RenderableConstellationBounds

Inherits Renderable

This Renderable type can be used to draw bounding shapes on the night sky, where each shape encapsulates a group of night sky objects, such as the stars of a constellation.

The shapes are defined in a file where each line specifies a vertex location in RA Dec coordinates on the celestial sphere. Each coordinate must also be marked with an abbreviation for the corresponding constellation that the shapes encapsulates. This gives each line the following order: RA Dec Abbreviation. The units for the coordinate values are hours for RA, and degrees for Dec. An example of a line corresponding to a vertex location may look like this: 23.5357132 +35.1897736 AND, where AND is the identifier of the constellation. In this case it is short for Andromeda.

The abbreviations act as identifiers of the individual constellations and can be mapped to full names in the optional NamesFile. The names in this file are then the ones that will show in the user interface, for example. A line in the file should first include the abbreviation and then the full name. For example, for the AND abbreviation in the example above, the line would look like this: AND Andromeda.

If labels were added, the full names in the NamesFile may also be used for the text of the labels. Note that labels are added using a different file, where each line may or may not include an identifier for that specific label, marked by id in the file. If a row in the label file has an id that matches the abbreviation of the constellation, the text of that label is replaced with the full name from the NamesFile.

Members

Name	Documentation	Type	Description	Optional
File	A file that contains the vertex locations of the constellations bounds, as RA Dec coordinates on the celestial sphere.	File	Value of type ‘File’	No
Color	The color of the lines.	Color3	Value of type ‘Color3’	Yes
Labels	The labels for the constellations.	Table	LabelsComponent	Yes
LineWidth	The line width used for the constellation shape.	Double	Value of type ‘Double’	Yes
NamesFile	Specifies the file that contains the mapping between constellation abbreviations and full names of the constellations. If this value is empty, the abbreviations are used as the full names.	File	Value of type ‘File’	Yes
Selection	A list of constellations (given as abbreviations) to show. If empty or excluded, all constellations will be shown.	Table	Table parameters	Yes

Inherited members from Renderable

Name	Documentation	Type	Description	Optional
DimInAtmosphere	Decides if the object should be dimmed (i.e. faded out) when the camera is in the sunny part of an atmosphere.	Boolean	Value of type ‘Boolean’	Yes
Enabled	Determines whether this object will be visible or not.	Boolean	Value of type ‘Boolean’	Yes
Opacity	This value determines the opacity of this renderable. A value of 0 means completely transparent.	Double	In range: ( 0,1 )	Yes
RenderBinMode	A value that specifies if the renderable should be rendered in the Background, Opaque, Pre-/PostDeferredTransparency, Overlay, or Sticker rendering step.	String	In list { Background, Opaque, PreDeferredTransparent, Overlay, PostDeferredTransparent, Sticker }	Yes
Tag	A single tag or a list of tags that this renderable will respond to when setting properties.	Table, or String	Value of type ‘Table’, or Value of type ‘String’	Yes
Type	The type of the renderable.	String	Value of type ‘String’	Yes

Table parameters for Selection

A list of constellations (given as abbreviations) to show. If empty or excluded, all constellations will be shown.

• Optional: Yes

Name	Documentation	Type	Description	Optional
*		String	Value of type ‘String’	Yes

Asset Examples

local coreKernels = asset.require("spice/core")



local data = asset.resource({
  Name = "Constellation Files",
  Type = "HttpSynchronization",
  Identifier = "digitaluniverse_constellations_data",
  Version = 1
})


local zodiacs = {
  "CNC", "TAU", "PSC", "ARI", "LIB", "AQR", "CAP", "SCO", "VIR", "SGR", "GEM", "LEO"
}

local Object = {
  Identifier = "ConstellationBounds",
  Renderable = {
    Type = "RenderableConstellationBounds",
    Enabled = false,
    File = data .. "bound_20.dat",
    NamesFile = data .. "constellations.dat",
    Color = { 0.45, 0.44, 0.30 }
    -- Selection = zodiacs
  },
  Transform = {
    Rotation = {
      Type = "SpiceRotation",
      SourceFrame = coreKernels.Frame.J2000,
      DestinationFrame = coreKernels.Frame.Galactic
    },
    Scale = {
      Type = "StaticScale",
      Scale = 10e17
    }
  },
  Tag = { "du_grid" },
  GUI = {
    Name = "Constellation Boundaries",
    Path = "/Milky Way/Constellations",
    Focusable = false,
    Description = [[As a continent is divided into countries, astronomers divide the sky
      into 88 regions called constellations. Every object falls into one of these 88
      regions. The boundaries of these regions are shown in this asset. Use these in
      concert with the constellation labels. Census: 88 constellations.]]
  }
}


asset.onInitialize(function()
  openspace.addSceneGraphNode(Object)
end)

asset.onDeinitialize(function()
  openspace.removeSceneGraphNode(Object)
end)

asset.export(Object)



asset.meta = {
  Name = "Constellation Bounds",
  Description = Object.GUI.Description,
  Author = "Brian Abbott (AMNH)",
  URL = "https://www.amnh.org/research/hayden-planetarium/digital-universe",
  License = "AMNH Digital Universe"
}