Orri: User Guide for Visualizing Celestial Bodies

Orri is a web application crafted to visualize celestial bodies within our solar system, utilizing authentic data for accuracy. Our objective is to faithfully represent the views of moons and planets through 3D renderings accessible in your web browser via specific URIs. These URIs can showcase various system states, such as a view of tonight's moon from your current location, real-time tracking of an eclipse, or any other celestial event from any location on Earth's surface or from space.

Check out these links for cool 3D scenes

• April 8 eclipse 'Penumbra' - 600X !
• April 8 eclipse 'Umbra' - @10X. Green dot is my saved location.
• April 8 eclipse 'Umbra' - That green dot represents your location if you accepted to share location
• How I will see eclipse from my location - Narrowly miss totality.
• The moon as seen on March 28th from my location - Notice that it was just cresting the horizon east of me.
• Europa and Jupiter - And jupiter has a subtle ring.

Please note that Orri is still in its early stages of development, and there may be some rough edges. We appreciate your interest and patience as we continue to improve and refine our application. We will soon offer up the source code on github.

This user guide is designed to assist you in discovering and utilizing Orri's features and functionalities. We hope you enjoy using Orri, ideally on a spacious display!

Navigating Between Celestial Bodies

In Orri, you can explore different planets and moons by selecting them within the application. Your movement capabilities are determined by the selected camera targeting mode. Orri offers three distinct camera modes:

• "Follow Target" Camera Mode: This mode maintains the camera at a constant position and direction relative to the selected target. It effectively keeps the target body within the camera view while pointing in the same direction in space.
• "Look at Target" Camera Mode: In this mode, the camera's position remains fixed, but it continuously points towards the selected target. This stationary perspective provides a sense of the slow and majestic movements of celestial bodies in space.
• "Follow From Surface" Camera Mode: This mode positions the camera on the surface of Earth, with the camera direction always pointing towards the selected target. Please note that the camera position remains fixed at the established coordinates on the Earth's surface, with an altitude fixed at 100 meters.

Camera Control Functions

While in either the "Follow Target" or "Look at Target" camera mode, you can perform the following camera control functions:

• Zooming: Use your mouse scroll button or two-finger drag on a touchpad or mobile display to zoom in and out.
• Orbiting: Click or touch and drag to orbit around the selected target.
• Selecting and Moving: Click on other celestial bodies to select and move towards them at speeds exceeding the speed of light!

While in "Follow From Surface" camera mode, the camera controls will remain fixed at the established coordinates/position on the surface (altitude is fixed at 100m) while the camera direction will ALWAYS be pointing towards the target. Be aware that it is possible for the camera target to be below/behind the surface horizon; in that case, the camera will be pointing down into the surface of Earth and have a 'blocked' view. If the "Show Alt/Az" option is enabled, a negative Alt property value means the target is below the horizon. So while in the "Follow From Surface" camera mode:

• You can click or select different targets. Once a target is set, the view remains pointed towards it regardless of the fact that it is above or below the horizon.

Time Control

Orri allows you to control the application's internal clock and time scale to observe celestial bodies at different times and speeds.

• Changing Datetime: Click on the datetime display to bring up the datetime picker. Apply changes by clicking outside the picker.
• Play/Pause: Cick '>' to play and '||' to pause. When play is enabled, the application clock progresses based on the selected time scale. Pausing the clock stops all time-dependent movements of celestial bodies.
• Rewind and Forward: Click repeatedly on '<<' to rewind and '>>' to fast forward, adjusting the time scale in either direction.
• Setting to Current Time: Click on 'Now' to set the clock to the current date and time.
• Resetting Time Scale: Click on '1X' to reset the time scale back to 1X.

If you want to view the bodies in 'real time' you simply: ensure time scale is '1X' and click on 'Now'.

Setting a Location on the Surface

In Orri, you have two methods to specify coordinates for positioning on the Earth's surface:

• Manual Input: Enter latitude and longitude coordinates to place a green dot on the Earth's surface. This will set the initial camera position when you switch to the "View From Surface" camera mode.
• Use Browser Location: Clicking this option will utilize your browser's current location via IP geolocation. You'll need to approve the initial location prompt; subsequent requests will bypass this prompt.

Shadows and Shadow Modes

Orri offers the option to enable/disable shadows with two distinct shadow modes: Penumbra and Umbra. Shadows are established using parallel light, with their centers accurately positioned.

• Enabling Shadows: Toggle the shadows on/off to visualize the shadow of the moon on Earth during solar eclipses and other shadow effects.
• Shadow Modes: Choose between Penumbra and Umbra modes. The Umbra represents the darkest, central part of a shadow, while the Penumbra is the surrounding, lighter region. The Umbra effectively represents the area experiencing a 'total' eclipse.

Field Of View Control

The Field of View (FOV) in Orri represents the angle of your view. Imagine opening your arms in front of your eyes—the angle between your arms represents the FOV. The wider you open them, the wider the FOV.

• Adjusting FOV: Use the FOV control to change the viewing angle. A smaller FOV results in a narrow angle with magnified targets. A FOV of approximately 0.5 will make the moon occupy the entire screen, while the minimum value of 0.05 represents a high-quality telescope view.

Displaying Labels in Orri

Orri offers the capability to display labels over celestial objects, which can be easily enabled or disabled according to your preferences. There are three types of labels available:

• Body Name: This label indicates the name of the celestial body.
• Body Distance from the Camera: Distances can be configured to display in Astronomical Units (Au), kilometers (km), or miles. This provides valuable context on the spatial relationship between objects and the viewer.
• Altitude/Azimuth Coordinates: This label is specific to the viewer's perspective and is only visible when using the "View From Surface" camera mode. For more information on the altaz coordinates, you can refer to Wikipedia's page on the Horizontal Coordinate System. This label also depicts a small arrow that is either pointing up: ↑ or down: ↓ which indicates if the body is currently trending/moving up or down in elevation.

Push State to Location Bar and History

One of Orri's (still in progress/querky) features is the "Push State to Location Bar and History", which allows you to save the current view's state. By utilizing this feature, the application updates the browser's history, enabling you to:

• Navigate using the browser's back and forward buttons to revisit previous views.
• Easily share specific views by simply copying and sharing the generated link.

For instance, if you want to share what you're currently observing, simply activate the "Push State to Location Bar and History" option and share the provided link!

Data Source for Orri

Orri utilizes real and accurate data sourced from another application within our system. This data serves as the foundation for visualizing celestial bodies with precision. You can explore the documentation for this data source here.

While Orri is still under development, we welcome contributions and assistance from anyone interested in joining our project.

For example, an application can retrieve the current position, speed, axis orientation, and axial rotation angle. of the Moon. This ensures that the moon's representation in Orri aligns with its actual appearance in the sky. :)