"GO TO"....AURIGA, The Celestial Charioteer
....but, say, isn't that a baby GOAT on his shoulder?
by: Clay Sherrod
The magnificently large constellation of AURIGA is our 28th Constellation Guide, "GO TO AURIGA" of the series "GO TO GUIDES" for the modern GO TO computerized telescope. As we enter the realm of the celestial charioteer, note that we are moving deeper into the "Orion Arm" of our Milky Way galaxy; from our vantage point of space - our sun as but one star in a spiral arm of our galaxy - we are peering OUT of the galaxy to intergalactic space, looking across the most distant Orion Arm of stars.
Hence, you can expect the number of stars and galactic clusters within this more distant spiral arm to increase dramatically and there is no better place to witness this density than within the boundaries of Auriga.
You will note that this large constellation forms a five-sided "pentagram" of sorts (see my star chart below); however, this is actually not the case from a traditional standpoint, even though most star maps (including this one!) also include Beta Tauri - Al Nath - in the five-sided asterism. Al Nath (or simply Alnath) is located precisely on the south border of Auriga and the north border of Taurus and hence it is somewhat of a "shared" star between the two, but the actual Bayer assignment goes to Taurus on this one.
In addition to familiar Taurus, the Bull, to the south, Auriga is bordered at the north by Camelopardalis, Perseus to its west, Lynx to the east, and Gemini to the southeast.
The Aurigid meteor shower is generally observable between January 31 and February 23, a fairly scant meteor shower that is better known for its bright fireballs than a large number of hourly meteors. It does not have a clearly distinguishable radiant, but rather the meteors appear to emanate from the direction of the entire group of stars that form Auriga. From August 25th until September 6th, the Alpha Aurigid (so named for the proximity of the shower radiant to the bright "alpha" star Capella) shower is active. Although the hourly maximum is about 9 meteors, outbursts of up to 30 meteors per hour were observed in 1935 and 1986. Another meteor shower - the Delta Aurigids - has an annual showing in Auriga. These may be observed between September 22 and October 23 each year with the maximum of this shower on around October 6 to October 15.
Within the borders of Auriga are at least 10 brighter galactic stars clusters of interest to amateur astronomers, all of which are visible in the widest range of telescope sizes, and certainly most even in binoculars. Three of those are designated as Messier Objects, although several others could just as easily be so assigned.
Click for full-size image
Auriga (pronounced "awe-REE-ga") mythologically has several designations, and there is much uncertainty as to specifically which original story is accurate (well, actually is ANY myth really accurate?). In some interpretations, Auriga represents the god of the seas - POSEIDON (or perhaps "Neptune") - but he is STILL a "charioteer" in such variations nonetheless. Only in this case his Chariot of Conch is being drawn by very large (and I must say frightful-looking!) "sea horses."
The interesting aspect of the entire confusion "charioteer" story is that the constellation has always depicted Auriga without ANY chariot whatsoever, although the reins of such an unseen vehicle are clearly typically shown in his right hand. Another confusing aspect is this association he has with GOATS....yes, GOATS. Here is either a mighty and brave charioteer of Greek hero status OR a Greek god of the seas, and he has this fascination with GOATS! On his left shoulder is always depicted a small goat, while in his left arm he cradles two kid goats tightly as he "chariots-away."
So....yet another Greco-Roman myth has a slight angle on the entire chariot/goat combination, this portraying our Auriga NOT as a mighty wheeled warrior nor god, but the actual INVENTOR of the chariot - ERECTHONIUS, the lame son of the mythological notables Vulcan and Minerva. A lover of gentle animals and handicapped, it is told that Erecthonius actually invented the idea of the wheeled chariot as merely a way to get around, as he could not walk. So...in this case, it is not an instrument of war or fighting...it is in essence a wheelchair for a kind and gentle young man as he traveled near and far to care for the gentle animals throughout the lands of milk and honey.....
To the naked eye, the constellation of Auriga forms a conspicuous geometrical outline, with the bright yellow star Capella marking the advent of fall. At latitude 35 degrees north, Auriga is one of the few constellations that actual pass directly overhead - through the zenith. Capella culminates (reaches nearly directly overhead at midnight) each year during the first week in December. Although not circumpolar like Cassiopeia, Auriga is nearly so, with Capella rising very far in the north-northeast at 8 p.m. local time on October 1 and reaching high overhead not only until a full eight hours later - 4 a.m. the following morning.
