Observe
1Physical Properties
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Medium | Hard+ | Hard |
| 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
6
Size Comparison
7
Compare Stars
8
Spectral Classification
9
Hertzsprung-Russell Diagram
10
Stellar Lifecycle
11
Blackbody Spectrum
12
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
13
Stellar Fusion
14
Exoplanets
4 known planets
View in 3D
| Planet | Radius | Mass | Period | Distance |
|---|---|---|---|---|
| HD 160691 d | 3.23R⊕ | 10.5M⊕ | 9.6d | 51ly |
| HD 160691 e | — | 7.00M♃ | 307.9d | 51ly |
| HD 160691 b | — | 4.30M♃ | 1.8yr | 51ly |
| HD 160691 c | — | 4.40M♃ | 10.8yr | 51ly |
Habitable Zone
Size & Mass Comparison
About exoplanets — how we find them and which host stars you can observe
Discover
15
Light Travel Time Machine
16
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.
Explore Nightbase
Related knowledge, tools, and stories — no observation planning required.