TPE Web uses a map, a primary red pin, and colored lines to show the position and direction of celestial bodies in relation to your chosen location.
Most of these lines are azimuth lines. In TPE Web, the lines radiating from the primary red pin show the azimuth toward a celestial body or event. There are two main types of azimuth lines on the map:
- Event lines show the direction of events such as sunrise, sunset, moonrise, and moonset.
- Selected-time lines show the direction of selected celestial bodies and targets at a specific time.
While scrolling the altitude chart, you may also see projection and shadow lines, which extend in the opposite direction from a selected body.
Depending on your subscription, the celestial bodies and targets you can display may include the Sun, Moon, Milky Way, planets, and other celestial targets.
Understanding Sun and Moon lines
The Sun and Moon lines provide the simplest way to understand how the azimuth lines work in TPE Web.
Orange lines represent the Sun, and blue lines represent the Moon. The thickness of each line tells you what it represents:
- Thick lines show the azimuth of specific events. For the Sun, these are sunrise and sunset; for the Moon, moonrise and moonset.
- Thin lines show the azimuth of the Sun and Moon at the currently selected time.
As you change the selected time, the thin Sun and Moon lines move to show their changing azimuth. The thicker event lines continue to show the direction of their corresponding rise or set event for the selected date and time.
- Selected time: 2:09 PM
- Moonrise azimuth
- Sunrise azimuth
- Moon azimuth at 2:09 PM
- Sun azimuth at 2:09 PM
- Sunset azimuth
- Moonset azimuth
How to Read Azimuth Lines in TPE Web
There are two ways to think about the lines:
- If you’re at the location of the red pin, the line indicates the direction you need to look in, relative to true north, to view the indicated event or celestial body.
- If you are photographing a subject situated at the red pin, the lines indicate the direction from which light will hit your subject.
Projection and shadow lines
As you adjust the selected time by scrolling the altitude chart, additional lines appear on the map for the Sun and Moon. These include projection lines and relative shadow length lines.
- Sun projection line
- Sun relative shadow length
- Moon projection line
- Moon relative shadow length
Projection lines can be used to help align your shots. For example, if you were to walk away from your subject situated at the red pin but wanted to keep the Sun aligned directly behind it, you should walk in the direction shown by the projection line.
Relative shadow length lines show the relative length of shadows for the selected time of day. A longer line means longer shadows. You’ll notice as you approach sunset, the shadows get longer, as you’d expect. You’ll only see shadows from the Moon when the Sun is down and the Moon phase is sufficiently illuminated.
Changing the displayed celestial bodies and targets
You can choose which celestial bodies and targets are shown on the map from the Bodies and Targets panel. The eye icon indicates which bodies are currently visible. Click the body or target to show or hide its azimuth lines on the map and altitude curve on the chart.
The Sun and Moon can each be shown or hidden. Depending on your subscription, you can also display the Milky Way, planets, and other celestial targets.
When you display additional bodies or targets, TPE Web uses different colors to help you distinguish them on the map and altitude chart. The Milky Way is shown in gray. Planets and other celestial targets are assigned green, purple, or pink when more than one is displayed.
You can also favorite deep-sky objects from the Celestial Targets catalog. Favorited targets appear in the Favorites section of the Bodies and Targets panel, where you can select them for display on the map.
