9:14 PMAstronomical twilight ends. Deep sky objects optimal.
11:30 PMJupiter at meridian. Best viewing window opens.
1:15 AMMilky Way core rises to 28° above horizon.
3:42 AMSeeing peaks — optimal imaging window begins.
Deep Sky Targets
Best objects visible from — tonight
OBJECT OF THE NIGHT
M31 — Andromeda Galaxy
GalaxyMag 3.4AndromedaAlt 68° — Excellent
The nearest major galaxy to the Milky Way at 2.537 million light-years. Visible to the naked eye under dark skies and spectacular in binoculars. Tonight it transits at 10:42 PM reaching 72° altitude — prime position all night.
2.537 MLy
Distance
3.4
Magnitude
10:42 PM
Transit
72°
Max Alt
Tonight's Catalog
Object
Type
Const.
Mag
Size
Alt Now
Best Window
M31 Andromeda
Galaxy
And
3.4
3°×1°
68°
9 PM – 1 AM
M33 Triangulum
Galaxy
Tri
5.7
67′
62°
10 PM – 2 AM
M42 Orion Nebula
Nebula
Ori
4.0
65′
34°
12 AM – 4 AM
M45 Pleiades
Cluster
Tau
1.6
110′
52°
9 PM – 3 AM
M81 Bode's Galaxy
Galaxy
UMa
6.9
21′
48°
10 PM – 4 AM
M57 Ring Nebula
Nebula
Lyr
8.8
1.5′
41°
9 PM – 11 PM
M13 Hercules Cluster
Cluster
Her
5.8
20′
38°
9 PM – 12 AM
M27 Dumbbell Nebula
Nebula
Vul
7.5
8′
55°
10 PM – 1 AM
M51 Whirlpool Galaxy
Galaxy
CVn
8.4
11′
44°
11 PM – 3 AM
M35 Open Cluster
Cluster
Gem
5.1
28′
43°
11 PM – 3 AM
Satellite Passes
Visible overhead passes for — tonight
NEXT ISS PASS
10:48 PM
in 2h 34m
72°
Max Elevation
-3.8
Magnitude
5 min
Visible
SW → NNE · Rises 10:48 PM · Sets 10:53 PM
ISS Passes Tonight
Object
Rise
Max Elev.
Set
Duration
Direction
Visibility
Search a location to load pass predictions
Times are local · Passes with max elevation <10° omitted · Source: Celestrak TLE + satellite.js
Constellation Guide
Visibility and best viewing times for your location
Orion Ori
Winter · Best Dec–Mar
One of the most recognizable constellations, visible worldwide. Home to the Orion Nebula, …
RA 5h 35mDec -5°Best DSO M42 Orion Nebula
Best viewing: Dec–Mar
Notable Stars: Betelgeuse, Rigel, Alnitak
Ursa Major UMa
All Year · Best Mar–Jun
Home to the Big Dipper asterism and two spectacular spiral galaxies M81 and M82. Circumpol…
RA 10h 40mDec 56°Best DSO M81 Bode's Galaxy
Best viewing: Mar–Jun
Notable Stars: Dubhe, Merak, Alioth
Gemini Gem
Winter · Best Dec–Mar
The Twins constellation dominated by the bright pair Castor and Pollux. Radiant of the ann…
RA 7h 30mDec 25°Best DSO M35 Open Cluster
Best viewing: Dec–Mar
Notable Stars: Castor, Pollux
Taurus Tau
Winter · Best Nov–Mar
The Bull hosts the Pleiades star cluster and the Crab Nebula supernova remnant. Aldebaran …
RA 4h 42mDec 15°Best DSO M45 Pleiades, M1 Crab
Best viewing: Nov–Mar
Notable Stars: Aldebaran, Alcyone (Pleiades)
Leo Leo
Spring · Best Feb–May
A prominent spring constellation shaped like a crouching lion. Regulus lies almost exactly…
RA 10h 40mDec 15°Best DSO M95, M96 Galaxy Group
Best viewing: Feb–May
Notable Stars: Regulus, Algieba, Denebola
Virgo Vir
Spring · Best Mar–Jun
The largest constellation in area. Contains the Virgo Cluster — the nearest large galaxy c…
RA 13h 25mDec -5°Best DSO Virgo Galaxy Cluster
Best viewing: Mar–Jun
Notable Stars: Spica, Vindemiatrix
Libra Lib
Spring · Best Apr–Jul
The Scales — the only zodiac constellation representing an inanimate object. Its two main …
RA 15h 12mDec -15°Best DSO NGC 5897 Globular
Best viewing: Apr–Jul
Notable Stars: Zubenelgenubi, Zubeneschamali
Scorpius Sco
Summer · Best Jun–Aug
A stunning summer constellation best seen from southern latitudes. Its heart star Antares …
