Owner's manual

Handbook for the SXVR-H814C Issue 1 February 2013

If the colour is roughly correct, then all is well. However, the colour decoding is

reliant on the filter pattern being properly registered with the processing software and

this can vary. Colour conversion involves running a software routine which uses the

brightness data from each pixel to generate colour values. As the brightness of each

pixel is related to the colour of light falling on it and the colour filter integrated onto

the pixel during CCD manufacture, we can translate this into true colour data. It is

very important that the software knows the colour filter positions, or the colours will

be translated incorrectly, so the software allows the user to define X (pixel) and Y

(line) offsets to correct this. If the colour is badly wrong, try opening the ‘Set program

defaults’ dialog box and altering the ‘Pixel’ and ‘Line’ offsets. Reload the raw file

and try synthesis again. If it’s still not right, experiment with just a pixel offset or just

a line offset until the colour is good.

There is every reason to expect that the image will be reasonably well colour

balanced, but if it is not, you can adjust the colour in the ‘Set Colour Balance’ dialog

box (Under ‘Colour’ in the main menu).

The colour balance controls seem complex, but are really quite easy to use. The most

useful controls are the ‘Start’ and ‘Saturation Factor’ settings. Saturation factor will

simply vary the colour intensity, without any alteration of the colour balance, but the

‘Start’ settings for each colour will alter the colour rendering of the dimmer parts of

the image. As most astronomical images are badly affected by light pollution, which

affects the dimmer background colours in particular, the start point settings are

particularly helpful for correcting this. If you move the start point of the Red

histogram a few points to the right and click on ‘Apply’, the new image will have

LESS red in the background and will appear more Cyan. Similarly, if you move the

Green start point to the right, the image will appear more Magenta and moving the

blue start point will turn it more Yellow. Do not move the start points beyond the start

of the main burst of histogram data, or you will introduce colour errors into low

saturation parts of the image. Just move the sliders by small amounts in the clear area

below the main peak, until the background is nicely balanced.

In some cases, the histograms may all start a long way above zero (usually in astro.

images with a lot of light pollution). In this case, slide the start point settings for all