Its

A

STRQNOMY.

hie An«i ^refore called the Heliocentric Latitude ; andI s ice n | e ° T p is the apparent Latitude, or that whichn . r °m the Earth at T, and is therefore called the

'"Of.

***** L

The

utitude.

arth *• Ue true -Distance of the Planet from the Sun andmeasured by the Lines S P and P T ; but S pTr^ ^ are called the Curtate Distances. Also in theS fT the Angle S T/> is called the Angle ofTh°>A or D.stance of the Planet from the Sun.Su n 4 §le % P T is called the Parallaaic Angle, as being>s s 5 ' Qer which the Semidiameter of the Earth’s Orbitth, > and the Angle pST at the Sun is usually called°f Commutation,

" ' 6 now proceed to shew the Methods os de-

cs a Planet; which may

h.

r tii

ir.av

!>,

by the Conjunctions or Oppositions off he p]„^. t ^ e S - n. Thus, for Example, observe^ to th- C Q J u P iter in the Ecliptic at his Oppo-} a ‘tiof! tQ h ^ Un > and also when he comes to be in Op-ijf bem C ^ un a S a in ; and note well the Time that.fj ee>l th e Then fay. As the Arch described be -

appositions is to the whole Circumference, so

Li ni ^ n v A>ich that Arch was described, to the Peri

«0vj

the jvi;

““"you

ir y nearly ; for it will not be exactly so,

hi,

, to.

btion os a Planet is not quite uniform, asan Ellipsis, and not jn a Circle. In the famec fiut proieed for an inferior Planet,y 7 th e T a 01016 accurate Method is by observingban G htcceYs 016 that elapses between the Planet’s being,h,* f hn 0Wn lV f y 'n the fame Node, (which may beT; 1 ° as ri 0 f because in that Part of its Orbit the Pla-tbe'xr °f the and that will be the Periodical

Janet j for in one Revolution of a Planet,(‘f thev

^ d ^des

^ in ,«;il not move sensibly,-u fn rney move at all) W-ii no

li 7 therefore be esteemed as quielcent. pi nets

t ;J n order to estimate the Distances °f the fstanets.

;r P c eed for Venus and Mercury in thefollowi

SitionT 1 the Place of the Planet '

btt-,. ^ * r Om * -h -

tk 1 Sun be

S). 5 i't. ,n ? ,h '

of , 111 be thethe Angl,

Or

in its greatest Elon-duly observed) the DifferenceSun’s Place (as seen from theQuantity of the greatest Elongation,e ATS, with -respect to the Planet

Venus