About
Sky, Science, Motion
Designed to support your exploration of the Moon, Solar System, and Deep Space, Nyidawa provides scientifically rigorous data derived from published ephemerides and celestial catalogues. Complex astronomical computations are paired with animations and videos to make space science instantly accessible.
My Sky
While Moon, Solar System and Deep Space introduce the objects in the sky in general, My Sky is your gateway to your own night sky: what is up over your place, on any night from 1900 to 2050.
Night
From sunset to the next sunrise. Sunset and sunrise are when the Sun’s upper limb meets a refracted horizon, the Sun’s centre then 0.833° below it. Where the Sun does not rise before the next solar noon, polar night, the night runs from one solar noon to the next. Where it does not set, the midnight sun, there is no night.
Darkness
From when the Sun’s centre sinks 18° below the horizon until it rises back to 18°, the end of astronomical twilight.
Up
An object counts as up if it is above the horizon at sunset or rises before sunrise. A planet, star or galaxy is counted by its centre on a refracted horizon. A meteor shower is counted by its radiant at the night’s middle, and only on nights within its activity window.
Sources
Software
NASA and JPL
- JPL DE440 ephemeris
- JPL Horizons
- NASA planetary fact sheets
- NASA SVS CGI Moon Kit
- Blue Marble Next Generation
- Black Marble 2016 night lights
- LOLA height maps, LDEM
- SLDEM2015, LOLA and Kaguya
IAU
CDS Strasbourg
- Bright Star Catalogue, V/50
- Hipparcos re-reduction, I/311
- Catalogue of Nearby Stars, V/70A
- NED-D galaxy distances, J/AJ/160/199
- NGC 2000.0, VII/118
- RC3, VII/155
Other
- IMO Meteor Shower Calendar
- GeoNames
- Natural Earth
- ASTM G173-03 reference solar spectra
- CIE 1931 colour-matching functions, CVRL
- O3 cross-sections, IUP Bremen
- US Standard Atmosphere, RFM profiles
Accuracy
Times are shown to the minute. Following standard astronomical practice, calculations assume a flat, sea-level horizon; local terrain and elevation will shift actual visibility times.
Scientific accuracy is our top priority, but given the complexity of the field, we cannot rule out errors or discrepancies. If you notice any deviations—no matter how subtle—please let us know.
Privacy & Local Data
Location and time zone settings are stored only in your browser’s local storage, to keep your preferences across visits. We do not track, harvest, or associate this data with IP addresses or personal identifiers.
Nyidawa?
Nyidawa is drawn from the Tibetan words nyima (ཉི་མ, sun) and dawa (ཟླ་བ, moon). The site is not about Tibetan astronomy — the name simply reflects its maker’s heartfelt connection with the Tibetan people and their traditions.
Contact
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