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How to setup and adjust an equatorial mount
This page is particularly for use with non-goto mounts which must be set up for an exact polar alignment even when the celestial pole is not in view.

First: Setting up an equatorial mount with a pole finder

Many commercial mounts such as the Vixen Great Polaris, SkyWatcher EQ-3, EQ-5 and EQ-6 have a built-in pole finder with a template in which one can 'fit' the star patterns by rotating the telescope around the RA axis and moving the polar altitude axis and azimuth.

Example of the areas within 3° from each pole marked stars are until mv = +6.5 circles are 1 degree declination increments and 1 hr (=15 degrees) RA increments where in the north pole area the RA increases clockwise and on the south pole anticlockwise. Set for Epoch 2014.0. Many star charting apps such as Skysafari (iOS, Android, OSX), Mobile Observatory Pro (Android), Skeye (Android), Stellarium (OSX, Linux, Windows) can be used for the correct overview of the polar area of the current epoch with which the field of view of the polar finder should match.

North Pole
North pole area with RA=0h on top

South Pole
South Pole area with RA=12h on top

Note that on the South pole area there is a brighter star (the +6.9 star BQ Octantis) very close to the Pole (top left of the pole) which can be seen in any polar finder. Around the North Pole no star closer to the pole is visible by a pole finder as the diameter of the small objective is usually no more than 2cm. This makes easier setup possible.

Polar alignment of an equatorial mount using level 26 Feb 2014.

play Polar alignment of an equatorial mount using level 26 Feb 2014.

Homemade balcony mount 14 Oct 2011.

play Homemade balcony mount 14 Oct 2011.

Setting up an equatorial mount with a level

Some people experience difficulties with handling an equatorial mount. However this method is based upon the same principle as the 'two star alignment' of many Goto mounts, using the zenith as one alignment 'star' and another object (can be even the Sun) as alignment stars. This method describes setting up with a simple level mounted on an angled hook which equals the local latitude. I have made an adjustable hook from aluminum strips but you van also make such a level from a piece of wood with two flat (straight) sides which exactly intersect with an angle equal to the local latitude. And alternative can be an electronic inclinometer e.g. the one from Toolcraft which measures vertical angles to 0.1 degree accuracy. Note: smartphone (Android / iOS) inclinometer apps are not accurate enough, usually they don't even get 1 degree accuracy which is inefficient.
The benefit of this method is:
  • Tripod exactly level is not required
  • In areas where the Pole Star is not visible, such as the tropics where it is too low or when you are in the south, the pole star is only the 5th magnitude star σ Octantis. But also when Polaris (or σ Oct) is hidden by a wall, mountain, etc from your observing location, e.g a south (north) facing balcony.
  • This procedure can be performed in daylight as well even with only the Sun in the sky (but more bright objects such as the Moon or Venus align better and using the Sun requires eye safety precautions). Refer to the yellow box text on this page.
It requires that you know the local sidereal time, latitude and positions of one or two alignment objects. These can be found below in this page where you must fill in your coordinates and timezone once. If you want to use it without sitting at the computer, this script can also be downloaded as a zip file, to a PDA or smartphone with a javascript enabled browser.Then it does not require a further internet connection on the device. To do this, unzip the zip archive and upload the files to the device (or upload the zip archive to the device and unpack it there if possible).
During night you need a red flashlight, the best is a headlight as you have your hands free.

The adjustable level hook made from Aluminum
The adjustable level hook made from Aluminum strips and a level bought in the local hardware shop.

The procedure I describe here is for a Vixen Super Polaris mount, but most, particulary transportable EQ mounts work similar.

Calculating positions of bright objects

This can help you to get the proper coordinates of objects for aligning the mount.

1 Set up the tripod and tighten the tripod screws firmly. It is not necessary to set the tripod exactly level, only roughly level suffices. As long as the RA axis points to the celestal pole as accurate as possible, then the mount is adjusted. The polar axis should be pointed as closely to true north (or south in the southern hemisphere) as possible. Have ready the positions of two bright objects. In the daytime this can be the Sun [!] (and Moon or Venus if possible). Note the local sidereal time changes by time (23:56 hours a day which means during the 5-10 minutes of alignment one minute for each minute of time).!! Use a low power eyepiece with a true FOV of at least 1 degree, for a 10 cm 25-40x is OK.
When the Sun is involved for alignment, have a cardboard aperture of 5 cm ready to stop off the objective to prevent overheating the star diagonal or eyepiece and DO NOT LOOK INTO THE EYEPIECE !!!.

2 Point the polar axis to roughly north (or south) within 15 degrees. Slightly unscrew the knob under the mount which connects the mount on the tripod and loosen the horizontal adjustment screws as far as possible. Loosen the lock screw of the polar altitude as well.

3Hold the wedge+level (or the inclinometer) on the tube of the polar axis and set the angle of the polar axis equal the current latitude with the altitude fine tune lever. When the altitude is correct (as seen the 34 degrees example in the video) tighten the lock screw again.

4 Now we use the zenith as the first alignment point. Point the scope to the zenith and check with a level in two directions along the tube or with a bidirectional level on top of the scope so the scope is exactly pointed vertically (fig 5). Lock both axes. Then adjust the declination circle to your latitude.

image 4
Figure 5

5 Get the local sidereal time. For this, refer to the Position calculator above, fill in your local latitude and longitude and time zone (if not already done), check the 'RA align to to setting circle value' checkbox and click on 'NOW'. Now the frame will refresh every 20 seconds to get the actual positions.
Adjust the RA setting circle to the current local sidereal time (fig 6).

RA setting circle
Figure 6
Decide which object you use to aligh with. This should be not higher than 60 degrees above the horizon otherwise the accuracy is too low as it is less than 30 degrees from the first alignment point: the zenith. Get the coordinates in the above mentioned position calculator. The RA is corrected for the time as there are a few minutes between the zenith alignment and now so no adjustments and further calculations shlould be made. Now point the telescope to the position of the first bright object with the setting circles.
NOTE: Some mounts, like mine, are equipped with northern hemisphere only RA circles. In this case, when you are in the south subtract the RA from 24 which means 16:29 reads 07:31 on your 'northern' circles.
horizontal adjust
Figure 7

6 Adjust the horizontal azimuth until the bright object is in the scope field. When the azimuth is far (> 10 degrees) off the real azimuth of the pole which means the polar axis azimuth is not true north/south) check the polar axis altitude as described in step [2] when the tripod is not level. And then go to step [5]. Otherwise, continue.

7 [!] You can check whether the Sun is centered by checking the exit pupil image centered on the eyepiece as shown in the image right. Sun centered in eyepiece
When another object watch through the eyepiece and the object will come into the field. If not you have made an adjustment error of used the wrong coordinates. When you see the object you are ready. You can optionally check with another object (which is the third alignment point) at least 60 degrees from the first one and when you see that one also: Congratulations.

For further adjusting (e.g. long exposure astrophotography) you can use the drift method

Avoid pointing the telescope at the Sun !