Observing Tips for the Messier Objects
The purpose of this detailed section is to pass along some tips and tricks for observing the Messier Objects. It is assumed that you'll be using the Messier Objects to help teach yourself the sky.
(If you are not an absolute beginner at this, you may want to scroll down the page until you see the the more advanced tips that may be interesting to you are shown...)
We will start with basic sky orientation and sky measures, and then will get into observing techniques, filters, recording observations and dealing with interruptions, and finally a listing of helpful books - some of which are 'must-haves.'.
Getting Started with an Observing Buddy
People always ask, "What is the best way to observe the Messier Objects for my Certificate?" The answer is, "Hook up with one or two other people who want to do the Messier objects, make them your observing buddies and do the Messier List together."
Many advantages exist in this working relationships Both of you will have someone right there to verify and sign off objects for you, you'll both have someone who can help you discover the subtle techniques and tricks that you'll only learn at the eyepiece, and last but not least, someone to have that good natured argument with as to whether or not(!) you've found that distended open star cluster in the Milky Way star field!
Progression of the Constellations
When attempting to learn the constellations, try taking the approach of learning one at a time, and learning each one well before moving on to the next. Going out with a star chart or a planisphere for several nights in a row will give you confidence that you can translate the little dots on the charts to the vastness of the constellations in the night sky. Each month the sky the sky advances 30 degrees to the west*, with the new season’s constellations rising earlier and earlier. From our latitude, you will see Orion, M42 highest overhead at 8:00 pm on February 1, 60 degrees above the western horizon at 8:00 pm on March 1, only 30 degrees above the western horizon at 8:00 pm on April 1, and setting in the western sunset on May 1.
Sky MeasuresHold your fist at arm's length and sight past it with one eye
Right Ascension and Declination
Seen from Earth, the night sky looks like a huge dome with stars stuck on its inside surface. If the Earth beneath us vanished, we'd see stars all around us — and we'd have the breathtaking sensation of hanging at the center of an immense, star-speckled sphere. Astronomers designate the positions of stars by where they are on this celestial sphere.
Picture the Earth hanging at the center of the celestial sphere. Imagine the Earth's latitude and longitude lines expanding outward and printing themselves on the celestial sphere's inside. They now provide a coordinate grid on the sky that tells the position of any star, just as latitude and longitude tell the position of any point on Earth.
In the sky, "latitude" is called declination and "longitude" is called right ascension.
Declination is expressed in degrees, arcminutes, and arcseconds north (+) or south (–) of the celestial equator.
Right ascension is expressed not in degrees but in hours (h), minutes (m), and seconds (s) of time, from 0 to 24 hours. Astronomers set up this arrangement long ago because the Earth completes one turn in about 24 hours, so the celestial sphere appears to take about 24 hours to complete one turn around Earth.
Using a Star Atlas
Suppose, for instance, you've learned Gemini as it's drawn on the monthly Sky & Telescope charts, where the stars are connected to form two stick figures holding hands. The brightest stars in Gemini (like Pollux and Castor) appear on Chart 5 of Sky Atlas 2000.0 — but at a larger scale and almost lost in a wealth of detail.
First get familiar with directions on the map. East, you'll notice, is left of North on sky maps, not to the right like on maps of the ground. The reason is simple: You look down at the ground but up at the sky.
First determine the size of your the field diameter of the main telescope's lowest-power eyepiece. Locate two stars that just fit into its edges (try pairs in the Big Dipper or Cassiopeia). Then see how many degrees apart these stars are on the map, by referring to the declination scale along the sides. That's the diameter of your eyepiece’s field. It will probably be only about 1° or so — the area of sky your little fingernail covers at arm's length. This is so small that it may be hard to identify a good star pair on your map to measure the field size.
Now, using the scale on the margin of the charts, make little rings out of wire — or draw circles on clear plastic — corresponding to your field sizes. By sliding these circles across the charts, you can see exactly what star patterns will pass through your field of view when you sweep across the sky.
