THE USE OF THE PLANISPHERE. IN this Planisphere the Centre represents the North Pole of the World, about which are these four Concentric Circles. 1. The Arctic Circle being a lesser Circle distant from the Pole 23 deg. 30 min. 2. The Tropic of Cancer distant from the North Pole 66 degrees 30 minutes, and from the Equator 23 degrees 30 minutes. 3. The Equator, which is distant from the Pole 90 degrees, numbered 10, 20, 30, etc. to 360. 4. The Tropic of Capricorn, distant from the Equator Southward 23 degrees 30 minutes. The Ecliptic makes an Angle of 23 degrees 30 minutes, with the Equator at the two opposite Points ♈ and ♎, and is divided into 12 Signs, marked ♈, ♉, ♊, etc. Any Right Line supposed to be drawn from the Pole or Centre of the Planisphere is a Meridian, but that which is called the Graduated Meridian is numbered from the Equator both ways, with 10, 20, 30, etc. By the help of this Planisphere, the following useful Problems may be resolved. 1. The Day of the Month being given to find the Sun's Place in the Ecliptic. 2. To find the Hour of the Night by any known Star, being upon the Meridian. 3, To know what Month and Day any Star will South at Midnight. 4. To find the Declination of any known Star. 5. To find the Right Ascension of any known Star. 6. To find the Time of the Moon's Southing any Day of her Age. 7. To find the Time of the Sun's Rising and Setting, any Day in the Year, in the Latitude of London. For the Solution of those Seven Problems, you have Directions at the Corners of the Planisphere. Prob. 8. Having the Sun's Place to find his Declination. Extend your Compasses from the Centre of the Planisphere, to the Degree of the Ecliptic that the Sun is in; then keeping one Point in the Centre, turn the other to the Graduated Meridian, and it will show the Declination required. Example. I desire to know the Sun's Declination when he is in 0 deg. 0 min. of Taurus. Extend the Compasses from the Centre to 0 deg. 0 min. of ♉ on the Ecliptic Circle, then turning them about as before directed, the movable Point falls on 11 deg. 30 min. which (because it is numbered from the Equator towards the North Pole) is North Declination, which was required. Prob. 9 Having the Sun's Place given to find his Right Ascension. Lay a Scale from the Centre over that Point in the Ecliptic that the Sun is in, and observe where it cuts the Equator; the Degrees and Minutes so found, is the Right Ascension of the Sun at that time. Example. The Sun's Right Ascension when he is in 0 deg. 0 min. of ♉, is required. Lay your Scale from the Centre of the Planisphere over 0 deg. 0 min. of ♉ in the Ecliptic, and it will cut in the Equator 27 deg. 54 min. the Sun's Right Ascension sought. Having thus found the Right Ascension of the Sun, and also the Right Ascension of any Star, by Prob. 5. you may find what time of the Day or Night the said Star will be upon the Meridian (besides the Method proposed in Prob. 2.) Thus, Subtract the Right Ascension of the Sun from the Right Ascension of the Star (borrowing 360 deg. if Subtraction cannot be made) the Remainder reduce into Time (allowing for every 15 degrees one hour, and for every degree 4 minutes) it gives the hour and minute Afternoon that the Star will be upon the Meridian; and if it amount to more than 12 hours, subtract 12 hours from it, the Remainder is the hour and minute that the Star comes to the Meridian next Morning. Example. It is required to know what time the Lion's Heart will be upon the Meridian on the Day that the Sun's Place is found to be in 0 deg. 0 min. of us. The Right Ascension of the Lion's Heart, is found (by Prob. 5.) to be 147 degrees 48 minutes, from which subtract the Right Ascension of the Sun (which is found by Prob. 9 to be) 270 degrees; the remainder 237 deg. 48 min. reduced to Time gives 15 hours 51 minutes Afternoon, from which abating 12 hours, the Remainder 3 hours 51 minutes is the hour of the Lion's Heart coming to the Meridian in the Morning. Note, If you put a small Bead upon the String that is fixed at the Centre of the Planisphere, the String and Bede so fitted will supply the Use of Scale and Compasses, the String serving instead of a Scale, and the Bead slipping up and down upon the String at pleasure, gives any Extent from the Centre upon the Graduated Meridian. A CELESTIAL PLANISPHERE By J. Seller. The Use of this Celestial Planisphere illustrated for want of room by the Examples only. Prob: 1. The day of the Month being given to find the Suns place. Example Let the day be the 5th. day of May, on which day the Sun's place is required, lay