... was standard using ordinary sky flats in J and H , and differential sky flats in K ... sky flats'' are those derived from some subset (usually close in time and space to ...
... Orion the Hunter is perhaps the best known constellation in the sky, well placed in the evening at this time of the year for ... Just below Orion's belt, the hilt of his sword holds a great jewel in the sky, the beautiful Orion Nebula . ...
... it in 1764 and included it as no. 27 in his famous list of extended sky objects [2 ... 2048 x 2048 pix, each covering 24 x 24 m and the sky fields shown measure 6.8 x 6.8 ...
... of extended objects, if A and B denote object and sky frames, the sky is subtracted by consid ering (A1 + A2)=2 \Gamma (B1 ... sky subtraction is almost never sufficient to properly eliminate the bright OH lines whose intensity varies on time scales ...
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Ссылки http://www.arcetri.astro.it/irlab/instr/longsp/publ/longsp.ps -- 1522.5 Кб -- 16.02.2000 Похожие документы
... Assuming a source (extended or seeing--broadened point--like) with an intrinsic flux level per pixel much lower than the sky flux, the typical observing procedure consists of a group of exposures on the source itself, interleaved by exposures on blank sky ...