polar alignment

[msh1]

hi guys can someone help me please ,when i go through my images the stars track down the images, I'm damn sure they are going east, i am also getting trails in each individual sub so my polar alignment is out  just a tad, north south is fine its east west, i have used phd 1&2 for polar alignment and it says its good i got a rms of 0.04 on average ,but it must be still out ,what i can't fathom out is which way to move the mount 

hope someone can enlighten me

mark

[jambouk]

I know nothing about phd, but your thread reminded me of one of mine earlier in the year, which may or may not help; good luck sorting it:

http://stargazerslounge.com/index.php?/topic/216035-Odd-drift-in-RA-axis

[ollypenrice]

If your trails run east west your problem is tracking error, probably of the periodic kind, and is normal (but annoying!) That's why autoguiders are so widely used. It can also arise from backlash in the worm drive. The solution is to run slightly out of balance and heavy on the east side so that the weight of the mount rests on one side of the play in the mesh of the gears. In perfect balalnce the payload will constantly swap sides across the play.

An error in polar alignment produces rotation, not linear errors.

Olly

[msh1]

If your trails run east west your problem is tracking error, probably of the periodic kind, and is normal (but annoying!) That's why autoguiders are so widely used. It can also arise from backlash in the worm drive. The solution is to run slightly out of balance and heavy on the east side so that the weight of the mount rests on one side of the play in the mesh of the gears. In perfect balalnce the payload will constantly swap sides across the play.

An error in polar alignment produces rotation, not linear errors.

Olly

thanks olly could it be too heavy on the east side its difficult to balance being a newish mount and belt driven its a AZEQ6GT

mark

[Owmuchonomy]

thanks olly could it be too heavy on the east side its difficult to balance being a newish mount and belt driven its a AZEQ6GT

mark

Not sure why you should find it difficult to balance. Anyway, assuming you are running in EQ mode, Olly is describing a slight off balance to create a small need for the mount RA drive to continuously 'tug' in one direction. Due to the Earth's rotation the imbalance should be so that the mount pulls 'uphill' from the East. Stand behind your balanced set up facing North with your scope already tracking on its night sky target. If your counterbalance shaft is to your right then slide a counterweight down the shaft a couple of cm. if your counterbalance shaft is to your left then slide a counterweight up the shaft a couple of cm.

[msh1]

Not sure why you should find it difficult to balance. Anyway, assuming you are running in EQ mode, Olly is describing a slight off balance to create a small need for the mount RA drive to continuously 'tug' in one direction. Due to the Earth's rotation the imbalance should be so that the mount pulls 'uphill' from the East. Stand behind your balanced set up facing North with your scope already tracking on its night sky target. If your counterbalance shaft is to your right then slide a counterweight down the shaft a couple of cm. if your counterbalance shaft is to your left then slide a counterweight up the shaft a couple of cm.

the thing is it is east heavy i just wondered if it could be too east heavy . i will look at the pec