Sh2-190 — Heart Nebula
HII Region in Cassiopeia
About
Emission nebula in Cassiopeia, nicknamed the Heart Nebula, roughly 7,000 to 7,500 light-years away. Melotte 15, an open cluster, sits at its centre. William Herschel found it in 1787. Its brightest region lies in the W4 superbubble, within the W3, W4 and W5 group of clouds.
Imaging tips
- It spans well over a degree (one write-up lists 150′), so it needs a wide view: that write-up suggests about 200–400 mm, and around 200 mm also takes in the Soul Nebula.
- Hα carries the strongest signal at 656 nm; one author used 12 nm and 6 nm Hα filters, and a light-pollution filter helped under bright skies.
- One imager's 360 mm refractor image used 82 two-minute frames, about 2.7 hours, on a modified DSLR; flat frames were needed to control gradients and vignetting.
- One author notes the red channel holds the strongest signal and can be processed separately as a luminance layer.
- Best in October and November; it peaks near 79° altitude from 50°N.
Facts
- Size
- 150′
- Magnitude
- —
- Coordinates
- RA 2h 32.0m, Dec +61° 27′
- Framing, APS-C
- 160–270 mm
- Framing, full frame
- 250–410 mm
- Best months
- Oct, Nov
- Peak altitude
- 79° from 50°N, 64° from 35°N
Nearby
- H-NGC1027 · 77.4′ away