This is the M31 galaxy in the Andromeda Constellation. The picture is “technically poor”, but in 1990, with a Canon AE1 camera piggy-back mounted on a Meade 2080 telescope, a 135 mm lens and a Scotch Chrome 800-3200 film, it took me a 15 minutes exposure and a ski suit to obtain a picture like this. Thus, the film got stuck into the camera the morning after and when i opened it sunlight burnt all the pictures exposed.
Yesterday evening, from a garden in the Beigua GeoPark, with my D810 and a 300mm f4 lens, it took me 3 seconds @10.000 ISO to shoot this one while i was playing with my father’s dog (astrophotographers will be indulgent).
M31 (Andromeda Galaxy)
f4 / 3,0 seconds exposure / ISO 10.000
Right ascension 00h 42m 44.3s Declination +41° 16′ 9″ Redshift z = -0.001001 Helio radial velocity −301 ± 1 km/s Distance 2.54 ± 0.11 Mly (778 ± 33 kpc) Type SA(s)b Mass ~1×1012 M☉size (ly) ~100kly diameter Number of stars 1 trillion (1012) Apparent dimensions (V) 190′ × 60′ Apparent magnitude (V) 3.44 Absolute magnitude (V) −21.5