Night Sky Astronomer
Welcome to the Night Sky Astronomer Page.
For centuries men, women and children have gazed into the dark night sky in awe and astonishment at the thousands of points of light overhead. Their eyes hypnotized, as they scan the beauty of the heavens, from one end of the horizon to the other. Stargazing is one of the most natural of hobbies and one that will always bring you back for more. Most of all stargazing is free, fun and educational for everyone!
To discover and enjoy the night sky and become more familiar with the many celestial objects visible, it is important to understand how to find these objects. The Observing the Night Sky for the Amateur Astronomer section located below, will help familiarize you with all areas of stargazing!
The resources and information on the internet is also vast and expanding just like our universe and the subject of astronomy is no exception. To help you with this overwhelming amount of information, I have simplified this Night Sky Astronomer page a bit further by breaking it down into basic general topics and categories of learning resources as well as learning illustrations for better understanding.
Scroll to view each topic & category and read the review, then click the icon. A new page will open to that information! As Cosmic Treasures Celestial Wonders grows I will add more links to other sites as I review them based on presented content. Please report any broken links by clicking HERE
Observing the Night Sky for the Amateur Astronomer
One of the most important things to learn and understand before observing the night sky as a beginner or novice amateur astronomer, is the basic language used in astronomy. The second most important thing to learn and understand, is the basic celestial coordinate system which is universally used throughout the world for all astronomers. By taking the time to understand this, it will make observing the many celestial objects such as stars, planets, constellations and such, much more pleasurable and less frustrating as you search with binoculars, telescopes, and the naked eye!
Below are 3 basic illustrations. I have added the definitions a little further below so you can become familiar with these most commonly used words. You have to remember that we all live on different parts of the Earth and because of this, each of us will only be able to see certain celestial objects at certain times, based on our time zones, the position of angle relevant to the sky from where on Earth we are observing, and the time/season of the year. I have also listed a very easy resource site page for you to click on, which will help simplify these diagrams and also help better direct you in finding your selected celestial object when observing the night sky.
The Earth's axis is tilted aprox. 23 1/2°
The Earth rotates on its own axis towards the East in the Northern and Southern Hemisphere.
The Sun rises in the East everywhere on Earth.
A sidereal day is approximately 23 hours, 56 minutes, 4 seconds corresponding to the time it takes for the Earth to complete one rotation relative to the Vernal Equinox.
Earth Tid Bits
Latitude - Are imaginary horizontal lines that run around the Earth from East-to-West. The Equator is an example of one of these lines and divides the North and South Hemisphere with a starting point of 0°. Latitude lines are given a + sign in the Northern Hemisphere and a - sign in the Southern Hemisphere. The North Pole equals +90° Latitude and the South Pole equals -90° Latitude
Longitude - Are lines that run perpendicular to the lines of Latitude, and pass through the North and South Poles. As a reference point for Longitude, the Meridian line is assigned a value of 0° which runs through Greenwich, England. The values of Longitude in degrees indicate the angular distance between what is known as the Prime Meridian and points East or West of it on the surface of the Earth.
Meridian - An imaginary circle on the sky that goes around the Earth through the North and South Celestial Poles at the highest point directly overhead of an observer known as the Zenith. This imaginary circle continues through Nadir, a point exactly opposite the Zenith on the other side of the Earth.
Nadir - An imaginary point directly below an observer, usually the exact opposite of the observers Zenith.
North Celestial Pole - Is an imaginary extended point in the sky of the Earth's axis for Northern Hemisphere observers of which all stars appear to revolve around.
Northern Hemisphere - Is half of the Earth's sphere North of the Equat0r.
North Pole - The Northern most point on Earth with a Latitude of +90°.
Polaris - Called the North Star for observers in the Northern Hemisphere and located in the constellation Ursa Minor.
Right Ascension - Known as the Hour Angle. It is similar to Longitude and is usually expressed in units of time broken into hours, minutes and seconds totaling 24 hours circling 360 degrees equally spaced along the Earth's Equator.
South Celestial Pole -Is an imaginary extended point in the sky of the Earth's axis for Southern Hemisphere observers of which all stars appear to revolve around.
Southern Hemisphere -Is half of the Earth's sphere South of the Equator.
South Pole - The Southern most point on Earth with a Latitude of -90°.
Zenith - An imaginary extended point in the sky directly above an observer.
Altitude - The angle between the object you are observing and your Horizon. Altitude = 0° at the Horizon and 90° at the Zenith. Remember that your Latitude = your Altitude of the North Celestial Pole or South Celestial Pole depending what Hemisphere on Earth your observing from.
Azimuth - Used to measure a celestial objects distance from True North along the Horizon. This is measured in increasing degrees starting at exactly North 0° heading Eastward to exactly East 90° then to exactly South 180° then exactly to West 270° and finally back to exactly North 360° /0°.