a third or Ruler from the Centre, to the Circle of Months to the 5th. of May. And it will show you in the Circle of Signs that the Sun is 25d. 20 in Taurus, & on the fifth day of November, the Sun is in 24. deg: of Scorpio, And on the 5th. of january yu. will find the Sun to be in the 26. of Capricorn. And on the Twentith day of February you will find the Sun's place to be in the 13th. deg: of Pisses. Problem 2. To find the Hour of the Night by any Star upon the Meridian. Example on the 30. of january. I see the Bulls eye upon the South part of the Meridian. I require to find the hour of the Night. Lay the third or edge of a Ruler from the Centre upon the Bulls eye. And note where it cuts the Hour Circle, from which point set one point of your Compasses, and extend the other point to the Hour of 12. the same Extent. the same way will reach from the 30th. of january to 50. min. past Six of the Clock. Problem 3. To know what time of the year the Bulls eye will be upon the Meridian at 12 of the clock at night. Lay a Ruler over the diameter of the Planispher & through the centre of the Bulls eye, then the oposite part of the Ruler will cut the 16 day of Novemb: the night on which the Bull's eye will be upon the Meridian. Prob. 4. To find the Declination of any Star. Example Extend your Compasses from the Centre of the Planisphere to the Bull's eye, then turn the foot of your Compasses to the graduated Meridian, and there it will show you the Declination from the Equinoctial to be 15. deg: 48. min. Problem 5th. To find the Right Ascension of any Star. Example of the Bull's eye. Lay a third or edge of a Ruler from the centre of the Planisphere over the Bull's eye, and you will find that it cuts in the circle of Signs 64d. 27′. counting it from Aries. Example of the Lion's hart, Lay a third or Ruler over the Centre of the Planisphere, & over the Lion's hart, you will find that the third or Ruler will cut in the circle of Sins in 27 deg: 48. of Leo. which being counted from the first Point of Aries is 247. deg: 48. minutes which is the Right Ascension of the Lion's hart. Prob 6 To find the Moons Southing any day of her Age And the time of full Sea Example I Requier the time of the Moons Southing when she is 6 days old. seek her Age amongst the small figures that are placed among the Hours, & thou will find the figure 6 stand at 4. a clock 53′. the time of the Moons Southing. To which if you a● the time of Flowing, it will give the time of high water in any place, for London add 3. which makes 7. of the clock and 53′. past the time of High water at London bridge. Prob. 7 To find the Rising and Setting of the Sun every day in the year. Example I Require to know the Rising and setting of the Sun on the 26 day of December. Therefore lay a third or the edge of a Ruler from the Centre over the day of the Month, then in the outer Circle it will show you that the Sun riseth at 8 of the clock 9 minutes past And Setteth at four of the Clock 9 minutes wanting celestial planisphere The Use of the Planisphere, upon the Plain of the Ecliptic. THESE two Planispheres upon the Plain of the Ecliptic, are one for the Northern Hemisphere, the other for the Southern; but their Use is the same, their Centres are the Poles of the Ecliptic, and their Periphery is the Ecliptic Circle, and the Poles of the World are 23deg. 30m. from the Centre or Pole of the Ecliptic. In the Northern Hemisphere you have the Pole-Artick, or North Pole, and about it is Described the Arctic Circle, the Tropic of Cancer, and one half of the Equator. In the Southern Hemisphere, you have the South Pole, (and respecting it for a Centre, you have) the Antarctic Circle, the Tropic of Capricorn, and the other half of the Equator. The chief Use is, 1. To find the Longitude of any fixed Star. Lay a Scale from the Centre, over the Star whose Longitude is required, and the Sign and Degree cut by the Scale upon the Ecliptic, or outermost Circle, is the Place of the Star in Longitude. Example. I desire the Longitude of Capella, (which is a bright Star in the Constellation called Auriga.) I lay a Scale as before directed, and I find it cuts the Ecliptic in 17deg. 30m. of Gemini; the Place of the Star required. 