Sky Object of the Month – May 2018

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Sky Object of the Month – May 2018

(Courtesy LVAS Observer’s Challenge*)
NGC4236 – Barre d Spiral Galaxy in Draco (Mag. 9.7; Size 22’ X 7’)

A galaxy with a magnitude of 9.7 should be an easy telescopic target, right? Wrong! Not if the light of said galaxy is spread across an area 21 by 7.5 minutes of arc in size. This is the situation with the barred spiral NGC 4236 in Draco. Testimony to its faintness comes from none other than William Herschel, who discovered it in 1793. He catalogued it as H.V.51 – his 51st Class V (Faint Nebulae) entry.

Nevertheless, NGC 4236 is notable enough to have made it into Patrick Moore’s Caldwell Catalog (it’s designated as Caldwell 3). Under a truly dark sky, it may be glimpsed with a 4-inch scope. If, however, your observing location is beset with even a mild amount of light pollution, NGC 4236 will challenge a 10-inch instrument.

To locate NGC 4236, look 1 ½ degrees west-southwest of the 4th magnitude star kappa (κ) Draconis. Because of the galaxy’s relatively large dimensions and low surface brightness, work with moderately low power. Be sure your eyes are well dark-adapted and use averted vision if nothing is visible with a direct view.

Glenn Chaple for the LVAS

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