Celestial Equator - Is an imaginary circular extension of the Earth's Equator projected out into space having the same tilt of 23 . 5°.
Declination - Is comparable to geographic Latitude. It is measured in degrees North and South of the Celestial Equator. Points North of the Celestial Equator have positive (+) declinations and points South have negative (-) declinations.
Ecliptic - The path the Sun traces out in the sky during the year as the Earth completes one revolution around the Sun.
Equator - Is an imaginary line on the Earth's surface dividing the Earth exactly in half from the North and South Poles, thus the Earth having a North and South Hemisphere. The Equator has a Latitude line of 0°.
Horizon - Is the visual line that separates the Earth's surface from the sky in all directions.
RASC Calgary Centre
Highly Recommended for Learning
This is one of the best resource pages for you to understand not only the definitions I have given, but also to understand the 3 diagrams that are shown above! With top notch easy to understand illustrations explained in simple text, this resource page will make total sense of the night sky for any observer on Earth!
The Night Sky This Month for Northern and Southern Observers
Another important set of definitions to understand that you will come across very often when starting your observing sessions is Magnitude. This is a measure of brightness of celestial objects as seen from Earth. Many star charts and astronomical references will list the magnitude with a + or - magnitude number for a particular celestial object. The 2 basic types of magnitude to be familiar with are Apparent Magnitude = a measure of its brightness as seen by an observer on Earth and Absolute Magnitude = the apparent magnitude an object would have if it were located at a distance of 10 parsecs or 32.6 light-years from Earth. I have listed 2 resource pages below to review which will help you understand this.
An excellent page that puts into perspective star magnitude and the differences of each magnitude.
A very simple page explaining Apparent & Absolute magnitude without getting to technical!
Listed below are the Apparent Magnitudes or limits of some very prominent celestial objects or man made optics.
Naked eye limit
1 meter telescope limit
Hale telescope limit
Hubble & Keck telescope limit
Understanding Degrees and Greek Letters used on Star Maps/Charts
The last thing I would like to cover before moving on to observing the night sky, is some tips and easy references on degrees and what the Greek letters mean that may appear on star maps/charts that you will use. This will guide you when observing the planets, stars, and constellations.
1) The Earth rotates 360° to complete
1 revolution in a 24 hour period.
2) This means the Stars will appear to
move 15° per hour when observing.
3) Degrees are further broken down
into arc-minutes and arc-seconds.
Below are the type of degree measurements used in astronomy.
Degree = 1/360th of a circle.
arc-minute = 1/60th of a degree.
arc-second = 1/60th of a arc-minute.
Full Moon = 1/2 degree wide.
Using your hand to measure degrees.
Hold your arm at full length then close one eye and sight along the arm with the other eye.
Based on how you hold your hand you can then measure different angles.
Hold your hand at arm's length and extend your fingers. The width of each of your fingers is approximately 1.5 degrees.
Hold your hand at arm's length and extend your ring, middle and pinky finger with all three fingers together. The width of your three fingers is approximately 5 degrees.
Below is the Greek Alphabet. In most if not all star maps/charts, you will see these letters in lower case. The purpose was to let the observer know the brightest on down to the dimmest star in a constellation. For example Alpha = α the first letter of the Greek Alphabet. Any star in a constellation having this letter tells you it is the brightest star in that constellation. If you see the letter β which is the second letter of the Greek Alphabet which stands for Beta, then that means it is the second brightest star in that constellation. This continues on down the Greek Alphabet from the brightest to the dimmest star in every constellation.
Now that we understand the celestial coordinate system as well as the language used in astronomy, including the many celestial objects that an observer can view on a dark night sky, its time to move on and put our skills to the test! Below I have listed some of the best page links on the internet to help you observe the night sky. You will find this part of my page the most interesting and rewarding of resource information. You may want to bookmark this page of my site to your favorites, since you will be able to check up on these resources each month for your observing needs. Remember that each month the night sky will have different celestial objects like galaxies, planets and constellations to observe due to the Earth's revolution around the Sun.
The Night Sky - Northern Observers
The Night Sky - Southern Observers
Jodrell Bank Centre for Astrophysics
An excellent top notch site page to check out each month for any celestial events or celestial objects visible in the night sky.
Amateur Astronomers Asson. of N. Y
A nice simple page of the month on any visible planets or celestial events. Be sure to click the month's "evening sky" on page. .
5 STARS! An excellent page site that uses a video to show you the monthly night sky!
A great page each month that lets you know the celestial events taking place such as comets, meteor showers ect. Illustrated!
Another excellent page/site that shows the celestial events for each month! Just click " The Sky this Month" for a catagory choice!
