"GO TO"....an "Odd Couple Menagerie" of Animals: DELPHINUS and EQUULEUS
The Leaping Celestial Dolphin Rides Herd on the Little Sky Horse
From: email@example.com (Clay Sherrod)
Our sixteenth Constellation Guide, "GO TO DELPHINUS & EQUULEUS" of the series "GO TO GUIDES for the ETX and LX 90 Telescope Users" takes us to two very small, but not often overlooked constellations. Although Equuleus (the "Little Horse") is either not known about entirely to casual stargazers, or is frequently ignored (you will see why), its partner in the celestial zoo, DELPHINUS (the "Dolphin") is very conspicuous and forms an interesting "asterism" (star pattern) in the summertime skies.
Although these two constellations are seemingly void of any bright "show-stopper" deep sky objects - and so far from the ecliptic that they are never visited by any of the major planets nor moon - there ARE many interesting doubles stars and some very fine long period variable stars that are worth checking out. For a complete list of the double stars, I highly recommend the Burnham's Celestial Handbook, Vol.. Two which lists nearly all observable double stars, coordinates, magnitudes, separations and many times good descriptive notes in "shorthand" form. For the list of variable stars (Burnham's also has a listing of these) as well as FREE observing and comparing charts, I recommend www.aavso.org , the American Association of Variable Star Observers in Massachusetts which has supported visual (and photoelectric) observations of these stars for nearly a century. There is much free (or very inexpensive) material available from that organization.
Equuleus (pronounced "u-QUE-lee-us") looks nothing like a horse....perhaps the early Greek philosophers had a horse left over that they needed to pay tribute to and found this random group of stars "left" over from all the other nearby constellations and decided that would be it. On the other hand, Delphinus appears strikingly like a leaping dolphin in the night sky!, its arcing tail formed by the brighter stars Eta, epsilon and kappa, while the body and head of the dolphin are formed by alpha, beta, gamma, delta and zeta (see the second chart "Job's Coffin" below).
Notice the ONLY two star names in the constellation of Delphinus. Do they appear to be somewhat "different" than those of previous constellations? Are they Russian? Slovakian? Nope....they are BACKWARDS! Most of the bright stars discussed in these "GO TO" TOURS were named centuries ago by ancient Arabian skywatches who provided us with beautiful, colorful and meaningful star names. Although the exact reason that this happened for these two stars is not know (there is some pretty wild conjecture, though), the names are actually BOTH first and last names of NICHOLAS VENATOR, a night assistant at a major observatory (Palerma Observatory) in the first decade of the 19th century. Whether he did the trickery, affixing his own backwards-spelled names to these two previously unnamed stars when the he Palermo Star Catalog was published in 1814....or whether someone else did it for him is not even important anymore. These stars will now ALWAYS be known as "Sualocin" and "Rotanev."
The Dolphin was very important to the preservation of Greek culture, as the legend states that Delphinus (pronounced "del-FIN--us") rescued and whisked away the imperiled Greek poet Arion from his enemies who were chasing him down for mortal harm. I am reminded of a fabulous Greek restaurant named "Boy on a Dolphin" in Pensacola Beach, Florida that was so-named as a result of this wonderful legend. This story was widespread for whatever reason, and it appears throughout the lore of Sicily, Southern Italy and throughout Athenian lore.
Very interestingly, even the early Indian and Hindu cultures recognized this small constellation as a "Porpoise" (also a dolphin), but the Arabians, who missed a bet on naming those two stars and saving us a lot of grinning, knew the constellation as the "Camel who rides" (can be ridden).
In Hebrew writings the constellation and its stars, like so much of the night sky, has connections to the writings of the Old Testament, with this star group denoting the Whale that devoured unfortunate Jonah. After the death of Christ, early Christian groups envisioned the cross of Christ in the small "body" of stars that makes a diamond-shape.
More recently, and amusingly, this same diamond pattern (see the chart immediately above) today is often referred to as "Job's coffin," and it indeed, does look like the old pine box of the wild west and early European cultures.
