Wilmslow Astro

First with the 'scope horizontal extend the dew-shield, then remove the large wire clip from the front of the dew-shield. It should come out easily with a fingernail. Take care not to allow the clip to spring back towards the lens.

Now pull the dew-shield back towards the focuser. It will now pull back clear of the lens cell.

If you look at the lens cell you will find three collimation screws around the middle. Mine were partially covered with the sticky backed foam that gives the dew-shield its snug fit. These screws are Nylon and so fairly fragile. Find a flat bladed screw driver that is a good fit in the slots.

If you are lucky, a slight tweak of the collimation screws will adjust your collimation. Make the required adjustments and reassemble your 'scope. Congratulations, you're done.

However if like me found it rather difficult to collimate, the screws requiring rather too much tension to make any adjustment at all, and when it does move, boy does it move! Then you will need to follow the steps below

The problem with my Megrez 80 was that the lenses were held rather too tightly in the lens cell. After getting somewhere near collimation I found that the optics had become 'pinched' - with triangular shapes to the stars (see the dark bands in the long exposure CCD image on the left).

Before I could collimate properly I had to free off the rear lens in the cell (the collimation works by moving the rear lens element laterally with respect to the fixed front element).

Carefully unscrew the lens cell from the main 'scope tube, and place it front element down on a clean worktop.

You will need a largish flat blade to slacken the retaining ring at the rear of the lens cell. Just back it off until it is 'snug' rather than tight. Check that the collimation screws now push the lens around rather more easily - careful, don't put the collimation too far out.

Carefully screw the lens cell back on to the main tube, and then adjust the collimation as normal.

After collimating I took the precaution of removing the lens cell again, and just snugging up the lens retaining ring a bit tighter. I figured on two reasons for this, firstly I didn't want it coming undone and the lenses dropping out(!) and secondly I figured it would help retain the collimation when I transport the Megrez around.

After reattaching the lens cell, I checked the collimation again, and great it hadn't shifted. Now reattach the dew-shield and you are done.