SH2-174 is a planetary nebula visible in the constellation of Cepheus.

It is one of the northern most planetary nebulae of the celestial vault; γ Cephei is located about 3 ° north of Alrai and is visible in long exposure photos taken with a powerful amateur telescope. Its strongly northern declination means that it can be observed almost exclusively from the northern hemisphere, where it is circumpolar up to tropical latitudes.

The cloud, cataloged as a generic emission nebula in the 1960s, has never shown signs of star formation in progress, nor was the ionizing star of its gases known; during the nineties the hypothesis was advanced that it was a planetary nebula, whose central star has over time slipped out of the gaseous envelope it created itself, given that its dimensions were too small to be an H II region, but comparable to those of a normal planetary nebula. This ionizing star would be the white dwarf cataloged as GD 561, located outside the cloud. The distance, from which the dimensions were derived, was obtained through the study of the radial velocity, and is indicated around 300 parsecs (about 980 light years).

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Datamerge: August 25, 2020 September 4, 2020 September 8, 2020 September 9, 2020 September 10, 2020 September 11, 2020 September 12, 2020 September 13, 2020 September 14, 2020 September 16, 2020 September 17, 2020 September 19, 2020 September 20, 2020 September 21, 2020
frames:
Baader B 1.25": 20x300" (1h 40') bin 1x1
Baader B 1.25": 30x60" (30') bin 1x1
Baader G 1.25": 30x60" (30') bin 1x1
Baader G 1.25": 20x300" (1h 40') -20°C am 1x1
Baader Ha 1.25" 7nm: 52x1200" (17h 20') -20°C am 1x1
Baader Ha 1.25" 7nm: 18x3600" (18h) -20°C am 1x1
Baader L 1.25": 147x300" (12h 15') -20°C bin 1x1
Baader O3 1.25" 8.5nm: 54x1200" (18h) -20°C am 1x1
Baader O3 1.25" 8.5nm: 18x3600" (18h) -20°C am 1x1
Baader R 1.25": 22x300" (1h 50') -20°C am 1x1
Baader R 1.25": 30x60" (30') -20°C am 1x1
integration duration: 90h 15'

=> core total 172 h