THE USE OF THE PLANISPHERE.

IN this Planisphere the Center re­presents the North Pole of the World, about which are these four Concentrick Circles.

1. The Artick Circle being a lesser Circle distant from the Pole 23 deg. 30 min.

2. The Tropick 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, numbred 10, 20, 30, &c. to 360.

4. The Tropick of Capricorn, distant from the Equator Southward 23 de­grees 30 minutes.

The Ecliptick makes an Angle of 23 degrees 30 minutes, with the E­quator at the two opposite Points ♈ and ♎, and is divided into 12 Signs, marked ♈, ♉, ♊, &c.

Any Right Line supposed to be drawn from the Pole or Center of the Planisphere is a Meridian, but that which is called the Graduated Meri­dian is numbred from the Equator both ways, with 10, 20, 30, &c.

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 Ecliptick.

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 Center of the Planisphere, to the De­gree of the Ecliptick that the Sun is in; then keeping one Point in the Center, turn the other to the Gra­duated Meridian, and it will shew 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 Center to 0 deg. 0 min. of ♉ on the Ecliptick Circle, then turning them about as before directed, the move­able Point falls on 11 deg. 30 min. which (because it is numbred 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 Center over that Point in the Ecliptick 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 Center of the Planisphere over 0 deg. 0 min. of ♉ in the Ecliptick, 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 Lyon'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 vs.

The Right Ascension of the Lyons 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 Lyons Heart coming to the Meridian in the Morning.

Note, If you put a small Bead upon the String that is fixed at the Center of the Planisphere, the String and Bead 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 Center upon the Graduated Me­ridian.

A COELESTIALL PLANISPHERE By J. Seller.

The Use of this Coelestiall Planisphere Ilustrated for want of roome by the Examples only.

Prob: 1. The day of the Month being given to find y e Suns place.

Example Let the day be the 5 th. day of May, on which day the Suns place is required, lay a thrid or Ruler from the Center, to y e Circle of Months to y e 5 th. of May. And it will shew you in the Circle of Signes that the Sun is 25 d. 20 in Taurus, & on the fifth day of November, the Sun is in 24. deg: of Scorpio, And on the 5 th. of Ianuary y u. will find the Sun to be in the 26. of Capricorn. And on the Twentith day of February you will find the Suns place to be in the 13 th. deg: of Pisses.

Problem 2. To find the Hour of the Night by any Star upon the Meridian.

Example on y e 30. of Ianuary. I see y e Bulls eye upon the South part of y e Meridian. I requier to find y e hour of the Night. Lay y e thrid or edg of a Ruler from y e Center upon y e Buls eye. And note where it cutts y e Hour Circle, from which point sett one point of your Compasses, and extend y e other point to the Hour of 12. y e same Extent. y e same way will reach from y e 30 th. of Ianuary to 50. min. past Six of the Clock.

Problem 3. To know what time of the yeare y e Buls eye will be upon the Meridian at 12 of the clock at night. Lay a Ruler over the diameter of y e Planispher & through y e center of y e Buls eye, then y e oposite part of y e Ruler will cut y e 16 day of Novemb: the night on which the Buls eye wil be upon the Meridian.

Prob. 4. To find y e Declination of any Star.

Example Extend your Compasses from the Center of the Planisphere to the Buls eye, then turne the foot of your Com­passes to the graduated Meridian, and there it will shew you the Declination from the Equinoctiall to be 15. deg: 48. min.

Problem 5 th. To find the Right Ascention of any Star.

Example of the Buls eye. Lay a thrid or edge of a Ruler from the center of the Planisphere over the Bulls eye, and you will find that it cutts in the circle of Signes 64 d. 27′. counting it from Aries.

Example of the Lyons hart, Lay a thrid or Ruler over the Center of the Planisphere, & over the Lyons hart, you will find that the thrid or Ruler will cutt in the circle of Sines in 27 deg: 48. of Leo. which being counted from the first Point of Aries is 247. deg: 48. minutes which is the Right Assention of the Lyons hart.

Prob 6 To find y e Moons So­uthing any day of her Age And y e time of full Sea

Example I Requi­er y e time of y e Moons Southing when she is 6 dayes old. seek her Age amongst y e small figures y t are plast among the Hours, & y u will find y e figure 6 stand at 4. a clock 53′. the time of the Moons Southing. To which if you a [...] y e time of Flowing, it will give y e time of high water in any place, for Londō add 3. which makes 7. of the clock and 53′. past y e time of High water at London bridge.

Prob. 7 To find the Rising and Setting of the Sun every day in the yeare.

Example I Require to know y e Rising and setting of the Sun on y e 26 day of December. Therefore lay a thrid or the edg of a Ruler from the Center over the day of the Month, then in the outer Circle it will shew you that the Sun riseth at 8 of the clock 9 minuts past And Setteth at foure of the Clock 9 minuts wanting

The Use of the Plani­sphere, upon the Plain of the Eclip­tick.

