How do you polar align using an EQ Mount?

Table of Contents

The polar axis is an imaginary line drawn through the mount’s centre. The axis remains at 90 degrees. It passes through the entirety of the mount.

Your mount might have a hole along the polar axis. For confirmation that you have accurately located the axis, use the slow-motion controls.

Slow-motion control will move the telescope in two directions. The first being the Right Ascension, and the second is the declination.

Along the polar axis, the mount is stable. It does not move, no matter the direction in which you move the telescope.

Can I adjust the mount’s polar axis?

As the polar axis is fixed, you cannot adjust it. For the mount’s polar axis to point in a specific direction, you move the entire system and turn it around.

If your goal is fine-tuning, you will find controls on the mount. These controls will move the polar axis up and down and left to right.

It is important to remember that these controls are different from the telescope’s control. These are the slow-motion control.

As mentioned earlier, slow motion controls will move the telescope, not the polar axis. This is a prevalent error, especially if you are a beginner.

Locating the Northern Celestial Pole

Directly above the Earth’s north pole is the Northern Celestial Pole. It is that site in the sky that remains constant throughout the day and night.

Visually, you will see all the stars in the sky rotate along this pole. The North Celestial pole is at a short distance from the Polaris star. Polaris is also called the North Star.

Many astronomers reference the North Celestial pole instead of the Polaris. Therefore, it is crucial to find the Polaris for EQ mounting.

The Northern Celestial Pole Bias

The Northern Celestial Pole is solely for Astronomers in the Northern Hemisphere. The astronomers in the South do not have the convenience of guiding stars.

For that, we have the polar alignment method. Follow along to know more.

How hard is Polar Alignment?

The Polaris is at a close distance to the NCP. This begets a question of how accurate the polar alignment must be?

This depends on what technique you use. For visual astronomy, accuracy is not a significant factor of polar alignment.

Go-to systems require accurate polar alignment. This is because the main goal is accuracy here. Only specific systems are equipped to compensate for the inaccuracy.

For extended exposure imaging, the telescope needs to stay in one direction. This why polar alignment must be accurate.

Telescope imaging needs an on-point polar alignment. This depends on the type of photography you are doing.

Polar alignment using an EQ mount

Now that you know how to locate the Polaris. We can get to the aligning using the EQ mount safely.

Method 1

Lining the RA axis on the mount.
Adjust your telescope to be in line with the RA axis.
Aim your RA axis with the Polaris. Some of the EQ mounts have a small hole through the mount’s length. If your mount doesn’t. Aiming is your best bet.

Fine Tuning

You now have a rough align after aiming at the RA axis. For fine-tuning, you can use the Azimuth and Altitude values.

This method is a bit crude. But it still makes up for an excellent trajectory to observe with.

Method 2

Set up a Latitude. You can use Google Earth to set up the Latitude. You will have to unlock the lock to adjust the mount.
Adjusting the Latitude. Adjust the knob of the altitude that has a scale around it. Lock on the accurate latitude value.

Aligning the telescope to the RA axis of the mount

At this point, your RA axis is roughly in the direction of the Polaris. You must ensure that the RA axis and telescope’s axis are in line.

Loosen the lock on the RA and the DEC knob. If you are using a more casual scope, your latitude scales might not be accurate.

With the RA and DEC lock loosened, you can rotate the scope. Keep rotating over the EQ mount. If your DEC scale is present, it is will at 90 degrees.

Set the telescope until it is aligned with the RA axis. Lock both the RA and DEC knobs back.

The Final Alignment

Using an eyepiece, you need to hunt the target. To do that, you can use the Azimuth and the Altitude scale.

If you have aligned accurately, the Polaris will be cantered. You need to verify if it is the Polaris you are viewing.

Release the RA knob’s lock to rotate the scope around the axis. Even while rotating your Polaris will stay centred. If that’s not the case, you need to redo the alignment.

Recommended Reading:

References