Beginners are always surprised at how tiny the view really is. Keep these little tools with the charts; you'll need them whenever you observe.
Now we're ready to go on our first deep-sky hunt.
The star-hopping route may seem like a lot of trouble to the beginner. But most deep-sky objects are many times dimmer than the faintest stars on the chart and won't catch your attention even if, by luck, your tiny telescopic field happens to sweep right across them. The only way to succeed is to know exactly where you are at all times. If you suspect you're lost, go back and start over. Have patience. You'll speed up later when practice increases your skill.
Keeping Track of North
The biggest pitfall in going from map to sky is keeping directions straight. Remember that in the sky, celestial north is not up but toward Polaris, no matter how cockeyed this direction may be in the eyepiece. To find north as seen in the eyepiece, just nudge the telescope a bit toward Polaris. New stars will enter from the field's north side, showing you where this is. Turn the map around accordingly, so north on the map is oriented in this direction. This north-nudging trick will become such a habit at the telescope that you'll forget you're even doing it.
Furthering Astronomical Skills
Learning how to see. Why would you have to do something that you may take for granted everyday? Any experienced observer will be able to see vast amounts of detail in an object because they have taken the time to train their own eyes to see more than a novice. This training comes from practice, certainly, but you can apply the essentials to your next viewing session and be amazed at the new things you see.
Low Contrast Deep Sky Objects
One of the most difficult class of objects for an intermediate amateur is of very low contrast, distended objects. These include diffuse nebulas, planetary nebulas, dark nebulas, and faint galaxies. The challenge lies in observing these objects during nights of less than optimum conditions. The first rule is to know what kind of object you are after.
What Will I See?
The easiest objects to find in the Messier Catalog are the brightest nebula (like the Orion Nebula) or the brightest globular star clusters. A couple of the open star clusters like M45 the Pleiades and the Beehive Cluster are seen naked eye quite easily. The brightest galaxy in the night sky is the Andromeda Galaxy, M31, and even this galaxy looks like a gray oval in 8" or smaller telescopes. One nice thing about the Messier list is that when you're looking for a particular object, it's usually the brightest thing in that area. Getting close to the right spot with the Telrad and then using about 40X and scanning the area and looking for subtle changes in contrast will usually let you pick even the dimmest Messier Object out from the background field.
Certain nebulae are more visible when using an O-III filter or a nebula filter that remove extraneous wavelengths of light, improving contrast. These filters are completely ineffective when trying to observe galaxies. To spot these, star hop as close as you can get and then there are methods for scanning the sky in a search pattern that will yield success. The trick to spotting dim galaxies is to know what you expect to see through the eyepiece.
Look at a picture of what you're going after and study not only the shape of the particular object, but the pattern of objects and stars in the immediate vicinity. This is crucial advice when tackling the Virgo Cluster of galaxies where there are so many galaxies, and only some of them are Messier Objects.
Recording Your Observations
It is fun to observe the heavens, that’s why many of us are amateur astronomers! However, in order to make scientifically useful observations or to compare your own observations over years of observing, it is important to record your observations in some permanent form. You might use a bound or loose-leaf notebook to maintain your records. Whatever format you use, certain standard information must be recorded.
The form below is one way to organize that information. It is the one suggested by the Astronomical League, but it is only a suggestion. You are free to make copies as you need for recording your own observations. A few comments follow on certain of the data fields.
Date and Time
Since most astronomical observations are made at night, they can span two calendar dates. This can lead to confusion in your records. There are several ways to avoid this confusion: use Universal Time as reported by radio station WWV and others; specify both standard calendar dates, e.g., January 25-26; just be careful of your observation time and report it properly in civil time, noting the date change after midnight. Just pick a method and use it consistently.
Many observers forget that the telescope's optical path includes a column of atmosphere equal in diameter to the telescope objective. The air within this column is constantly moving, changing density and composition. These factors combine to degrade the observed image. Some estimate of these "seeing conditions" should be included in your observing report: the "seeing" may be important when interpreting your observation at a later date.