RA 16h 53mDec -30°Best DSO M6 Butterfly Cluster
Best viewing: Jun–Aug
Notable Stars: Antares, Shaula
Sagittarius Sgr
Summer · Best Jul–Sep
Points toward the Galactic Center — the richest part of the Milky Way. Contains more Messi…
RA 18h 55mDec -28°Best DSO M8 Lagoon Nebula
Best viewing: Jul–Sep
Notable Stars: Kaus Australis, Nunki
Capricornus Cap
Autumn · Best Aug–Oct
The Sea Goat — a faint zodiac constellation best seen in early autumn. Despite its faintne…
RA 21h 0mDec -20°Best DSO M30 Globular Cluster
Best viewing: Aug–Oct
Notable Stars: Deneb Algedi, Dabih
Aquarius Aqr
Autumn · Best Sep–Nov
The Water Bearer houses the magnificent Helix Nebula — the nearest planetary nebula to Ear…
RA 22h 18mDec -10°Best DSO NGC 7293 Helix Nebula
Best viewing: Sep–Nov
Notable Stars: Sadalsuud, Sadalmelik
Pisces Psc
Autumn · Best Oct–Dec
The Fish — a faint but large zodiac constellation. The vernal equinox currently lies withi…
RA 0h 30mDec 15°Best DSO NGC 628 Messier 74
Best viewing: Oct–Dec
Notable Stars: Eta Piscium, Alrescha
Aries Ari
Autumn · Best Nov–Jan
The Ram — a small but historically important zodiac constellation. Mesarthim was one of th…
RA 2h 38mDec 20°Best DSO NGC 697
Best viewing: Nov–Jan
Notable Stars: Hamal, Sheratan, Mesarthim
Cancer Cnc
Winter · Best Jan–Apr
The faintest zodiac constellation but home to the Beehive Cluster (M44), one of the closes…
RA 8h 40mDec 20°Best DSO M44 Beehive Cluster
Best viewing: Jan–Apr
Notable Stars: Asellus Borealis, Acubens
Astrophotography Planner
Imaging windows and settings for your location tonight
Andromeda Galaxy
M31 · Galaxy
Beginner
Our nearest large neighbor. Wide-field imaging reveals its full structure with dark dust lanes. Minimal processing needed.
2.537 MLy
Distance
300–600mm
Focal Length
2–5 min
Exposure
ISO 800
ISO
Orion Nebula
M42 · Emission Nebula
Beginner
The brightest nebula in the sky. The Trapezium cluster in its core burns bright — use short exposures to avoid overexposure.
1,344 ly
Distance
400–800mm
Focal Length
30–120s
Exposure
ISO 400
ISO
Lagoon Nebula
M8 · Emission Nebula
Intermediate
A stunning red nebula best captured with Hα narrowband filters. Pairs beautifully with the nearby Trifid Nebula M20.
4,100 ly
Distance
300–600mm
Focal Length
3–8 min
Exposure
ISO 800
ISO
Crab Nebula
M1 · Supernova Remnant
Advanced
Remnant of a supernova observed in 1054 AD. Its filamentary structure requires long exposures and good seeing conditions.
6,500 ly
Distance
1000mm+
Focal Length
5–15 min
Exposure
ISO 1600
ISO
Eagle Nebula
M16 · Emission Nebula
Intermediate
Home of the famous Pillars of Creation. Best captured with narrowband Hα filters to reveal the intricate dust pillars.
7,000 ly
Distance
600–1200mm
Focal Length
5–10 min
Exposure
ISO 1600
ISO
Ring Nebula
M57 · Planetary Nebula
Advanced
A perfect smoke ring 1 light-year across. Requires long focal lengths to resolve its central white dwarf star.
2,300 ly
Distance
1500mm+
Focal Length
3–8 min
Exposure
ISO 800
ISO
Helix Nebula
NGC 7293 · Planetary Nebula
Intermediate
The nearest planetary nebula and largest in angular size. Low surface brightness demands dark skies and long integrations.
650 ly
Distance
300–600mm
Focal Length
5–15 min
Exposure
ISO 1600
ISO
Horsehead Nebula
B33 · Dark Nebula
Advanced
A dark nebula silhouetted against emission nebula IC 434. Nearly impossible without Hα filters and excellent dark skies.
