4.Loosen the R.A. lock lever and rotate the mount about the R.A. axis until the March 1 indicating mark (the long line between the “2” and the “3”) on the date circle lines up with the
4PM mark (the long line above the “16”) on the R.A. setting circle. You may find it convenient to remove both the counter- weights and the telescope optical tube to do this.
5.Now, loosen the three thumbscrews on the polar finder housing and rotate the polar finder so the small circle where Polaris will be centered is located straight down from the inter- section of the crosshairs. Retighten the thumbscrews.
The polar axis finder scope is now properly set in its initial position. Next, you must align it so that it is exactly parallel to the mount’s R.A. axis:
6.Look through the polar finder at a distant object (during the day) and center it in the crosshairs. You may need to adjust the latitude adjustment
7.Rotate the mount 180° about the R.A. axis. Again, it may be convenient to remove the counterweights and optical tube first.
8.Look through the polar finder again. Is the object being viewed still centered on the crosshairs? If it is, then no further adjustment is necessary. If not, then look through the polar finder while rotating the mount about the R.A. axis. You will notice that the object you have previously centered moves in a circular path. Use the three thumbscrews on the housing to redirect the crosshairs of the polar finder to the apparent center of this circular path. Repeat this procedure until the position that the crosshairs point to does not rotate
The polar axis finder scope is now ready to be used. When not in use, replace the plastic protective cover to prevent the polar finder from getting bumped, which could knock it out of alignment.
Using the Polar Axis Finder
When using the polar finder in the field at night, you will need a red flashlight to illuminate the finder’s reticle. Shine the flashlight at an angle into the front opening in the R.A. axis. Do not shine it directly into the opening, or the light will be too bright, and you will also obstruct the view of the polar finder. It may be helpful to have a friend hold the flashlight while you look through the polar finder.
For most accurate polar alignment, you will need to know the approximate longitude of your observing site. This information can be obtained by looking at a local map. Now, figure the difference between the longitude of your observing site and the closest standard time meridian. The standard time merid- ians are 75°, 90°, 105°, and 120° for the 48 continental states (150° and 165° for Hawaii and Alaska). Choose the standard time meridian that is closest in value to your local longitude, and then calculate the difference. If your local longitude has a value less than the closest standard time meridian, you are east of the standard time meridian by the calculated amount. If your local longitude has a value greater than the closest
standard time meridian, you are west of the standard time meridian by the calculated amount. For example, if you are in Las Vegas, which has a longitude of 115°, the closest stan- dard time meridian is 120°. The difference between these two numbers is 5°. Since Las Vegas’ longitude value is less than the standard time meridian value, you are 5° east of the clos- est time meridian.
Take your calculated difference from the closest standard time meridian and rotate the date circle so that the merid- ian offset scale line that corresponds to your calculated differ- ence lines up with the engraved time meridian indicator mark on the polar finder housing. Each line of the meridian offset scale represents 5° of longitude. Lines to the left of the “0” on the meridian offset scale indicate east of the closest standard time meridian, while lines to the right of the “0” indicate west of the closest standard time meridian.
Continuing with the prior example of observing in Las Vegas, you would rotate the date circle so that the first line to the left of the “0” on the meridian offset scale lines up with the time meridian indicator mark.
Make sure that the “0” mark on the R.A. setting circle lines up with the pointed indicator cast into the mount, and that the large thumbscrew just above it is tightened. Now, rotate the mount about the R.A. axis of the mount until the line on the R.A. setting circle that corresponds to your current local time lines up with the line on the date circle that indicates the current date. If you are on daylight savings time, subtract one hour from your current local time. For example, if it was November 1 at 9 PM, standard time, you would rotate the telescope in R.A. until the line above the “21” (9 P.M.) on the R.A. setting circle lines up with the long line between the “10” and “11” on the date circle. The long line indicates the first day of the higher numbered month, i.e. the line between “10” and “11” marks November 1st.
Finally, look through the polar alignment finder scope while shining a red flashlight at an angle down the front opening of the R.A. axis, and center Polaris in the small circle. Adjust the tilt of the altitude
Once Polaris is centered in the small circle, you are done. The telescope is now accurately polar aligned, and can be used for advanced observational applications, such as astro- photography or precise use of the manual setting circles. As mentioned before, only move the telescope along the R.A. and Dec. axes; if you move the tripod, or change the tilt of the equatorial mount, you will need to polar align again.
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