THESE two Plani­spheres upon the Plain of the Ecliptick, are one for the Northern Hemisphere, the other for the Southern; but their Use is the same, their Centers are the Poles of the Ecliptick, and their Periphery is the Ecliptick Circle, and the Poles of the World are 23deg. 30m. from the Center or Pole of the Ecliptick. In the Northern Hemisphere you have the Pole-Artick, or North Pole, and about it is Described the Artick Circle, the Tropick of Cancer, and one half of the Equator. In the Southern Hemisphere, you have the South Pole, (and respecting it for a Center, you have) the Antar­tick Circle, the Tropick 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 Cen­ter, over the Star whose Lon­gitude is required, and the Sign and Degree cut by the Scale upon the Ecliptick, 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 Ecliptick in 17deg. 30m. of Gemini; the Place of the Star required.

2. To find the Latitude of any Star.

Extend your Compasses from the Center of the Plani­sphere, to the Star, then keep­ing one foot in the Center, turn the other to the Gradua­ted Line of Longitude; which (in both Hemispheres) is one of the Lines drawn from the Center to the Periphery and numbred towards the Center, with 10, 20, 30, &c. 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 Center 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 Starrs in both He­misphears to y e year 1678
A Table of 20 of the Principal starrs in the first Quadrant of Right Ascension
Names of the starrs 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 Tayle 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
Whales Iaw 2 41 25 2 49 n
Medusas head 3 41 51 39 40 n
Right side of Perseus 2 45 23 48 35 n
Brightest of the Pleiades 3 52 4½ 23 4½ n
Bulls eye Aldebaran 1 64 22½ 15 49 n
Capella 1 73 11½ 45 37½ n
Orions left foot Rigel 1 74 48 8 36½ s
Bulls north horn 2 76 28 28 21½ n
Orions left shoulder 2 76 58 6 1 n
First in Orions Belt 2 78 56 0 35 s
[...]urigas right shoulder 2 84 1½ 44 49 n
Orions right shoulder 1 84 27 7 18 n
A Table of 20 of the Principal starrs in the second Quadrant of Right Ascension.
Names of the starrs Aug R. A Dec:
    0 ′ ″ 0 ′ ″
Canobus 1 94 13 52 26 s
Bright foot of Castor 2 94 45 16 38 n
Great Dogg 1 97 46 16 15 s
Head of Castor 2 108 29 32 32½ n
Little Dogg 1 110 38 6 2½ n
Head of Pollux 2 111 24 28 45½ n
Bright * in y e Shipps Waste 2 119 52½ 46 19 s
Bright * under the Keel 2 123 52½ 58 23½ s
South in y e section of y e keel 2 137 0 57 52 s
Root of y e Royall Oak 2 137 5 68 19 s
Hydras Heart 1 137 58 7 16 s
Lyons Heart 1 147 48 13 31½ n
Lyons Neck 2 150 31 22 27½ n
Southern Pointer 2 160 23½ 58 6½ n
Northern Pointer 2 160 53 63 30½ n
Lyons Back 2 164 12 22 18 n
Lyons Tayle 1 173 8 16 23 n
Great Bears Thighs 2 174 3 55 31½ n
Formost 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 starrs in the fourth Quadrant of Right Ascension.
Names of the starrs 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
Sagittarys left shoulder 3 278 47½ 26 40 s
Swans Back 3 289 26 27 19 n
Ʋultures heart 2 293 45 8 4 n
Peacoks Eye 2 299 56 5 [...] 38 s
North horn of Capricorn 3 300 2 13 28 s
Swans tayle 2 307 36½ 44 9 n
Dolphins head 3 307 57 1 [...] 01 n
Aquarys le [...]t shoulder 3 318 11½ 6 55 s
Pegasus mouth 3 322 7 8 25 n
Following in Capricorns tayle 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 starrs in the third Quadrant of Right Ascension
Names of the starrs 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 Bears tayle 2 189 56½ 57 45 n
Ʋrgins Spike 1 197 5 9 26 s
Second in Great Bears tayle 2 197 40 56 39½ n
Last i [...] Great Bears tayle 2 203 40 50 59 n
Left knee of y e Centaure 2 204 23½ 58 21½ s
Arctur [...]s 1 210 16 20 56½ n
Right foot of y e Centaure 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 y e Serpents neck 2 232 2 7 31 n
Northern in y e ♏. forehead 2 236 41 18 52 s
Scorpions Heart 1 241 23 25 37 [...]
Sting of the ♏. tayle 2 257 52 36 47 s
Fift joynt in ♏. tayle 2 258 26 4 [...] 4 [...] [...]
Dragons eye 3 267 17 5 [...] 3 [...] [...]

printed & sold by John Seller

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. 2 h. 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—

Ia Clark sculp:
ZODIACUS STELLATUS CUJUS LIMITIBUS PLANETARUM OMNIUM VISIBILES VIAE COMPREHENDUNTUR

Autore Jo: Seller Serenisimi Reg: Hydrographo

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