View source for Dustier, Messier Messier Marathon

=Introduction=

A [https://en.wikipedia.org/wiki/Messier_marathon Messier Marathon] is an event held in the Spring often by amateur astronomy clubs. If you pick your night and phase of the Moon properly, you can see all of the 110 Messier objects in one night, admittedly with the extremes seen through many airmasses of atmosphere.

([https://en.wikipedia.org/wiki/Charles_Messier Charles Messier] was a comet hunter in the late 1700s, and he made a list of all the things he knew were not comets so that he wouldn't be fooled.)

If your local Messier Marathon tanks due to weather, or you just really like climate control and sleep, you might be interested in doing a Messier marathon online instead. There's a lot of astrophysics to be had in multi-wavelength observations of objects!

=Why "dustier, messier"?=

Infrared light is particularly sensitive to the dust and "mess" in some celestial objects. By exploring images of these Messier objects in the IR, you will be seeing dust.

=Getting images=

==All Messier objects==

You need to create an IPAC table file that is a list of the Messier objects. You can let IRSA services get the coordinates if you want. See [https://irsa.ipac.caltech.edu/applications/DDGEN/Doc/ipac_tbl.html IPAC table format definition] -- plain text with a header. Get something close-ish that is a list of the Messier objects, one per line. