Plate solving and object labels

What else is in the frame

Almost every deep-sky image holds more than its target. The galaxy you framed has companions; the nebula has a reflection nebula tucked beside it; there is a cluster in the corner you never noticed. Annotation is how you find out what you caught.

One click, from stack to labeled image

Press Identify objects. Akastroid matches the stars in your image against its catalog, works out where the telescope was looking and at what scale, and draws the names straight onto the preview. There is no separate apply step and nothing to set up first.

• Deep sky: about twelve thousand galaxies, nebulae, clusters and planetary nebulae, with the familiar names people search for (the Running Man, De Mairan's Nebula, the Flame).
• Stars: bright stars labeled with their magnitude and color.
• Coordinate grid: optional, drawn faintly.

Galaxy shapes

A circle is the wrong shape for a galaxy. Where the catalog records an object's size and orientation (over ten thousand of them do), the marker is an ellipse turned to the object's real angle on your frame, because the plate solve knows how your camera was rotated. Andromeda is traced along its length; the Leo Triplet gets three ellipses that match three galaxies.

Readable in a crowded field

The Orion Nebula is the classic test: four cataloged objects in one patch of sky. Objects inside a larger one get a small marker that says "here" without drawing a second ring across the first; two big neighbors shrink until their rings touch; large rings carry their label inside so it cannot be read as naming the next one along; and a star label that would print over another is left out.

Written into the export

The labels are part of the image you export (JPEG and PNG for posting, TIFF for printing), so you can share the annotated picture itself rather than a screenshot. Remove them with one click when you want the clean version too.

What it needs

The solve starts from where your files say the telescope was pointing. FITS from a smart telescope, ASIAIR, N.I.N.A., Ekos or any tracking mount records that, and a stack that already carries a WCS is verified star by star rather than trusted. A tripod DSLR raw carries no coordinates, and Akastroid tells you so instead of guessing: a blind all-sky solve is not attempted, because a confident wrong answer is worse than none. A stacked image that came out mirrored is handled: the field is tried both ways round.

Where it sits in the workflow

Annotation sits at the end of the same deep-sky workflowthat calibrates, stacks, removes gradients and calibrates color against measured stars. If you are coming from PixInsight, the comparison page covers the rest of the difference.