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SMAS
Southwest Montana Astronomical Society

Frequently asked questions

Questions relating to SMAS

General astronomy questions

What is SMAS?

The Southwest Montana Astronomical Society (SMAS) is a nonprofit organization dedicated to the study of the universe for recreational and scientific purposes, and promoting interest in amateur astronomy. Membership is open to all members of the public interested in the study of the night sky. It's members promote interest in astronomy throughout the state, sponsoring or co-sponsoring a number of public events as well as astronomy projects.

Membership is open to all members of the public with any interest in astronomy.

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Do I need to own a telescope or know a lot about astronomy to join the club?

Absolutely not! A lot of what drives the society is its social astmosphere of Fun and Learning about the hobby of stargazing. The club provides a variety of activities for all levels of interest and experience. Families and older children are welcome!

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When and where does SMAS meet?

The Society meets on the last Friday of each month (January through October) at 7:30 p.m. at the Museum of the Rockies, and are always open to the public. The meeting may include a speaker, demonstration, workshop, telescope viewing, and updates on current club events. In order to avoid conflict with the holidays, the November-December meetings are combined into one on the first Friday of December.

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What events does the club sponsor?

Every year SMAS holds two state-wide events. The annual Montana Astro Fair, which takes place in winter, is an exciting blend of seminars, planetarium shows, workshops and displays. Daytime and night observing sessions are part of the activities. Held in conjunction with the Museum of the Rockies, it is an event well worth attending. During the summer, SMAS hosts the annual Montana Starwatch, a weekend campout of dark sky observing that features guest speakers, daytime activities, a BBQ, door prizes and other activities. Attendees come from all over the country.

Other common activities of SMAS include informal stargazing at the museum or at dark-sky sites, a winter astronomy lecture series, family campouts, workshops on choosing, using and making telescopes, observing techniques seminars, "sidewalk astronomy" events, and technical projects.

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How do I become a member of SMAS, and what are the benefits?

There are dues which are used to cover the cost of Society functions.

For only $25 single or $30 family, a year you can enjoy the following benefits:

Click here to join SMAS.

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Who do I contact for more information about the club?

Fred Birk (president) at 406-586-6476.

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What is the telescope loaner program?

Many members of the club have their own telescopes, but if you don't have one or are thinking about buying one and want to "try some on for size," SMAS has a loaner scope program for its members. We have a wide range of scopes to accommodate everyone from beginners to experts! There are several telescopes available, of varying apertures, that can be checked out for two weeks (or more) at a time, depending on availability. For more information, call David Binnewies at 994-6891.

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What telescopes can I check out?

Newsome Scope: This 4" Criterion reflector was donated for club use by Bill Newsome, and restored to working order by himself and Don Nisewanger.It is equatorially mounted, and has a clock drive.

Roby Scope: This 6" reflector on a Dobsonian mount was built in 1946 by Robert Grasmehr, was donated to the club by his sister, Lois Roby. It was restored and placed on a new mount by SMAS in 1996. A TelRad finder is included on this tube.

Moss Scope: This is a 10" reflector on a Dobsonian mount, with parts collected and donated by SMAS, "Night Skies" telescope store, and the Museum of the Rockies. It was finished by the Moss family in 1997.

Gorski Scope: Wayne Gorski acquired this 13.1" Dobsonian reflector and has placed it on permanent loan to the club. It was recently rebuilt by club members Erik Green and Shane Larson into a collapsible truss-tube structure, to make it easier to transport, but it is still considered "large"!

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What is the largest telescope the club has?

SMAS and the Museum of the Rockies were the joint benefactors of a donation from the Testamentary Trust of Laura D. Pasley in 1997. The estate's gift is to provide a portable telescope system of large aperture to further astronomy outreach and education with children in southwest Montana. A 20" Starplitter II Dobsonian telescope made its public debut at the 1998 Montana Starwatch, and is being used at special "star parties." While this scope is not considered a "loaner," club members can have access to it by completing a short training session and participating in the club's educational outreach programs.

