About Ukdah
Description
Ukdah, Iota Hydrae, is a K-type giant of spectral class K2 III about 263 light-years away in the body of Hydra. It shines at magnitude 3.91. Ukdah is a relatively normal red-clump giant with mass about 2 Suns and radius about 20 Suns.
Observing Tips
Ukdah lies in the middle of Hydra's long body, southeast of the head cluster. Because Hydra is the longest constellation in the sky (stretching over 100 degrees from head to tail), finding any specific star requires patience with a good star chart. Best observed February through June.
History
The name Ukdah comes from the Arabic "al-'uqdah," meaning "the knot" — referring to a pre-Islamic asterism of coiled ribbons or entangled threads. The IAU adopted the name in 2017.
Fun Facts
Hydra winds across an enormous span of the celestial sphere, from near Cancer to near Centaurus. Ukdah is one of the handful of named stars along this vast constellation, serving as a useful landmark for tracing the water-snake's meandering path.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Medium+ | Medium+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Survey Image
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Explore
7
Size Comparison
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
Relativistic Travel
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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