Astronomy Now Online
A beautiful page of the night sky done on a weekly schedule for each month! Excellent.
How to Find & Understand your Latitude & Longitude
The connection with Star Maps/Charts & Planetarium Software
Many Star Maps and Charts including Planetarium Software, will want you to type in your observing location based on your Latitude and Longitude. This is done so you will be able to get accurate Star Maps/Charts of celestial objects visible in the night sky for your observing location site on Earth. Latitude is very easy to understand because we have the Equator that separates the Earth's sphere in half. Simply put, every location North of the Equator is positive (+) Latitude degrees. Every location South of the Equator is negative (-) Latitude degrees. If for example you see a Latitude that's written 45° South and the negative sign (-) is not there, it is still considered to be a negative (-) because it is written with the word South and we know that any location South of the Equator is in negative (-) Latitude degrees. So when you use Latitude make sure the sign is right... North of the Equator = Positive (+) and South of the Equator = Negative (-). Longitude is a bit tricky but I will make it easy for you to understand below.
Diagram A (Longitude)
The Longitude of your observing site on Earth is based on where your location is from the Prime Meridian. The Prime Meridian is the STARTING POINT! In the Diagram A to your left, you will see that the Prime Meridian is an imaginary line that goes completely around the Earth through the North and South Poles and divides the Earth in half, separating the Western Hemisphere from the Eastern Hemisphere. The Prime Meridian is the Starting Line of many lines of Longitude. This is very similar much like the Equator for Latitude that separates the Northern Hemisphere from the Southern Hemisphere! The Prime Meridian was given a zero (0°) degree Longitude measurement on the Earth's globe by International agreement in 1894 and this line of Longitude runs through the Royal Observatory, Greenwich, London.
Diagram B (Longitude)
Top view of Earth looking down on the North Pole
Diagram B will help better explain the Positive (+) and Negative (-) degrees of Longitude which are important to help locate your observing site for Star Maps/Charts and Planetarium Software. We know there are 360° in a circle. In Diagram B we see there are 180° of Longitude in the Western Hemisphere from the Prime Meridian and there are 180° of Longitude in the Eastern Hemisphere from the Prime Meridian. Added together this totals 360° for the circle of Earth. Notice the degrees of Longitude are negative (-) West of the Prime Meridian and positive (+) East of the Prime Meridian! Simply put, any location West of the Prime Meridian will be in negative (-) degrees Longitude and any location East of the Prime Meridian will be in positive (+) degrees Longitude. Remember the Prime Meridian 0° is the starting point, NOT your observing site!
If for example you see a Longitude that's written 105° West and the negative sign (-) is not there, it is still considered to be a negative (-) because it is written with the word West and we know that any location West of the Prime Meridian is in negative (-) Longitude degrees. So when you use Longitude, make sure the sign is right... West of the Prime Meridian = negative (-) Longitude degrees and East of the Prime Meridian = positive (+) Longitude degrees.
North = Positive (+)
South = Negative (-)
East = Positive (+)
West = Negative (-)
Finding your Latitude & Longitude by using your Observing Site Address
Converting Degrees, Minutes & Seconds into Decimal Form & Vice Versa
Now that you understand Latitude & Longitude, I have 2 incredible easy to use resource site pages that you can go to! Anyone in the world will be able to get their exact Latitude & Longitude by simply typing in their Home or Observing Site Address!! You will now be able to to use that Latitude & Longitude for Star Maps/Charts & Planetarium Software to view the Night Sky at your Observing Location on Earth! Also, I have listed a resource page that will convert Degrees, Seconds & Minutes into Decimal Form or from Decimal Form back into Degrees, Minutes & Seconds. You may want to keep these 2 handy resource site pages in your favorites for future use. Just click the icons below to go to each of the resource site pages.
5 Stars! Converts any address in the world to Latitude & Longitude! Shows that Latitude & Longitude in Degrees, Minutes & Seconds. Will show it in Decimal Form as well.
5 Stars! Type in any Latitude & Longitude in Degrees, Minutes, & Seconds to convert into Decimal Form, or type it in Decimal Form to get Degrees, Minutes & Seconds!
Below I have listed a variety of some fantastic resource pages to help you with observing your night sky of celestial objects. Some are beautifully well done and interactive online observing resources. They consist of Moon Maps/Atlas - Moon Phase Calculator - Star Maps/Charts - Constellations, to name a few. I have included Astronomical Time and some other unique interesting resources as well. Most of these resource pages will allow you to print out any/all Star Maps/Charts via PDF file from your printer if you choose. You will then be able use these outside at night for your observing needs! You will find these resource pages to be some of the best on the internet!! I guarantee these to be very rewarding, fun, educational, well worth your time, but most of all entertaining as you pursue deeper into your hobby of Astronomy.
