MLUnsold Digital Imaging

A set of 21 x 15 minute light frames of IC 443 were collected using a 10" Meade SCT at F4.9 and SBIG ST4000 color camera. After calibration the light frames were converted to color, aligned, and stacked with excluded min max average.

The goal is to brighten the stacked image and maintain star color.

Initial stacked image

Step 1

First the mouse pointer is moved across the initial image to check the background levels at different corners of the image. The background level is found to be (3,3,2) on an 8 bit scale as shown by the (R,G,B) level pane at the bottom right of the main ImagesPlus window.
The Color | Color Balance tool will be used to flatten the background to (3,3,3) before digital development is used to increase brightness and contrast. A flat background will enable digital development or other stretching function to maintain a uniform background.

Check background levels by moving the mouse pointer over the image and note the level shown by the (R,G,B) pane at the bottom right of the main ImagesPlus window. (3,3,2) is displayed in the (R,G,B) pain for the intial image.

Step 2

Check the Nuetralize Background box on Color Balance then left-click on the dark background where the level is (3,3,2). Color balance will adjust the background level to (3,3,3).

Color Balance is used to neutralize the background of (3,3,2) to (3,3,3) in preparation for digital development.

Step 3

Color | Digital Development is used to increase brightness and contrast.
The break-point and background weight slider sensitivity are tuned to match the image.

Digital development brightness and contrast increase.

Step 4

Color | Digital Development color emphasis is used to increase star color.

Digital development star color emphasis.

Step 5

Note the brighter background in the lower left of the image in step 5 compared to the top right corner of the image.
The Point | Background Comp | Planar tool is used to flatten the image. Check the select background maximum box then left-click in the lower left background to select its value.
Check the select background minimum box then left-click in the upper right background to select its value. Set the minimum value to 0 so that this area is not effected.
Adjust the background weight slider to reduce the lower left background to match the upper right background.

Lower left corner background is reduced to match the top right background.

Step 6

Color | Color Balance command is used to neutralize the background and adjust color.
Check Neutralize Background then left-click on a typical background area.
The Red, Green, and Blue sliders can be used to adjust color.

Neutralize background and adjust color.

Step 7

The Copy A Portion Of An Image toolbar button is used to enable cropping.
Left-click and drag the mouse around the object to define the crop area.

The image is cropped to remove the uneven edge caused by alignment shift and stacking.

Step 8

The Geometric | Geometric Transform | Scale command is used to resize the image for display on the web.
File | Save Copy As is used to save the FITS image as JPEG.

Scale the image by 0.5 for display on the web.

Final image of IC 443 after digital development. The Local | Local Mouse Effect tool could be used with the blur option to remove the few hot green pixels, satellite streak, and soften the blue star centers.

Initial stacked image

Check background levels by moving the mouse pointer over the image and note the level shown by the (R,G,B) pane at the bottom right of the main ImagesPlus window. (3,3,2) is displayed in the (R,G,B) pain for the intial image.

Color Balance is used to neutralize the background of (3,3,2) to (3,3,3) in preparation for digital development.

Digital development brightness and contrast increase.

Digital development star color emphasis.

Lower left corner background is reduced to match the top right background.

Neutralize background and adjust color.

The image is cropped to remove the uneven edge caused by alignment shift and stacking.

Scale the image by 0.5 for display on the web.

Final image of IC 443 after digital development. The Local | Local Mouse Effect tool could be used with the blur option to remove the few hot green pixels, satellite streak, and soften the blue star centers.