1,500 ly
Distance
600–1200mm
Focal Length
10–20 min
Exposure
ISO 3200
ISO
Carina Nebula
NGC 3372 · Emission Nebula
Intermediate
One of the largest and brightest nebulae in the sky — only visible from the Southern Hemisphere. Contains Eta Carinae.
7,500 ly
Distance
200–400mm
Focal Length
3–10 min
Exposure
ISO 800
ISO
Tarantula Nebula
30 Dor · Emission Nebula
Intermediate
The most active star-forming region in the Local Group, located in the Large Magellanic Cloud. Southern hemisphere only.
160,000 ly
Distance
300–800mm
Focal Length
5–15 min
Exposure
ISO 1600
ISO
Dark Site Finder
Light pollution levels and nearest dark skies from your location
YOUR LOCATION
—
Search a location to load
SQM: — · Mag limit: —
Nearest darker skies
~45 mi
Bortle 3–4
~90 mi
Bortle 2
~150 mi
Bortle 1
Bortle Scale
1 Darkest9 Brightest
The Bortle Scale Explained
Class 1
Zodiacal Light visible
Truly dark sky
The Zodiacal Light is prominent and M33 is visible with the naked eye. The gegenschein is easily seen.
Class 2
Typical dark site
Truly dark sky
Airglow weakly visible near horizon. M33 directly visible with averted vision. Milky Way shows extensive structure.
Class 3
Rural sky
Rural
Some light pollution domes visible on horizon. Milky Way shows complex structure overhead. M33 easily visible.
Class 4
Rural/suburban
Rural/suburban
Light pollution visible in several directions. Milky Way is still impressive but lacks detail near horizon.
Class 5
Suburban sky
Suburban
Milky Way is washed out near horizon. Light pollution glow obvious in multiple directions. M33 difficult.
Class 6
Bright suburban
Bright suburban
Milky Way only visible near zenith. Most Messier objects easily visible with binoculars.
Class 7
Suburban/urban
Suburban/urban
Sky background gray to orange. Milky Way barely visible. Bright Messier objects visible in small telescopes.
Class 9
City sky
Urban
Sky is bright gray or orange. Milky Way invisible. Only bright clusters and double stars observable.
Tips for Finding Dark Skies
Time it right New moon nights offer the darkest skies. The 5 nights before and after new moon add roughly 20% more observable sky.
Head north or west In the Northern Hemisphere, light pollution domes typically stretch east from population centers. Driving into rural areas to the west often yields the fastest improvement.
Elevation helps Gaining elevation reduces the atmosphere column above you and puts you above valley haze and light domes. Even 2,000 ft makes a measurable difference in transparency.
Let your eyes adapt Full dark adaptation takes 20–30 minutes. Avoid white light completely; use a red flashlight. Your sensitivity can increase up to 100,000× during this period.
Lunar Anatomy
Surface features, maria, and impact craters of Earth's Moon
Surface Feature MapFull Moon Reference
Maria (Seas)
Dark basaltic plains formed by ancient volcanic eruptions 3–4 billion years ago. Named by early astronomers who mistook them for actual seas. They cover about 16% of the lunar surface, predominantly on the near side.
Mare TranquillitatisMare ImbriumOceanus ProcellarumMare SerenitatisMare CrisiumMare Nubium
Impact Craters
Bowl-shaped depressions formed by meteorite impacts over 4 billion years. Prominent craters often show bright ray systems — streaks of ejecta that extend hundreds of kilometers. Over 300,000 craters larger than 1 km exist.
The Moon's terminator — the line between light and shadow — is the best zone for observing surface relief. Craters and mountains cast dramatic shadows there. First and last quarter phases offer prime conditions; avoid full moon for detail work.
Use 50–200× magnificationStudy the terminatorSketch what you seeTry a lunar filter
Quick Facts
384,400 km
Avg Distance
3,474 km
Diameter
29.5 days
Synodic Period
-12.7
Max Magnitude
1.62 m/s²
Surface Gravity
4.5 Byr
Age
About AstronoSight
How the forecast works and where the data comes from
How the Score Works
The Viewing Score (0–100) is a weighted composite of eight atmospheric and environmental factors. Each factor is normalized to a 0–100 sub-score and blended using the weights below. A score above 80 means conditions are excellent for telescope viewing or astrophotography.
Cloud Cover
28%
Atmospheric Seeing
22%
Transparency
18%
Wind Speed
12%
Humidity
10%
Light Pollution
6%
Jet Stream
4%
Data Sources
Open-Meteo Weather API
Hourly cloud cover, wind (10 m & 180 m), humidity, temperature (°F), visibility, and precipitation. 48-hour forecasts using Unix timestamps. Models: ECMWF, GFS, ICON. Free, no API key.
Open-Meteo Geocoding API
Forward geocoding — resolves city names and zip codes to lat/lon, elevation, timezone, and population. Powers the search autocomplete (6 candidates per keystroke).
BigDataCloud Reverse Geocoding
Converts GPS coordinates to city/state/country text for "Use my location," and provides county-level population as a Bortle fallback when VIIRS is unavailable. Free, no key.
NOAA VIIRS — ArcGIS ImageServer
Annual nighttime radiance composites (VIIRS/NighttimeLightsMDNB) via the ArcGIS ic.img.arcgis.com REST identify endpoint. Primary source for Bortle class, SQM, and the Light Pollution factor in the viewing score.
Celestrak — NORAD TLE Data
Fresh Two-Line Element sets for the ISS (NORAD #25544). Propagated with satellite.js v4.1.3 SGP4 to predict passes ≥ 10° elevation for the next 24 hours.
Astronomy Engine v2.1.19
All celestial mechanics: moon phase, rise/set/transit for Sun, Moon, and planets, astronomical twilight (SearchAltitude at −18°), and deep-sky altitude. Times localised to searched location's IANA timezone.
NASA Image and Video Library
Planetary photography (Mercury–Neptune), eight moon phase images, ISS photo, and deep-sky images in the Astro Planner. Moon anatomy diagram from public-domain astrophotography.
Frequently Asked Questions
What does the Antoniadi scale mean for Seeing?
The Antoniadi scale rates atmospheric stability from I (perfect, no quivering) to V (very bad, barely allows rough sketching). A score of III or better is generally needed for planetary detail work. AstronoSight converts this to a 0–100 sub-score for the composite.
How often is the forecast updated?
Weather data refreshes every 15 minutes from Open-Meteo's API. Seeing estimates update hourly. Light pollution data is static and based on the most recent atlas version (2022).
Why does my score differ from Clear Outside or Clear Dark Sky?
Different services weight factors differently and use different NWP models. AstronoSight emphasizes cloud cover and seeing most heavily, since these dominate the visual experience. We recommend cross-referencing multiple sources for critical observing sessions.
Can I use AstronoSight for astrophotography planning?
Yes — the Astro Planner tab lists 10 deep-sky targets with recommended focal lengths, exposures, and ISO settings. The atmospheric factors panel shows transparency and seeing independently so you can judge whether conditions suit wide-field imaging or high-resolution planetary work.
What is the Bortle scale and how does it affect my score?
The Bortle scale runs from 1 (truly dark, remote desert) to 9 (inner city). AstronoSight fetches your sky brightness from the NOAA VIIRS nighttime satellite dataset via ArcGIS, then converts to Bortle class. This contributes 8% of your viewing score — enough to distinguish a dark rural site from a suburban one, but balanced so a perfectly clear city night isn't unfairly penalised.
What does "Dark Until" mean on the forecast card?
"Dark Until" shows the end of astronomical twilight — when the Sun drops 18° below the horizon and the sky reaches true nighttime darkness. Before this time, scattered sunlight still washes out faint nebulae. This is the earliest you should start serious deep-sky work. It's calculated in real time by Astronomy Engine for your exact coordinates and date.
Why does my location show "BigDataCloud" instead of VIIRS data?
The ArcGIS VIIRS endpoint covers global data but can occasionally return no result for remote ocean coordinates or rate-limited requests. When that happens, AstronoSight falls back to a county-level population model from BigDataCloud. The source label on the Dark Sites and Forecast pages always shows which method was used.
How accurate are the ISS pass predictions?
ISS passes use fresh TLE data from Celestrak, propagated with satellite.js SGP4 directly in your browser. Accuracy is typically within 30 seconds for passes in the next 24 hours. Passes below 10° elevation are filtered out since horizon obstructions usually block these. TLE accuracy decreases slightly for passes further in the future due to atmospheric drag variability.
Is AstronoSight free? Do I need an account?
Completely free. AstronoSight runs entirely in your browser with no account, no subscription, and no ads. All APIs used (Open-Meteo, Celestrak, BigDataCloud, ArcGIS VIIRS) are free or open-source. Your location is only used to fetch current data and is never stored on any server.
Can I see the planets with just binoculars?
Absolutely. Venus, Mars, Jupiter, and Saturn show significant detail even in 10×50 binoculars — Jupiter's moons are visible, Saturn's rings are resolved at 20×+, and Mars shows polar cap hints near opposition. Uranus is a naked-eye object in dark skies (magnitude ~5.7). The planet panel shows current altitude, magnitude, and rise/set times so you know exactly what's accessible tonight.