The stars of Delphinus are ideal for making visual magnitude estimates of bright variable stars nearby in summer skies. Also, use these magnitudes I have provided above for the valuable determination of METEOR magnitudes during the many meteor showers of summer and early fall. Merely compare the brightness of the "shooting star" to that of the closest star given in the chart and writing down (I use simple hash marks) each meteor for each given brightness group. The total number at each magnitude is important to understanding the nature and density of many of the meteoric clouds and their tiny fragments that result in the fine meteor displays. As with all "GO TO" TOUR guide star charts, please click on these charts to open; you can save them to file, resize to paper size and print each for a nice usable desk reference or good field chart as you proceed through the Delphinus and Equuleus "GOT TO" TOUR.
Note from the sky chart included here that the CELESTIAL EQUATOR passes way SOUTH of both Delphinus and Equuleus, and thus all angular measures (declinations) are NORTH of the celestial equator and positive ("+"); hence you will see references in this "GO TO" GUIDE to "(+)" declinations for all celestial objects in both constellations.
As with every "GO TO" TOUR guide, each GO TO object in Libra and Lupus is discussed for your telescope regarding the type of conditions necessary for you to view it optimally for discern the very faintest details.........magnifications and aperture necessary for most objects, and much, much more. This is YOUR complete GUIDE to get you on your way to exploring the best (and few!) objects in these two constellations. The following listing of "BEST" objects contains the finest or most interesting from my own observing experience and preference.
Use the attached star chart and the following Guide as an excellent reference for your next star party itinerary, or a beginning for further study into the thousands of objects visible in this part of the sky. Truly these extensive Constellation Study Guides will most definitely put your AutoStar to work for you in the most efficient and enjoyable way possible! As a matter of fact, MANY AutoStar users are now programming their own "Tours" based on these guides, using each constellation as a separate GO TO Tour for the AutoStar library that can be added in or deleted through the main edit screen on your PC or MAC computer.
We hope you enjoy these comprehensive GUIDES to touring the constellations via your AutoStar and its computer-driven telescope. Each new installment is 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!
YOUR DELPHINUS AND EQUULEUS CONCISE DIRECTORY OF INTERESTING OBJECTS -
Although there are slim pickings to choose from in both of these constellations, I have chosen the finest (or most interesting) 12 objects in this DELPHINUS / EQUULEUS "GO TO" TOUR; as with all GUIDES, all objects listed below will be visible in most telescopes (some naked eye) 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 for FINDING the objects initially. And remember that not ALL objects listed are visible in some telescopes.
If you have difficulty identifying any object I strongly encourage you first FIND the target object, or its approximate location through your GO TO function with your lowest power and then - once IDENTIFIED positively - move up slowly in steps with magnification if necessary. Remember, not all objects "like" magnification. If, after you have reached a beautiful view of your object, more magnification results in 1) dimming of the object; 2) loss of contrast; 3) loss of color, then you have exceeded the optimum magnification for that object.
The rule for determining "optimum magnification" is that: 1) too low power results in sky background glow detracting or diminishing the contrast against the deep sky object; 2) too high magnification darkens BOTH the sky background AND the object; 3) medium magnification can be achieved at which you have MAXIMUM contrast between the object and its darkened background sky. I have found through three decades of direct observing that about 15x per inch aperture (36x for the ETX 60/70; 55x for the ETX 90; 75x for the ETX 125; and, 125x for the LX 90).for deep sky observing is PERFECT for most objects. That being said, always remember that DOUBLE or multiple stars require whatever power you can crank out....the seeing conditions are the limiting factor here.
For my complete and comprehensive discussion regarding seeing conditions and sky transparency, see: http://www.weasner.com/etx/buyer-newuser-tips/seeing.html .
With all deep sky objects, avoid attempting to observe when the moon is in the sky, even a very thin crescent, as its brightness in the sky will overshadow the very dim contrast afforded by even the brightest deep sky object; if you see the object at all against moonlight, you will NOT see the subtle outlying areas or the full detail of what is presented.
The high declinations of Delphinus and Equuleus offer good and long-period observing for ETX and LX 90 users in the northern hemisphere. All deep sky objects and difficult double stars are ALWAYS best observed when they are located nearly overhead (or as high in the sky as possible), thus requiring the observer to look through the thinnest portion of the Earth's "lens" of atmosphere and haze.
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.
