Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
Using MIRA to do simple aperture photometry
You should first download the images to your computer's desktop.
Each one should appear as an icon with a large capital "M"
surrounded at the upper right with red markings;
this means that the image processing program
MIRA
will be used to open the image.
- double-click on the first image's icon to start running MIRA
- rotate the image to match the chart:
- use Math -> Geometry -> Rotate center and pick 180 degrees
- (if desired) zoom in on the image
- prepare the aperture photometry tool
- Measure -> Aperture Photometry
- a set of icons should appear at the left side of the image
- click the "P" icon with no asterisk -- a crosshair cursor should appear
- move the cursor to star A and left-click -- circles should appear
- use the check-mark icon ("Options") to adjust the size of
the "Object" aperture so it is a bit bigger than the visible
extent of the star, and the "Inner bg" and "Outer bg" apertures
so that they are clear of any starlight and 5-10 pixels apart
- click on the calculator icon at left ("Calculate")
- a new window should appear, with an entry showing the
position of star A and its instrumental magnitude through
your aperture
- measure the instrumental magnitudes of stars A, B, C and RX
- click on stars B, C and RX; a new entry in the list will appear for
each
- repeat for all your images
Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.