In the diagram below, note the familiar asterism "the Kids" of Auriga, suggesting three baby goats that the charioteer is carrying cradled in his left arm. The first of these naked eye stars is ZETA Auriga, or "Sadatoni", a variable star of about magnitude 3.8 but suspected of being slightly variable in brightness; next in the baby goat nursery and just slightly east is ETA Auriga (sometimes called "Hoedus II, with Zeta paired as "Hoedus I"), magnitude 3.3. The most "famous" of the "Kid Stars" is EPSILON, the northernmost of the three. It is a VERY unusual eclipsing binary star (hence slightly variable from magnitude 3.0 to 3.8, with the dimmest point lasting well over one year! The largest component of Epsilon Auriga is perhaps nearly 200 times larger than our own sun....the other star, also an even-larger supergiant star is likely 3,000 times LARGER than the sun!! That is an incredible three billion miles across! Yet it is also perhaps the COOLEST (in terms of temperature, not because of a fashion statement) of all stars known.
For the full listing of all brighter stars (to naked eye limit) which includes: 1) Bayer; 2) Flamsteed; 3) SAO #; 4) R.A. & DEC; 5) brightness; 6) most notable double and multiple stars; 7) variable star designations; I encourage you to visit the wonderful Constellation reference site http://www.deepskywatch.com/deepsky-guide.html as well as all other constellation Star Tables. This is a great reference to print and put into a binder for cross referencing star designations, locating double and variable stars, and current coordinates in the sky.
As with every "GO TO" TOUR guide, each GO TO object in Auriga 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 or GO TO star program 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 other 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 AURIGA CONCISE DIRECTORY OF INTERESTING OBJECTS -
In addition to our regular listing of a few selected objects, I have included the complete abstract listing for the ten (10) nice galactic star clusters that are viewable in this constellation via modest instruments; that listing will be found at the end of this concise description of our TOUR.
For our visit into the borders of the celestial charioteer I have chosen the finest (or most interesting) 11 objects in this AURIGA "GO TO" TOUR (as with all GUIDES, all objects listed below will be visible in most telescopes (some naked eye) from the smallest to largest telescopes; 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. Indeed, 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. Sometimes better "field of view" (such as the wonderful wide fields provided by smaller telescopes) is desired over light gathering (like an 8-inch) and magnification.
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. 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 a complete discussion on magnification and how it applies to YOUR telescope, visit my under the GUIDES section of this website.
For my complete and comprehensive discussion regarding seeing conditions and sky transparency, see also this topic under the ASO GUIDES..
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.
Also, as I always suggest with all of the "GO TO" TOUR constellation lists, 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. For multiple stars and many listings of the finest deep sky objects, the classic work, Burnham's Celestial Handbook, Vol. One is highly recommended.
FOR AUTOSTAR: 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 AURIGA; you may wish to find the majority of the objects from the AutoStar Library (for example, you can easily go to the beautiful and rich star cluster Messier 37 if you pull up "Object/Deep Sky/Messier/..then type in '37'...." and then press "Enter", followed by "GO TO" to access this very delicately star-laced gem. On the other hand, if you want to experiment and become a "better AutoStar user" try entering the exact R.A. and DEC coordinates (given in the listing below) of that same object as described by 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!
You will access your FIRST GOTO target - (usually the brightest star in each constellation) - via the command "SETUP / OBJECT / STAR / NAMED....and scroll to "Capella"", then press "Enter" and subsequently "GO TO" to move your this bright star. Remember also that many distinctive objects are sometimes listed among the "named" objects. So, likewise for that object you might merely go to SETUP/OBJECT/DEEP SKY/NAMED....and then scroll alphabetically to the "common" name of the object if you are not already there; press "enter" and then GO TO and your scope is off and running! For Auriga, there are NO objects other than the brighter stars that are listed as common "named" objects in the Autostar library by name.