Following is the concise object list for your "GO TO" TOUR of DELPHINUS and EQUULEUS; you may wish to find the majority of the objects from the AutoStar Library (for example, you can easily go to NGC 7006 if you pull up "Object/Deep Sky/NGC/..then type in '7006'...." and then press "Enter", followed by "GO TO" to access this FAINT but very enjoyable globular cluster On the other hand, if you want to experiment and become a "better AutoStar user" try entering the exact R.A. and DEC coordinates of that object 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: brighter star - ROTANEV (beta Delphini) - R.A. 20h 35' / DEC + 14 25 - Magnitude: 3.8 OBJECT 2: brighter star - SUALOCIN (alpha Delphini) - R.A. 20h 37' / DEC + 15 44 - Magnitude: 3.8 OBJECT 3: (Equuleus) brighter star - KITALPHAR (alpha Equulei) - R.A. 21h 13' / DEC + 05 02 - Magnitude: 4.1 OBJECT 4: (Delphinus) good double star! - gamma Delphini -R.A. 20h 44' / DEC + 15 57 - Magnitudes 4.5 & 5 - yellow stars OBJECT 5: (Delphinus) nice variable star - V Delphini - R.A. 20h 46' / DEC +19 09 - Mag. 8.2 to 13.6 - good for ETX 125 + OBJECT 6: (Delphinus) interesting nova - HR Delphini (nova Del 1967) - R.A. 20h 40' / DEC + 18 59 - Very unusual and active star OBJECT 7: (Equuleus) very nice double - 2 Equulei - R.A. 21h 00' / DEC +06 59 - Magnitudes: 7 & 7 - great star for ETX 90 + OBJECT 8: (Equuleus) good quad star! - 5 Equulei - R.A. 21h 08' / DEC + 09 57- Magnitudes: 4, 11, 12, 6 - interesting star OBJECT 9: (Equuleus) variable star - R Equulei - R.A. 21h 11' / DEC + 12 36 - Magnitude: 8.7 to 14.8, 261 days OBJECT 10: (Delphinus) globular cluster - ngc7006 - R.A. 20h 59' / DEC +16 00 - Magnitude: 10.7, most remote of all globulars! OBJECT 11: (Delphinus) globular cluster - ngc6934 - R.A. 20h 32' / DEC + 07 14 - Mag. 9, very small but easier than ngc7006 OBJECT 12: (Delphinus) planetary nebula - ngc6891 - R.A. 20h 13' / DEC + 12 35 - Mag. 10 with 11th mag. central star! ETX 90+
A VISUAL GUIDE TO OUR DEEP SKY OBJECTS IN DELPHINUS AND EQUULEUS
Object 1 - Our "Starting" Brighter Star - "ROTANEV" (beta Delphini)
Our starting point for every "GO TO" TOUR is always (or usually!) the brightest star of the constellation or region but in Delphinius, the TWO brightest stars share nearly the same magnitude. I have already relayed the story (true) on how these two stars were assigned their names, albeit perhaps illicitly by scientific standards. Rotanev (beta Del) is magnitude 3.7, while Svalocin (alpha Del) shines at magnitude This is by far the DIMMEST bright star we have used as our "starting target" for any constellation "GO TO" TOUR, surpassing the "dim bulb award" of Zuben El Genubi from the inconspicuous Libra constellation. Rotanev is actually a pair of 4.0 and 4.9 stars, orbiting VERY close to one-another; a keen-eye observer with the 8" scope or larger MAY be able to resolve these two, at only about 0.7" separation.
Object 2 - The other "Brighter Star" in Delphinus: "SVALOCIN" (alpha Delphini)
This star and Rotanev - as well as gamma and delta Delphini - "may" be part of an actual star "association," a configuration of stars all at the same distance that appear to be moving synchronously or gravitationally bound to one-another and hence a very "loose and sparse" cluster of sorts. All are moving at about 12 kilometers per second TOWARD earth, and are presently some 125 light years distant.
Object 3 - Yet another "Brighter Star" - "KITALPHAR" (alpha Equulei"
Of course ALL stars in the sky should be interesting and important to us....it's just that this one is really not. I have placed this star on your "GO TO" TOUR merely to allow you to familiarize yourself with the otherwise easy-to-miss constellation of Equuleus, and because frankly....there is just not very much in that constellation to look at. Even if you spell THIS star backwards ("RAHPLATIK") it still means absolutely nothing (other than perhaps a good name for a rock band). At least NOW you know where Equuleus is! AT magnitude 4.14, it is actually a spectroscopic double star, with both components very much like our sun on the evolutionary scale. This star is VERY similarly placed (45 parsecs) as are the four stars of "Job's Coffin" in Delphinus and may well be part of this loose association.
Object 4 - A Very Nice Double Star - Gamma Delphini - Nice Colors!
Finally, amidst all the seemingly uninteresting primary stars of these two constellations is something of better-than-average interest! Gamma Delphini is an excellent double star, making the northeast corner of "Job's Coffin." This is a true binary star (both stars orbit one-another), with the primary star (magnitude 4.3) being an easy 10.3" arc (about one-fourth the size of Jupiter's disk in the same eyepiece) nearly due NORTH of the 5.1 magnitude secondary star. This pair can be resolved with high magnification in the ETX 60 and 70 and with relatively low powers in the ETX 90 and larger scopes. Look at the colors of these two stars; most observers see the brighter star as a pure "yellow" color, while the fainter star seems to have a green glow to it, a rather "greenish-yellow" color.
Object 5 - A Good Long Period Variable Star - "V Delphini" - (beyond limiting magnitude when faintest!)
This is a GREAT star to PUSH the limiting magnitude extreme on the ETX 125 and the LX 90. The star, when at brightest every 534 days, can easily be spotted even in the ETX 60/70, followed about halfway through its very rapid plunge toward minimum with the ETX 90, and then fading from even the LX 90 as it approaches minimum. Even though it disappears during minimum in all of our ranges, it still bears watching since - even though it is "classified" as a long period variable (see my discussion on variable stars at: http://www.weasner.com/etx/ref_guides/variable_stars.html - the star goes through VERY erratic changes in its light curve. For example (see diagram below), the star's peak may be delayed from one cycle to another by as much as 20-50 days; many times the star will attain a maximum brightness near 8.0, and sometimes will BARELY top 11th magnitude! You really never know what to expect out of V Delphini!
To both find and follow this star requires excellent star charts and comparison stars with magnitudes that have been carefully confirmed; such can be obtained from the American Association of Variable Star Observers through the link: http://charts.aavso.org/DEL/HR_DEL/HRDEL-AA.GIF which will provide the "a", or low power wide field finder chart to first located the exact spot for this star; this chart is ALSO used to locate the NOVA "HR Delphini", described below! Once found, and when the star is near brightest, you will want to actually make your magnitude estimate comparisons by using the "b" chart at: http://charts.aavso.org/DEL/S_DEL/SDEL-B.GIF . However, with the ETX 125 and LX 90, the star can be followed via the "d" chart, http://charts.aavso.org/DEL/V_DEL/VDEL-D.GIF which gives very faint stars and their magnitudes to monitor when the star is approaching minimum brightness. Note that there are several OTHER variable stars posted on the "b" chart; this should encourage you to monitor those stars as well! Full details about variable star reporting can be obtained from the AAVSO as described at the beginning of this "GO TO" tour. For V Delphini - since its period is just under TWO YEARS for a complete cycle - estimating the brightness about every week or ten days is adequate.
Object 6 - A Nova That Won't Go Away! HR Delphini - "nova Delphini 1967"
With the AAVSO "a" star chart http://charts.aavso.org/DEL/HR_DEL/HRDEL-AA.GIF that you downloaded above, you can find HR Delphini, a nova that reached naked eye brightness in July 1967, rising from a star only magnitude 11.9 month before! It remained at this very bright maximum for nearly the remainder of 1967, with yet another outburst in November that put it at a bright magnitude 4.8, and another around Christmas that shot the star up to a brightness of 3.5! After two years, the star had only faded to magnitude 8.3 and even today it fluctuates around magnitude 11.2 to 11.7. Hence, it is still easily observable in the ETX 90 using the "b" chart http://charts.aavso.org/DEL/HR_DEL/HRDEL-B.GIF for that star. This is a remarkable star, a great example of a nova within our own galaxy and once which is STILL visible in amateur telescopes! If you do not monitor but ONE variable star during the summer months this one - and SS Cygni (see my Cygnus "GO TO" TOUR at http://www.weasner.com/etx/ref_guides/cygnus.html ) - should be the star. You will not be disappointed, with minor light changes you can easily record with every observing session!