2. To find the Latitude of any Star. Extend your Compasses from the Centre of the Planisphere, to the Star, then keeping one foot in the Centre, turn the other to the Graduated Line of Longitude; which (in both Hemispheres) is one of the Lines drawn from the Centre to the Periphery and numbered towards the Centre, with 10, 20, 30, etc. and you have the Latitude of the Star required. Example. I desire to know the Latitude of the Star Capella, or the Goat, before mentioned. Extend the Compasses from the Centre to the Star, then turn it to the Graduated Line of Longitude, it falls upon 22deg. 50min the Latitude of the Star required. Note, Always if the Star whose Latitude is sought, be found in the Northern Hemisphere, the Latitude is North; (as in the Example above) and and if it is in the Southern Hemisphere, the Latitude of the Star is South. The Right Ascensions and Declinations of the Principal Fixed Stars in both Hemisphears to the year 1678 A Table of 20 of the Principal stars in the first Quadrant of Right Ascension Names of the stars Aug R. A Declin: 0 ′ ″ 0 ′ ″ The Phoenix's head 2 2 28 44 4½ S Cassiopeia's breast 3 5 36 54 47 N Southern in the whales Tail 2 6 49 19 47 S Pole Star 2 8 3 87 35 N Andromedas' Girdle 2 12 53 33 56½ n Last in Eridanus Achernar 1 21 15 58 55 s Andromedas' foot 2 26 1 40 45½ n Bright * of Aries 2 27 17 21 55½ n Whale's jaw 2 41 25 2 49 n Medusa's head 3 41 51 39 40 n Right side of Perseus 2 45 23 48 35 n Brightest of the Pleyades 3 52 4½ 23 4½ n Bull's eye Aldebaran 1 64 22½ 15 49 n Capella 1 73 11½ 45 37½ n Orion's left foot Rigel 1 74 48 8 36½ s Bulls north horn 2 76 28 28 21½ n Orion's left shoulder 2 76 58 6 1 n First in Orion's Belt 2 78 56 0 35 s ●urigas right shoulder 2 84 1½ 44 49 n Orion's right shoulder 1 84 27 7 18 n A Table of 20 of the Principal stars in the second Quadrant of Right Ascension. Names of the stars Aug R. A Dec: 0 ′ ″ 0 ′ ″ Canobus 1 94 13 52 26 s Bright foot of Castor 2 94 45 16 38 n Great Dog 1 97 46 16 15 s Head of Castor 2 108 29 32 32½ n Little Dog 1 110 38 6 2½ n Head of Pollux 2 111 24 28 45½ n Bright * in the Ships Waste 2 119 52½ 46 19 s Bright * under the Keel 2 123 52½ 58 23½ s South in the section of the keel 2 137 0 57 52 s Root of the Royal Oak 2 137 5 68 19 s Hydra's Heart 1 137 58 7 16 s Lion's Heart 1 147 48 13 31½ n Lion's Neck 2 150 31 22 27½ n Southern Pointer 2 160 23½ 58 6½ n Northern Pointer 2 160 53 63 30½ n Lions Back 2 164 12 22 18 n Lion's Tail 1 173 8 16 23 n Great Bears Thighs 2 174 3 55 31½ n Foremost of the Crosiers 3 179 39½ 56 54 s Great Bears back 3 179 52 58 49½ n A Table of 20 of the Principal stars in the fourth Quadrant of Right Ascension. Names of the stars Aug R. A Declin: 0 ′ ″ 0 ′ ″ South end of 〈◊〉 Bow 2 270 39½ 34 26½ s Bright * of the Harp 1 276 29 38 30 n Sagittaries left shoulder 3 278 47½ 26 40 s Swans Back 3 289 26 27 19 n Vulture's heart 2 293 45 8 4 n Peacocks' Eye 2 299 56 5● 38 s North horn of Capricorn 3 300 2 13 28 s Swans tail 2 307 36½ 44 9 n Dolphin's head 3 307 57 1● 01 n Aquaries le●t shoulder 3 318 11½ 6 55 s Pegasus mouth 3 322 7 8 25 n Following in Capricorns tail 3 322 19 17 31 s Cranes head 3 323 33½ 38 47 s Cranes wing 2 3●6 51 48 27 s Cranes rump 2 335 40 48 32½ s Fo●●alhaut 1 339 54½ 32 18½ s Pegasus Legg 2 342 3 26 19 n First in Pegasus wing 2 342 11 13 29 1/2 n Head of Andromeda 2 357 58 27 29½ n Last in Pegasus wing 2 359 12 13 24 n A Table of 20 of the Principal stars in the third Quadrant of Right Ascension Names of the stars Aug R. A Dec: 0 ′ ″ 0 ′ ″ Foot of the Crosiers 2 182 20 61 14½ s Head of the Crosiers 2 183 27½ 55 14½ s Following of the Crosier 2 187 24 57 50 s First in the Great Bear's tail 2 189 56½ 57 45 n Vrgins' Spike 1 197 5 9 26 s Second in Great Bears tail 2 197 40 56 39½ n Last i● Great Bears tail 2 203 40 50 59 n Left knee of the Centaur 2 204 23½ 58 21½ s Arctur●s 1 210 16 20 56½ n Right foot of the Centaur 1 214 ●2 59 24½ s South Ballance 2 228 27 14 38 n Little Bears shoulder 2 2●2 42 75 37 n North Ballance 2 224 56 8 8½ s Bright * of the Crown 2 230 16 27 50 n Bright * in the Serpents neck 2 232 2 7 31 n Northern in the ♏. forehead 2 236 41 18 52 s Scorpions Heart 1 241 23 25 37 ● Sting of the ♏. tail 2 257 52 36 47 s Fift joint in ♏. tail 2 258 26 4● 4● ● Dragon's eye 3 267 17 5● 3● ● printed & sold by John Seller celestial planisphere Schema Solis ad ingressum Mercurij S tae Helenae, Anno 1677 Octob 28 9●. 26′. 40″ A. M. Schema Solis ad exitum Mercurij. S tae. Helenae. Anno. 1677. Octob 28. 2h. 41′. 00″. P.M. Schema exhiben● Triangulum Sphericum▪ in calcul● Ascensioris ●e●●e et Declinationis, e longitudine et latitudine dotis, resolutim. Schema exhibens Triangula Sphaerica, in calculo loci Stellae incognitae, e distantijs a duabus cognitis, resoluta— ja Clark sculp: ZODIACUS STELLATUS CUJUS LIMITIBUS PLANETARUM OMNIUM VISIBILES VIAE COMPREHENDUNTUR Autore Jo: Seller Serenisimi Reg: Hydrographo constellation chart