Need some help with Polar alignment (LX90)

[Zincberg (Andrew)]

Hey guys,
I have been having great fun with my scope, seeing some amazing things and have been stepping into the astrophotography.
I purchased an Ultra wedge for my 10" LX90 ( and the adaptor plate) and finally this week have had a couple of decent clear nights to give it a go.
The first night I nearly smashed the wedge with a brick after 3 hours of unsuccessful alignment
The second day, I read up another 3274 pages of peoples definition on how to get a polar alignment, went and bought an "angle finder" (protractor substitute) and a better "level" and tried again.
Firstly, I was surprised that after spending a good 40 minutes setting everything up, to turn on the scope, have it slew to Sigma octantis and have it right there in my viewfinder. I adjusted the mount to bring it dead centre, then decided to do a back up "drift alignment".
(dont worry, the questions are coming)
And thus the frustration of everything I had read became apparant.
There are so many variations of the drift alignment that I had to chose one that made most sense to me.. that may be my first mistake.

Anyways, I got my Azimuth adjustment right, I was so impressed, the star was sitting right in the middle (dec) for a good 1/2 hour.
I went to do the second part of my adjustment (the Alt adjust) and found a real problem, there is a two story house on the eastern side of my house, and I cant get low enough to the horizon and still find a bright enough star with the scope in the "Dec 0" position. (and west is not much better, I have the beautiful glare of Gosford that wipes out a good portion of my western viewing)
So..finally I get around to my question,
When I do the Alt adjustment, how low to the horizon do I have to be? and how far away from Dec0 can I go before it doesnt work properly?

I tried for about an hour and had stars sitting fairly still, but not perfect.. and when I took my first 30 sec photo of Orion, there were small trails appearing.
Any help would be appreciated.

[GrampianStars (Rob)]

Latitude (Alt) adjustment = knob on back of wedge Nth/Sth to match your latitude, i.e. 37 deg Sth. need to set only once usually.
Azimuth adjustment = East /West by knobs on side of wedge.
Baz has a good write up here...........
http://www.asignobservatory.com/inde...=77&Itemid=116
The Basics....
Work out which is Nth/Sth in your reticle eyepiece, adjust reticle line to match when rotating in RA.
1) Point the telescope at a bright star low (20 degrees) on the eastern horizon. Centre the star in a cross hair eyepiece.
Now watch for up / down drift of the star. Don't worry about the star drifting left or right.
If the star drifts NORTH its heading towards the North celestial pole, so your polar axis is too low. Turn your latitude (Alt) rear wedge knob to raise your wedge plate higher. This will cause the star to move in the opposite direction.
If the star drifts South its heading towards the South celestial pole, so your polar axis is too high. Turn your latitude (Alt) rear wedge knob to lower your wedge plate. This will cause the star to move in the opposite direction.

Next point the scope at a bright star that is close to directly above your head (the Meridian on the celestial equator). Repeat above steps.
Now watch for up / down drift of the star. Once again don't worry about the star drifting left or right.
If the star drifts NORTH your polar axis is too far east, so use the Azimuth side knob to turn the wedge west.
If the star drifts SOUTH your polar axis is too far west, so use the Azimuth knob to turn the wedge east.

You should repeat them again as one adjustment can throw the other one off.

[Zincberg (Andrew)]

Thanks for your reply, but moreso thanks for the link, In the link it explains that I can use a little bit of DEC if I need to to find a nice bright star, thats a relief.

Thanks again for your help there

[GrampianStars (Rob)]

Originally Posted by Zincberg

Hey guys,
I have been having great fun with my scope, seeing some amazing things and have been stepping into the astrophotography.........
I tried for about an hour and had stars sitting fairly still, but not perfect.. and when I took my first 30 sec photo of Orion, there were small trails appearing.
Any help would be appreciated.

G'day Zinc,

Whoops 30 sec's not MIN. is maybe Too Long for shots. I think what has happened is the dreaded PEC (imperfections in worm) has shown up. cut the shots down to multiple 10 Sec max and stack them

[jenchris (Jennifer)]

30 mins? - where?
I took my first 30 sec photo of Orion

[Zincberg (Andrew)]

Yeah.. might have misread that one? I said 30 sec? lol