Mark Centroid

If checked, the apertures are centroided near where you click the mouse to mark an object. The centroid position is a refined coordinate based on the intensity profile of the object.

Positive/Negative points

Selects whether to centroid on positive-going values (peaks) or negative-going values (valleys).

Radius

Defines the distance from the target point within which pixel data are used to compute the centroid position. A reasonable radius value is approximately half the diameter of a point source, such as a star image.

Tracking

Defines the maximum distance from the current position that Mira will search in the next image to lock onto a new position. This is only used when tracking objects through an Image Set.

Track Centroids

Controls the duplication of markers when the positions are "tracked" through an image set. If this option is checked, the positions are centroided in every image.

Calibrate when Tracking

Instructs Mira to compute and apply the zero point to all objects when tracking through an image set. This is a time saving feature that makes it automatic for the Tracking command to be followed by a Calibrate command (see below).

Object

Sets the color used for marking target objects.

Standard

Sets the color used for marking standard stars.

Recenter

Recenters all apertures. Use after changing the centroid radius or after moving or placing apertures with Mark Centroid unchecked.

Reset ZP

Reset the photometric zero point for all images. This removes the zero point information from the image headers, including the keywords ZERO-PT, ZERPTERR, and NPHOTSTD.

Loads a catalog of coordinates and optional magnitudes for automatically marking objects. This calls the Import Photometry Catalog command.