Stack Images – RGB (monochrome camera)

This tutorial explains how to create a color image from 3 sets of filtered images. It is advisable to review the simpler grayscale tutorial prior to this.

Click(New Job) to open the Select Task form:

Press the Stack Images button.

If you have not yet created a profile then you will be prompted to do so (Manage Profiles).

If you have only one profile, that profile will be used automatically (use Utilities to add a new profile).

Confirm Input Image Type. (Input images are monochrome even though the combined image will be color.)

Select groups of Input files by color filter and association with calibration files. (See Create Calibration Masters). This example will use three groups, one for each color filter.

Press Select group of image files button and select all RED image files:

Change the Color Assignment to Red:

If desired, select the appropriate Dark and Flat files (see grayscale tutorial for example of how to select).

Press the Select another group button to select Green files.

Select the Green filtered files.

Assign Color to Green and use the appropriate dark and flats (as was done for Red above).

Press the Select another group button to select Blue files.

Select the Blue filtered files.

Assign Color to Blue and use the appropriate dark and flats (as was done for Red above).

Now all files (R, G, and B) have been selected. Press the Continue button:

Modify the suggested Job Name.

Combine File: The default name is the same as the Job Name. Click on the name to change it.

Registration: If your images are already aligned (e.g. guider did not move) then uncheck that box. The top image selected has been chosen as the reference. Click that name to specify another reference (the reference does not have to be one of the processing images).

Normalize: images will adjust the background levels and intensity scales in each image to improve the effectiveness of data rejection. Normalization can compensate for different sky conditions or even different exposure times. Short sets of images taken under identical conditions do not normally need this but it is generally advisable to normalize.

Data Rejection: Spurious events such as airplanes or cosmic rays can be removed via data rejection.

Expand Job: This may have to be checked for processing large images on a 32 bit OS computer. If you get any “out of memory” errors then always check this box. (This tutorial assumes the Job is not expanded).

Save Job: Allows you to easily re-use the Job, changing parameters or files.

Edit Job: Access all directives that control processing. Use to this override Quick Job default settings.

Run Now: This starts the processing using Quick Job default settings.

Press the Edit Job button to open Forms (see grayscale tutorial Forms for short tutorial). Open Stack Directive then Image Files to review the files, color assignments, and preprocessing:

An exercise to change color assignments (and change them back):

1) Select all rows for the new assignment (drag the mouse over several rows or use [<ctrl> click] to accumulate individual selections).

2) Click on any selected cell in the AssignToColor column:

3) Select the new color assignment

4) Change back to Green.

After you have made the edits then it is useful to save the Job:

Then use the Job Processor controls to run the Job:

Forms will be minimized (Jobs may not be edited while running) and the Job will run.

The Start button changes to Pause while the job runs. See Job Processor for more information.

The [Stack] process viewer is opened automatically and shows the combined image as it is built. Other process viewers are available from the Viewers drop down control.

The running Job looks like this:

Upon completion the screen looks like this:

The combined file is automatically saved (unless the save directive was unchecked). But it can also be saved via the save button when that viewer form is active (an active form is indicated by a darker-colored frame; click a form to make it active).

Press the Reset button to restore the Job forms.