Photographing Shooting Stars.

Hokitika Guardian, 7 April 1923, Page 4

Photographing Shooting Stars.

!!•,- Dr \V. S. d.cekver, Uireetur <il ti;i- Am i.mii I .deliver Observatory). h veryone, sii some iism- nr another. Inns at llijilil a briadil siiontmt; .-tar or meteor mow across the sk\ ala! ot .'iiiiially fade array amoin; the ••tar'. Nome o! these met -ors move very quickly. leaving lor a moment or tiro a briudit trail, while others seem to (hurdle and mure wry like a shy i rocket. 'Jo astronomers tl'.e'e ushers bohum i to various suarlii' or families, eacli i family consist ino oi a la r;;e inurdier of i small parties lavellinp; in 'pace, i some ot the individuals of v hicli meet > 'he earth’:, atmosphere, a- the earth i -(•!(. ssc.s their path oi' flio'lit, and are rendered luminous. A careful watcher will notice that : niai'y of the trails observed seem io ! radiate from one point in the heavens. 1 Kuch Inmilv has its own radiant point, and it is with the object ot' determinin'; exactly I lie positions of these radiant point' that astronomers observe them at all. To smile people tile sill in.; up at nielli to watch the heaven,, for meteors may seem rather tedious, and may even be an impossible task ovine- to other occupations. To these, and especially iho.-e who are keen photographers, the. employment of camera in this work i makes the task at once fascinatiim and I interest in;;. Ihe prorc" is quite simple. On some clear and moonles' niyht place j tlm camera aiiv camera will do. the I harper the hotter) on some rijsid sup- ! port, eiiher out of doors or on a eon-I venieiu window sill, pointinp the earn- I era diroe' ly towards the Pole Star and j lixitu.; it -r, urelv as a precaution ! against movement hv the wind. The Pole 'c,r ionsil vbe found, i as it i- situated due north and lies on the prohmya; ,f :■ H,„. ioiniim- the j two bri'.thi stars, known n> "the point- i ors." in idle eo n . tel la i ion of riie Croat { Hear or Plough. The objeel in 11 intinjr the enmera to :

the Pole Star is that, as the camera is fixed, most of the stars v.ill make their trails completely on the photographic plate and these trails will all he portions of small circles. By comparing such trails with a star atlas all the stars can easily lie identified. Having thus fixed your camera, and set the focus for some distant object, open the dark slide and take the cap v off. The camera can then he left for any number of hours; the longer the time the longer will be the trails, ami also the greater will he the chance of catching a meteor. ■Should a Inight meteor pass in front of the camera during this interval its i trail will lie automatically photograph- ' ed. I lie position 11 1 the meteor trail i in relation io the star 1 rails can lie seen at a glance and the direction of tlie radiant point at muo determined. The main precautions to be taken are: l-e’.eel a position where no lights -'lab a • street lamp . are in front of the camera: fix the camera rigidly to avoid vibration : protect Hie camera an I lons from dew by covering them v.iili a simple form of hood; use rapid plate., lor choice ; and do not expose them on nights when the moon i-- vc v bright. I)n any night ol i in* year there is a chance ol photographing an intere-ting meteor, hut, of eoiirs**, the most favourable nights are tho-e when special swarms are expected, the dates of which can lie ascertained from published table-.