Making a Radar

Make a new document, 1000x1000 pixels, white background.

Set your foreground color to #2c8e01 and background color to black. Using linear gradient tool, make a gradient from lower right corner to upper left corner, like this:

On a new layer, create some lines, 8-10 pixels thin and position them like in the example. Choose for them a mid-range color, let's say #1b5901. With the lines layer selected, press CTRL+E (command+E on Macintosh) to merge layers.

Now go to filters>distort>polar coordinates and choose "Rectangular to Polar" Now you have the basic radar. Let's enhance it a little.

Using the elliptical marquee tool, make a circle around the image, invert the selection and fill it with black. Your image should look like this:

Invert again the selection, in order to have the radar selected. Right click on selection and choose "free Transform". Now rotate the selection like in the example:

Further enhancements: create a new layer and make a crosshair using a brighter green: #257801. Take care that the crosshair should intersect the middle of the radar.

Using the brush tool, make some "targets" with the same bright green.

Using the Type tool, write "Target 1, Target2, Target." Near each "target" with a real small font and red color. I have chosen Arial, 9pt, red color. Add some more text in another corner. That's it.