CONSTELLATION GUIDE Last updated: 8 May 2001

"GO TO"....LYRA
Honing in on the Heavenly Harp and its Hidden Treasures!

From: sherrodc@ipa.net (Clay Sherrod)

ABOUT THE CONSTELLATION "GO-TO" GUIDES!

This seventh Constellation Guide, "GO TO LYRA" of the series "GO TO GUIDES for the ETX and LX 90 Telescope Users" explores one of summer's "early arrivals," the constellation of Lyra, heralded by the bright diamond among stars, VEGA. As with all constellation guides, you will start your "GO TO" with a routine and easy slew to a bright star, in this case Vega. From there you will proceed to explore this small but wonderful constellation, a fantastic "planetary nebula" that remains from a massive stellar explosion, a fine globular cluster, and some beautiful and challenging multiple stars. Along the way, you will be treated to short descriptions of the mythology of this wonderful constellation and its inhabitants, astronomical history and interesting tidbits of information to make YOUR explorations of the heavens much more enjoyable and diversified..

As always, all objects will be described - first in a concise list with exact coordinates and magnitudes and then individually - with specific details of what YOUR SCOPE.....the ETX 60, 70, 90, 125 or the LX 90....can expect to show you....and what you can expect to NOT see. So many times casual observers are disappointed when they attempt to find an object beyond their telescope's capability....or perhaps let down from what the photographs of the great observatory telescopes have shown them in the textbooks, magazines and advertisements.

Each GO TO object is discussed for your telescope regarding the type of conditions necessary for you to view it optimally for discern the very faintest details....double star challenges for each size telescope .....magnifications and aperture necessary for most objects, and much, much more. This is YOUR complete GUIDE for deep sky observing enjoyment and satisfaction. In addition these guides make an excellent reference for your next star party itinerary!

Truly, as reports continue to come in on these extensive Constellation Study Guides, they will most definitely put your AutoStar to work for you in the most efficient and enjoyable way possible!

We hope you enjoy these comprehensive GUIDES to touring the constellations via your AutoStar and its computer-driven telescope. Each new installment will appear frequently, complete with diagrams, charts and illustrations that you will find nowhere else. Please let us hear YOUR feedback and your observations of each and every constellation after YOU have toured its vast reaches of our skies!

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Introduction -
The constellation LYRA (pronounced "LIE-rah") ranks among the smallest of the entire regime of official l88 recognized constellations seen from both the Northern and Southern hemispheres. Though small in size, it is indeed "Mighty" in memories and imagery....as well as ancient and even more modern history.

As mentioned in the last installment of the Constellation "GO TO" TOUR Guides, the constellation of Lyra will hold special meaning in 15,000 or so years, not that it does not already to many people. As Thuban (alpha Draconis) was the Pole Star (the "north star") for the Egyptian pyramid-builders some 5,000 years ago, so will the bright star VEGA (alpha Lyrae) be in 15,000 years! This is due to the Earth's PRECESSION (wobbling on its axis as it moves through space, like a top askew from its perfect spin) over tens of thousands of years. At the present time, of course, POLARIS (alpha Ursa Minoris) just happens to be lined up in such a way as we see it superimposed over the distant line transcribed into space by the Earth's axis of rotation.

The tiny but beautiful constellation of Lyra represents the LYRE OF HERMES, fashioned from the shell of a tortoise, according to Greek legend; interestingly earlier Persian sages also denoted the star pattern as ZURAH LYRE, an association that survived middle eastern conflict and religious persecution all the way through the 15th century when the "harp of Phoenicia" shone brightly in the skies over Arabia.

In later Greek myth, the lyre fell into the hands of noted Orpheus who turn his stringed song into a magic spell of sorts that mesmerized all - including animals and insects - who fell upon its melody. It was with Hermes musical instrument that Orpheus was able to enter the famed "underworld" attempting (without success) to rescue his sweetie, Eurydice from the forces of darkness.

As you gaze at the beauty of such a small gathering of stars, it is quite easy to see Hermes' little harp suspended majestically among the stars; to me it is a wonderful reminder of the warmth, the smells and the wonderful innocent traditions of an impending childhood summer....