You may also access the constellation by: SETUP/OBJECT/CONSTELLATION/"Auriga".....Enter....GO TO, which will take you close to the central position of the constellation's boundaries.
bright star - CAPELLA (alpha Aurigae) - R.A. 05h 13'' / DEC +45 57 - Magnitude: 0.1 - deep yellow
triple star! - Theta Aurigae - R.A. 05h 56' / DEC + 37 13 - Mags: 2.7, 7.5 & 11, nice target!
double star - 5 Aurigae - R.A. 04h 57' / DEC + 39 19 - Mags: 6.0 & 9.7 @ 3.2" apart - nice stars!
great easy double - 41 Aur - R.A. 06 08' / DEC + 48 43 - Mags: 6.8 & 6.1 - good in smaller apertures!
tough test double - 54 Aur - R.A. 06h 36' / DEC + 28 19 - Mags: 6.1 & 7.7 - test for 5", 8" - tough
3" test double - Burnham 1053 - R.A. 05h 50' / DEC + 37 20 - Mags: 7.5 & 9.3 - at limit for 3" !
variable star - RW Aur - R.A. 05h 05' / DEC + 30 20 - irregular, Mag 9-12, very erratic!
variable star - SS Aur - R.A. 06h 10' / DEC 47 46 - Dwarf nova - Mag 10 to 15, very peculiar star
galactic cluster - Messier 36 (ngc1960) - R.A. 05h 32' / DEC + 34 07 - Mag: 6.3, 60 stars
galactic cluster - Messier 37 (ngc2099) - R.A. 05h 49' / DEC + 32 33 - Mag: 6.2, 150 stars
galactic cluster - Messier 38 (ngc1912) - R.A. 05h 25' / DEC + 35 48 - Mag. 7.4, 100 stars (fine!)
** Plus: GALACTIC CLUSTERS IN AURIGA:**
Following is an abbreviated listing of the ten (10) brightest and most interesting open, or galactic, clusters in the constellation of Auriga; this area of the sky if VERY rich in wonderful star fields for scanning with the very low power and wide field instruments as well as a standard pair of 7 x 50 or 10 x 50 binoculars, since it is located just on the edge of the dark and rich winter Milky Way skies. The listing following gives the NGC #, the R.A. and DEC of the object, the Magnitude, Size, # of stars and a brief and very concise description and/or notes as necessary:
ngc RA DEC (+) MAG SIZE ('arc) #stars
1664 04 47 43 37 7.5 15 40 not much "cluster" effect; good in very wide field views
1857 05 17 39 18 8.6 9 45 very nice and compact; use med. mag.
1893 05 22 33 21 8.0 12 20 only a few stars, pretty scattered, low power
1907 05 25 35 17 9.9 5 40 very faint and small, compact....med.-high power
1912 05 25 35 48 7.4 20 100 M38, very large and scattered, best in wide field
1960 05 32 34 07 6.3 12 60 M36, brighter stars over wide area; low powers
2099 05 49 32 33 6.2 20 150 M37, the best of the bunch, many tiny stars!
2126 05 58 49 55 9.8 7 30 very small and compact; medium power
2192 06 11 39 50 10.9 6 30 similar to above, small, faint stars, nice object
2281 06 46 41 07 6.7 17 30 very large with few stars; brighter members
A VISUAL GUIDE TO OUR DEEP SKY OBJECTS IN AURIGA
Object 1 - Our "Starting" Bright Star - "CAPELLA" (alpha Aurigae)
Known as "The Goat Star" (because our charioteer is carrying a bunch of goats, remember?), this star also has signified the head of Auriga on many occasions, particularly if you subscribe to the sea-god chariot being drawn by the curiously-large sea-horse myth. This beautiful golden star is among my favorites, perhaps because - like Arcturus is a the signal of impending springtime - Capella is the harbinger of the crisp, cool skies of Autumn in the northern hemisphere. As mentioned earlier, Capella reaches its highest point in the sky (culmination) at midnight in the second week in December. At magnitude minus 0.06, it is the 6th brightest star of the sky, only 45 light years away from our own sun. Capella is actually a VERY complex multiple star system. The primary star "A" is a binary that cannot be seen with telescopes, only spectroscopically; this pair has another component "H" which is a red dwarf 10th magnitude star 12' due SE from Capella; if you look VERY closely at this faint star (use the 5" and larger telescope), this star will also split into two stars, in a SE to NW direction (Position Angle 137 degrees), nearly 3" arc apart. Have fun with this one!
