The spatial resolution matters a lot when comparing images across wavelengths, or even just between telescopes.
Most coherent, developed, tested materials
- Resolution Overview -- Dr. Luisa Rebull (created 2010, last substantially updated 2017)
- Resolution and YSOs, examples and exercises (used to be integrated with the overview above) -- Dr. Luisa Rebull (created 2010, last substantially updated 2017)
- Resolution: Calibrating your expectations - worksheet addressing what sizes you expect to find in the sky and in images -- Dr. Luisa Rebull (2020 but refined over nearly 10 years)
Less coherent, developed, tested materials
Questions to think about and things to try having to do with resolution
- What is the size of a typical HST image? How does it compare to a single Spitzer image, or a 'typical' Spitzer mosaic, or a single POSS plate, or the field of view of an optical telescope you have used, all compared with the size of the full moon? How does that compare to the size of a recent comet that visited the inner Solar System? or the size of a spiral arm of the Milky Way? You will have to go find on the web things like the field of view of these telescopes and these objects.
- Can you create a 3-color mosaic using just Spitzer data where the different resolutions of the various cameras is noticeable and important?
- How does the spatial resolution of all those telescopes listed above compare? (e.g., what is the smallest object you can resolve as more than a point source?)
- Are you going to laugh out loud the next time you're watching a crime drama, and someone says, "can you enhance that?" when referring to a blurry black-and-white image from a security camera, and someone else waves a magic wand and suddenly all sorts of small details are visible? (Can I wave my magic wand over that DIRBE image above and ever get that Spitzer/IRAC image?)
Useful Related Links
Article on resolution from Bad Astronomy - this is in the context of debunking the moon hoax, but resolution issues are important for his discussion.
Another resolution discussion from Bad Astronomy.
Why can Hubble get detailed views of distant galaxies but not of Pluto? by Emily Lakdawalla at the Planetary Society
xkcd on angular size (link is actually to the explainer, which has more information than just the comic.)