The Pointers and Crux

Full view for maximum effect.

The Pointers in Centaurus and the Southern Cross (Crux)

The Pointers, also known as the Southern Pointers, is an asterism in which Rigil Kentaurus and Hadar mark the front hoofs of Centaurus, the Centaur. The line formed by these two stars points to the Southern Cross. Rigil Kentaurus is also known as Alpha Centauri, the famous bright member of the closest star system to Earth. Hadar is also known as Beta Centauri.

The Southern Cross is located in the constellation of Crux, the smallest of the 88 constellations. The four stars that mark the famous Southern Cross asterism are Mimosa/Becrux, Gacrux, Acrux and Delta Crucis.

Crux may be the smallest of all the constellations, however, it is also the most recognisable. The long arm of the cross points to the South Celestial Pole, which, unlike the northern hemisphere, has no bright star (Polaris) to mark it. Crux is on both the Australian and New Zealand flags.

This composite consists of two sets of images; one set of 20 images taken at ISO-1600 and the other set of 20 images taken at ISO-800.
Each individual image was a 30 second exposure.
IRIS was used to calibrate each image (dark subtraction [median combined master dark] and flat field division [median combined master flat {lights, darks and offsets}]), to register, align, and finally stack.
Photoshop CS2 was used to adjust levels, curves, saturation, frame and resize the final composite.
Observed closely, diffraction spikes can be seen on the brightest stars -- my polar alignment was spot on.

Target: The Pointers in Centaurus and the Southern Cross (Crux)
Date: Sunday, January 29th, 2006
Time: First image: 3:24 AM
Time: Last image: 3:49 AM
Location: Lostock, NSW, Australia
Camera: Canon EOS-350D (unmodified)
Lens: Canon EF 50mm F/1.4 (stopped down to F/2.5)
Focal length: 50mm
Mount: Piggy-backed onto an 8" Meade LX90 LNT (F/10)
Alignment: Equatorial; via equatorial wedge
Exposure: 20 x 30 seconds @ ISO-1600 and 20 x 30 seconds @ ISO-800 (RAW)
Software: IRIS: Calibration, registration, stacking; Adobe Photoshop CS2: post-processing and framing