The Lobster Claw Nebula is a sprawling Sharpless emission region in Cassiopeia. It does not present itself as a simple, isolated object; the appeal is in the overlapping shells, ridges, and wispy edges spread across the star field.
The narrowband palette helps organize that complexity. Hydrogen, oxygen, and sulfur data give the frame its layered look, with warmer emission wrapping around cooler pockets of structure.
- What am I looking at?
- The Lobster Claw Nebula is a curved emission nebula shaped by stellar winds and radiation from nearby massive stars.
- How far away is it?
- About 11,000 light-years away.
- Where is it in the sky?
- In Cassiopeia, in the rich Milky Way star fields of autumn.
- Why does it matter?
- Shows how massive stars sculpt gas into dramatic arcs and shells.
- When is the best time to photograph it?
- Autumn when Cassiopeia is high in the evening sky.
Capture summary
Nebula in Cassiopeia
9 days / Moon 59%
Ha, OIII, SII
Autumn target / wide composition
- H-alpha 10h 120 x 300s / 4 days in Dec 2022 / Moon 90%
- SII 7h 30m 90 x 300s / 3 days / Moon 46%
- OIII 10h 25m 125 x 300s / 4 days / Moon 37%
- Totals 27h 55m 9 days / Moon 59%
When to image this target
Nebula in Cassiopeia; best planned for September through November from New Jersey.
Autumn is a strong window for Cepheus, Cassiopeia, Andromeda, and late Cygnus fields.
Assumes a New Jersey backyard horizon and evening imaging.
Emission nebulae are good candidates for narrowband filters; reflection nebulae prefer darker skies.
Sh2-157 is listed here in Cassiopeia.
Current frame: Narrowband / Ha, OIII, SII.
Live altitude, moon, and filter guidance
Calculating target altitude and moon context.
Use the full planner to enter a ZIP code, choose a date, and compare the target from your sky.
Based on the current time.
Green marks usable dark-sky altitude.
Next upper transit.
Approximate horizon crossing.
Moon phase and altitude.
Acquisition & processing notes
Filter channels, integration times, and capture dates for this frame. View on AstroBin.
- H-alpha 120 x 300s, 10h, 4 days in Dec 2022, Moon 90%
- SII 90 x 300s, 7h 30m, 3 days, Moon 46%
- OIII 125 x 300s, 10h 25m, 4 days, Moon 37%
- Totals 27h 55m, 9 days, Moon 59%
How I captured this
| Channel | Frames | Time | Moon |
|---|---|---|---|
| H-alpha | 120 x 300s | 10h | 90% |
| SII | 90 x 300s | 7h 30m | 46% |
| OIII | 125 x 300s | 10h 25m | 37% |
| Totals | — | 27h 55m | 59% |
- Equipment used
- From my current rig
- Mount
- iOptron CEM60
- Telescope
- Explore Scientific FCD100 127mm Carbon Fiber Triplet APO
- Camera
- ZWO ASI2600MM Pro
- Filters
- Chroma 36mm Ha, OIII, SII, and LRGB (ZWO EFW 7×36mm)
- Focuser / rotator
- MoonLite NiteCrawler
- Reducer
- Starizona Apex ED 0.65×
- Guiding
- ZWO off-axis guider + ASI290MM Mini
- Control / power
- PrimaLuceLab Eagle 4S, Powerwerx PSU, Bioenno field battery, and MEGAbox