Here you can plug in any date be it past, present or future and see the phase of the Moon on that date!
Moon Phase Calculator
Luna Society International Awesome interactive atlas of the full Moon which by clicking any area you can get a closer look. Also by moving your mouse over the area, the names
of features, craters will be displayed!
Full Moon Atlas
By Larry McNish
5 Stars! Just plug in your Longitude and instanly see Local PC Time, Local Sidereal Time (LST), Greenwich Sidereal Time (GST) & Coordinated Universal Time (UTC).
Jim Kaler's STARS
Awesome! Click any Constellation to see actual photographs or a labeled photograph as well!
Jim Kaler's STARS
5 Stars! Here not only is the Constellation listed but so is each star in that Constellation. Just click on that star and read its history and other info.
Jim Kaler's STARS
Here you can view Constellation Maps based on seasons for Northern observers and also shown is a map for South Polar Constellations.
The Night Sky Atlas
5 Stars! This atlas creates images of any part of the night sky & allows easy location of any object.
These are Uncle Al's Star Wheels that you can make via PDF File and print from your Printer! Choice for Northern or Southern Hemispheres.
Southern Hemisphere Only. A very nice Star Wheel/Planisphere you can print from your printer via PDF File. Has easy instructions on how to use.
Printable Planispheres 2
5 Stars! Printable 2 page Evening Sky Map of the month for Northern or Southern Hemispheres with choice of Latitude and in several languages!
Printable Monthly Sky Map
Here you select your Universal Time (UT), then type in a year and select a month to see a calender of celestial events that will occur in your area.
Sky Events Calendar
Time Zones/Universal Time
Designed for United States Observers to help understand time zones and Universal Time (UT) = (GMT) that is used for celestial events.
World Time Zones
Here you can click on maps of the world and find your city which will show the Universal Time (UT) in GMT time which = the same as UT.
Configure in your location & a list of Satellites, Comets, Planets, Asteroids & other unique Sky Events in your area will show.
Sky Events in an Instant
AstroViewer Online 3.1.2
5 Stars! Simple & Fun. Allows you to:
display the night sky for any time and any position on Earth. Find stars, constellations and planets.
Interactive Night Sky Map
The Night Sky Atlas
5 Stars! Beautiful colorful sky maps that allows viewing any part of your sky. You then can print these maps via PDF file. Click the "About" at the top of page which will explain how to use the Atlas.
Interactive Night Sky Atlas
Deep Space Objects
The Night Sky Atlas
This page lists popular Deep Space Objects (DSOs) known by a common name, that shows its location on a star atlas with a white + sign. Atlas can be printed via PDF file from your printer.
The Night Sky Atlas
Find all Planets and our Moon amongst the stars/constellations on an atlas by selecting a date. Times are at bottom based on Universal Time (UT). Location is with a white + sign. PDF file printable as well!
Planets & Moon Finder
HC NGC Catalog Data
The Night Sky Atlas
The Historically-Corrected New General Catalog of The NGC/IC Project grouped by constellation and catalog number for deep sky objects. Click a constellation then a catalog #, an atlas with a white + sign will show where that object is located. Printable via PDF file as well!
The Night Sky Atlas
The Index Catalog of Nebulae and Star Clusters (IC), revised version. Grouped by constellation and by catalog number. Click a constellation then a catalog #, an atlas with a white + sign will show where that object is located. Printable via PDF file as well!
IC Catalog Data
The Night Sky Atlas
The Abell all-sky catalog of 4073 rich clusters of galaxies grouped by constellation and by catalog number. Click a constellation then a catalog #, an atlas with a white + sign will show where that object is located. Printable via PDF file as well! Need Help? Click "About" at top.
Abell Catalog Data
The Night Sky Atlas
The Messier objects are some of the first deep space objects to be cataloged. The brightest and most accessible objects in the sky after the stars. Just click on an "M" number and a atlas with data and a white + sign will show where the object is located. Printable via PDF file!
Messier Catalog Data
Yearly Meteor Shower Atlas
The Night Sky Atlas
5 Stars! A list of the yearly Meteor Showers. Simply click on the Meteor Shower name and an atlas will show. The white + sign will be in the center of the atlas to show you the radiant or the point in the sky to an observer that meteors appear to originate. Printable via PDF file as Well.
Online Interactive + Free Planetarium/Astronomy Computer Software
Below are some very excellent 5 star FREE Planetarium Software programs that you can download on your computer and use at your own leisure. I have included one that is online interactive as well. I have used these for years and find them very fun and educational. I did not list on this page those planetarium software programs that are not free. You will find them on my Tools of Both Trades Page by clicking HERE
Here online you can make custom maps of the sky for any location on Earth and any date from 4713 B.C. into the distant future. Has an asteroid/comet tracking feature and a virtual telescope feature too!
