NGC 4755 (Jewel Box, Kappa Crucis Cluster, Caldwell 94)
NGC 4755 or Caldwell 94 (also known as the Jewel Box, or the Kappa Crucis Cluster) is an open cluster in the constellation Crux. It has an apparent visual magnitude of 4.2 and its angular diameter is 10 arc-minutes. NGC 4755 lies at an estimated distance of 4900 light years. The Equinox 2000 coordinates are 12h 53.6m, -60° 20´ which makes NGC 4755 a Southern Hemisphere object that is best seen during the spring. The Caldwell Spring Star Chart shows the position of all Caldwell objects visible during that season. Visit the Caldwell Catalog Photo Gallery to see more objects from this catalog. As one of the more famous objects in the Caldwell Catalog, it is commonly known as the Jewel Box.
The Jewel Box as a star cluster was first found by Nicolas Louis de Lacaille while doing astrometric observations for his 1751–1752 southern star catalogue Cœlum Australe Stelliferum at the Cape of Good Hope in South Africa. See Wikipedia for more information.
Visit NGC4755 at 300mm to see this region imaged with smaller telescope.
Technical Details
- Object: NGC 4755
- Other Names: Jewel Box, Kappa Crucis Cluster, Caldwell 94
- Object Type: open cluster
- Object Data: Apparent Magnitude = 4.2, Angular Size = 10 arc-minutes
- Object Position (Equinox 2000): 12h 53.6m, -60° 20´, Constellation = Crux
- Date: 2021 Feb 10 - Feb 15 (6 nights)
- Location: Chile Remote Observatory, Observatorio El Sauce, Chile
- Partnership: Operated in partnership with David Churchill
- Telescope: Planewave CDK-17 (with Focal Reducer: f/4.5; FL = 1945mm)
- Camera: QHY 16200A with Integral 7-position Filter Wheel
- Mount: Astro-Physics 1600GTO
- Sub-Exposures: Astrodon Filters
- Luminance: 48 x 5 min = 240 min
- Red: 24 x 5 min = 120 min
- Green: 24 x 5 min = 120 min
- Blue: 24 x 5 min = 120 min - Total Exposure: 10h 00m
- File Name: NGC4755-CDK21-C01w.jpg
- Field of View: 38.9' x 58.3' at 0.64 arc-sec/pixel
- Original Image Size: 3630 x 4540 pixels (16.5 MP); 12.1" x 15.1" @ 300 dpi
- Data Acquisition: David Churchill
- Image Processing: Fred Espenak
- Maxim DL: Image Calibration, Stacking, Digital Development Processing
- Adobe Camera Raw: Noise Reduction
- Photoshop CC: Curves, Levels
- Topaz Labs: Sharpen AI - Copyright: Fred Espenak