Part 2Q: Two Asteroid Images
Now we are ready to look at two asteroid images.
1. Open Afterglow Access if you do not already have it open.
- Go to the File Library folder, click on Sample.
- Go to the Solar System folder and open the folder, Asteroid 216 Kleopatra (not the ‘dense’ folder). You already have the first image in your File Library (you did this in Part O). Open another one of your choosing.
- Display the two images in Afterglow Access using one of the split screen options (recall, to use the split screen options, you need to click on the settings icon on the far left side under the icon for the File Library List).
a) Can you find the asteroid in the images when you have two images open?
- If you are having trouble, remember that the asteroid should be in a different position in each image.
- If the images are oriented the same, you may be able to spot the difference in the two images.
What could you do to make this easier? Can you think of another method?
b) Record in tyour journal what your method was to find the asteroid.
**Note: Afterglow Access does not allow you to examine more than two images at at time. The reason for this is that astronomers rarely examine images. They deal in data. Astronomers use coding to do what is called “batch” processing on many images at once. Remember, it is the DATA that is researched.
2. Question: What is the source of any of the images you see in Afterglow Access?
- Answer: you can get images from the “Sample” files. The second option is the “Workspace” folder where you can store other sources of image files.
3. Use the Aligning tool (9th one down in the column on the right).
- You do not need to have a split screen. First select the images you want to align.
- The drop down menu will list all the files in your file library. For now, we only have two asteroid images open, so you should only be clicking on those two.
- The next drop down menu asks for the reference Image File. Simply pick the one you want every other one aligned to.
- Then click the “submit” button on the lower right. Check to see if the images you selected are aligned to the active image file.
Choosing Kelopatra_01 and Kleopatra_10 should show you if it is working, since these are originally rotated with respect to each other.
**NOTE: Now, for optimal conditions in finding the asteroid, open Kleopatra image numbers 01, 10, 20, 30, 40, 50, 60, 68. Why do you think this would be optimal?
After aligning the images, describe in your journal how you think the this tool is useful.
4. Now that you have aligned the 8 images, stack them together with the “Stacking” tool, the last tool in the list.
- After clicking on the Stacking tool, the first drop down menu on this tool panel asks you to select which images to stack.
- Select the 8 Kelopatra images. You can ignore the other settings (or experiment after you have stacked your asteroid images).
- Click “Submit”. When processing is complete, a file will appear at the top of your library list. Open that.
5. Once you have the “stacked” file open, try sonifying it. Can you locate the asteroid?
6. Another tool to explore in the list on the far right is called the “Image Calculator” tool.
- Can you relate this to the matrix work you did previously?
- What might be a good use for this tool?
- Experiment!
**NOTE: Astronomers also like to use a “Blink” tool to help them find an asteroid. This tool allows a user to alternate between 2 images quickly. It is not available (yet) on Afterglow Access.