The Dufferin Astronomy Association 

New to Astronomy.

 

For those who are new to astronomy, the whole endeavour can feel a little overwhelming.  Where to Start?  What telescope should I buy?  How much should I be willing to spend?

 

We hope that this page will be of some assistance to aspiring astronomers thinking of exploring this exciting hobby.  The Dufferin Astronomy Association is also available to assist you in this regard, so drop us a line if we can be of assistance or if you have any questons.

1. Where to Start

A lot of times the first question asked by someone thinking of getting involved in astronomy is "what telesope should  buy?" 

 

You don't need to buy a telescope right away.  In fact I would recommend against running out and spending money until you have more of an idea as to what your focus will be.   This is discussed in more detail in the "What telescope is right for me" section.

 

Naked eye astronomy is a great place to start .  This gives you an opportunity to get to know the night time sky and be able to navigate the constellations.  It is easier to learn the night sky with a thumb on a sky map and looking up at the sky without an instrument.  People who rush out and buy a telescope without first learning the night sky can become frustrated and lose interest in astronomy because they can't find objects through their new instruments.

 

A good introductory book on astronomy can also be of great benefit for those just starting out.  Terence Dickinson's book "Exploring the Night Sky" is highly recommended.

 

Free Sky maps can be found here:  <Skymaps>

A logical next step beyond naked eye observing is to purchase a pair of binoculars.

 

Binoculars offer some advantages over telescopes.  First, they provide wider fields of view which makes things easier to find for those who are new to the night sky.  Second, they offer more mobility then telescopes, no step up or take down time.  You can just grab them and go to a dark viewing spot.


Here are some basic considerations when buying a new pair of binoculars:

Binoculars have two numbers ie 8x56.  The first number is its magnification.  The second number is the diameter of its objective lens.  In the above example the magnification is 8 times and the diameter of the objective lens is 56mm. 

 

Generally speaking, the larger the diameter of the objective lens, the better.  A larger diameter means more light collecting power.  This will allow you to see fainter objects.

 

As for magnification, there are differing views as to what magnification is best for astronomy.  The problem with higher magnification is the binoculars tend to weigh more which can make holding them for long periods of time difficult.  Also, the higher the magnification the more pronounced the slight movements of your arms will be, meaning objects in your view will be constantly moving around.   For hand held binoculars,10 to 15 times magnification is recommended.  Any more than this should be used with a tripod to mount the binoculars.

The answer to this question depends on many factors.  What do you plan on observing?  Do you have to lug your telescope up and down stairs?  Do you have to travel to your observing site?  Do you want to do astrophotography?   The answer to these questions will have a huge effect on the type and size of telescope you will want to buy.  This section is broken into three parts:  Telescope,Telescope mounts and size considerations.

Telescopes:  Generally speaking there are two types of telescopes; refractors and reflectors.   A refractor has an objective lens at the front which bends light to a focal point at the back of the telescope where a eye piece is used.  Good refractors can offer excellent views of the moon and planets.   The down side to them is that large good quality refractors are very expensive and heavy.  Cheap refractors suffer from colour aberations.  Reflectors make use of mirrors.  The primary mirror is located at the back of the telescope.  Light is reflected off a primary mirror to a secondary mirror which then directs the light the eye piece.  The benefit of reflectors is that larger apetures are available at a fraction of the costs of the equivalent size refractor.  A downside to reflectors is that the mirrors need to be periodically re-calibrated.  This is called collimation.   Reflectors are ideal for observing deep sky objects such as galaxies.  

 

Mounts: Just as important as deciding on a telesope, the mount you choose for the telescope will depend on what you want to accomplish with your telescope.   There are two basic types of mounts; Alt-Az and Equatorial.

 

Alt-Az mounts are the cheapest.  A type of Alt-Az mount called a "Dobsonian" allows very large apeture telescopes to be purchased at very reasonable prices.  The downside to Alt-Az mounts is they cannot be used for long exposure astrophotography.  However, you can take very short expoures of brighter objects like Jupiter and the Moon.

 

Equatorial mounts are a must for astrophotography.  These mounts, when coupled with a tracking motor, can follow an object across the night sky allowing astronomers to take long exposures to produce stunning pictures of astronomical objects.  However, these mounts costs more than their Alt-Az counter parts.

 

Just a thought on computerized mounts, often referred to as GoTo mounts.   These mounts are available in either Alt-Az or Equatorial type mounts.  They have databases with thousands of astronomical objects that the telescope will automatically move to when so instructed.  The benefits of these mounts are obvious.  However, they do cost more.  When I first started out in astronomy  I enjoyed star hopping from star to star with my thumb on the star map.  Searching for and eventually finding a deep sky object on your own can be very exciting.   I will always remember the sense of accomplisment I felt when I tracked down M81 and M82 for the first time.  A non-GoTo scope forces you to learn the night sky.   Now however, I have a job and my observing time is limited.   It is nice to have my GoTo scope do the work for me.  It is a real time saver.

 

Size Considerations:  For refractors and reflectors, the larger the diameter of the telescope the more light it is capable of gathering.   An eight inch diameter telescope offers far better views than a four inch telescope.   A twelve inch is far better than an eight inch.    However, as the diameter increases so does the price.    Another VERY important consideration is portability.  Bigger telescopes are heavier and more difficult to transport.   If you live in a second story apartment and have to go up and down stairs with your telesope, then that 16inch Dobsonian is probably not right for you.   If you have to set up and take down your telesope before and after each observing session an 8inch scope is probably the maximum I would recommend.  If you have to navigate stairs I would go even lower.    It is far better to have a small scope that you use often rather than a large scope collecting dust in your closet because you dread having to carry and set it up.

 

The above disscussion is very basic.  Before you rush out and buy a telescope I hope you will consider the discussion above.  The last thing we would want is for you to spend money on a telescope that is not right for you.

 

If you are considering a telescope purchase and would like some assistance feel free to contact us.