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Submitted: Tue, 2015-12-01 10:54
NGC 7023
The Iris Nebula, also NGC 7023 and Caldwell 4, is a bright reflection nebula and Caldwell object in the constellation Cepheus. NGC 7023 is actually the cluster within the nebula, LBN 487, and the nebula is lit by a magnitude +7 star, SAO 19158. It shines at magnitude +6.8. It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star Beta Cephei (Alphirk). It lies 1,300 light-years away and is six light-years across.
L = 19 * 1200 sec. bin1, RGB = 9 * 1200 sec. bin2, HaOIII = 10 * 1200 sec. bin2, in each filters.
Total exposition - 22 hours