Object 2 - Triple Star - Theta Aurigae
The primary "A" star of this triple system is a bright 2.7 magnitude, so it is easy to locate in the finderscope if you are not using the GO TO function of your computerized telescope. The system is more than twice the distance as bright Capella and is known as a "Silicon star", with a great deal of its chemical "fuel" now fused into a silicon state.
Look for the "B" companion, magnitude 7.4, in Position Angle 318 degrees, or about NW from the primary "A" star. It is just over 3" arc away, so it will required medium to medium-high power to see this star in contrast to the very bright primary. The third star "C" is in Position Angle 300 degrees (almost in line with A and B) but is a much farther 52" arc (about the size of Jupiter in the same eyepiece), and is considerably fainter at magnitude 11. Thus, although the 3" scope can theoretically show all three of these stars, the 5" and larger are recommended for best success.
Object 3 - 5 Aurigae - A very nice and easy double star for all telescopes!
Currently this double star is separated by nearly 3.4" arc, with the stars in a nearly East-West orientation....no excuses on this one folks. It is a good and fun star. The primary is magnitude 6.1 and very bright white, while the fainter secondary star is magnitude 9.5 and more yellow-orange.
Object 4 - Another Good Double - 41 Aurigae - Here is one for everyone!
This is my "so-you're-frustrated-and-need-an-easy-object" double star. This one will take the stress off after trying to glimpse the multi-faceted nature of Capella. 41 Aurigae is relatively bright and easy double for all telescope, provided that you are assured you are looking at the right star (there are several stars of similar magnitude nearby, but none with a companion!). This yellowish star of magnitude 5 has a 7.7 magnitude companion nearly 8" arc away (easily resolvable) near DUE NORTH....again, no excuses on this one! Just observe it for a long time, take a deep breath, and then go on to more challenging objects! You've earned the break.
Object 5 - Test Double for 5" / 8" Telescopes - 54 Aurigae
Here is an excellent test object for the 5" telescopes under very steady conditions. We have not discussed the "resolution limit" of telescopes much here, the general standard is termed "Dawes' Limit" or "Dawes' Criteria" based to entirely empirical data compiled from many telescopes observing a wealth of stars exhibiting various degrees of separation. Suffice it to say, the if your divide your telescope's aperture (in inches) into the value "4.54", this is as CLOSE a double star in arc seconds (") as you can resolve with your scope. Thus, for telescopes of various apertures:
2.5" inches = 1.81" arc
3.0" = 1.51
3.5" = 1.30
4.0" = 1.13
5.0" = 0.91
6.0" = 0.76
8.0" = 0.57
10.0" = 0.45
12.0" = 0.38
In my over-30 years experience in direct astronomical observation, I will attest to Dawes' accuracy in regard to these actual "reachable" numbers. They are very realistic and precise for all apertures. There are some variation with very good and very bad optics as well as with seeing conditions and/or the type of telescope used; Maksutovs general will resolve closer stars inch-for-inch than a Schmidt Cassegrain, while a "pure-aperture" refractor will surpass resolution in most cases of both of those instruments.
The star 54 Aurigae is at present 0.91" arc, just at the Dawe's limit for the 5" scope; however, my latest observations on a night of "fair-to-moderately poor" steadiness failed to reveal the duplicity of this star with powers ranging from 127x through 404x. It does split readily in the 6" Unitron refractor, and very easily with the 10" LX 200. It is a test object, however, for the 8" on the same night....
However, I do believe that a good quality 5", well collimated Maksutov will split this star; the primary star "A" is at magnitude 6.0, so it is easy to isolate; increase the magnification to at least 200x and even more on a very steady night. The companion 8th magnitude star, "B", will be found NE of the brighter star and VERY close, nearly "touching" the image (the "Airy disk") of the brighter star. In a well collimated telescope keep in mind that many times a fainter star will appear embedded in the faint rings known as "Airy diffraction rings," so if you do not first see this faint and close companion, be sure to examine the closer ring(s) closely...it might be hiding in there!