Object 7 - A Double Star in a Little Horse - "2" Equulei
This is a very nice pair of stars, both 7th magnitude and maybe a bit hard to find because of their "dimmer-than-average brightness of most doubles on these "GO TO" TOURS of constellations. At equal brightness, look for this relatively easy (with the ETX 90 and larger scopes) double oriented in about a north-south position relative to one-another; both are type "F" stars, similar to our sun in many respects. The current separation is about 2.8" arc which might make it a challenge for the ETX 90 at 7th magnitude; however, the ETX 125 and LX 90 should have NO trouble resolving this very nice pair, provided that your GO TO was pretty accurate; remember the rule: start off with low power and center what you "think" is the target; then gradually increase your magnification until you can verify the star is double.....this may take about 150x with the ETX 90 and perhaps the same with the ETX 125 and LX 90, although the keen-eyed should see both stars at about 70x. This is not a good object for the ETX 60 and 70.
Object 8 - Another Good Multiple Star in Equuleus - "5" Equulei, a Quadruple Star
This is a not-so-easy Quad-star, or 4-star stet; the primary star "5 Equulei" is 4th magnitude and fairly easy to identify. Okay....now you have found the easy part. Look DUE WEST of this 4th magnitude star only 1.9 arc seconds (remember, the theoretical resolution limit of the ETX 90 SHOULD be about 1.3", so you CAN resolve this star!) and try to spot an 11th magnitude (that's right - 11th) tiny image of the first companion star. THAT one is star #2. It will be VERY difficult, except in the LX 90, because of the brightness of the main star. High power helps, about 150x is ideal. If you have a cross hair eyepiece, block the brilliance of the 4th magnitude star with a cross hair while looking for the faint star; that will greatly help. NOW: look for star #3 - at 12th magnitude! - almost DUE NORTH of the 4th magnitude star, but this time a whopping 48" arc, the same distance that Jupiter is large in the same eyepiece. This can only be seen under very dark night skies, and perhaps in the ETX 90.....it should be a relatively easy star to find in the ETX 125 and larger scopes. Three down....one to go. STAR #4 is the easiest to spot (other than the main star), as it is 6th magnitude and VERY far away - 6 minutes (not seconds) arc! in a SSE direction. Star #4 and the primary star will make a good pair even in the ETX 60 and 70 and should be seen in medium power in all scopes. Whew! That makes me star-whipped just thinking about it!
Object 9 - A Great Variable Star - R Equuleus
Like V Delphini, this long period variable has a tremendous magnitude range, stretching from its brightest at magnitude 8.7 to dimmest at 15.0. Thus, at dimmest, do not expect to see this star in any telescope less than 16" in diameter. Nonetheless, it can be tracked with the ETX 90 through about 20 percent of its 261-day cycle, about 45 percent of it in the ETX 125 and some 70 percent in the LX 90. For a finder chart, log onto charts.aavso.org/STANDARD/EQU/R_EQU/ and select first the "BR" which is the "b" chart that I often speak of, the "R" denoting a "reversed" chart to correspond with the image orientation of the ETX or LX telescopes with NORTH at top and EAST at right; most of R Equulei's cycle will require the "DR" chart, however, the "d" chart being a much fainter magnitude comparison star field.
Object 10 - Oh Boy! A Deep Sky Object! Distant Globular Cluster ngc7006
Yes, there ARE deep sky objects in Delphinius and Equuleus.....just not many of them and not very bright ones.
This is perhaps the most distant of all globular clusters - 185,000 light years away from Earth. It shares that distinction with another such cluster, ngc2419 in the constellation of Lynx. It is highly possible at that distance that these two clusters are "shared" in a common gravitational bond by both our Milky Way and the Large Magellenic Cloud, or at least that the clusters MAY NOT BE associated with either at all! They may truly be non-galactic objects, perhaps the only objects known to NOT be associated with a galactic system in some way. This globular will be mistaken for a star in the ETX 90 because of its tiny size of only 1' arc!
You can appreciate how tiny this object is when you realize that the famous globular Messier 13 is a full 24' arc across, almost the size of the full moon's disk! Thus, ngc7006 is only 1/24th the size of Messier 13, as compared in the photo composite that I created above showing both to actual scale. Indeed, you can see there is QUITE a difference! Hence, do NOT expect to see any stars with any telescope of any size in ngc7006, other than the world's giants. The photograph above of ngc7006 was taken with the large 48" Schmidt camera and just barely shows a few perimeter stars. This 11th magnitude globular will NOT be seen in the ETX 60 or 70 and likely will be missed in the ETX 90; the ETX 125 will show a very tiny fuzzy "star" in its position as will the LX 90 only a bit brighter. But....if you DO see it, you have the distinction of saying you have seen perhaps the most remote globular cluster of the galaxy in which we live!