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What if all I want to do is stargazing?

Members are free to pursue whatever services the club offers, even if it's just to observe. Star parties take place (weather permitting) after each general club meeting at the Museum of the Rockies, but also at special times and places announced by the club. Some may be held in other towns around the area (Three Forks, Big Timber, Belgrade, Livingston, BigSky,Townsend, etc.) or simply at someone's home.

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What is meant by "Right Ascension" and "Declination"?

In reading star maps, coordinate lines are often drawn in and refer to Right Ascension (R.A.) and Declination (Dec.). These are simply astronomical "buzz-words" for sky longitude and latitude. They are very much like Earth longitude and latitude; in fact, they are based on Earth's coordinates. Imagine extending the equator and poles of the Earth out onto the sky -- if you could mark them with something visible, you would see the celestial poles and celestial equator.

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What do the symbols °, ', and " mean when measuring angles?

Angular measure on the sky is a useful way of describing how big an object looks or how far apart two objects may appear. For example, the width of the Moon in the sky subtends about 1/2 degree (°) as seen by the eye (An aspirin tablet held at arm's length covers about the same width!). The height of the north star above the northern horizon is between 45 and 49 degrees for Montana observers.

A degree can be divided into smaller increments, and comes into play when telescope viewing since the field of view is often covering only a fraction of a degree. Think in terms of time:

60 minutes of arc (60') = one degree (1°)

60 seconds of arc (60") = 1 minute of arc (1')

These units can be used in describing Declination, but do not confuse the "hours" and "minutes" of Right Ascension with this. Right Ascension really IS related to time -- specifically, the rotation of the Earth. If you need to know the angles when reading maps, the relationship for Right Ascension is:

1 Hour of Right Ascension = 15 degrees (15°)

1 Minute of R.A. = 1/4 degree = 15 minutes of arc (15')

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Why use binoculars?

Even if you have a telescope, binoculars can be an invaluable aid to locating and viewing sky objects. Their low power combined with wide field of view makes them the ideal scanning instrument -- things look right side up and it's easy to find what you point at! Plus you get to use both eyes, thus your power of resolution and ability to detect faint objects are dramatically improved. Color perception and contrast are enhanced as well. Binoculars make an excellent intermediate step between naked eye and telescope viewing. They can help you locate those small, dim objects so you know where to point the telescope later. However, keep in mind that binoculars can show celestial details that many people think require a telescope.

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What is meant by "averted vision technique"?

When viewing through binoculars or telescopes, most deep sky objects look like faint fuzzy blotches of light - at first. The ability of the human eye to see intricate detail even in faint objects is truly impressive if one takes the time to develop the needed observing skills. First and most important is to make sure the observer is DARK ADAPTED. This means setting up in a dark-sky site with no white lights (streetlights, car headlights, porch lights, flashlights) in view. The pupils in the eye take a minimum of 15 minutes to fully dilate and thus adjust to see faint details in the dark.

Now you are ready to use AVERTED VISION to discern fine details on astronomical objects. When viewing through the eyepiece, look not only directly at the subject but around the edges or even slightly off to the side. Slowly look back and forth and around it in this manner, and finer details will seem to flicker in out of the "corner of your eye"! This is happening because your peripheral vision is more sensitive to faint light than your direct vision, which is more constantly used. To preserve your night vision, use a red-filtered flashlight to read star maps or find your way around.

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What is a light year?

Its name implies it has to do with time, but it is actually a measure of distance. Because objects beyond the solar system are so immensely far away, 'miles' becomes too small a unit. It becomes necessary to use a larger scale.

The light year is the distance light will travel in one year. At 186,285 miles per second, a beam of light will travel nearly 6 trillion miles in one year (5,878,700,000,000 miles to be exact). With this scale, we would say that the nearest star to our Sun (called Alpha Centauri) is 4.3 light years away.

Compare this with light-speed distances to these objects:

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Is it possible to see planets or stars during the day?