Click for larger view

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THE "SUMMER TRIANGLE" -

Perhaps the real beautify of this small constellation is in its association with so many other striking star patters of the late spring and early summer skies. As it heralds in the great bright clouds of the Milky Way through Cygnus, Aquila, Sagittarius and Scorpius, the first sighting of Vega each year signals - at least to me - the advent of exciting explorations of our Milky Way galaxy!

Note from the sky chart above the arrangement of the bright stars VEGA, DENEB (alpha Cygni) and ALTAIR (alpha Aquilae); all are very bright stars, with Deneb and Altair appearing distinctly yellowish and Vega its brilliant blue-white color. Together, these three stars form an "asterism" in the sky known as the "Summer Triangle," a very conspicuous (particularly from lighted city and suburban sites) isosceles triangle in the night sky.

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YOUR LYRA CONCISE DIRECTORY OF OBJECTS -

I have chosen the finest nine (9) objects in this tiny constellation to showcase for your "GO TO" TOUR of Lyra; in this case, all objects listed below will be visible in all telescopes from the ETX 60 through the LX 90; of course larger apertures may "show" an object a bit closer and "better," but frequently a wide field and low power view is more desirable than aperture. This is the case for MANY of these objects (as well as scores of fantastic views in Lyra that are not included here), as Lyra skirts the outer periphery of the fantastically star-rich summer Milky Way skies.

The constellation's high declination in northern skies allows for ideal viewing during dark sky conditions as objects pass high in the sky, rather than low to horizons as does Scorpius or other southerly constellations for northern hemisphere observers.

As with all of the "GO TO" TOUR constellation lists, I recommend a good star atlas and/or chart which will list all the finest objects, constellation-by-constellation. One very handy reference guide is the PETERSON FIELD GUIDE TO THE STARS AND PLANETS, which features complete lists with declinations, right ascensions, magnitudes, and all pertinent information for you to expand your observing horizons beyond this brief GUIDE.

Note that your AutoStar will NOT have every object listed on every constellation GO TO tour....this is intentional. You can access some of the most interesting objects of the sky directly from their coordinates. It is quite simple as you merely enter these coordinates as follows in the 10-step process:

1) Press the "MODE" key and hold down for 3 seconds and release;
2) Displayed will be the current Right Ascension and Declination of the center of field of view of where your telescope is presently pointed (assuming that you have properly aligned from "home position");
3) [NOTE: if you have the Meade electric focuser attached to any of the ETX or LX telescopes, holding down the "MODE" key will bring up the "Focus" command first....merely scroll (lower right scroll key) down one step to access the RA and DEC to enter your desired coordinates]
4) Press the "GO TO" button on AutoStar;
5) This will change the display and you will note the cursor blinking over the first digit of RIGHT ASCENSION (R.A.); merely use the number keys and dial in the R.A. of the object you are searching for;
6) When done, press "Enter;"
7) This moves the blinking cursor over the "DEC" coordinates;
8) [NOTE: the declination, unlike R.A., can be either positive or negative and you will see the "+" or "-" sign displayed depending on where your telescope is aimed at that time; if it is NOT the desired setting (plus or minus), merely use your arrow key to move the blinking cursor OVER the "+" or "-" sign and change by using either of your lower corner SCROLL KEYS;
9) Proceed to enter the DEC using number keys;
10) Press either "Enter" or "Go To" when finished and the telescope begins slewing to your desired object!!

The constellation tour Star Chart above (click on and save to a file on your PC; then open it and re-size to fit the page and print for a very handy at-the-scope star chart) will get you started on your journey for this constellation. That and the "close-up" insert for Lyra (click on the small chart icon below, save to file, open, resize it to fit your page and print!) demonstrates the relative positions for all objects listed on this tour and the conspicuous stars outlining the distinct shape of Lyra the Celestial Harp.

