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Sh2-173
Sh2-173 — Phantom of the Opera Nebula
Emission Nebula
· CassiopeiaAdvanced
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Observing: Tonight · 8:00 PM–5:00 AM
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Target information
- Object type
- Emission Nebula
- Constellation
- Cassiopeia
- Right ascension
- 0h 21m 16s
- Declination
- +61° 43′ 30″
- Magnitude
- Not recorded
- Angular size
- 30′
- Surface brightness
- Not recorded
- Difficulty
- Advanced
- Best months
- August, September, October, November, December
- Catalog IDs
- Sh2-173;Simeis 21
About this target
Faint HII region in Cassiopeia, particularly suited to H-alpha imaging.