In general, the answer is no. The only celestial object besides the Sun which is normally visible during the day with the unaided eye is the Moon, and even that is easy to overlook. But for several months each year, the next brightest object, Venus, is dazzling enough to be seen with the unaided eye in broad daylight. However, actually seeing Venus this way means waiting for the right time and knowing exactly where to look.

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What is meant by "magnitude"?

Magnitude refers to the brightness of an astronomical body. Apparent magnitude 1 is exactly 100 times brighter than magnitude 6, each magnitude being about 2.5 times brighter than the next. Magnitudes brighter than 0 are minus figures, thus Sirius is -1.4, and the sun is -26.8. The faintest objects yet photographed are about magnitude +29. For simple backyard observing, see the following chart:

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What is meant by "open cluster" and "globular cluster"?

These are physical groupings of stars in space, moving together as a unit. They were all formed together at the same time, but there is a big difference between "open" and "globular" in size, age, numbers and types of stars:

Open clusters are loose gatherings of stars, usually numbering from the tens to the hundreds. They are usually quite young, from the tens of millions to hundreds of millions of years. They may be so young that some of the dust and gas (nebula) that formed them may still be present. Found in our galaxy's spiral arms (like the sun), most open clusters dissociate, finding their own indivual orbits about the center of the Milky Way.

Globular clusters are much larger, spherical groupings. Numbering in the hundreds of thousands to millions of members, these clusters contain some of the oldest stars in the galaxy, up to 12 billion years in age. Because of their great numbers, they stay intact as a cluster their entire lives. Globulars orbit the Milky Way in a spherical halo around the central bulge of our galaxy, thus they are usually quite distant from the earth (tens of thousands of light years). Over 160 globulars are known to exist in our galaxy.

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What is a nebula?

The Milky Way is not just made of stars. The space between the stars has gas and dust, and in some places concentrations of this material can be found in clouds called nebulas. Some clouds that we see glowing are Emission Nebulae, glowing to fluorescence due the radiation of nearby stars. Some of those that glow may exhibit an obvious ring or circular shape, called Planetary Nebulae; these are the leftover remains of a dying star which has puffed away its outer atmosphere into a shell of gas. Other clouds, however, emit no light (Dark Nebulae) and can act as curtains hiding the more distant stars from our sight. In the summer Milky Way, an apparent dark lane can be seen dividing its faint band right down the middle. This is in fact enormous amounts of dark nebulosity hiding the thousands of stars beyond.

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What's the difference between "solar system," "galaxy," and "universe"?

A solar system is just a star (like our sun) whose gravity holds planets, asteroids, comets and meteoroids in orbit around itself. Each other star we see in the night sky is potentially another solar system.

A galaxy is a vast island of hundreds of billions of stars (solar systems), nebulas and star clusters. Our Milky Way has over 200 billion stars in a spiral shape, over 100,000 light years wide.

The universe encompasses all the galaxies -- billions of them, some coming in clusters of their own. At the edge of the visible universe we see bizzare, super-energetic objects called Quasars, the fiercely eruptive cores of young galaxies.

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Why can I sometimes see the moon in the daytime?

It is not uncommon for people to be surprised at the appearance of the moon in the daytime. The moon, in fact, CAN be seen quite easily at times because it is still sufficiently brighter than the bright blue sky caused by scattered sunlight. The stars are still there too, only their brightness is too low to overcome the skyglow.

The moon is always moving in orbit around the earth, thus it's constantly changing position in the sky relative to the sun. At certain periods it will be at a position alongside the sun, sometimes small and difficult to see (crescent), sometimes almost full (gibbous), but visible nonetheless if one takes a moment to search.

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Why does the moon look so big when it's rising?

Almost everyone has noticed the same effect: the moon indeed appears larger when it is close to the horizon than when it is overhead. Yet you can prove to yourself that this is strictly an illusion. Hold a dime at arm's length in front of the moon. Regardless of the moon's elevation in the sky, the dime will just cover it.

The "moon illusion," as it is sometimes called, is entirely conjured up by the human brain. There are still several explanations for what the actual process might be -- some contend it's brought about by having terrestrial frames of reference right near the moon when its rising (trees, houses, telephone poles, etc.), allowing the brain to "focus" on it more closely.

