Align Your Telescope

[sjj1805]

Balancing the Declination Axis

The first thing we need to do is set the scope on the mount, and balance it. Put your weight on the mount, then the scope. As you look at the mount, you will see the two setting circles on it. One right under the scope tube is the Declination Setting Circle.

There are also screws to hold the two major axis' tight. Make sure the screw that holds the axis with the weight is tight, and then loosen the screw that will allow the scope to turn. Next, move the scope back and forth in it's mounting rings until you can move it to any position, and it stays where you leave it. Try to do this part with an eyepiece and any other accessories you may be using attached to the scope, so as to get an accurate balance.

Balancing the Right Ascension Axis

Next, we want to tighten the Declination Axis screw, and loosen the other one, for balancing the Right Ascension Axis. The Right Ascension, or R/A axis, is the one that your weight is screwed into. The other setting circle here is for this axis. R/A Setting Circle Once we have loosened the screw holding this axis, we want to get the weight adjusted so that the scope can swing from side to side, again, staying in place wherever you place it. Balancing the scope saves wear and tear on your mount's gears, and allows for easy movement when looking for objects. You never really loosen the dscrews all the way up, but just enough so that the scope moves with just a slight resistance on either axis. Usually, once you have balanced the R/A axis, the weight need not be moved again, so when you take the scope down, just unscrew the weight, shaft and all, and store it this way

Aligning to the North Star

Now that we have the scope balanced so that it will move in either direction freely, and stay put wherever we let go of it, it's time to "Polar Align" it. First, we will need to set the "Latitude Adjustment" to our particular Latitude, Here is one web site that provides this information. (Birmingham U.K. = 52° 30' North)

The object of adjustment to the latitude, is to have the scope point right at the North Star when the Declination axis is set to 90 degrees, and the R/A axis is set to your latitude.

While aligning the scope to the North Star, have the weight pointing straight down also. With the declination setting circle set exactly to 90 degrees, and the weight pointing straight down, BOTH axis' LOCKED at this point, simply move the Latitude adjustment until the North Star is centred in the scope. You may have to move the base of the mount, or the whole tripod to one side or the other now to centre the North Star. The closer you can get the North Star to the centre of the eyepiece, the better the mount will track, and the more accurate the setting circles will be for finding objects by their "Celestial Coordinates".

Also important, is to have the base of the mount level. This can be accomplished by using a small level, and adjusting leg heights until the base is level. Most mounts have a screw stop for the Latitude adjustment on them. Once you have set the Latitude, it's a good idea to set this stop screw so that the scope doesn't "creep down" during your observing session. Now that you have completed this process, we are ready to track objects that we find by simply turning only the gear on the R/A Axis. As the object moves across the sky, simply turn the R/A axis, and follow it. This is also the axis the motorized mount moves.

REMEMBER.. the Polar Axis MUST remain pointing at the North Star.

Using the Mount to Locate Objects

Now that we are all set up, balanced and Polar Aligned, we can use the mount to find objects by their "Celestial Coordinates". First, you will notice that the Declination Setting Circle does NOT rotate. It is set at the factory, and needs to remain where it is. The Right Ascension Setting Circle DOES rotate, and is changed when we use it to find objects. To begin, we must first set the scope to a star with a known address. We will use a "circumpolar star", or one that is visible all year long from a Latitude of 40 degrees North... Beta Ursa Major, or Merak. This star is the bottom right star of the bowl of the Big Dipper. Its Celestial Coordinates are..11 hours, 1 Minute of R/A.. so.. we get this star in the centre of our eyepiece, and quickly set the R/A setting circle to 11 Hours. The numbers on this circle represent hours and minutes. on my mount, the divisions are in 10 minute increments. The declination of this star is +56 degrees.. 23 minutes. This should already be where the declination circle is, if you have set up the mount properly. Now, moving quickly, because as the stars move across the sky, the R/A moves with them, find the coordinates of an object you wish to find, and move the scope on its two loosened axis' until both the R/A setting circle, (without touching the R/A circle) AND the Declination circle read the stars address. If you have done everything correctly, the object should be in or near the centre of the eyepiece in the scope. You MAY need to move the scope around just a LITTLE to find the object, but it will be very near to where you are pointing the scope.

[sjj1805]

This is more accurate than a rough alignment using the mechanical scales on your mount or roughly pointing the whole mount towards Polaris.

Working with Polaris, start by setting up your mount as you would for polar alignment. The Dec setting circle should read 90 degrees. Unclamp the RA and rotate the mount until the telescope and finder are all the way to the left or right, Dec axis horizontal. Get Polaris in the field of view of the finder and centred in the cross-hairs by moving the mount (using fine adjustment screws). Now move (flip) the mount all the way to the opposite side (180 degrees or 12 hours RA away from the original position). Note the shift of Polaris off the cross-hairs. Actually the finder-scope and the cross-hairs themselves have rotated in a small semicircle around where the polar axis points. You can see where that is by looking through the finder-scope as you rotate the mount, watching for the centre of motion. Clamp the mount and turn the three set-screws around the finder-scope to move the cross-hairs over this pivot point. Recentre Polaris by only moving the mount.

Even with the telescope positioned 180 degrees away around
the mount, the telescope (and finder-scope) should still be
pointing at the same object in the sky.

Repeat the flipping-set screw-recentre Polaris procedure. Each time you go from one side to the other, the off-centre distance of the cross-hairs from the pivot point will be smaller. After three or four repeats, the cross-hairs won’t move when you flip the mount. You will be pointing at Polaris. Your polar finder-scope optical axis is now pointing in the same direction as the polar axis.