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Leveling the Mount - I don't see the importance

 

Lately I have read many posts that put a lot of emphasis on leveling the mount accurately.? I may show my ignorance here but I just do not see leveling the mount as being very important.? What is important is aligning the polar axis with the Earth's axis.? How the polar axis is supported has no bearing on anything that I can see.? Everything would work just as well if the mount could levitate as long as the polar axis is properly aligned with the Earth's rotational axis.? I view spending a lot of time leveling the mount as a waste of a lot of time.? Now it may make your latitude (elevation) scale read a bit more accurately but you are probably going to have to adjust this anyway to achieve polar alignment - so why worry so much.

Please tell me what I am missing.? I don't spend time leveling my mount every time I take it out.? It still works just fine after polar alignment.? CWD is still CWD.? Nothing really changes except it takes you longer to set up if you level your mount.

Dave...
 

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Dave, you are absolutely right. Leveling the mount might also make drift alignment slightly faster, but only if you¡¯re using a star almost exactly on the meridian. Once the polar axis is made parallel to the Earth¡¯s axis, the mount doesn¡¯t care how it got there.?

??-Les


On Nov 4, 2017, at 3:35 PM, cochrun@... [Losmandy_users] <Losmandy_users@...> wrote:

Lately I have read many posts that put a lot of emphasis on leveling the mount accurately.? I may show my ignorance here but I just do not see leveling the mount as being very important.? What is important is aligning the polar axis with the Earth's axis.? How the polar axis is supported has no bearing on anything that I can see.? Everything would work just as well if the mount could levitate as long as the polar axis is properly aligned with the Earth's rotational axis.? I view spending a lot of time leveling the mount as a waste of a lot of time.? Now it may make your latitude (elevation) scale read a bit more accurately but you are probably going to have to adjust this anyway to achieve polar alignment - so why worry so much.

Please tell me what I am missing.? I don't spend time leveling my mount every time I take it out.? It still works just fine after polar alignment.? CWD is still CWD.! ? Nothing really changes except it takes you longer to set up if you level your mount.

Dave...
 

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Dave,

Levelling the mount is useful for repeatability and takes only a minute or two.

The more accurately you start should speed up the aligning.

Regards

Paul

On 5 Nov 2017, at 9:35:39 am, cochrun@... [Losmandy_users] <Losmandy_users@...> wrote:


Lately I have read many posts that put a lot of emphasis on leveling the mount accurately.? I may show my ignorance here but I just do not see leveling the mount as being very important.? What is important is aligning the polar axis with the Earth's axis.? How the polar axis is supported has no bearing on anything that I can see.? Everything would work just as well if the mount could levitate as long as the polar axis is properly aligned with the Earth's rotational axis.? I view spending a lot of time leveling the mount as a waste of a lot of time.? Now it may make your latitude (elevation) scale read a bit more accurately but you are probably going to have to adjust this anyway to achieve polar alignment - so why worry so much.

Please tell me what I am missing.? I don't spend time leveling my mount every time I take it out.? It still works just fine after polar alignment.? CWD is still CWD. ? Nothing really changes except it takes you longer to set up if you level your mount.

Dave...
 

I get the mount reasonably level because it gives me a warm fuzzy feeling...? and takes literally seconds.
That being said,It is however probably completely pointless.

-Jeff
 

For a GEM, once the computer is aligned leveling the mount or tripod makes no difference for GOTOs operation. But a mechanically plumb tripod or pier is more stable, settles faster and your elevation and azimuth mount alignment controls will make true movements not diagonal which makes polar alignment easier to nail more quickly.

For an Alt/Az mount leveling the mount is typically fairly important for single star GOTO performance unless you are going to shoot multiple stars to build a model to compensate for the mount's leveling error but even then a level and plumb mount will work better.

Chip
 

Thanks to all for your comments on this issue.? I believe it is clear that having a precisely level mount does not preclude an accurate polar alignment or accurate GOTO performance.? ?Certainly, as Chip pointed out, it is more critical on Alt-Az mounts but this group is all about equatorial mounts.
Thanks,
Dave...
 

Pointless?? I would disagree if you wanted the best tracking you could achieve.? Three factors play into the alignment:

1:? Has the polar-scope been calibrated to the mount?? If not the mount is correcting for misalignment between what it sees as NCP and where the mount is actually pointing.

2: Has the cone error been corrected between the NCP and the view in the telescope? Wouldn't it be better if the telescope and the polar scope point at exactly the same point.

3: Did the mount start out at the magical CWD position?? This is a perfectly leveled mount in RA and DEC.? Are these setting repeatable each time setup is conducted?? You can mark the setting circles once this has been established not a time consuming action each time.? Also note where the leveling bubble is after these three are completed and use this position next time you set up. If the mount is not level then CWD is not repeatable.

So when you set up, if the three factors are established, just leveling the mount puts you the best tracking position.? Why make the mount correct in Dec and RA when you can just let RA do most of the work?? ?

I roll my set up out and place in the same position each time.? I level the mount, plug in the power and my 3,0 usb cable and turn on My polemaster. I then run my QHY Polemaster program to establish polar alignment and I'm off to imaging after aligning with the SkyX. I can do a bright star alignment or three on each side or have The SkyX do a T point run.? Usually after one star the mount is dead on because it builds on what it did the last time.??

IMHO.? I take leveling serious. And it doesn't take that long, and is easier when it is daylight.??

Thomas Glynn
Springfield, MO
Losmandy G11-G?
 

Yep, pointless. There have been 1,243 posts made on this forum over the years about this subject (I counted them...)? and I believe the consensus agrees with my personal findings? - tracking error log shows no difference attributable to the difference between "reasonably" level mount and a "precisely" leveled mount. Search and you will see . Do what you want if it makes you feel better

-Jeff

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