The ABC's of Backyard Astronomy

You're here because you're interested, like me, in learning about space exploration from your vantage point. I've been interested in viewing the night skies for over 35 years when my parents bought a 4" refractor scope for me for Christmas. Until recently, however, I never really took the time to go outside and look up with the intention of locating and identifying celestial objects.

About 8 months ago I purchased a 6" reflector scope for my wife mostly because we do spend a great deal of time outdoors and because it was only $200 brand new. She is also interested in the night skies and has been a great influence on my desire to locate and identify especially since I purchased a copy of Starry Night Astronomer for her on her birthday which just passed.

She almost immediately loaded it on her notebook and began exploring. Her simple first goal was to find "The Little Dipper". It's a fond childhood memory for her from her days spent with her grandmother in her home state of Alaska.

During our first few nights out with the purpose of looking skyward she taught me how to find the duck constellation Cygnus, the "W" which is Cassiopeia

As she began to show me the things she was learning and we started gazing skyward I became more interested as well. Dragging the 6" scope out and setting it up is sometimes a hassle and it has no azimuth adjustment or tracking guides whatsoever so it's really just a point and shoot. Any magnification over about 50x is very difficult to use because of this reason so I decided to bring out a little pair of 3x50 binoculars. Amazing. I mean it's very amazing at what you can see just through a small pair of binocs like that.

For the first time in my life I was able to locate and identify The Pleiades, also know as The Seven Sisters and Messier's 45th object M45. To the naked eye, at least to mine, this looked like a little blurry spot in my eyes just a little below and to the left of Mars. Then I got really interested and started finding all sorts of things. Oh if my dad had only lived long enough to have the Internet! It was really he who fed my interest as a child.

As I began to look at the Web for more information I realized that I was going to have to learn a bit of new terminology just so I could understand what I was reading. It seemed, at first, that even the most elementary websites used technical terms and presented data about a particular planet, star, galaxy or other point of interest in such a way that I felt lost. I would see the photo which I could understand but when it was accompanied by text like: Right Ascension 00 : 42.7 (h:m); Declination +41 : 16 (deg:m); Distance 2900 (kly); Visual Brightness 3.4 (mag); Apparent Dimension 178x63 (arc min), I was lost.

Since I'm a reasonably intelligent, grown man trying to decipher this information I realized that what we could use is at least one more website for amateur astronomers which explained the basics and how to understand what you're reading. Even though I searched for a good website like Introduction To Astronomy, or Astronomy 101, Basic Stargazing or Amateur Astronomers, I still couldn't find a place to teach me my ABC's and 123's! Even the simplest sites I found didn't have a good dictionary or explanation of the most basic terms.

So here we are! And, thanks to the folks at Blogger.com you who have come here with the same level of understanding and types of questions shared by thousands of other beginners can have a part of the discussion as well. I'll publish what I can, when I can but you don't need to be silent on your questions, answers and even discoveries. What we share together we learn together. So if I'm too elementary for you today come back in a few weeks or months and maybe I'll have a little more knowledge and skill and we can discover together.


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Here's a great first telescope

Sometimes it's cost that keeps us from getting started on a new journey. Here's a scope anyone can afford. If you can't afford it now just do a little recycling and you'll afford it soon enough. It's great for learning about telescopes, too. Read the text below the image for a little basic learning about telescopes.

This is a 42x scope and for the beginning explorer or for the professional wanting a great little instrument to keep in your car or truck.



This is the "spec sheet" on this telescope. Spec is short for specifications. The spec sheet tells you about focal lengththe F#, eyepiece diameter, etc. So, since this may be your first look at a telescope technical data specification sheet take a look and then we'll examine each line indivually.

Design: Newtonian Reflector
Diameter: 80mm
Focal Length: 550mm
F/#: 7
Eyepiece: 13mm
Magnification: 42x
FOV: 10
Length: 14 inches
Weight: 5 lbs.

