Trans­lat­ing astronomy jar­gon for the av­er­age ev­ery­day stargazer

South Burnett Times - - NEWS | COLUMNIST -

IN EV­ERY line of work there is some form of jar­gon we use to com­mu­ni­cate.

In astronomy it’s no dif­fer­ent. So what are the mean­ings, for in­stance, of dark skies, light pol­lu­tion, good see­ing, twin­kling and NGC?

DARK SKIES: Means just that. A night sky not af­fected by the glow of street, res­i­den­tial and com­mer­cial light­ing (light pol­lu­tion) beam­ing up into the night sky as known over large towns, cities and suburbs.

Dark sky con­di­tions al­low one to see the Milky Way band and faint stars clearly. A re­ally dark sky is away from civil­i­sa­tion, where it’s so dark one can hardly see a hand or the ground.

That’s why pro­fes­sional as­tronomers choose moun­tain tops for large tele­scopes to carry out se­ri­ous re­search of the cos­mos.

The only or­gan­i­sa­tion that is try­ing to save what dark sky sites we have left is the In­ter­na­tional Dark Sky As­so­ci­a­tion, a vol­un­tary body of pro­fes­sional as­tronomers and light­ing spe­cial­ists based in Tuc­son, Ari­zona, who for the past 31 years have as­sessed and awarded more than 100 dark sky awards for parks, re­serves, sanc­tu­ar­ies and a com­mu­nity.

The IDA has three lev­els: gold, sil­ver and bronze.

Each of th­ese are based on a sky qual­ity me­ter read­ing of mea­sur­ing the square arc sec­ond of the stars un­der a dark sky canopy and the faintest star mag­ni­tude to be seen with the eye.

From my South Bur­nett Dark Sky Sur­vey car­ried out over the past two years, the Bunya Moun­tains, Boon­dooma Homestead, BP and Boon­dooma Dams and Mof­fat­dale fit a gold level, while Mur­gon, Nanango and Wondai sil­ver and Kin­garoy bronze, as the town has too much light pol­lu­tion to get a higher award.

GOOD SEE­ING: Is a term used by as­tronomers on a scale of one to 10 to judge the steadi­ness and clar­ity of an im­age as seen in a te­le­scope.

The higher the num­ber, the stead­ier the sky is, al­low­ing finer lu­nar and plan­e­tary de­tail to be seen at high mag­ni­fi­ca­tion in a te­le­scope and vice versa.

The best time is au­tumn/ win­ter when the skies are clearer, sta­ble and colder.

Av­er­age see­ing in au­tumn/ win­ter/spring is eight to nine and sum­mer a seven.

TWIN­KLING: Is starlight be­ing dis­torted as it passes through Earth’s at­mos­phere, bounc­ing off smoke, dust and wa­ter par­ti­cles.

On those nights it’s not good to do any astro pho­tog­ra­phy or high mag­ni­fi­ca­tion ob­ser­va­tions of bright stars, the moon or a bright planet.

NGC: Means New Gen­eral Cat­a­logue, which is the of­fi­cial list­ing of thou­sands of gal­ax­ies, neb­u­las, star clus­ters and quasars.

Drawn up by John Louis Dryer in 1880, the NGC has been in use since by as­tronomers and in astro-data­bases world­wide.

If you want to book a night at the ob­ser­va­tory, email [email protected]­pond.com, phone 0427 961 391 or visit the web­site, www.kingaroy­ob­ser­va­tory.com.

PHOTO: CON­TRIBUTED

TER­MI­NOL­OGY: Dark sky places, noc­tur­nal ecol­ogy and species need to be pro­tected from light pol­lu­tion.

DARK SKIES JAMES BAR­CLAY

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