C45
Galaxy in Boötes
About
NGC 5248 is a grand-design spiral in Boötes, about 42 million light-years away, with prominent arms sweeping outward from a faint central bar. Many starburst knots dot the disc, and its nucleus is circled by two nested rings of intense star formation. William Herschel found it on 15 April 1784, and it is Caldwell 45.
Imaging tips
- At most about 6′ across, so it is too small to frame: use a long focal length and a fine pixel scale.
- Starburst knots dot the arms, but for a galaxy broadband colour is the filter choice.
- A published LRGB image used about 3 hours of luminance (16 × 12 min) plus 10 × 5 min per colour.
- At 21.1 mag/arcsec² its surface brightness is moderate, not faint, for a galaxy of this size.
- Best from March to May; it peaks near 49° altitude from 50°N.
Facts
- Size
- 4.1′ × 2.4′
- Magnitude
- 10.0
- Coordinates
- RA 13h 37.6m, Dec +8° 53′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Mar, Apr, May
- Peak altitude
- 49° from 50°N, 64° from 35°N