I have recently acquired a Meade LXD75 mount without a polar scope. I noticed that a small finder scope could fit in the polar scope slot, thus, serve as an improvised polar scope. I looked for a small finder scope and it so happened that an 8 x 20 Celestron finder fits the slot. I have made some modification in the finder scope’s barrel to make sure it clears the polar scope slot. Notice that the finder scope’s barrel has been modified, with a smaller barrel diameter towards the objective lens, otherwise it would not fit all the way through and protrude too much.
A repurposed 8 x 20 Celestron finder scope used as a polar scope
I tested the improvised polar scope on a clear night to see if I would be able to spot Polaris and roughly polar-align the telescope. While it lacks a star map overlay, a usual feature in a standard polar scope, it has a cross hair for tracking the position of Polaris relative to the position of the mount’s RA axis.
For astrophotography, a more accurate polar alignment method is needed such as the drift alignment method. In drift alignment method, when the telescope is pointed and tracking a star in the east, minimize the north-south drift in the eyepiece by moving the polar axis higher or lower (altitude adjustment). When the telescope is pointed and tracking a star in the celestial equator (near meridian), minimize the north-south drift by moving the polar axis to the left or to the right (azimuth adjustment).
Night Sky in Focus © Anthony Urbano | Bacoor, Philippines
Night Sky in Focus 