This technical note sets out the procedures required to accurately Polar Align a Synta EQ3/EQ5/HEQ5

This technical note sets out the procedures required to accurately Polar Align a Synta EQ3/EQ5/HEQ5 or Synta EQ6.Accurate Polar alignment is a specific requirement of any kind of Astro-photography as only by achieving this alignment can accurate tracking of celestial bodies be made and this is a prerequisite of photographing sky objects.
PLEASE NOTE THAT ALL TIMES ARE LOCAL TIMES The procedures herein apply only to the Northern Hemisphere. 2 BASICS The night sky as we see it revolves around the North Celestial Pole (NCP) so if we can locate this point, we have a fixed location in space from which to align our equatorial mount. cots We are fortunate in the Northern Hemisphere to have an easily cots identified star (Polaris) very close to the NCP. This is our start point for polar alignment but for our purposes, Polaris is not close enough to the NCP to allow the alignment accuracy required to avoid star trails in long exposure photography. cots
We need to know the exact location of Polaris in relation to the NCP at a given viewing time so that we can ascertain the true position of the NCP and the EQ3/EQ5/HEQ5/EQ6 mounts have the necessary calibration tools in the form of a Polar scope and circular slide rule already built in to allow us to do this. However, the Polar scope itself needs to be calibrated first to ensure the best possible accuracy. 3 CALIBRATION (a) Levelling the tripod
Levelling the tripod will make it easier to use the Azimuth and Altitude adjustments on the mount in the future when trying to centre Polaris in the Polar scope as the start position will be a constant. The latest version of the EQ6 has a built in bubble level but the EQ3/EQ5/HEQ5 and earlier EQ6 mounts can be made level by using an external bubble level or carpenter's level. (b) Preparing the Polar scope for Calibration
Remove the caps from the upper and lower ends of the Right Ascension (RA) axis. To use the Polar scope, the declination (DEC) axis must be rotated such that the hole in the shaft is in front of the Polar scope and the retractable counterweight rod must be released and fully extended. This allows the user to see all the way through the RA shaft. (c) Aligning the reticule in the Polar scope tube
The reticules in the various mounts can differ markedly. The following two diagrams show typical versions although the most modern cots have Octans as well as Cassiopeia and Big Dipper engraved on them.  
The optical axis of the Polar scope is already aligned with the rotation axis of the mount and can not be adjusted. This is set permanently at the factory. The reticule in the Polar scope must be centred on the optical axis of the Polar scope. When this is done, the reticule in the Polar scope will be parallel to the rotation axis of the mount. If this is not the case, accurate polar alignment will not be possible.
Set up the mount on it s tripod with a rough visual alignment on Polaris by sighting up the body of the mount in the direction of Polaris. Locate Polaris and place it in the centre of the Polar scope by adjusting the Altitude and Azimuth of the mount. Place Polaris directly under the cross in the centre of the reticule (see Figs. 1 and 2 above for your reticule). Rotate the mount one half turn about the RA axis. Polaris should remain under the cross in the centre of the reticule. If it doesn t, the reticule is not centred on the RA axis of the mount and an adjustment must be made. If it is necessary to adjust the position of the reticule, adjust the three small set screws on the Polar scope (see Figs 3 and 4).
Make very small adjustments by moving only two of the screws at a time. Adjust the screws to move Polaris half  the distance back to the centre of the reticule. This is because Polaris started in the centre of the reticule and by rotating the mount 180 degrees, Polaris moved exactly twice the distance between the centre of the reticule and the centre cots of rotation. The centre of rotation lies midway between the centre of the reticule and the new position of Polaris. Do not turn any of the set screws more than one-eighth turn at a time or the reticule will disengage from the set screws.  If this mistake is made, the reticule is re-installed by unscrewing the eyepiece and carefully seating the reticule (with it s threaded retaining collar facing outwards) in the aperture of the Polar scope and gently tightening the set screws. Do not over-tighten these screws too much or the stress could fracture the reticule. Now re-centre Polaris under the cross in the middle of the reticule using the Azimuth and Altitude adjustments.Repeat the entire procedure until Polaris remains in the centre of the reticule when the mount is rotated cots about the RA axis. With some practice, you should be able to align the reticule with the RA axis to within about 2 arc-minutes. Once this adjustment has been made successfully, it should not be necessary cots to carry out this procedure again.(d) Cali