Following is the complete 9-object list for your "GO TO" TOUR of Lyra; you may wish to find the majority of the objects from the AutoStar Library (for example, you can easily pull up "Object/Deep Sky/Messier Object/..57...." and then press "Enter", followed by "GO TO" to access the famous Ring Nebula. On the other hand, if you want to experiment and become a "better AutoStar user" try entering the exact R.A. and DEC coordinates listed below as described above after holding down the MODE key. You will find the accuracy of entered GO TO's to be somewhat less than those stored in AutoStar, but the capability of acquiring unlisted objects is fantastic!

OBJECT 1:
    very bright star - Vega (alpha Lyrae) - R.A. 18h 35' / DEC + 38 44 - Magnitude:  0.04
OBJECT 2:
    multiple star - Epsilon Lyrae - the famous "DOUBLE-DOUBLE" - R.A. 18h 43' / DEC +39 37 - 4 stars
OBJECT 3:
    nice low-power double - Delta Lyrae - R.A. 18h 53' /  DEC + 36 54 - Magnitude:  4.5
OBJECT 4:
    variable star - R Lyrae (a good beginner's variable) - R.A. 19h 24' / + 42 41 - Magnitude range:  3.9 to 5.0
OBJECT 5:
    nice test double - Eta Lyrae - R.A. 19h 12' / DEC + 39 04 - Magnitudes:  4.5 & 8.7, wide double
OBJECT 6:
    nice globular cluster - Messier 56 (ngc6779) - R.A.19h 15' / DEC + 30 05 - Magnitude:  8.2
OBJECT 7:
    very difficult planetary neb. - ngc6765 - R.A. 19h 09' / DEC + 30 38 - Magnitude:  11.1 (tough!)
OBJECT 8:
    nice variable star - W Lyrae -  R.A. 18h 13' / DEC + 36 39 - Magnitude range: 7.3 to 13.0 (196 days)
OBJECT 9:
    best planetary there is! - Messier 57 (ngc6720) - R.A. 18h 52' / DEC + 32 58 - Magnitude: 9.3

A VISUAL GUIDE TO OUR DEEP SKY OBJECTS IN LYRA -

Object 1 - Very Bright Star VEGA (Alpha Lyrae)
At 27 light years distant, this brilliant blue-white orb is the fifth (or some say fourth) brightest star of the night sky. It is frequently called the "Harp Star" from its association with the mythological Hermes' lyre. However, "Vega" gets its name from the Arabic skywatchers of thousands of years ago who called it "Alnasr al Waki" or "The Bird of Prey", signifying a hunting eagle, falcon, or vulture as was the entire constellation known for those early skygazers. Personally, I prefer the more modern and mundane "harp" to a blood-thirsty raptor. Early Chinese astronomers knew Vega as "the girl who weaves" who was always accompanied by her friend Altair, "the boy who herds."

Vega, at magnitude 0.04 has a more brilliant blue color than even bright Sirius, whose light is more pure white. It is only 58 times brighter than our sun would appear at the same distance, yet is about 2.5 times larger. Although Vega is somewhat variable, it is not of interest to common telescopes for that reason.

As mentioned, this star will be the brightest of all possible northern pole stars in about 12,000 A.D where it will be farther from the true pole - some 4.5 degrees - than Polaris is today. Historically, you might want to remember for your next "teaching guide" at the local star party that Vega was the first star to be actually PHOTOGRAPHED! (boy have we come a long way!). In 1850 William Bond and his assistants used the "Daguerreotype Process" to capture its brilliance in a 1.7 minute exposure. The 15-inch telescope at Harvard University in Cambridge was then the largest refractor in the world, and is still in use at the same location today.

