The Planets
At night you may see one or more planets and/or the moon.
Venus, Mars, Jupiter and Saturn look like bright stars. On a given night, each planet may be visible the entire night, just part of the night or not be visible at all. This will change over the course of weeks or months. Also each planet moves over time relative to each other and to various stars.
It is not possible to see any detail on these planets without a binoculars or a telescope. The planets always appear along an imaginary line called the ecliptic.
To see which planets are visible tonight, see https://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury/ . There are also computer programs/phone apps that will provide this information.
The Moon
The moon can appear as a “full moon” or as a crescent. When the moon is in the “new moon” phase it is not visible. The moon cycles through the phases over the course of a month. The new moon and full moon phases both last about 3 days. Depending on the phase, the moon will appear at night or during the daytime or both. The moon always appears along the ecliptic. While you can see some detail naked eye, you will get a better view with binoculars or a telescope.
To learn what phase the moon is today/tonight see https://www.space.com/18880-moon-phases.html .
The following is a guide to when the moon is visible at each phase. (Keep in mind these times are affected by daylight savings time and the observing location, and are approximate).
New Moon – not visible
Waxing Crescent -8 AM to 10 PM
First Quarter – 11 AM to 1 AM
Waxing Gibbous – 2 PM to 4 AM
Full Moon – 5 PM to 7 AM
Waning Gibbous – 8 PM to 10 AM
Last Quarter – 11 PM to 1 PM
Waning Crescent – 2 AM to 4 PM
The Constellations
This page is for beginning amateur astronomers who are still learning how to identify constellations. It is designed for observers at about 40 degrees north latitude (though it will work for latitudes somewhat north or south of that).
If you live in city or a suburban environment, you probably will encounter light pollution. Light pollution will prevent you from seeing all of the stars shown in these charts; you can see the brighter stars, but you might not see the fainter stars. Your ability to see fainter stars will improve if you can find a location away from bright lights and if you are patient: your ability to see faint sees will improve if you allow your eyes to adjust to the darkness for a half hour or more.
You may need to find a location away from obstructions like trees, buildings and mountains and away from bright artificial lighting (such as street lights and car lights).
Below are four different charts, you should select a chart based on the time of year, and whether you are observing in the evening or in the morning. These charts offer suggestions for locating the brighter constellations.
Spring – Mornings Evenings
Summer – Mornings Evenings
Autumn – Mornings Evenings
Winter – Mornings Evenings
Spring Evenings & Winter Mornings
To be written.
Summer Evenings & Spring Mornings
To be written.
Autumn Evenings & Summer Mornings
The Great Square is a group of four stars and is a good landmark to use in Autumn evenings and Summer mornings.
- Start by looking for the four bright stars that make up the Great Square. They are marked S1, S2, S3 and A1. S1, S2 and S3 are part of the constellation of Pegasus, and A1 (it has the name Alpheratz) is a star in the constellation Andromeda.
- If you follow along the backbone of Andromeda, you will locate stars marked A2 and A3 – note the gap between A1 and A2 is rather wide and there is moderately bright star in the middle. Somewhat above the backbone is a fuzzy spot that will be visible in relatively dark skies, it is marked G on the chart and is the Andromeda Galaxy.
- Continuing along the backbone, you will reach P2 (called Algol). P2 along with P1 (Algenib or Mirfak) make up the constellation of Perseus.
- Nearby look for a group of five stars in a “W” shape. This is the constellation of Cassiopeia.
- In dark skies, you may notice the Milky Way passing through Cassiopeia.
- Next to Cassiopeia, look for the constellation of Cepheus.
- If you follow S1 and S3, they point to D (Denebe) which is part of the constellation of Cygnus.
- Near Andromeda is the constellation of Aries. Aries has two relatively bright stars and several dimmer stars. The brightest of these stars, Hamal (Alpha Arietis), is marked H on the chart.
- Between Andromeda and Aries is the constellation of Triangulum. Triangulum consists of three stars, two of which are brighter than the third.
- If you see a bright “star” along the green curve, it could be a planet. Planets are not shown on this chart.
Note: The other constellations are only visible from dark sites.
Winter Evenings & Autumn Mornings
Orion is a bright, easy to recognize constellation visible in Autumn mornings and Winter evenings. Use Orion as a landmark as follows:
- The star pattern of Orion is distinctive and made of bright stars. You should note three stars in particular: Betelgeuse (B), Bellatrix (Be) and Rigel (R). Halfway between the shoulder of Orion (Betelgeuse and Bellatrix) and his feet (Rigel) are the three belt stars. You will note a set of stars that form a sword hanging from the belt; the middle star is not a star at all – it is the Orion Nebula (marked N on the chart), you may notice that appears blurry (look at it through binoculars).
- Orion is the part of the so called Winter Hexagon – to make out the hexagon start at Rigel and work clockwise. You will find five other bright stars: Sirius (S), Procyon (P), Pollux (Po), Capella (C) and Aldebaran (A).
- Note, you may see bright “stars” along the green curved line, they may be planets. Planets are not marked on this diagram.
- Sirius is part of Canis Major; try to make out the rest of Canis Major (dark skies are needed to see all of the stars).
- Procyon is part of Canis Minor. There are only two bright stars in Canis Minor, Procyon and Gomeisa (G).
- Pollux is part of Gemini. The outline of Gemini is relatively easy to recognize once you find Pollux (however some of the stars will not be visible in light polluted skies).
- Capella is part of the constellation Auriga.
- Aldebaran is the brightest star in Taurus. Nearby you should see a compact group of six or more stars. This is the Pleiades (marked Pl on the chart).
- Next to Auriga and Taurus, is Perseus. You should find Algol (marked Al on the chart), then try to make out the rest of the constellation. Algol is a variable star; if you carefully observe it over the course of few days, you might notice a change in brightness.
- Below Orion, you will be able to see the four brightest stars of Lepus (at least in dark skies), the rest of the constellation is harder to locate.
Note: The other constellations are only visible from dark sites.