Newtonian Reflector - this tells us that this a telescope which makes use of lenses and mirrors instead of just lenses. In another posting I said my first telescope was a refractor scope. That scope used only two lenses, one small to look through called the eyepiece and the other larger called the objective lense. This telescope uses an eyepiece to look through but everything else is handled by curved mirrors. The refractor telescope was invented by a Dutch eyeglass maker named Hans Lippershey in 1608. It was Isaac Newton who used mirrors to perfect the image. Reflector scopes give a clearer image because of the way they handle the light. More on that elswhere. Another type of scope popularized recently may be the Dobsonian named after a still living American from California by the name of John Dobson. More on Dobson elsewhere.

Diameter 80mm - this tells use the diameter of the primary mirror in this case. In some cases is gives the diameter of the primary mirror or the objective lense. In any case this refers to the largest optical compenent of these telescopes which are, in actuality, called the arpeture. There are two mirrors in this telescope: the primary mirror which we mentioned already is at the "bottom" of the tube and the secondary mirror which is mounted on the "spider" in front of the eyepiece. The secondary mirror aims the image into the eyepiece. (80MM is nearly 3.15 inches. There are 25.4 millimeters in 1 inch.)

Focal Length - is both simple and mildly complex. In it's simplest form it is the distance from the optical device (lense or mirror) to the point where the image is in focus. Anyone who has used a simple magnifying glass has dealt with focal length. In that case it is the distance from your eye to the lense where the object you are viewing appears to be in focus. The focal length of this scope is given as 550mm. Using the numbers we learned above we can determine that length in inches by dividing 550 by the number of mm per inch. So 550 / 25.4 = 21.654 inches. (Anytime you want to convert mm to inches just divide the number of mm by 25.4 - to convert from inches to millimeters multiply the number of inches by 25.4)

F# - shouldn't frighten or puzzle you like it did me because I'll teach you the simple definition! In fact it just uses the two numbers above to calculate. Simply divide the focal length by the arpeture. For this little telescope that would be 550 / 80 = 6.875 and rounded up to the nearest whole number would be 7. This is also referred to as the F/Stop or a focal ratio. The focal ratio is a more important number when it comes to photography. Specifically because the lower the F# the more light (or the lighter the image) is apparent in the image.

Eyepiece 13mm - describes the part you actually look into. On this telescope it is the part sticking out of the side of the tube near the large opening at the top. The eyepiece has a great deal of control over the field of view (FOV described below) and magnification. The field of view is simply how much you can see. For example with your eyes wide open and nothing interfering (obstructing) your sight your field of view is about 165 degrees more or less. If you put your hands on the side of your face to block what you can see you narrow (decrease or diminish) your field of view to about 50 degrees. The smaller the opening in the eyepiece the higher the magnification and the smaller the field of view. Using a smaller opening eyepiece such as a 10mm would increase the magnification and decrease the field of view.

Magnification 42x - is how many times larger the object appears through the telescope compared to just looking at it with your naked eyes (naked eyes means no help from a magnifying device). It is written as a number followed by a small x which is the international mathematic symbol for times (as in multiplication).

FOV 10 - tells us that the field of view we learned about above is 10 degrees. That means that what you see through the telescope is about 10 degrees of what you see with your naked eyes. 10 degrees is equal to about one width of your fist held at arm's length (with your arm fully extended). The moon, for example, is about .5 degrees (one half [1/2] of a degree) across as seen with your naked eyes. This means with this telescope in it's default (the way it comes) setup you would be able to see all of the moon with plenty to spare through the viewer.

Length 14 inches - is usally the length of the tube.

Weight 5lbs - us how force is required to keep the telescope off the ground ... but that's a physics lesson in the waiting.

If this explanation is still too difficult for you please feel free to post your questions and I or some real professional will answer as quickly as possible.

My First Astronomy Software - Should be yours, too!

