I thought I would post a picture of my Polaris Reflectors, the 130, 127, and 114, in that order left to right. The 130 and 127 required extensive modification to combat my light pollution, but the 114 actually has the same or slightly better contrast and light pollution control as it comes out of the box with no modification for that problem.
Another change I made to all three is the support strips that hold the focuser draw tube in place, centered in the focuser body. As they come, which is the same way focusers in all brands of entry level reflectors are made these days, is to have a single strip running down the tube, opposite the rack and pinion used to move the tube in and out. A flat metal spring pushes the pinion gear into the draw tube's rack which keeps the draw tube pushed against the support strip. That is OK as long as the scope is pointed horizontally, but no stars there! The situation gradually changes as the scope is moved upward. By the time the scope is pointed straight up, both the support strip and the pinion gear are on the sides of the draw tube and not above and below as before. The draw tube can sag with a heavy eyepiece in place, affecting the scopes collimation.
What I do is replace the original single support strip with three of my own devising, one in place of the original strip, and two more strips identical to the first one, placed 120 degrees from the first on either side of the rack and pinion. This holds the draw tube in place evenly and lets the rack and pinion simply do the work of pulling the draw tube in and out.
For the Polaris 114, with its long focal ratio, the effect may not be much at all. For the Model 130, with its shorter focal ratio of 5, compared to 8 of the 114, the effect of miscollimation should go up inversely proportional to the square of their focal ratio, or 1/8^2 for the Model 114 and 1/5^2 for the Model 130. Another way to put that is any miscollimation affects the Model 130 2.56 times as much as the Model 114.
For the Polaris 127, whose primary mirror has a focal ratio (as best as I can tell) of 3.5, the effect for the primary mirror alone is 5.22 times the Polaris 114. Then, there is the booster lens in the way, with massive amount of spherical correction in it to counteract the spherical abberation of its primary mirror....I have no idea how to calculate that. Let me just guess, that miscollimation from any source is pretty much intolerable in the Model 127.
Another way of putting it: The Polaris 114 is a pretty forgiving scope when it comes to optical errors. The Polaris 130 does not like errors much and will show you in the view. The Polaris 127 cannot stand them at all and will do really weird things to stars, as well as mess up what you can see on planets. The 127 will do reasonably well with the Moon with some miscollimation, but don't get wild with it.
I will be talking about these scopes for a while and thought I would start with this.
If anyone has any questions about any of them, let me know.
Thanks,
Bill Steen