Another theory says the illusion centers of the human perception of the sky as an overturned bowl, more distant on the horizon than overhead, which fools the brain into "correcting" the size of the moon for that scenario. In any case, here is a final test to prove that it's all in the mind. When no one is watching and the full moon is near the horizon, bend over and look at the moon upside down from between your legs (!). The effect vanishes, presumably because you have flipped the scene reaching the brain by placing the horizon above the moon.

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Why do stars twinkle?

Stars appear to twinkle because they are pinpoint sources of light. In reality, of course, the stars are far from tiny, but their enormous distances from earth reduce them to dimensions so miniscule that even the largest telescopes are unable to reveal them as disks. They are mere point sources. Thus a beam of light from a star entering your eye is a fragile thread that is easily rippled by the ever present turbulence in the earth's atmosphere, which causes the twinkling.

You might notice that planets, on the other hand, do not twinkle (or at least not nearly as much as the stars). This is because planets do notappear as pinpoints, they appear as tiny disks since they are much closer than the stars. The bigger bundle of light from the planet is less easily disrupted by atmospheric turbulence.

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When is the best time to look for the Northern Lights?

On certain occasions, the northern night sky is alive with dancing, luminous curtains of red, green, purple or yellow light, swaying and pulsating and sometimes converging near the zenith (overhead). Experiencing such a display of northern lights, or aurora borealis, is like standing inside nature's kaleidoscope. Some of the largest displays can surge trillions of watts through the high atmosphere, creating an unforgettable experience from a dark sky location.

Dazzling all-sky auroras have been seen by few people, but lesser displays are visible several times a year from mid-northern latitudes. The fact is, our indoor television-oriented culture in combination with modern outdoor lighting mean that many people have never seen an aurora at all. Some displays can, however, be seen from the city.

Auroras peak and subside in harmony with the 11-year sunspot cycle. The last sunspot maximum was in 1991, and spectacular all-sky auroras were visible in March 1989, March 1990 and November 1991. In between maxima, auroras are less frequent and less intense, although an impressive show can still occur. Specific predictions are impossible. There is no favored time of night, although the strongest displays seem to occur in March, April, September and October. The only way to see an aurora is simply to go outside every clear night and look for an unusual brightening in the northern sky.

Ranging from a pale greenish white glow near the horizon to intense red, green and blue spears and curtains that fill the sky, auroras magically float among the stars. The phenomenon originates when eruptions on the sun's surface, called solar flares, liberate vast amounts of charged particles into space. The charged particles -- actually just parts of normal atoms -- reach earth, follow our planet's natural magnetic field and are funnelled into a continent-sized ring around the magnetic north pole in Canada's Arctic (a similar ring occurs over Antarctica).

The interaction between air molecules 60 to 500 miles above the surface and the incoming solar-charged particles releases energy in the form of light, making the earth's upper atmosphere act like a glowing television screen. This happens all the time, but usually, it is dim or the auroral ring is too far north to be visible from the more populated parts of Canada and the U.S. When solar activity increases and more particles reach earth, the aurora brightens, the ring expands to the south and display may become visible to millions.

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Why don't you see color when observing sky objects in a telescope?

Many times we see astro photographs that reveal a variety of deep colors in most deep sky objects, yet when we look at them through a telescope they usually show a faint gray or bluish haze. This has to do with the way our eyes sense light. The retina contains sensors called rods and cones. Rods detect black and white, and are seven times more sensitive than the cones, which detect color. Ever noticed that when you're in a room with very low light, that it's difficult to discern any colors? Just remember that when the rods are dark adapted, the level of fine detail that can be picked out can truly be amazing!

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If the stars are always like pinpoints, why do the brighter ones look bigger?

This is another physical effect the eye plays on you - the brighter stars actually measure the same in angular size, but due to their greater brilliance they activate some of the nearby sensors in your retina and cause your brain to interpret it as being "larger."

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