 April 2015 - 04:31 PM

Hi Chase,

Welcome to the Forum!

Normally, when the scope hits something, there is a spring mechanism inside that will cause the worm gear that meshes with what I call the bull gear and allows the worm gear to rise out of the teeth of the bull gear. Normally, you will hear a thumping sound when the worm gear pops back into the bull gear.

It is really not a good idea to have the mount do that. There is a place in the programming menus where you can limit how far up the scope can go to keep it from hitting the tripod legs. That takes some objects out of your capacity to view, but you can wait a few hours and those objects will descend back into your viewing space.

Whenever the scope does hit a tripod leg or some other item and either stalls or keeps driving and makes the popping sound, your alignment is now off. You need to reset the scope to level and North, then go through an alignment procedure again.

If your scope ever seems to argue with you about final placement of an object in the view, or the object seems to move across the field for a while before the scope starts tracking, the drives need to be calibrated. What this amounts to is going through the calibrating routine to let the scope know how much backlash (slop) there is in each drive train from the time the motor starts turning until the scope moves. All gear trains have to have some of this or the gears will not move. The scope just needs to know how much there is.

Hope this helps. If not, let me know where I got off base and I will try again.

Best Regards,

Bill Steen

I will try to limit the amount the telescope can go upwards, but where is it in the menus? I will also make sure to recalibrate it if it ever happens again.



#4 MistrBadgr

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Posted 30 April 2015 - 05:28 PM

Chase,

I am not sure about the AudioStar handset's menu. I expect that the option you want is in Setup.

I will check around a bit and see what I can find.

Bill
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#5 chase172

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Posted 30 April 2015 - 05:31 PM

Chase,

I am not sure about the AudioStar handset's menu. I expect that the option you want is in Setup.

I will check around a bit and see what I can find.

Bill

Okay, thank you! I have an AutoStar controller, not an AudioStar but thank you very much!



#6 MistrBadgr

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Posted 30 April 2015 - 05:44 PM

Chase,

In the AutoStar menu, go to "Setup," arrow down to "Telescope" and select that item. Under "Telescope" go to the option called "Max Elevation." On the particular list in an older instruction book I have on my computer, it is the 13th item on that list. "Training Drives" comes a few options before "Max Elevation."

The basic AutoStar menu is about the same from version to version with a few changes. AudioStar is just the newest one. The 494 handset is the oldest model still being used. The 497 is in between those two.

Hope this helps,

Bill
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#7 chase172

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Posted 01 May 2015 - 06:35 AM

Chase,

In the AutoStar menu, go to "Setup," arrow down to "Telescope" and select that item. Under "Telescope" go to the option called "Max Elevation." On the particular list in an older instruction book I have on my computer, it is the 13th item on that list. "Training Drives" comes a few options before "Max Elevation."

The basic AutoStar menu is about the same from version to version with a few changes. AudioStar is just the newest one. The 494 handset is the oldest model still being used. The 497 is in between those two.

Hope this helps,

Bill

It can still hit the tripod legs, but thanks!



#8 MistrBadgr

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Posted 01 May 2015 - 10:23 AM

Chase

You will need to enter a value, I think in degrees, and keep lessening the amount until the scope does not hit the legs.

Bill
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#9 MeadeGuy

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Posted 01 May 2015 - 01:12 PM

Hi Chase, 

 

If the StarNavigator 90 is hitting the leg I suspect something is wrong in the initial home position (the tube must be level to the horizon as well as pointed north) or in the two star alignment. If those are set correctly the scope should know where the mount is.

 

You can shut down at any time without damaging anything and that is probably the best way to avoid an imminent strike, which can definitely cause damage to the mount. It is either that or hitting MODE very quickly should interrupt a slew. The power switch is probably faster and the best bet.

 

Can you post a photo of your setup showing the scope on the mount in what you are using as the home position? That might help in the troubleshooting.

 

John Piper

Customer Service Manager

Meade Instruments Corp.  



#10 chase172

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Posted 02 May 2015 - 07:22 AM

Hi Chase, 

 

If the StarNavigator 90 is hitting the leg I suspect something is wrong in the initial home position (the tube must be level to the horizon as well as pointed north) or in the two star alignment. If those are set correctly the scope should know where the mount is.

 

You can shut down at any time without damaging anything and that is probably the best way to avoid an imminent strike, which can definitely cause damage to the mount. It is either that or hitting MODE very quickly should interrupt a slew. The power switch is probably faster and the best bet.

 

Can you post a photo of your setup showing the scope on the mount in what you are using as the home position? That might help in the troubleshooting.

 

John Piper

Customer Service Manager

Meade Instruments Corp.  

I did not do the two star alignment but I did do the home position stuff. It has not hit the legs because I panicked and pressed the off button when the telescope was slewing so far upwards. I can't provide a picture but I can tell you that I am only using the stuff that came with the StarNavigator 90. I have not bought any other mounts or anything, I'm just using the stuff that came with the Telescope.



#11 MistrBadgr

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Posted 02 May 2015 - 09:14 AM

Chase,

Are you trying to tell the scope to go to an object or are you just running the scope around manually? If you are telling the scope to go to objects itself, you have to go through the alignment procedure for the scope to know where it is pointing. You need to have your position and the correct time entered into the scope also.

Hope this helps.

Bill
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#12 chase172

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Posted 02 May 2015 - 09:24 AM

Chase,

Are you trying to tell the scope to go to an object or are you just running the scope around manually? If you are telling the scope to go to objects itself, you have to go through the alignment procedure for the scope to know where it is pointing. You need to have your position and the correct time entered into the scope also.

Hope this helps.

Bill

No, the alignment has nothing to do with my question. Alright, here is a new question that will answer my previous questions. Is it okay to press the off button when the telescope is slewing?



#13 MistrBadgr

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Posted 03 May 2015 - 03:05 PM

Hi Chase,

I thought I answered this earlier today, but I apparently did not hit the send button.

Yes, you can turn the scope off while it is moving. That will not hurt a thing.

One note on aligning or not aligning for any new person that might be reading this post, if you go though an alignment when you have put the scope pointing North and level, then the scope has an idea where it is and can go to objects. Without that alignment, the scope is in terrestrial mode. I found out for myself that if you tell the scope to go to an object from terrestrial mode, it assumes the scope is pointing level and North and takes off from there. Most likely, it will hit a leg or simply go as far up as it can and try to keep going while traveling one way or another in azimuth.

Best Regards,

Bill Steen
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#14 chase172

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Posted 03 May 2015 - 04:46 PM

Hi Chase,

I thought I answered this earlier today, but I apparently did not hit the send button.

Yes, you can turn the scope off while it is moving. That will not hurt a thing.

One note on aligning or not aligning for any new person that might be reading this post, if you go though an alignment when you have put the scope pointing North and level, then the scope has an idea where it is and can go to objects. Without that alignment, the scope is in terrestrial mode. I found out for myself that if you tell the scope to go to an object from terrestrial mode, it assumes the scope is pointing level and North and takes off from there. Most likely, it will hit a leg or simply go as far up as it can and try to keep going while traveling one way or another in azimuth.

Best Regards,

Bill Steen

Oh, thank you! I make sure to point it north and level it when automatically making it go to planets and stars. I mostly use the manual mode after using it for a while, but thank you!






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