Caldwell 66 — Globular Cluster in Hydra
NGC 5694
About C66
Description
NGC 5694 is a remote globular cluster in Hydra, about 113,000 light-years from Earth. It is one of the most distant globular clusters in the Milky Way's halo and has a very low metallicity, suggesting it formed early in the galaxy's history.
Observing Tips
A small, faint, unresolved glow in an 8-inch telescope. Cannot be resolved into individual stars with amateur equipment. Located in a relatively sparse star field. Best in spring evenings.
History
Discovered by William Herschel on May 22, 1784. Its extreme distance and low metallicity have led some astronomers to suggest it may have been captured from a satellite dwarf galaxy.
Fun Facts
NGC 5694 is one of the oldest objects in the Milky Way, with an estimated age of about 12 billion years. It may have originated in a now-destroyed dwarf galaxy that was absorbed by the Milky Way.
Observe
1Properties
Position & Identifiers
2How easy to spot?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Medium+ | Medium | Hard+ |
| 150 mm Newton 150mm Newt. | Easy | Medium+ | Medium+ |
| Celestron C8 (203 mm SCT) C8 203mm | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
3Visibility
Set a location in User Settings to see visibility data.
4
Eyepiece View
5
Best Magnification
Explore
6
Classification Decoder
Discover
7
Light Travel Time Machine
8
Relativistic Travel
Community Photos (1)
Credit: Judy Schmidt. License: CC BY 2.0. (Wikimedia Commons)
Skybred Mar 2, 2026
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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