This is the software I purchased on a lark for my wife's birthday. It is very simple to use and comes with a great DVD. I'm sure you'll enjoy it as well:

I love this software! From the first moment my wife loaded it on her notebook we started studying astronomy. Finally, after all these years, my parent's purchase of a 4" refractor scope back in 1971 paid off. Of course that scope is long gone, sold to a friend in 1979 who, I may add, never paid me! We absolutely love this software and it has made our journey into space much more enjoyable. We take it outside with us and have it available to identify everything we see. It even locates and names most man-made satellites! I know you will love and get great use from this software. This is the "entry level" version. Below I have linked more advanced versions.

List of Messier Objects

Listing of Messier objects

M1 The Crab Nebula
M2
M3
M4
M5
M6 The Butterfly Cluster
M7 Ptolemy's Cluster
M8 The Lagoon Nebula
M9
M10
M11 The Wild Duck Cluster
M12
M13 The Great Hercules Globular Cluster
M14
M15
M16 part of the Eagle Nebula
M17 The Omega, Swan, or Horseshoe Nebula
M18
M19
M20 The Triffid Nebula
M21
M22
M23
M24 Milky Way Patch
M25
M26
M27 The Dumbell Nebula
M28
M29
M30
M31 The Andromeda Galaxy
M32 Satellite galaxy of Andromeda
M33 The Triangulum Galaxy
M34
M35
M36
M37
M38
M39
M40 Winecke 4
M41
M42 The Great Orion Nebula
M43 part of the Orion Nebula, de Mairan's Nebula
M44 Praesepe, The Beehive Cluster
M45 The Pleiades
M46
M47
M48
M49
M50
M51 The Whirlpool Galaxy
M52
M53
M54
M55
M56
M57 The Ring Nebula
M58
M59
M60
M61
M62
M63 The Sunflower Galaxy
M64 The Blackeye Galaxy
M65 Little Dumbbell Nebula
M66 Little Dumbbell Nebula
M67
M68
M69
M70
M71
M72
M73
M74
M75
M76 The Little Dumbell, Cork, or Butterfly
M77
M78
M79
M80
M81 Bode's Galaxy or Bode's Nebula
M82 The Cigar Galaxy
M83
M84
M85
M86
M87 Virgo A
M88
M89
M90
M91
M92
M93
M94
M95
M96
M97 The Owl Nebula
M98
M99
M100
M101 The Pinwheel Galaxy
M102 The Pinwheel Galaxy
M103
M104 The Sombrero Galaxy
M105
M106
M107
M108
M109
M110 Satellite galaxy of Andromeda

Astronomy Definitions

These are the definitions I have needed. Some of the words I already knew but wondered if other beginning astronomers would know them. Some of the words I had heard but didn't know their meaning well enough to answer someone else with a definition should they ask me during the course of conversation.

Asteroid - is an object in space that is inside of our solar system and is smaller than a planet or a moon and orbits the sun.

Astronomy - the study of stars, planets, moons, asteriods: any object in space including man-made satellites.

Binoculars - is short for Binocular Telescopes meaning "two telescopes" but joined together so that they focus together and you can see through both at the same time. I love binoculars for night sky watching because they let you see more of the sky (called the "field of vision") and are simple to use - you really just point them at what you want to see and focus. Binoculars up to about 10x or 10 power (which means what you see through them seems ten times as big as seeing it with just your "naked" eyes) are good to use without a tripod and make it easy to find many objects unseen to you before.

Refractor - the oldest form of telescope. You look in an eyepiece at one end, through a tube and through a larger lens at the other end. You can make a refractor telescope by using a pair of reading glasses and a magnifying glass. It's that simple.

Messier - pronounced messy-ay was a French Astronomer. His first name was Charles. He lived from June 26, 1730 to April 12, 1817. In 1774 he published a list of 45 space objects which he numbered from M1 to M45. So when you see M44 you will soon know we are talking about The Beehive Cluster. If you are a member of the Ameteur Astronomers of America you can get a sort of "merite badge" for identifying several Messier Objects.

Meteor - when a "shooting star" leaves a streak of light in the sky we call that a meteor. A "shooting" star is called a meteoroid. If any part makes it to the ground without burning up in the sky it is called a meteorite.