Difference between revisions of "Nebulosity"

Revision as of 20:27, 6 November 2014

Installing Nebulosity

Download the appropriate file (Mac or Windows) from the Stark Labs Downloads page. After installing the software, input your registration code for full access.

Nebulosity comes with a very detailed User's Manual. However, most of the information you will require can be found on these pages.

Creating 3-Colour Images

If you are working with your own telescope data, you may need to pre-process your data for optimal 3-colour image results.
If the red, green, and blue frames that you are combining have already been pre-processed, follow the steps below to create your 3-colour image:

• Open the Image menu, then select LRGB Color Synthesis.
  • The simplest mode is RGB. Use this if you have three colour frames, but do not have a luminance frame.
  • If you do have a luminance frame, use LRGB: Color Ratio mode.
• Click on the "Red frame" button to load your red filter frame.
• Repeat with "Green frame" and "Blue frame".
• If you have a luminance frame, click on "Luminance frame" to load it.
• Click "Apply." You should see your combined (L)RGB image in the main window. Use the "Zoom" buttons on the right-hand menu to adjust the frame so that you can see your object of interest. Your image will likely not look the way you want it to yet. There is a good chance that it may be too green, for example.
• Use the sliders to adjust the relative amount colour in each of the filters. Sliding the "Green" slider from 100 to 75, for example, will decrease the amount of green in your image. Click "Apply" to see how increasing or decreasing the slider affects your frame. It is a good idea to adjust just one filter at a time.
• Once you are satisfied with the colours in your image, click "Apply" and then "OK."
  IMPORTANT: Once you have clicked "OK", you CANNOT use the sliders to adjust the relative amounts of each colour. You may therefore wish to record what the values on each slider were in case you wish to recreate your image later.

Pre-processing

Align and Combine Filter Exposures

If you are working with data that you have taken from a telescope, you will likely need to stack and align your exposures before you can combine them into a 3-colour image. This section will step you through this process using images of NGC 1232 taken with iTelescope.
We start with two exposures in each filter: R, V, and B.

• First, we must combine the two exposures in each filter. To do this, open the "Batch" menu in Nebulosity and select "Align and Combine Images."
  • Under "Output mode," select "Save stack" - this will ensure that the merged exposures are saved as a single image.
  • Under "Alignment method," select "Translation + Rotation + Scale".
  • Leave the rest of the options as the defaults.

Align Stacked Exposures