Astronomy – Telescope under the tree?

As we approach Christmas, I often get asked, ‘what is a good, cheap telescope I can buy?’ Nine times out of 10, the type I recommend is a Dobsonian.

There are several different kinds of telescope – Newtonian, Cassegrain and so on, but the Dobsonian is one of the most simple. Despite being simple, it is very good for both amateurs and professional astronomers. And best of all they are pretty cheap.

Light enters the tube, reflects off of the primary mirror at the base and is then focused onto the smaller flat secondary mirror and then finally, into an eyepiece. The benefit of this is that it has great light gathering ability. This allows you to see very faint objects.

Dobsonian telescopes are measured by the size of their mirror – and despite metric, they are always in inches. A good beginner Dobsonian starts at 6-inch diameter. An 8- inch would be even better, but of course costs a bit more. The largest Dobsonian sits at a whopping 30 inches, but these are more for professionals and very expensive!

The other important aspect of a Dobsonian is the mount. They have made a standard mount very simple. A basic manual mount supports the optical tube and can be manually moved by hand in the Altitude (up/down) and Azimuth (left/right) axis. More recently, you have been able to buy them with a GoTo motorised, computerised tracking system built in. 

The final important part is gazing into the cosmos. What can you see? Where can you find it? Often you can learn this yourself – particularly if you have a GoTo mount. 

A good idea would be to attend a meeting of the Hibiscus Coast Astronomical Society, once we are out of lockdown, and learn about the night skies from other amateurs.

A Dobsonian is a great all-around telescope, and readily available in telescope stores. There is a great store on the North Shore that provides some of the best Dobsonians out there. Of course, our local Hibiscus Coast Astronomical Society will also be able to assist you. Some of our members have even made their own Dobsonian scopes!

Resist the urge to spend lots of money on telescopes that will eventually never get used, as they can be too complicated or you may not see much through them apart from the brightest objects such as the Moon. These are either gimmicks or designed for astrophotography.

I wish you all clear summer skies!