The Astronomy Nexus

Quick Start

When you first load a chart, you start off in "Atlas" mode. This gives you a moderately detailed star chart centered on the default target (the constellation Orion) as seen from the Sun (Sol).

To recenter the chart on something else: Type the name or catalog ID of a star or other object you wish to see -- such as "Polaris" or "Messier 31" -- in the "target" field (the right text box). Then either hit Enter or click "Redraw". This recenters the chart on the selected target. Once the chart redraws, you can then use the navigation tool to move the chart a small distance in one of the 4 major directions.

To get details about any object on the chart: Just click its symbol when the object's name or ID appears on screen. Detailed information will then appear for that object. Click its symbol again to hide the details.

To recenter the chart on an object whose details are visible: Click the "Recenter" (crosshair) icon in the object's details.

To see the sky from another star: Enter that star's name as the "target" and either hit Enter or click "Redraw". Alternatively, for many stars, you can go directly to that star by clicking the "Go To..." (rocket) icon in that star's details when the details are visible.

To get back to the Earth from any other point in space: Click the Earth icon in the navigation tool, or the Earth icon in any object's details near the object name.

About Charts, Locations, and Sizes

The Chart Types menu enables various "prefab" chart settings.

  • Atlas: Charts in several detail levels with medium to high magnitude limits, celestial coordinates marked, and constellation boundaries identified.
  • Naked Eye: Several charts with very wide image scales, low magnitude limits, and fewer labels. For more details, see the Naked Eye help page.
  • Classic Star Atlases: These settings mimic the layouts and fields of view of famous printed star atlases such as Sky Atlas 2000, Uranometria, and the Millennium Star Atlas. For more details, see the Classic Star Atlas help page.

The Location (left text box) and Target fields (right text box) let you specify where you're viewing from (the 'Location') and where the chart is centered (the 'Target'). You can enter a star or deep-sky object by name or catalog ID, a constellation name, or an exact 3-D coordinate value. For format details, see Location Formats.

To update your chart with any updated settings, click "Redraw".

Additional Help

Chart Options

Chart Types

Additional Background Information