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[badbye]

My meade 10" newtonian after being aligned goes to everything from the meridian to the west, but will just miss things when I go to the east. What is out of wack?

[karateman]

My meade 10" newtonian after being aligned goes to everything from the meridian to the west, but will just miss things when I go to the east. What is out of wack?

Could it be backlash in the gears. When I had a skywatcher auto track you had to set it up in a certain way when polar aligning to take up any backlash in the gears when tracking objects, otherwise the objects went out of view while the gears were taking up the slack. I know it wasn't a GoTo but maybe the principal is the same.

Am I making sense?

Phil

[badbye]

Yes Phil you are making sense but it is not the backlash. I think my polar axis is not ligned up with my optical axis. Can you align this on the mount using polaris because this scope is mounted in my 10' X 10' observatory with a roll off roof?

Glen

[karateman]

Yes Phil you are making sense but it is not the backlash. I think my polar axis is not ligned up with my optical axis. Can you align this on the mount using polaris because this scope is mounted in my 10' X 10' observatory with a roll off roof?

Glen

I think the mount has to be horizontally leveled with a spirit level before aligning with Polaris. I suppose if you then make sure the optical axis is also level, then the two will be parallel. I believe you also have to align somewhere close to Polaris rather than bang on it. see here..

http://www.astroleague.org/al/astrnote/astnot01.html


Sounds like you may not be properly polar aligned....


Phil

[RickJ]

With various Meades I've seen at Hyde that patrons have brought in for help when they point well on one side of the meridian but not the other it means something is loose. It sags one way on one side and the other on the other side of the mount. This is especially true if alignment was done using stars only on one side of the meridian. With a GEM I found many do this to avoid flipping the scope.

I've found so many different causes that I can't begin to list them all. You should take it to a local club where an experienced member can likely track it down quickly.

Some I've found with Newtonians is a loose spider or secondary in the spider, wobbling focuser or draw tube, Screws holding the scope to the mount or the mount head wobbling. Collimation lock screws not locked down so only the springs are supporting the mirror which then sags. One had installed second source rotating rings that were not properly adjusted. A worm gear not properly adjusted was another problem. The list is nearly endless but a quick hands on by an experienced user will likely quickly find the problem. Also as you flip from one side to the other of the meridian listen for a noise signifying something moved. That's how I found a mirror clip missing on a scope allowing the mirror to flop in the cell. It almost flopped out! I don't know if Meade uses those any more but it shows the list is very long.

You may be able to rule out optical axis problems by checking the finder. It will be off if the optics are shifting but still pointing where the scope is pointing if it is a mecanical issue.

When selecting reference stars be sure to use at least one on the other side of the meridian. Small errors due to mechanical issues will be compensated for by the software but only if you use reference stars on both sides of the meridian. Major errors don't repeat the same so can't be software eliminated. Optical and mechanical axes being solid but not in alignment is easily handled by the software and not the cause of the problem if stars on both side of the meridian are used for set up alignment. Nor is accurate polar alignment all that important. These issues cause errors on both sides of the meridian, not just one.

Rick

[badbye]

Well I tweeked my scope on polaris and know items in the east are in the eyepiece close to the edge but still in the eyepiece, maybe a little more tweeking. A little ajustment on the Dec. and a little ajustment on the screws on the cradle tube rings. Also using a 20MM eyepiece.