Planetarium Software 1
5 Stars! Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. Excellent Software!
Amazing! A free space simulation to explore our universe in 3D! Celestia allows you to leave the surface of the Earth & travel throughout the solar system or to any of over 100,000 stars, or even beyond our galaxy.
Planetarium Software 2
Planetarium Software 3
Cartes du Ciel
5 Stars! For Windows, Linux, and Mac OS X. Software can use 16 different star and nebula catalogues including downloadable asteroid and comet data. Has the ability to drive several types of electronic telescope mounts.
SETI @ home
SETI@home is a scientific experiment that uses Internet connected computers to Search for Extraterrestrial Intelligence (SETI). Run a free program that downloads and analyzes radio telescope data.
Binoculars & Telescopes - Equipment of the Astronomer
This is the last section of the Observing the Night Sky for the Amateur Astronomer As one gets more involved in the hobby of astronomy, the desire to purchase equipment to observe the night sky is something every new astronomer feels. Though there is so much to see with the naked eye of the night sky, the thrill to get a closer look has, and always will be, a desire for any newcomer to astronomy. Looking back on my early years with astronomy, I too felt that desire. The first look through binoculars or telescopes always gave me the impression I was in a spacecraft looking out the window at the spectacular beauty of the cosmos. 37 years later I still feel that same way every time I look through an eyepiece.
Star Atlas/Maps/Charts & other Observing Aids for Celestial Objects
In this section, I will help guide you to the basics on Equipment of the Astronomer. I will help you understand about what things to look for when deciding to purchase binoculars or telescopes and the accessories used with them. I will only touch base on astrophotography very little here. The learning curve for astrophotography is very steep and expensive and should only be attempted by those who are at an advanced level of astronomy. There is not enough room on this site to even scratch the surface of astrophotography! Lets keep it simple for now, and as you grow into this hobby, you can then decide on what direction and how deep into this hobby you want to go. If the time comes you decide your ready to purchase binoculars or telescopes, you will find links to recommended trusted Astronomy Equipment Companies/Dealers/Sellers that I use, listed on my Tools of Both Trades page by clicking HERE
A short review about Binoculars
For those just starting out with astronomy I would highly recommend the use of binoculars as the first step up from naked eye observing. There are several reasons for this. First is that purchasing a pair of binoculars is much less expensive then the purchase of a telescope. Secondly, the field of view or FOV (in simple terms is the amount of sky one can see at one time through an optical instrument) is far larger in binoculars then any telescope! Thirdly, the unaided eye can usually see about 3,000 stars in the night sky, but with just a small pair of binoculars lets say 7 x 50 the amount of stars increases to a whopping 150,000 stars!
There are 2 basic types of binoculars to choose from, Porro-Prism and Roof-Prism. Each has a unique way that incoming light is focused to the observers eye through the eyepiece lens. Each design has their pros and cons. To save allot of confusion, the best type for astronomy is the Porro-Prism type. Diagram "A" is of the Porro-Prism type. This type is easier to make thus are cheaper in price. The Porro-Prism type will produce a brighter image due to less light loss as compared to the Roof Prism type. This alone is a major plus why Porro-Prism types are the choice for astronomy observing. I won't dwell on the design of these two types, but for those interested in understanding them more, I have provided a link to your right.
This page will give you a great info. on understanding the differences between Porro-Prism and the Roof Prism type binoculars. Also explains Field of View, Magnification, Objective Diameter, Eye Relief, and astronomical uses like comet search.
Let's look at Diagram "A" above. All binoculars are marked with 2 main numbers. The binoculars in Diagram "A" are 10 x 50. The first number 10 means magnification or simply 10 power. This means the binoculars will show an object 10 times (10x) closer then the unaided eye. The second number 50 refers to the size of the objective lens measured in millimeters. The larger the objective lens the more light will enter the binoculars to be focused by your eyes. The magnification and diameter of the objective lens will determine exit pupil size. The diameter of the exit pupil determines how much light is transmitted to your eye. The exit pupil can be seen by holding the binoculars at arm's length and looking through the eyepieces. The small circle of light you see is the exit pupil.
The best size binoculars for the beginners would be 7 x 50 or 8 x 56. I use a pair of 10 x 50 Bushnell's. Remember that the bigger the binoculars the heavier they will be to hold and this may cause shaking. You want to avoid shaking which will make observing difficult, so from experience these recommended sizes are best. You can purchase a reasonable quality pair for under $100. I have listed some manufactures on my Tools of Both Trades page - click HERE. The quality of binoculars is very essential when it comes to astronomy, particularly the optical quality of the objective lens, prisms and eyepiece lenses. Most binoculars called High-eye point, have rubber eye cups at the eyepiece end. This is not for comfort but mainly used to properly position the observers eye to achieve proper exit pupil distance. Those that need to use eyeglasses due to astigmatism can just roll the rubber eye cup down out of the way to observe.