Object 2 - The Famous "Double-Double Star (Epsilon Lyrae)....a fantastic object for all scopes!
This is a FAVORITE at all star parties, and one that - no matter how many times you have seen it before in no telling how many different telescopes -you keeping coming back to view time and time again! It is THAT good.....if you have NOT seen this remarkable star system you have either been living in a CAVE or merely did not know it was there. Epsilon Lyrae - the "double-double star" is located very close to Vega and is the closest bright star to it with the unaided eye. Your finderscope will begin to show TWO stars of equal magnitude....the 8 x 50 finder of the LX 90 will clearly show both stars at only 8 power. Using the standard 26mm eyepiece in the ETX 90, 125 and LX 90 will reveal that EACH of those two stars is ALSO TWO STARS! A bit more magnification is required for the ETX 60 and 70, but these scopes will show this beautiful system clearly. So, you have two bright stars that orbit one-another; those two stars are actually also two stars that orbit each other; thus, you have two stars revolving around a common center that are synchronously revolving around yet ANOTHER pair doing the same thing! Wow. Look for all four stars to be pretty much "white" in color, as they are ALL type-A stars. The two brighter pairs are actually separated in space by about only 5 trillion miles.

Object 3 - Nice Double Star With Color Contrast - Delta Lyrae
This is a good objects for all telescopes. With a huge separation of 10' arc (1/3 the size of the moon at the same magnification), this pair can be seen easily with the ETX 60 and larger scopes at very low power. The dimmer star ("Delta-1") is magnitude 5.5 and the brighter star ("Delta-2") is magnitude 4.5. At 800 light years, it appears that these two stars are ACTUALLY the two brightest members of a very sparse and loose cluster of stars of magnitudes 7 to 10; so, likely the stars that you see with your wide field view around these two brighter stars are, indeed, part of a loose cluster of stars. Be sure and note the interesting contrast of colors of these two stars, even though both are thought to be the same age. ALSO....scan this area around Delta Lyrae with very low power and a wide-field eyepiece (here is where the ETX 60 and 70 have the "big boys" beat!) for some of the most gorgeous views of the rich star fields imaginable. It is truly a beautiful sight, but one that must be enjoyed at the darkest sky location possible.

Object 4 - Good Beginner's Variable Star....R Lyrae
Here's one you can actually use your finderscope on....or try a pair of binoculars....it is ideal for the wide fields of the ETX 60 and 70. R Lyrae is a fairly bright (magnitude 3.9 to 5.0) star with a short period of only 46 days. It is ideal for beginning a pursuit in understanding recording techniques of variable stars! Variable star observing requires only that you routinely observe the brightness of a given star over time and record what that brightness is.....this is ONE area that the amateur astronomer can greatly contribute to the body of scientific knowledge that the professional astronomer has neither the time nor equipment to do. Stars like "long period variables" have very long light curves (see my OBSERVING GUIDE: VARIABLE STARS at http://www.weasner.com/etx/ref_guides/variable_stars.html for a complete description) and do not need to be observed every night. They are so predictable that observing them once a week or so is fine; on the other hand there are "cataclysmic variables" that are violent and tend to have unannounced outbursts....observing these as often as possible! Stars like R Lyrae, with a short period of only 46 days should be "looked at" every time you are out since you do not even really need a telescope.

A great comparison star chart from the American Association of Variable Star Observers (AAVSO) can be accessed, saved to file, resized and printed for outdoor use from the following link:

http://charts.aavso.org/LYR/R_LYR/RLYR-A.GIF

In only three months you will have recorded two full cycles of this interesting star; use this experience to begin accessing more and more charts via these free and useful links to the AAVSO; there are hundreds of charts for all constellations and star types as well as important and helpful information about variable star observing!

OBJECT 5 - Nice very wide Double Star; great wide field views of the sky! Eta Lyrae.
This is a beautiful field surrounding the star Eta Lyrae. The double is a very wide star, equally about one-half the diameter of Jupiter as seen with the same magnification, from the brighter (magnitude 4.5, easy in your finderscopes) to the companion star (magnitude 8.7). This is a good test for your visual acuity with the telescope and the star is NOT as easy as you might think based on the separation. The tiny 8.7 magnitude star tends to get "lost" in the field if too low power is used...on the other hand, if too high a magnification is attempted, the glare of the 4th magnitude star will obliterate the tiny image. This is a true challenge for a double with the ETX 60 and 70. It begins to show more easily with the ETX 90 almost DUE EAST of the brighter star and is fairly simple to find in the ETX 125 and LX 90. Both stars are very young "B" types stars and are true white in color.

