Explore ! Hold down the left click to navigate, use the scroll wheel to zoom in/out.

Add a new survey. Click on the 'Add survey' button under the Image Layer section. Either select the survey from the dropdown menu, or click on the magnifying glass icon to select an image HiPS. Click on the eye icon to hide/show this Image Layer.

Change the visualisation parameters. Click on the small arrow next to the survey name and adjust the parameters: adjust the contrast, stretch, cuts, opacity, format...

Add a new catalogue. Click on the 'Add catalogue' button under the an Overlay Layer section. Select from the pop-up form the url or name of the catalogue to load. Tick the box next to the catalogue's name to hide/show it.

The video below and the images show you how to use the drawing tools.

Click a shape icon to select a drawing shape. Then click and drag anywhere on the image to begin your drawing.

These are examples of shapes drawn: an ellipe, rectangle, line, and polygon.

Click on the shape to highlight it.

Change the shapes size by dragging one of the surrounding small white boxes.

Rotate the shape by dragging the small green box.

Delete a shape by clicking on the bin icon. Delete all shapes by clicking on the spiral arrow icon. Remove the last shape drawn by clicking on the left arrow icon.

Display the table by clicking on the table icon.

All drawn shapes are listed in this Table here.

Click a row to highlight a shape and conversely.

Tick the 'Hide' column to hide/show a given shape.

Some features are clearly associated to a given galaxy (such as spiral arms or tidal features).

In such cases, report in the 'linked_to' column the ID of the Galaxy it belongs to. Leave to -1 (default) if not associated. Note that in the case of stellar streams, when there is no clear Galaxy where the stream originate i.e. when it is orphan, indicate '0'.

Several features are worth annotating. They can be of stellar origin or sources of contamination that hinder the detection of the features of interest. We follow the definitions of Duc+2015, Bìlek+2020, and Sola+2022

• Galaxy : Any galaxy that you are studying, ranging from dwarf galaxies to massive elliptical. It encloses all visible light. Use Ellipse to delineate its contours.
  

• Background Galaxy : Any other galaxy that you are not studying, that is clearly a background objects. It encloses all visible light. Use Ellipse to delineate its contours.
  

• Tidal tails : tidal tails are gas and stars stripped away from the Galaxy during interactions and mergers between with similar-mass galaxies (i.e. major merger). They are elongated stellar features. Use Region, Freehand or Snake to draw them.
  

• Streams : streams originate from a smaller galaxy companion (i.e. minor merger). The progenitor of the stream can either be still visible or be completely disrupted (i.e. the stream is 'orphan'). They are generally thin and elongated. Use Region, Freehand or Snake to draw them.
  

• Shells : shells are often present in groups. They are concentric arc-shaped features generated during intermediate-mass radial mergers. Use Line to draw them.
  

• Cirrus : dust clouds in our Galaxy, scattering the optical light. Cirrus appear as diffuse but extended structures (often filamentary) that usually cover large parts of the image. Use Region or Freehand to draw it.
  

• High background : regions in deep images, with background levels higher than the blank sky values, not clearly identified as structured cirrus. These regions may trace dust illuminated by bright objects. They are not flat field defects but are really due to higher foreground emissions in these regions. High background regions make tidal features identification difficult. Use Region, Freehand or Snake to draw them.
  

• Ghosted halo : artificial and extended round halos round bright stars caused by internal reflections on the detector and optical elements of the camera. Use Circle to draw them.
  

• Satellite trail : any satellite trail too close to the galaxy of interest. Use Rectangle to draw them.
  

• Instrument : any artifact related to the instrument, such as CCD gap. Use Rectangle to draw them.