Equipment for Observing the Night Sky

Any time of year is a great time to enjoy the night sky, be it a warm summer night or crisp and clear winter evening.  By yourself, with family or with friends, there’s a lifetime of ever changing sights to enjoy.  But what do you need to do it?

Your Eyes

By far the best value-for-money equipment is something you already have - your eyes.  From tracking the constellations and motion of the planets to being mesmerised by a meteor storm, from a blood-red lunar eclipse to the eeriness of a total solar eclipse, your unaided eyes offer the best (and cheapest!) views.  A $15 planisphere to help you navigate the sky is highly recommended.

Binoculars

Often overlooked, a pair of binoculars offers a relatively cheap but effective viewing aid.  As with telescopes, the main benefit of binoculars is not magnification but rather light gathering – compare the size of the lenses in a pair of binoculars to the pupils in your eyes.

Binoculars give a relatively wide field of view and are suited to observing the Moon, constellations, larger nearby galaxies and open clusters (groups of stars).  Binoculars are also very portable and can of course be used for terrestrial, daylight viewing (birds, scenery, etc.)

So which binoculars?  There is a huge selection of binoculars for sale, but something around 8x40 or 10x50 offers the best all-round performance.  The first value in the size (e.g. ‘8’) is the magnification – don’t go above 10x for this size binocular – and the second value (e.g. ‘40’) is the size of the objective (front) lens in millimetres – anything above 50 mm becomes too heavy to hand hold.  Prices start around $100-$200.

Telescopes

When most people think about astronomy, they think of telescopes.  And while there is much you can do ‘naked’ eye or with binoculars, a decent telescope opens the door to the cosmos.  Unfortunately though, too many people purchase a cheap, poor-quality telescope, only to be very disappointed with the views and difficult to use components – and the telescope ends up gathering dust in a cupboard.  The old saying, “You get what you pay for” certainly applies to astronomical equipment.  But that’s not to say the price has to be ‘astronomical’ – there are some really good value telescopes available nowadays, it’s just a matter of knowing what to buy.

So what should you buy?  Not surprisingly, “that depends!”  What is your budget?  What are you interested in observing?  Does it need to be easily portable?

Refractors, Reflectors, Equatorial mounts, Alt-Az mounts, Go-to mounts, …

Telescopes fall into two broad categories – refractors and reflectors.  Refractors have lenses and operate similar to one half of a pair of binoculars.  Reflectors use mirrors instead of lenses.  The main value describing a telescope is the diameter of its objective (front) lens (for a refractor) or the main mirror (for a reflector).

Most smaller telescopes are refractors and a good starting point is something in the 60-80 mm range.  This size refractor is small and light, making it easy to carry, while offering good views of the Moon and reasonable views of planets and deep sky objects, such as some galaxies and globular clusters (‘balls’ of many stars).  Very importantly, most refractors are easy to operate and require little maintenance over time.

However, it is cheaper to manufacture a large mirror instead of a large lens, so most larger telescopes (and some small ones) use mirrors, i.e. they are ‘reflectors’.  Reflectors come in a variety of designs.  Although they generally require more set-up and care than a refractor, the big benefit is size – they gather a lot more light and provide great value for money for visual observers.  Sizes range from 100 mm to 300+ mm diameter (with some measuring over 0.5m!).

The telescope mount (similar to a camera tripod) is often neglected, yet it is a critical component.  It must provide a stable platform but must also be easy to operate.  The easiest mounts are ‘alt-az’ mounts.  The other common option, the ‘equatorial’ mount, has advantages for some applications, but is generally more difficult to use.

An option that is becoming more common on lower cost mounts is ‘go-to’ – these are motorised mounts with a small computer that is able to locate 1000’s of objects and then track them across the sky.  Although there is a short set-up required before viewing, the best mounts make this process easy (and some are even fully automated).  The disadvantages are cost and that they require power – from either a battery or mains power adaptor.  But the benefits are huge – just enter what you want to look at and the scope will point to it.

Summing it up

Ultimately, your main goal should be to purchase something that you will actually use and not leave in the cupboard.  And the best advice to achieve that goal is to seek advice from your local astronomical society and to shop at reputable dealers who specialise in astronomical equipment.  Prices start around $300 for something worthwhile.  But don’t be afraid to wait and save – it’s better to save a little extra rather than purchase something you won’t use.  In the meantime, join your local astronomical society and enjoy the equipment they have for members to use!

Other items

Other useful items include:

  • a planisphere (search the internet for various free designs or buy for about $15)
  • a star chart, atlas and/or observing guide (the annual ‘Astronomy Australia’ book is highly recommended)
  • planetarium software (‘Stellarium’ is excellent and free, there are also various apps for phones)
  • warm clothes and hot chocolate!