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Polar alignment problem with EQ5

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#1 Stenji

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Posted 13 April 2009 - 02:54 AM

Hello - I am new to this forum
I am also new to using the EQ5 mount (bought it used) and I must be doing something wrong at some very basic level. When I prepare for a rough alignment I set the latitude scale to almost 60 N (Uppsala, Sweden). Then I set the tripod so it roughly points north and make sure it is placed on a level surface (using the leveling bubble). Then I attempt to adjust the mount so Polaris should be visible by looking through the R.A axis shaft. However, at this point Polaris is placed too high in the sky (perhaps five degrees) although the mount is level. To make it visible through the shaft the angle has to be changed significantly. How can this be? I thought that if the mount is placed on level ground and the latitude scale I correct, then the correct angle for seeing Polaris thorough the shaft should automatically be obtained?
Any advice on this is highly appreciated.
Sten

#2 John Carruthers

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Posted 13 April 2009 - 03:46 AM

Hi Sten and welcome, my first guess is your altitude scale is off, Polaris is almost the definitive measure of latitude (exactly so twice a day). I use Jason Dale's 'Polar Finder' to get Polaris' RA correct then set up on that, fine for visual work.
For photo work you'll need a better alignment method, the drift align technique is the usual way. EQAlign is a good free ap used in conjuction with a webcam to get really good polar alignment.
Good luck, and let us know how you get on.

#3 Skylook123

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Posted 13 April 2009 - 06:00 AM

The EQ5/EQ6 latitude scales are not very accurate; mine is off by more than 5 degrees. I use an inclinometer to set mine after leveling.

#4 fetoma

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Posted 13 April 2009 - 09:55 AM

Sten,

Welcome to CN. Nothing works better than seeing it with your own eyes.

#5 Stenji

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Posted 16 April 2009 - 01:09 AM

Many thanks for the good advice. And you are right about trusting ones eyes instead of the scales. Made a quick experiment yesterday. I ignored the scales and when I arranged the mount I only made sure polaris was visible through the shaft. Then all major drifting was gone!. Some more work needed on this however. Hopefully I get a chance for some observation tomorrow. Soon this observation season is over.
Sten

#6 John Carruthers

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Posted 16 April 2009 - 02:05 AM

You could calibrate your scale using Polaris when it's alt = the pole.
Any planetarium programme will give the correct time to do this.
jc






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