Object 6 - Now....here is one for the 3" scopes! Double Star Burnham 1053
Once again, you will access this star either by using the R.A. and DEC manually entered via the hand controller, or by the "old fashioned" setting circles on your scope (they actually work very well....and it's fun!). Burnham 1053 is a very close star for the 3" to 5" size range, separated by 1.4" arc, right at the Dawe's limit for the 3" scope. The primary "A" star is magnitude 7.5, so it is not the brightest of our Auriga objects by a long shot. Center that yellowish star and increase the magnification to about 200x and look for a faint 9.6 magnitude star near DUE NORTH (a bit to the west) and very close. You will require a very steady night and very high magnification (take it on up if the air will hold it!) in the smaller of the two scopes.
Object 7 - A Very Unusual Variable for Amateur Telescopes - RW Auriga
Here is an excellent and fairly bright variable star that is one of the most unusual known. RW Auriga varies between magnitude 9.0 and 11.6 with no particular period; it is one of many stars known as "T Tauri" variables which are thought to have NOT reached equilibrium yet and are still settling down from their original formations!
Looking at the light curve, you can clearly see that there are distinctive "peaks" at which RW Aur surges upward in brightness, making it an easy object for the 5" and larger telescopes; as a matter of fact this star can be studies throughout its erratic light variations with such telescopes. Although the star can vary dramatically in less than one day, note that there is some indication of a "periodicity" or frequency of about 10 days at which the star may or may not surge to maximum. Observations should be made at EVERY opportunity as this is one of those stars that can change brightness literally within hours!
As with all variable star observing, the ideal source for information, comparison star charts, and to report YOUR valuable observations (badly needed on these irregular stars, by the way!), is the American Association of Variable Star Observers (AAVSO - www.aavso.org) in Cambridge, Mass. The charts for nearly every variable star - as well as "new stars" that appear from time to time - can be downloaded off the internet into a file in your computer; save the file and bring it up.....the image will be huge. Resize this image to fit your page, resave, and then print for a good chart to use at the telescope!
To make estimates on this peculiar star, use the AAVSO "t" chart found at:
https://www.aavso.org/apps/vsp/ . Note for these charts, simply type in the NAME of the variable at top to generate your choice of chart.
This is the narrow-field chart which shows faint comparison stars, and a "locator" chart from the AAVSO is not available for this star. Also, note that this is the AAVSO "standard" chart and not the "reversed chart"; the reversed editions of the charts are newer and are matched to the reversed field of view of the Maksutov and Schmidt Cassegrain telescopes, which result from the diagonal prism or mirror.
Object 8 - A Dwarf Nova Variable - SS Auriga - Faint, but an excellent star for the 5" and larger scopes!
The star SS Auriga is an incredible object for amateurs with moderate to large aperture telescopes. It varies in light from brightest at about magnitude 10.5 to the very dim 15th magnitude minimum. To locate the star as well as making estimates when it is at its brightest, use the following AAVSO "a"chart:
https://www.aavso.org/apps/vsp/ . Note for these charts, simply type in the NAME of the variable at top to generate your choice of chart.
however, when faintest, the "g" chart which will give stars to compare down to 14th magnitude.
For observers with 5" scopes and large, this is an exciting star to monitor on a regular basis....SS Aurigae's brightness will fluctuate unexpectedly from brightest to dimmest, hence it is very important that observers constantly monitor this star. Your observations are quite valued by the AAVSO to "fill in the gaps" as to the true nature of this curious star and others like it. Note that from the light curve above, the star will usually have a spiked outburst about every 55 days. This is very similar to the star SS Cygni, also a dwarf novae and which was discussed in the ASO CYGNUS Constellation Guide .
Object 9 - The Beautiful Galactic Cluster Messier 36
The next three objects of your AURIGA "GO TO" TOUR are all beautiful galactic star clusters found in the southwest "corner" of this constellation. The photograph below, taken through the wide field astrograph at Lowell Observatory, demonstrates the proximity of these beautiful clusters to one-another. It ALSO points out clearly that aperture is NOT needed for your best views of these clusters (although my favorite memory of Messier 37 with its very faint stars was, indeed, through a 12" Meade LX 200). As a matter of fact, this photography was taken through Lowell's sky patrol camera which is fitted with a 5" lens! Note the richness of the star field in this immediate area, as the Orion arm of the Milky Way stretches through southwest Auriga, filling it with tiny images of delicate stars. South is at the TOP of this photograph.
