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Ophiuchus


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Abbreviation:
Oph
English name:
Serpent Holder
Coordinates
see Stellar data

Particulars:


General:

One of the larger constellations located in the equatorial regions of the sky. To the north Ophiuchus is neighboured to Hercules. On the western border one finds one part of the constellation Serpens, Serpens Caput (head of the snake). Libra and Scorpius, which also covers the complete southern border. To the east it is flanked by Sagittarius (south) and the second part of Serpens (north), Serpens Cauda (tail of the snake). It streches from DECL= +14 degrees to DECL=-30 degrees and roughly from RA=16h to RA=18h 40m.
From Hercules through Ophiuchus to is south-east border and beyond the background of the stars increase significantly. Random gazing is just a joy.
Although this constellation is not part of the zodiac the sun passes through Ophiuchus in December each year. When the zodiac first was invented by the Babylonians 3000 years ago, the sun just passes through the twelve constellations to which we still refer as the zodiac. Due to the precession of the Earth the apparent way of the sun through the sky has changed through the milleniums.

Stars and objects

After the triple system of alpha Centauri Barnard's Star (named after Edward E. Barnard, the discoverer of this star), a red dwarf of 9.5 mag, is the next closest star to us lying in a distance of about 6 light years. Although it is quite faint it is within the reach of small telescopes and well worth being observed. Its proper motion is with one degree each 350 years the largest of all stars in the sky. This object is one of the candidates which may have a planetary system. At least there are indications that there could be a planet of the size of Jupiter. Please find more information on one of the following pages:

  • An article about Barnard's Stars
  • Photometry Of Proxima Centauri And Barnard's Star Using Hubble Space Telescope Fine Guidance Sensor 3: A Search For Periodic Variantions (July 1999)
  • Hartmut Frommert's page about Barnard's Star
  • The binary tau Oph is not easy to split. The two 5th and 6th mag main sequence stars (F2 and F5) require scopes with an aperture of at least 100 mm and high magnification for separation. The two stars revolve each other with a period of 224 years.
    Nearly the same technical support is required to split 70 Oph, a close but wonderful consisting of an yellow and an orange star of 4th and 6th magnitude. The binary has a revolution period of 87.7 years and lies just about 17 light years distant..
    Another quite difficult double is 68 Oph. The components are of 4.4 mag and 9.2 mag.This star is associated with some meteor showers.
    Even more difficult is 73 Oph. Scopes with an aperture of at least 250mm will be necessary to split it into its components which revolve each other each 423 years.
    The double 36 Oph can be viewed with small scopes. It consists of two orange stars of 5th magnitude.
    Rho Oph (north of Antares (alpha Sco)) is a nice multiple star system. Small telescopes reveal two B stars of 5.02 mag and 5.92 mag, repsectively. At each side of the stars a companion of 8th mag can be spotted. These four stars form a V-shaped group. Rho Oph itself is embedded in a nebulosity, IC 4604. The nebulosity is quite faint with dark lanes and an interesting stellar background. IC 4604 and can only be made visible on long-exposure photographs.
    On September 9th 1604 has been observed in Ophiuchus. By this time the brightness of V 843 (the star which went to supernova) was already higher than any other star in the sky. Eight days later Kepler saw this supernova and started a detailed study of the object. Its nowadays called Keplers Supernova.
    The planetary nebula NGC 6572 belongs to the most interesting planetaries. The nebula itself shows up as a bright oval disk, but in this region there are several nebulous clusters which make NGC 6572 well worth observing.
    The open star cluster IC 4665 is an easy object to observe. Quite in the field of beta Oph a binocular shows about 20 stars of 7th mag and fainter scattered over an area of about 1 degree.
    A larger object but still easy to view is NGC 6633. This cluster has more than 60 members.
    There are a good amount of globular clusters in this constellation:
    With a distance of about 5500 light-years M 9 (NGC 6333) belongs to the nearer globular clusters. Interstellar dust is dimming the light of this 7th mag cluster at the north-western edge.
    The globular clusters M 10 (NGC 6254) and M 12 (NGC 6218) are the most prominent of the visible globulars in Ophiuchus. Both can be spotted with the naked eye; Binoculars or small scopes are sufficient to resolve them as misty patches. M 12 is a bit larger, yet fainter than M 10 which form is more condensed.
    A globular with a lesser condenced center is M 14. The shape appears slightly elliptical.
    M 19 (NGC 6273) is the most oblate known globular cluster. Its about 27 thousand light years from earth yet only about 4600 light years distant to the Galactic Center.
    Even closer to the Galactic Center is M 62, which shows a highly irregular shape (in fact, it is the most irregular shaped globular cluster we know of). These last two globular clusters well deserve telescopic observation.
    M 107 shows something unusual for globular clusters: it contains some dark regions. Its smaller and fainter than M 10 or M12.
    NGC 6356 is in the area of M 9; yet it is a bit faint.
    The meteor shower Ophiuchids can be seen from May 19th to July 2nd. The maximum of the shower activity occurs on June 20th. The meteors are usually fainter than 3 mag.
    From April 8th to June 16th the northern May Ophiuchids are activ. The maximum is mit 2 to 3 meteors between May 18 and May19th.
    Another stream with a long duration is the southern May Ophiuchides extending from April 21st to June 4th. Between May 13th and May 18 the maximum of the shower activity occurs.
    The Theta Ophiuchids can be observed from May 21st till June 16. The Maximum of the shower activity is not very remarkable lying somewhere around the 10th of June.

    Mythological Background:

    There are several stories who Ophiuchus is thought to represent:
    He might be King Karnabon of Seythia. Ceres gave order to Triptolemus to teach humanity in how to grow grain. King Karnabon showed friendly hospitality when Triptolemus came to him, but after a short while he changed his attitude completely and tried to kill Triptolemus. To prevent his flight Karnabon killed the dragon which pulled the wagon of T. Yet Ceres sent immediately another dragon and let Karnabon kill himself. To keep the memory of his cruelity alive she placed him next to the dragon on the sky (Hyginus, Astron. lib.II.c.14)
    On the other hand there is a story that Ophiuchus is Hercules, slaing a giant snake near the river Sagaris in Lybia. He is also thought to be Triopas, who destroyed a temple of Ceres. He was punished with hunger and finally with even that snake (or dragon) clinching him permanently (Ap. Hyginus, Poeticon Astronomicum l.II.14).
    Some see him for Phorbas who had slain that very dragon on the island Rhodos (Polyzelos Rhodius ap. eumd.l.c.)
    Another story gives him as Aeskulapius, healing and revitalising Glaukus, son of Minos, after he was bitten by a snake (Hyginus l.c.Cf. Erastothenes Catasterismi 6).



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    C. Kronberg --- 99/09/08 --- smil@agleia.de