There are many things you can see and observe in the night sky with just a pair of 7 x 50 binoculars. Examples would be the Star Clouds of the Milky Way, the Moons of Jupiter, dozens of Craters on the Moon, several Galaxies, 7 of the 8 Planets, dozens of Star Clusters to name a few! You will find in time that if you move on to purchasing and using a telescope, that your binoculars will be right there with you next to your telescope! I still use my binoculars all the time. Now that we know the basics about binoculars, I have listed several more links below for your convenience to some great information on binoculars and observing the night sky with binoculars. Next we will cover the Telescope and its use in astronomy.
5 Stars! An excellent page that explains many areas of binocular astronomy along with reviews of selected binoculars.
Binocular Stargazing 2
A nice short simple page that covers binocular basics with advice on the proper use including books to read.
Binocular Stargazing 3
Great page with some good advice on observing with binoculars. Has some links to a few binocular astronomy clubs and suggestions for books.
Telescopes - Mounts - Eyepieces – Maintenance
As the Amateur Astronomer advances from using binoculars to using telescopes, the choice of telescope and accessories can become quite confusing. I will do my best to simplify this area of astronomy by directing you to some very good learning resources and a couple of interesting videos. All this should help in your quest to advance not only in choosing a telescope but also on how to use a telescope. I have also included a bit about proper care and storage when your telescope is not in use.
There are 3 basic types of telescopes, Refractor type, Reflector type and Catadioptric type. I would highly recommend anyone just starting out in astronomy and deciding to purchase a telescope, that their first telescope be of the Refractor type and that they use a Altazimuth type mount with it. There are many reasons why, which my resources will help explain, but the main reason why is simplicity! I have listed several links for you to first understand the telescope types including an excellent 5 star video!
A simple page that describes each of the 3 basic types of telescopes. Also explains the advantages and disadvantages of each!
Excellent page using animation to show how each type works! The Hybrid Type is just another name for the Cadadioptric type.
Basic Telescope Mounts
There are 2 basic types of mounts. Altazimuth and Equatorial. The simplest and easiest to use is the altazimuth type because it allows the telescope to swing in a horizontal (side to side) and vertical (up and down) plane. The altazimuth type mount is the first choice I would recommend to beginners just starting out with their first telescope. The equatorial type is similiar to the altazimuth except the horizontal axis is designed to line up with the axis of the Earth's rotation. On equatorial mounts, this is known as the Polar axis. The equatorial mount can then track the stars and planets accurately by rotation about this Polar axis only, the altazimuth cannot. You may see or read about different type mounts with different names. Don't panic, these mounts are designed from these 2 basic types, the altazimuth type or equatorial type. Below are several resources you can click on which will resolve any confusion on these type mounts.
Excellent short animation on how an altazimuth and equatorial mount moves when viewing the sky.
The Telescope Nerd
Another simple page with a video that describes the altazimuth and equatorial type mounts.
Memphis Astonomical Society
A 5 star page explaining good points and bad points on the use of the altazimuth and equatorial mounts.
5 stars! Worth viewing! Explains pros & cons of telescope types & mounts!
NEVER EVER look at the Sun through your telescope, binoculars or other optical equipment. You will severely damage your eyes or go blind, including damaging your optical instrument. Special equipment and methods are necessary to view the Sun. Heed my warning!!
Eyepieces & their use with Telescope Magnification/Focal Length
The most important parts of a telescope are the optics and of course the mount. The eyepieces are no exception. In fact eyepieces can actually somewhat correct or help a poorly made objective lens or mirror of a telescope! If I can give one bit of advice, it would be, NEVER buy a telescope from your local department store! The optics are usually flawed and the eyepieces that are supplied are usually worse! So you can just imagine what kind of mount comes with it as well! Its important to have decent optics, decent eyepieces and a decent mount. Having all this guarantees you will have a decent time observing the night sky. Even the Hubble telescopes mirror was flawed when made, and this, by some of the best engineers in the world. It suffered from spherical aberration a term used where light from a celestial object reflects on a mirrors edge instead of more toward the center of the mirror, thus the images were poor. Correction mirrors were made on Earth and were installed in space which fixed the problem. The point here is to invest in a decent but affordable telescope so you can avoid these frustrations. Let's continue on and I will explain about eyepieces and determining focal length, magnification and other useful information.