Object 11 - Another Globular Cluster in Delphinus - ngc6834
Although no Messier 13 by any means, this globular should comes as a relief to you after attempting to zoom in on ngc7006. ngc6834 is a bit larger - 3' arc across - a and brighter at magnitude 9.0. Thus, it will be unmistakable (although still star-like) in the ETX 90; a glowing "fuzz ball" can be expected with the increased light gathering and image scale of the ETX 125 and LX 90. This globular is by no means a showstopper, but owes its increased visibility to being only one-fourth the distance as ngc7006.
Object 12 - A Planetary Nebula! - ngc6891
This is an object for the ETX 125 and LX 90 only, at magnitude 11.4 and spread out over a diameter that is the same size as Jupiter's disk (44" arc). By comparison, the famous Ring Nebula (Messier 57) boasts a magnitude of only 9.3 but a huge disk size of TWICE that of ngc6891. This will appear as a very faint glow of light and requires about 170x to 225x to view adequately; make sure you have located the object first in medium power (about 100x) and then gradually increase the magnification. This planetary nebula - a gaseous shell expelled from the explosion of an unstable star (magnitude 14.2 and still visible) - is nearly FOUR TIMES more distant than the Ring Nebula.
WANDERING ABOUT....YOUR NEW "USER OBJECT" IN THE DELPHINUS-EQUULEUS REGION
I doubt it is any surprise that our new "User Object" for the "GO TO" TOUR of Delphinus and Equuleus is NOT going to be a deep sky object! You have been exposed to all three deep sky objects of any interest to telescopes less than the Hubble, and there is not much left to tantalize you in these two "object-starved" constellations. But I DID intentionally leave out the BEST double star (actually a "quadruple star" for the LX 90 and maybe the ETX 125) for amateur telescopes in this area, EPSILON EQUULEUS at Right Ascension: 29h 57m, Declination + 04 degrees 06m. The primary star is Epsilon Equuleus, at magnitude 5.5, which should make this an easy target to begin on. STAR # 2 is the closest, and the one that will most definitely be NOT seen in the ETX 60, 70 and 90. It is a bright star of magnitude 6.0 almost DUE WEST of the primary star by about 0.9" arc; this is most definitely at the ETX 125 limit of resolution but I have seen this star on numerous occasions with powers in excess of 227X; my 4.7mm UWA on the ETX 125 shows clean separation between these two, although not much of it! It is not easy in the LX 90 either. STAR # 3 is a 7.0 magnitude star that is MUCH easier, and is likely to be seen in all telescopes at 11" arc away from Epsilon, nearly DUE EAST (and a tad north). This pair can be seen in the ETX 60 and 70. NOW.....STAR # 4 is a toughie and likely is NOT going to be seen except in the LX 90, even though at magnitude 12.5 is "should" be visible in the ETX 125 for observers with high altitude and very dark skies. Look for this elusive faint star 1.2' arc (minutes, not seconds.....so it is a good distance away, more than the disk of Jupiter at the same power) nearly DUE WEST (just like star # 2!, but just a bit further south). GOOD LUCK on this interesting foursome of stars, all part of this true multiple-orbit star system.
On AutoStar, go to: "Select/Object [enter]...." scroll down to "User Object" [ enter]. Now enter the coordinates given above for "Epsilon Equuleus", using the number keys on AutoStar. After entering the coordinates and pressing "Enter" yet again, scroll down one and you can list the magnitude of the object as "5.5"[Enter].
Now you have at least ONE quadruple star on your AutoStar listing in its library! You might not be able to actually SEE all four stars, but it sure creates a nice "talking point" during your next star party....just verbally describe where each and every star ".....should be" to your visitor. It is sure to please!
Next Constellation GO TO" TOUR Installment: constellations of VULPECULA AND SAGITTA, the watchful wolf and the errant arrow of Sagittarius. These, like you have just seen in Delphinus and Equuleus, appear to be fairly mundane constellations on the surface, but they will present a wonderful array of objects that you have likely been ignoring! You will be pleasantly surprised, indeed! Hey....if we can make it together through Delphinus and Equuleus, the only direction left for us to go is UP!
Good Observing and explorations of this wonderful world of deep space!
P. Clay Sherrod
Arkansas Sky Observatory
Conway / Petit Jean Mountain
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