Editing Polar Alignment (section)

=== Polar alignment scopes ===
----/u/plaidhat1 on Reddit contributed the following directions of use of the Orion Sirius's built-in Polar Alignment Scope.  While these directions are specific to that mount, they are a good practical set of guidelines for using any polar alignment scope.  The process will be generally the same for most mounts and PA scopes.

Using a PA scope, of course, relies on both the quality of the scope, and the accuracy of your mount's alignment with the scope.  A well aligned quality PA scope can certainly give you a polar alignment capable of tracking stars for several minutes.  Be aware, however, that even the best equipment and alignment will still be less accurate than the results offered by precise drift alignment. /u/plaidhat1<blockquote>I regularly run my Sirius EQ-G for 3 minutes, unguided, without it showing up too badly in my shots.  There are two main things I'm trying to do when I set my mount up:

# Make sure the mount is level.
# Make sure it's aligned with Polaris.

Here's what I do to accomplish that:

# Set up the mount and point it approximately toward Polaris.
# Make sure that the mount is level.  I have a plumb-bob app I use for this purpose.  I set my phone on the accessory tray with the Y-axis of my plumb-bob app aligned with North leg and the X-axis aligned with the other two legs.  Adjust the North leg and one of the other two legs until it's level.  I try to be within ±0.1°.
# Release the Declination lock lever.  Point your scope toward the horizon and lock it there.  We're going to want to use the polar alignment scope built into the mount, and to do so we need to make a hole in the declination axis (which you may not have seen yet) line up with that scope.  Pointing your scope toward the horizon should do that.  Oh, you'll also need your counterweight shaft extended to see through the polar alignment scope at all.
# Take the cap off the front opening, and the cover off the polar alignment scope.  (It's possible to put these things back on the mount in the dark, but it takes a little practice with the cap to get the threading right)
# Look through the polar alignment scope.  You may need to focus it.  Hopefully you've got your mount pointed close enough to Polaris that you can see it in the polar alignment scope's field of view.  I prefer to have my mount powered off when I do this, since when it's powered on, there's a light that comes on for the polar alignment scope and drowns out my view of the star.  Still, there's a really useful diagram that you'll want to see to conduct the alignment properly.  I usually hold my phone up next to my eye or in front of the front opening, and give myself just enough light to see this diagram without drowning out Polaris.
# The diagram shows the Big Dipper and Cassiopeia, and a little circle on a big circle which marks where Polaris should be.  Grab your scope and release your right ascension lock, then tilt the mount until the Big Dipper (or Cassiopeia, whichever is in season) looks like it is where it ought to be.  Now you need to get Polaris into the little Polaris circle.  Move the mount around until Polaris is aligned with that circle in the horizontal direction, then use the latitude adjustment knobs to move it up or down until it's right in the center of that little circle.
# Go back to step 2 and run through this procedure until you don't need to make any further adjustments.
# Put the cap and cover back on, turn the mount on, and go through your normal 3-star alignment procedure.

I've tried to use much of the same terminology here that Orion does.  If you load up the Sirius EQ-G manual (PDF) and flip to page 5, that should make it easier to figure out what I'm talking about if you have any questions.

'''Warning''': Never stick your finger through the hole in the declination axis.  If something happened and your scope flipped around on you suddenly, it would be a very bad day for you and your former finger.</blockquote>