Object 6 - Messier 56 - A very nice Globular Cluster
If it were not for the fact that SO MANY globular clusters are scattered in this region of sky (see my Guide OBSERVING GLOBULAR CLUSTERS at http://www.weasner.com/etx/ref_guides/globulars.html) Messier 56 would be an outstanding deep sky objects. However, rivaled by larger and closer M-13 and M-5 in Hercules and Ophiuchus, respectively, this is an often overlooked compact and interesting globular. Look for this object under your "Object/Deep Sky/Messier...." library on AutoStar, or find it about half way from Gamma Lyrae to Alberio (beta Cygni). The first person to actually resolve this "faint ball of light" as it was know to Messier was Sir William Herschel; he realized that the object was comprised of thousands of 11th and fainter magnitude stars. This object can be seen clearly as a small and compact "ball of light" in the ETX 60, 70 and 90 telescopes with no resolution; however, magnifications of about 156x are ideal for beginning to see actual stars around the edges -NOT the center - of this cluster with the ETX 125 and LX 90. Even on the best nights, only a couple of brighter members toward the center can be glimpsed with the 8" scope; otherwise it appears as a uniform glow surrounded by "star dust" in the larger apertures. This is an extremely distant globular; hence its small size and low brightness....it is about 46,000 light years - very close to the center hub of our Milky Way galaxy - from the Earth.

Object 7 - NGC 6765 - Faint Planetary Nebula
This is one of two planetary nebula located in Lyra, the other being the famous and un-challengeable "Ring Nebula", Messier 57. This small and faint object is a very difficult challenge for the ETX 125 and is barely visible to the LX 90 even on the best of nights. See if YOU can see this distant object. It is only one-half the size of the Ring Nebula and requires averted vision and VERY dark skies to see. You must let your eye adapt very long to see this one. If you do not first see it in the larger apertures, don't stare....merely scan the field of view at about 156x and eventually your averted vision will spot the object.

Object 8 - A Fine Variable Star - W Lyrae
Now that I have gotten your feet wet as a "veteran variable observer" with R Lyrae above, how about trying out one of those "long period variables?" These stars required that you aim your scope at them every two weeks or so and compare the brightness to some very similar nearby star. With your telescope's GO TO function, this makes easy work out of a valuable observation.

W Lyrae can be seen throughout its entire cycle of 196.4 days with the ETX 125 and LX 90 as it varies in brightness from a relatively bright magnitude 7.3 to a very dim 13.0. When at its brightest period and for three weeks either side of that, the LX 60 and 70 telescopes can keep up with the light changes easily. For the ETX 90, observers can watch about two thirds of the interesting cycle provided that good finder and comparison charts are at hand. The link below to the AAVSO provides a "medium field" ("B") finder chart for W Lyrae; when it is dimmer, you must also download the more narrow field and fainter comparison star chart ("C" or "D") to follow this star through its dimmest periods. Like many long-period variable stars, R Lyrae is a supergiant very large and red star that pulsates through diameter to result in the light changes that we see.

http://charts.aavso.org/LYR/W_LYR/WLYR-B.GIF

Object 9 - And here is the grand finale: Messier 57 - the RING NEBULA - Planetary Nebula
It may not be the largest that we can see....and it certainly is NOT the closest. It is by far not the most curious as to shape and morphology....but it is a "ring" and looks like a "ring" and has a cute name. So it is the most famous of all planetary nebulae. A PLANETARY NEBULA is a (usually) spherical shell of gas (no, not a "ring") that is ejected from a star that has violently "shed" its outer layers of gas. As the star ages, the pressures inside build until a minor collapse of the outer layers plummets downward, increasing the pressure until the star "can't take it anymore....." and it hiccups. The ring nebula is the hiccup of a tiny star (see the attached Palomar photograph below) that still remains in the center of this beautiful object, some 1800 light years distant.. In a smaller telescope such as the ETX 60 and 70, Messier 57 is clearly visible. It appears as a very dull ghost-like planet (hence the name "planetary nebula"....it has nothing to do with planets other than that appearance). The central region of M-57 are very difficult with the low power instruments. The ETX 90 begins to reveal a bit of the darkened center of the nebula however and with the ETX 125 much detail can be seen with magnifications between 150x and 200x. I used the ETX 125 in combination with the LX 90 to render the drawing accompanying the color photograph (courtesy Mount Palomar Observatory) of M-57 below; I have oriented both the same way for your comparison. Note for reference the very faint star just to the right of the Ring Nebula that is seen in both the drawing and photo. This is a very blue dwarf star, very close to the end of its "life." In neither the ETX 125 nor the LX 90 was the central star seen. Although the star is referenced at "magnitude 14.2" it is very difficult because of the bright cloud of gas that you can clearly see in the drawing. I have never been able to see it with a 14" to 16" telescope, but can clearly make it out in the 24" at about 300x.

