The faint planetary nebula Abell 72 (PK 059+18.1) in the constellation
Delphinus on July 24 / 25, 2014 and on July 29 / 30, 2016. Abell 72 is an expanding glowing shell of ionized gas ejected from an old red giant star. The beautiful object of
George O. Abell's Catalog of Planetary Nebula is 5'700 ± 1150 light years from earth and about 2 light years across. (Sources:
The binary fraction of planetary nebula stars, Mon. Not. R. Astron.Soc. 000,000-000 (0000), Oct. 2012; Wikipedia).
Forty-four 3 minute exposures at ISO 800 with no dark frame subtraction were stacked with Deep Sky Stacker (resulting in a 2 h 20 min exposure)
and further processed in Adobe Photoshop.
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Equipment: Canon EOS 450D Baader modified camera, TeleVue Paracorr Type II coma corrector,
16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform,
Lacerta MGEN autoguider, Lacerta off axis system (field of view comparison:
image of the moon with the same equipment).
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