Green’s Dictionary of Slang

a look, a glance; thus take a lunar, to glance at.

1848		Bell’s Life in Sydney 3 June 2/4: A diminutive gentleman [...] whose ogles were evidently fashioned for the special purpose of taking a lunar round a corner.
1852		Bell’s Life in Sydney 17 Apr. 2/7: She took a lunar at me.
1858		Bell’s Life in Sydney 25 Dec. 3/2: Slewing round on his perch in front, and taking ‘lunars’ of that worthy whip, with his extended thumb and fingers applied to his proboscis.
1885		Bulletin (Sydney) 3 Oct. 10/4: ‘In Willum Shakespear’s time, it were the custom ov Patience to squat on a monument an’ take lunars at Grief, but in our days, the patients seems to prefer getting’ under the monuments, an’ keepin’ mum until the day o’ Judgment comes.’.
1900		Bulletin (Sydney) 6 Oct. 11/3: [I]t was found that the S.A. Act only applied to vessels loading within the limits of that province. The vessel that arrived could ‘take a lunar’ at the Act with impunity. A law with a hole in it big enough to let two ships through is a pretty well-ventilated law.
1912		Bulletin (Sydney) 5 Sept. 9/3: These are the days when the more rampant variety of Australian child-warrior ‘takes a lunar’ at his commander-in-chief with impunity.
1938		N. Marsh Artists in Crime 65: Let us take what used to be called a ‘lunar’ at the case.
1950		‘J. Guthrie’ Is this what I Wanted? 71: Charles took a lunar [OED].