Remember when looking at this object, total magnitude 9.3, that it is NOT a ring of gas...it is a spherical SHELL of gas. You are merely looking through a thinner portion of gas toward the center; the perimeter appears brighter and "ring-like" because you are looking horizontally through a much more extended cloud of gas. NOTE that in most telescopes, particularly larger ones, the Ring Nebula has been described as "bluish." I have never, ever seen this coloration; indeed, if anything it has always (even back in my youth with good eyesight) appeared a rather brownish-gray color. I would be very interested in hearing of YOUR impressions of color of this fantastic object!

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WANDERING ABOUT....YOUR NEW "USER OBJECT" IN LYRA

There are not many "showcase objects in this small constellation of the northern skies, but what there IS, is very impressive indeed. We have rarely entered a "double star" into our "User Object" list, so in Lyra we will take that opportunity with a fairly obscure double known only as "17 Lyrae," located at: R.A. 19h 06', DEC + 32 degrees 25 minutes.

I have selected this star because of three reasons:

1) it is likely that you might never search it out if it were not in this guide....and NOW ready to enter into your user list;
2) the star pair can be seen and resolved (though very difficultly in the ETX 60 and 70 because of magnification limits!) in all of our telescopes, and appears pretty in all of them as well;
3) it actually is a very nice and often overlooked classic double star.

THE DOUBLE "17 Lyrae" is magnitudes 5.0 and 9.4, and thus is easily accessible via the brighter star in even the finderscopes of the ETX 90 and 125; the GO TO will get you very close and you can determine the actual star from there. Once found, increase the magnification in the ETX 60 and 70 to just over 100x (closer to 120x is ideal) and you should begin to split this star with a hint of a thread of dark sky between them. The ETX 90 will do the same thing at 83x (the 15mm eyepiece); the ETX 125 requires only 73x using the standard 26mm Plossl. The same is true for the LX 90. The separation of 17 Lyrae is about 3.7" arc so you would think this would be easily resolvable in all of our telescopes.....but the fact of the matter is that the brighter star outshines the dim one so greatly that it actually is NOT an easy object!

SO LET'S LOAD THIS CHALLENGING STAR INTO OUR USER OBJECTS! Take your Autostar and let us key in the particulars for "17 Lyrae." This will add yet another multiple star system to your AutoStar library of interesting and unusual "User Objects."

On AutoStar, go to: "Select/Object [enter]...." scroll down to "User Object" [ enter]. Now enter the coordinates just given above for 17 Lyrae, using the number keys on AutoStar. After entering and pressing "Enter" yet again, scroll down one and you can list the magnitudes of both stars [Enter]. One scroll more after that and you may type in your brief description of the object....but look at it first! [Enter again].

Next Constellation GO TO" TOUR Installment: SCORPIUS, one of the most incredibly-object-packed constellations of our skies. Although very low on the southern horizon for northern hemisphere observers, Scorpius provides a lifetime of observing thrills....from a brand new semi-nova of one of its bright stars, to two of MY favorite globular clusters....fantastic double stars....gossamer nebulae throughout the bright clouds of the Milky Way as they pass through this bright arachnid....and more and more....

Good Observing and explorations of this wonderful world of deep space!

P. Clay Sherrod
Arkansas Sky Observatory
Conway / Petit Jean Mountain
Arkansas

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