How to Polar Alignment in the Southern Hemisphere

So you’ve decided to get an equatorial mount? Good choice. While an azimuth mount is the easier option for first time telescope owners, an equatorial mount offers a plethora of benefits that will ultimately be more beneficial in the long run.

Equatorial mounts are hugely beneficial as they allow you to continuously track a celestial object, which is required for deep sky astrophotography, planetary astrophotography to a better precision and observing difficult-to-find celestial objects for longer periods of time. But despite these benefits, people tend to be deterred from getting an equatorial mount because of how daunting polar alignments appear.

Through this guide, we hope to illustrate how to polar align your telescope in the Southern Hemisphere so you can do it with ease.

Why Must We Do A Polar Alignment?

The Earth is constantly rotating on an axis. This is evident when we look at one object in the sky only to find that it moves out of view after a while. This is problematic for those who want to take astrophotography or want to gaze for long periods of time because the object just keeps drifting! In order to remedy this, we need to take into account the Earth’s rotation by moving the telescope in the opposite direction at the same rate.

We do so by pointing our mount at the Southern Celestial Pole which is a single point in the night sky that does not appear to move. It does not appear to move because everything moves arounds around it. Thus, once we have aligned the  equatorial mount to the South Celestial Pole, we rotate against the natural movement

The Steps

Polar aligning your telescope can be split into three main steps:

1. Setting up your mount
2. Balancing your scope
3. Polar aligning your mount.

Setting Up your Mount

Step 1. Set up your new equatorial mount on a flat surface. Ensure that the mount/tripod is level by using a spirit level (some mounts have one built in).

Step 2. Find out the latitude of your current position. This can be accomplished by inputting the address of your current position into an online calculator such as mygeoposition.com, whatsmygps.com or LatLong.net.

Taken from MyGeoPosition.com, Map data (c) 2016 Google

 

Step 3. Locate the latitude adjustment on your mount. Unlock the latitude adjustment knob and adjust the latitude adjustment pointer to the latitude of your current location by turning the latitude adjustment nut. When it is set, tighten the latitude adjustment knob again to secure it.

Balancing your Scope

Step 4. Attach your telescope to the mount as per usual. Ensure that it is properly attached and secure.

Step 5. Locate the setting circles of your equatorial mount. One will be the axis of the telescope and one of the axis of the counterweights (Look below).

Step 6. In order to balance the Right Ascension Axis, unlock your right ascension clutch and release the setting screw on the counterweight. While moving your telescope around that axis, slide the counterweight up and down the counterweight shaft until the telescope stays put on its own. After balancing the telescope, retighten the setting screw to keep the counterweight in place. You have now balanced the Right Ascension Axis.

Step 7. In order to balance the Declination Axis, unlock the declination clutch knob and loosen the telescope rings attaching the telescope tube to the mount. Slide the telescope tube along the tube within the telescope rings until the telescope is balanced, then retighten the telescope rings and move the telescope back to its normal position (with the telescope directly over the mount). Relock the declination clutch knob.

From this point onwards, your telescope is balanced.

Polar Aligning

Step 8. Select a bright star in the night sky and centre it in your telescope. Adjust the finderscope to accurately point at that star. Your finderscope is now aligned.

Step 9. Through your finderscope, locate the Southern Cross (distinguished as a cluster of five stars in a cross shape) in the night sky and imagine a line between the two furthest opposing stars. The Southern Celestial Pole is roughly 4.5 times of that length away from the Southern Cross. Point your telescope towards that point. This method gives you a quick and effective approximation of where the Southern Celestial Pole is.

Photo credit: Ryan Wick, taken from Myers Russell Cook (The Conversation) Edited.

Step 10. Your EQ mount is now polar aligned. You can now freely  release the Right Ascension Locking Knob and Declination Locking Knob and move your telescope around.

Conclusion

This is the most basic of polar alignment methods but appropriate for entry level to basic general observation. 

How did you go? If you need any further help with polar alignment, please don’t hesitate to contact us! We’re here to help. Also, if you want to stay up to date with our helpful information for amateur astronomers, don’t forget to ‘Like’ us on Facebook.