The form includes two provisions for estimating seeing: transparency and steadiness. Various observing programs may specify a particular "seeing scale." Be sure to indicate the basis of your estimates. If transparency is the faintest naked eye star visible, enter it as "5.5 mag." If steadiness is on an arbitrary scale of 1 to 10, 10 best, enter it as "7/10."
Field Size and Orientation
You should include an indication of scale in any sketches or drawings you make. The angular size of the eyepiece field is often convenient for this. You should also include two perpendicular directions in any field sketch: North (or South) and East (or West). Two directions will indicate any field rotation caused by star diagonals or secondary mirrors.
Trying to Log Messier Objects at a Public Star Party
You've got all of your stuff set up, the night is looking clear and steady, you have planned out what you're going after...you've decided to tackle some of the dim objects in Leo...and maybe even start on the Virgo Cluster... but you're at a Public Star Party and occasionally someone comes up and asks, How far away is Messier 61? Kind of throws you off. But take a step back a moment from your scope and realize that you have a real opportunity to add to your own astronomical knowledge as well as the knowledge of the person asking the sincere question. If you happen to know the answer, great! But if you don’t, why not take a minute or two and see if you can get the answer from another club member or from a book. You’ll find that 99% of people who have taken their time to come out to a Star Party are genuinely interested in finding out more about the universe around them and are happy to wait to get a good answer. I have found that knowing solid answers for the questions above will get you through a high majority of the evening’s questions. Above all, Have Fun!!
Typical Questions and Answers
· How powerful is your telescope?
Telescope magnification is the telescopes focal length divided by the eyepiece focal length. A 2000 mm focal length telescope with a 20 mm eyepiece is viewing at 100 X magnification.
· How far away can you see?
Galaxies that are 40,000,000 light years away are seen through most amateur telescopes. With the naked eye, the Andromeda galaxy is visible as a faint smudge at 2,200,000 light years away.
· How far away is what I’m looking at through your telescope?
Refer to your Messier Guide (Sky Publishing), a copy of The Night Sky Observer’s Guide (Willman-Bell), or of Burnham’s Celestial Handbook as starting points.
· How big is our galaxy?
The Milky Way Galaxy is approximately 100,000 light years across and 30,000 light years thick at its core. There are approximately 1 billion stars in our galaxy. Our solar system is located on the outer edge of one of the spiral arms. Our entire solar system orbits once around our galaxy about every 250 million years. For a sense of the size of the Milky Way, if our entire solar system could be shrunk down to the size of a coffee mug, on that same scale the Milky Way Galaxy would be twice the size of the entire North American continent.
· What is a shooting star?
A meteorite. Most meteorites are no larger than a grain of rice, but they are moving extremely fast (50,000 mi/hr!) when they hit the upper atmosphere of the Earth. All of that velocity is converted into heat and light, making a memorable streak of light in the night sky.
Helpful Messier List Books
Deep-Sky Companions: The Messier Objects
Stephen James O'Meara
Introducing the Messier guide for the modern age! This first book in the Deep-Sky Companions series by noted observer and Sky & Telescope contributor Steve O'Meara provides a fresh perspective on these perennially favorite viewing targets. Along with pages of observing tips for novice stargazers, O'Meara presents the most recent scientific data about each object, accurate drawings done at the eyepiece, new insights on the "missing" Messier objects, and more! Copublished by Sky Publishing Corporation and Cambridge University Press.
Messier Card (Laminated)
This quick-reference sky chart shows the location of all 109 Messier objects on the front and tabulates their coordinates, sizes, and visual magnitudes on the back. Laminated finish protects it against moisture and wear.
Nightwatch: A Practical Guide to Viewing the Universe
Build Your Own Telescope - Complete Plans for Five Telescopes You Can Build With Simple Hand Tools
Sky Atlas 2000.0 : Deluxe (or preferably, the Deluxe Laminated Version)
The Backyard Astronomer's Guide; Terence Dickinson
Splendors of the Universe: A Practical Guide to Photographing the Night Sky
Send the title of your favorite Messier Book or Messier tip to: