How to read the sky on a specific date

Today's page and dated pages show different moments

Read the timestamp first, then each planet's sign, degree and motion. The sky page gives positions for one moment. Today's page uses a current server calculation. A dated page uses noon Coordinated Universal Time (UTC).

Check the timestamp printed above the positions before you compare them with another result. Noon UTC can fall on a different local date in some time zones. The date in the page address is the UTC reference date. Listed positions don't hold unchanged across your whole local day.

Choose a date and select View sky to open its dated page. Previous day and Next day compare successive noon UTC snapshots. Save the dated address to return to that reference moment.

• Open the sky and date browser

Read the sign, then the degree inside it

Each row gives a body's position in Astriel's tropical zodiac, where the sign is a 30-degree section and the degree places the body inside it. These are geocentric positions, measured from Earth's center.

A position of 12 degrees 30 minutes Taurus sits halfway between 12 and 13 degrees of Taurus. Each degree holds 60 arcminutes. Those minutes measure an angle, not elapsed time.

A Moon sign at noon UTC is a snapshot. The Moon can enter another sign elsewhere in the day, so the noon value can't settle a birth Moon sign. Use the Moon calculator with the birthplace and known time information for that.

• Calculate a birth Moon sign

What the retrograde label means

Retrograde on Astriel's sky table means the body's zodiac longitude is decreasing as seen from Earth. Direct means it's increasing. The label describes apparent motion in this coordinate system.

NASA's explanation of Saturn and Neptune shows how Earth overtaking slower outer planets makes them appear to move backward against the stars. Those planets keep moving along their orbits. Our changing viewpoint creates the reversal.

Astriel estimates motion from positions on either side of the displayed moment. Near a station, where the apparent direction changes, the label can't give you an exact station time. It also can't tell you that a particular event will happen to you.

• NASA on the apparent retrograde motion of Saturn and Neptune

Compare the sky with your birth chart

A personal transit compares a moving body with a placement in your birth chart. The shared sky page supplies the moving positions. Your natal degrees supply the other side.

Take Mars at 12 degrees Taurus and a natal Sun at 14 degrees Leo. The smaller angle between them is 92 degrees. That puts Mars 2 degrees from an exact 90-degree square to the Sun.

Move that natal Sun to 28 degrees Leo and the separation becomes 106 degrees. It's the same sign, and much farther from the exact square. That's why a sign-only forecast can't identify your personal contacts.

Select Compare with a birth chart on the sky page to use your own placements. Keep unresolved natal degrees as ranges. One moment can't tell you when a contact becomes exact or how long it lasts.

• Compare the sky with your birth chart
• How aspect angles and orbs work

Read a sign change between 2 dates

Adjacent dated pages compare positions 24 hours apart, at noon UTC on each date. If a planet changed signs, it crossed the boundary somewhere between those snapshots. The table doesn't give the exact entry time.

Say the Moon shows Gemini at one noon and Cancer at the next. You know it changed sign in that interval. That doesn't mean it happened at midnight, or that everyone born on the second date has a Cancer Moon.

A direct or retrograde label describes the displayed moment too. Comparing two snapshots can't show every direction change between them. Use the date browser to inspect positions, and use a calculation across time when timing matters.

• Retrograde motion and stations

Match the method before comparing websites

Match the timestamp and zodiac before comparing two position tables. Tropical and sidereal results use different zodiac references. A midnight calculation and a noon calculation describe different moments.

Open Calculation details on the sky page to see the ephemeris version and computation time. An ephemeris is the source used to calculate celestial positions. Keep those details with any saved reference when you check a discrepancy.

A dated position page isn't a full list of that day's events. Exact sign entries, stations and personal contacts need calculations across time. Use the snapshot for the moment it names.

• Astriel's current calculation method