There are many eyepieces to choose from. It is the eyepiece used that will determine the magnification of a telescope. The eyepieces I use and recommend are the Kellner, the Orthoscopics, and the Plossl. These are very affordable and excellent choices for those on a budget. The cheaper telescopes like those sold in department stores such as the small refractors, will supply you with eyepieces called Huygens, which are simple 2 element lenses. Pardon my bluntness, but they are junk! Get rid of those and replace them with a better quality brand. You will be glad you did.
Eyepieces come in 3 sizes to fit into the focuser tube of a telescope. These sizes are 0.965", 1 1/4", and 2" diameter eyepiece tubes. Most if not all eyepieces are marked usually on the top with a number. This number is the eyepieces focal length. It is marked in millimeters. For example 25mm. This number will help you find your magnification when used with your telescope. We will cover this a bit later. A simple thing to remember with eyepieces when you use them or purchase them, is the bigger the number (focal length) the wider the field of view and the lower magnification you will have. Thus the smaller the eyepiece number (focal length) the smaller your field of view and higher the magnification. High magnification is not always the best thing. Reason is, since your field of view is smaller, this makes it difficult to locate celestial objects. Even if you locate the object, if your telescope mount is flimsy, then you will notice your object wiggling in the eyepiece, even with the slightest breeze! So don't get fooled with department stores or advertisements promoting 600x or 600 power telescopes. The more magnification of an object the more distorted the image will get. Below I have listed several link pages about eyepieces I recommend you look at, this way you will learn the different types and best choices for field of view and magnification.
Excellent page that explains the different type eyepieces and what to expect when using them observing!
5 stars! Worth looking at! Explains the different eyepieces & why some are better then others.
A simple well informative page of question & answers related to eyepieces beginners should know!
Learning about Telescope/Eyepiece Magnification & Focal Length
The telescope and eyepiece work together to produce magnification. This is based on the focal length of the telescope and the focal length of the eyepiece being used. I have listed several definitions of words below that you need to know of which are used frequently when looking up information on telescopes and eyepieces. Magnification and focal length are very simple to calculate. I have listed below a simple page that can calculate your magnification and focal length for you. First though lets understand a bit more on how these numbers are acquired and what they mean.
Aperture - refers to the size of the main optical or objective lens of a refractor telescope or the mirror in a reflecting type telescope. It can be specified in inches or millimeters. Remember the larger the aperture the more light gathering power, thus the brighter the image.
When shopping for a telescope, the telescope will usually be advertised with 2 numbers, its objective or aperture size and its focal ratio. Its best to convert all numbers into millimeters since some telescopes are marked in inches. This is very simple to do. Please refer to the math formulas I have listed above.
EXAMPLE: An 8" f8 reflecting telescope, means the Aperture or mirror is 8 inches in diameter and the f8 where "f " stands for focal ratio is 8. BUT WHAT ABOUT FOCAL LENGTH!! Glad you asked! Some refractors and reflectors will mark on the scope the focal length in millimeters and some do not. In this case, we have to find the focal length by converting Inches to Millimeters the old fashioned way by using simple math. We know that our aperture is 8"and our focal ratio is 8. All we do now to find our focal length is multiply 8" x 8 and we get 64". We now need to convert 64 inches to millimeters. There are 25.4 millimeters in an inch. We multiply 64" x 25.4 mm = 1625.6 mm. So our focal length = 1625.6 millimeters.
Now we can use this number to find Magnification with any eyepiece! Remember that most eyepieces are marked with a number on the top of the eyepiece or on the barrel with a focal length in millimeters. For example lets say 25 mm. The mm is short for millimeters. Since we converted our telescope focal length in millimeters, the math to figure out Magnification is now very easy! The math formula to find Magnification above states: FL of Telescope ÷ FL of Eyepiece. FL is short for Focal Length. Our Telescope FL is 1625.6 mm and our Eyepiece FL is 25 mm. Thus we have 1625.6 mm ÷ 25 mm = 65.024 This Magnification can be rounded off to 65. Thus we have a Magnification of 65 times or simply 65x
Below is an excellent link page that will walk you through all of this figuring. It will do all the work! All you have to do is plug in the numbers/values that it requires. An excellent simple useful tool to use!!
Focal Length - is the distance from the objective lens or mirror at which the light comes to focus at the eyepiece. This is measured in inches or millimeters.
Focal Ratio - is the relationship between the aperture and focal length. The focal ratio is defined as the focal length divided by the aperture. For example, a reflector with a focal length of 48" and an aperture of 6" has a focal ratio of 48 divided by 6 or 48 ÷ 6 = 8 or f8.
