Sh2-174
Planetary Nebula in Cepheus
About
A very faint shell of glowing gas in Cepheus, nicknamed the Valentine Rose and put at 930 to 980 light-years depending on the source. Long thought a planetary nebula, it is now regarded by one source as ionised interstellar medium, and its white dwarf sits off-centre.
Imaging tips
- About 17′ across, so it fits a 22′ frame with only a little room to spare.
- Hα and OIII are the usual route: one imager shot 22 half-hour Hα and 22 twenty-minute OIII frames, plus short RGB, for 21.9 hours.
- Another imager used 40 Hα and 40 OIII frames of 20 minutes, 26.7 hours, and called its magnitude of 14.74 a challenge.
- Best from August to October; it peaks near 59° altitude from 50°N.
Facts
- Size
- 10′
- Magnitude
- —
- Coordinates
- RA 23h 45.1m, Dec +80° 57′
- Framing, APS-C
- 2420–4040 mm
- Framing, full frame
- 3710–6190 mm
- Best months
- Aug, Sep, Oct
- Peak altitude
- 59° from 50°N, 44° from 35°N