Messier 36 is probably the most compact-looking of all the three, and is, indeed, the smallest in terms of observed area, at only 12' arc across....half the size of the other two. It contains about 60 stars which range from magnitude 8.7 to less than 13th; the brightest of these can be seen in scopes smaller than 3"; this is an ideal object for a 3 inch scope. Use very low power and a wide field of view to appreciate the beautiful star fields surrounding all three of these wonderful clusters!
Object 10 - Number Two of the Trio - Galactic Cluster Messier 37
Other than the "Wild Duck" cluster (Messier 11), this is my favorite of all galactic star clusters. In a pair of good binoculars on a dark and moonless night, this cluster appears as a large glow of light, unresolvable in any optics less than about 2" diameter. However, even the smallest of telescopes at very low power can begin to see many of the nearly 200 stars embedded in this truly spectacular cluster, the northernmost of the three in Auriga. In 3" and larger telescopes with very wide fields, one is immediately impressed with what appears to be hundreds of tiny diamonds scatter against a blanket of black. Just look at the photograph above and note the dense concentration of very faint Milky Way stars that pass ever so close to M-37! The stars are nearly uniformly between magnitude 10 and 12, but some brighter members do exist. I think that it is this uniform brightness of well over 150 stars that gives it such a dramatic view. Look carefully near the very center of this cluster....right there is the 9th magnitude RUBY STAR of Auriga, a red giant that stands out among all the other yellowish members of this cluster!
Objects 11 - The Final Triplet of Galactic Clusters: Messier 38
Messier 38, in my opinion is "better than M36.....but not as spectacular as M37." As the northernmost of the three big galactic Auriga clusters, M38 is positioned slightly out of the thickest and most star-dense part of the Milky Way stretching through this constellation. However, if you use VERY wide fields and low magnifications and scan just to the east and north of this star a couple of degrees, you will not be disappointed at all, as the "clumps" of stars - some of them star clusters themselves - seemingly never end. M-38 is the same size as Messier 37 (20' arc, almost as large as the moon appears) and contains about 100 stars....again, more than M-36 but not as many as M-37! In low power, look for the distinct shape of a CROSS in this cluster of stars, with each arm having a double star at the end! A fantastic object for public attention at your next star party! There is one very yellow (giant) star of magnitude 7.9 in the cluster which definitely stands out. If you are using the 5" and larger telescopes, look just to the southeast of M-38 for the tiny cluster ngc1907, a beautiful "jewel box" contain some 40 very faint stars!
WANDERING ABOUT....YOUR NEW "USER OBJECT" IN AURIGA
In the constellation guide "GO TO" ARIES (in he Constellation Guides on ASO website here), we discussed three stars that were known as the "Runaway Stars" from their point of "birth" in the Orion Nebula. These three stars - 53 Arietis, MU Columbae and now AE Aurigae - were somehow and for some strange reason "ejected" after forming in the central region of the famous nebula some 2.7 million years ago and all three are flying away from one-another in totally different directions! (see the diagram below)
Of the three Mu Col is the brightest (5.2), followed by AE Aurigae at 6th magnitude (although it is an irregular and erratic variable, from 5.4 to 6.2).
AE Aurigae is located at coordinates: R.A. 05 13 and DEC + 34 15, and can be found through the following diagram...NOTE: if you use stars # 14, 16, 17 & 19 as a "line", AE will make a northwestward right angle from #19 Aurigae!)
On AutoStar, go to: "Select/Object [enter]...." scroll down to "User Object" [ enter]. Now enter the coordinates given above for "AE Aur", 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 "6"[Enter].
With the addition of this star, you now have a runaway star in the collection of celestial curiosities for your next star party or family outing with the telescope!
Next Constellation GO TO" TOUR Installment: PERSEUS, the fabulous Greek hero who rescued poor Andromeda from her father's tethers to the sea monster Cetus, and who seems to have more than a casual liking to both her and her mother, Cassiopeia. More on this philandering Fabio in our next "GO TO" TOUR constellation guide.
Good Observing and may the stars serve as your sentries as you explore the frontiers of space!
Arkansas Sky Observatory
Conway / Petit Jean Mountain