Simple Telescope Math to Remember
To find Focal Length (FL):
Aperture x Focal Ratio
To find Focal Ratio:
Focal Length ÷ Aperture
Converting Inches to Millimeters:
25.4 x Inches
To find Aperture:
Focal Length ÷ Focal Ratio
Converting Millimeters to Inches:
Millimeters ÷ 25.4
To Find Magnification:
FL of Telescope ÷ FL of Eyepiece
Shore's A & A Site
5 Stars! This page is 5 calculators all on 1 page! Will help and figure focal ratio, focal length, magnification, Dawes Limit and true field of view. Wow!
Telescope focal ratio numbers. Which one to choose?
f4 -- f5 >>> Best for low power wide field observing.
f11 to f15 >> Best for high power, lunar, planetary & binary star
f6 to f10 >> Can be used for all general observing.
Below are links to pages that will help you with maintenance of your telescope. PLEASE REVIEW THEM!! NEVER EVER clean your objective lens on your refractor or the mirrors of your reflecting telescope including your eyepieces UNTIL you have learned the proper way of doing this! Failure to educate yourself on this will result in you ruining the optics. Do not clean your optics unless it's absolutely necessary. More damage is done to mirrors and lenses by cleaning than any other telescope maintenance! When cleaning your optics, Isopropyl Alcohol is one of the cleaning agents that is sometimes used. Use only a minimum of 91% content Isopropyl Alcohol. Trust me on this! Proper handling and proper storage of your telescope & eyepieces when not in use, will help minimize dirt & dust on your optics.
Cleaning Telescope Mirrors (Only)
Arkansas Sky Observatories
5 Stars! An excellent page with a step by step procedure for cleaning protective and non-protective overcoated telescopic mirrors!
Another decent page with a step by step procedures that includes warnings when cleaning your telescopic mirrors.
A short very simple step by step procedure for cleaning your telescope mirror. I have used this method for years as well.
Cleaning Telescope Lenses - Eyepieces - Schmidt Cassegrain Corrector Plates (Glass Only)
Arkansas Sky Observatory
5 Stars! Step by step procedure with great advice on cleaning telescope objective lenses, eyepieces and SCT corrector plates.
5 Stars! Excellent page describing how to clean your eyepieces. Also explains the products to use for doing a cleaning.
5 Stars! Explains how to remove, clean, and reassemble the corrector plate on Schmidt Cassegrain telescopes known as SCT's.
Proper Telescope Storage/Care
Oceanside Photo & Telescope
A nice page with plenty of common sense advice on storage & care.
A short page with tips on how to care for, store & deal with dew.
A short 3 minute video that shows simple telescope care.
How to Align your Finderscope
5 Stars! Explains very easily how to align your finderscope with telescope including troubleshooting.
5 Stars! Has step by step method by illustrations on aligning your finderscope or Unit Power types.
Excellent Video!! This video will show you how to easily align your finderscope during the daytime!
How to Collimate a Reflecting Telescope & Schmidt Cassegrain Telescope (SCT)
Newtonian Type Telescope
5 Stars! Shows by illustrations the easy way of collimating the mirrors.
5 Stars! A very detailed step by step with illustrations & photos.
Thierry Legault - The Collimation
Excellent! Collimates by using stars and shows the effects with pictures!
Schmidt Cassegrain (SCT)
5 Stars! Very detailed method on collimating your SCT! Excellent.
Thierry Legault - The Collimation
Excellent! Collimates by using stars.
Page can be used with SCT's as well!
3 part video using a Hotech SCA laser to collimate a SCT. Sweet n Easy!
As I mentioned earlier I would only touch very little on this art. The reason is the lack of space on this site. There are sites on the internet created solely for astrophotography. This is for the very advanced of all
astronomer enthusiasts. The learning curve is STEEP! Not only that it requires thousands of dollars in equipment, including knowing how to use as many as 5 or more software programs and lots of time! For those interested I have listed several sites for you to delve into. This is a very rewarding hobby in itself!
Gives an overview of the many areas
invovled in CCD astrophotography.
Shore's A & A Site
Great site with tons of info on DSLR astrophotography!!
Rob's Amateur Astronomy Guide
A great page to help you decide on SLR, DSLR or CCD astrophotography.
Tips for buying a telescope
Excellent page with advice and tips on purchasing a telescope.
Nice page with a 9 part FAQ's of tips and advice on a telescope purchase.
Amateur Telescope Making
5 Stars! Gives you an idea what is involved in all areas of making a telescope from mirror to mount!
5 Stars! A fantastic page filled with links to telescope making links that include designes & techniques!!
Mirror Coating Services
An excellent company to have your mirror aluminized or re-aluminized. Has very reasonable prices as well!
An excellent company thats been around 30+ years to send your mirror or diagonal to be coated.
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about these miscellaneous items
Tools of Both Trades
Mix of Links
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Aligning finderscopes + Collimation of reflecting telescopes
Proper cleaning of optics + Storage/Care of telescopes
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