VITAL STATS

Price Sensor

WORDS: PETE LAWRENCE • £795 • Sony

ICX825ALA • Pixels 1,392x1,040 array (8.9x6.7mm, 11mm diagonal) using 6.45µm square pixels • Readout noise 6e• Dimensions

110x70x25mm • Weight 340g • Supplier Atik Cameras • www.atik-cameras.

com • Tel 01603 740397

Anyone who has ever taken a group of people out to look at the night sky through a telescope, or perhaps yearned to share the wonders they’re viewing to the world, will love the Atik Infinity. This is a camera that combines astronomical CCD quality imaging with essences of video broadcasting.

This review is of the monochrome variant of the Infinity, though a colour one is available. At the camera’s heart is a Sony ICX825 CCD sensor, which has excellent low noise characteristics. Designed for relatively short exposures, the Infinity has no active cooling. However, we found its passive cooling to be acceptable for relatively noise free results.

The camera is controlled by a Windows-based program also called Infinity. This is dedicated to the Infinity hardware and is well designed and easy to use. The main controls adjust exposure and binning. Binning makes groups of pixels work together as a ‘super-pixel’: for example, 2x2 binning groups a square of 2x2 pixels so their recorded values are used together. This increases sensitivity at the expense of array size, so a 2x2 bin of the Infinity’s 1,392x1,040-pixel sensor effectively reduces its array to 696x520 pixels. Other binning modes are also available.

There also a ‘finder’ mode, in which the camera performs a short exposure, high-binned loop. The somewhat noisy result is perfect for locating faint objects. When you are centred up, select video mode and you’re all set. Using a 4-inch, f/9 refractor, we found that finder mode was great for scanning the fainter sections of the Rosette Nebula as well as centring on faint galaxies.

Mesmerising streaming

In video mode the camera exposes in a continuous loop, sending two or three full frames to its host computer every second. The Infinity software checks image quality and, if good enough, adds it to a stacked result to produce a cleaner image. It was mesmerising to watch the way the spiral arms of the Whirlpool Galaxy, M51, became better defined after only a few stacked images. You have control over the definition of quality and whether you want the results stacked.

A session can be recorded for replay if required. If activated, each stack image is individually stored for later access using other processing packages. Strangely, we found we couldn’t open the recorded FITS files using PixInsight, a high-end processing application. PixInsight apparently didn’t like the FITS header written by Infinity.

The camera’s 16-bit images require processing to optimise them for the computer screen, but the Infinity software makes this task simple via a number of histogram presets. For example, we found that the bright Orion Nebula, M42, was best shown using a ‘medium’ or ‘high’ setting, whereas faint objects such as the Running Man Nebula (NGC 1977) benefitted from the ‘low’ setting, which stretched out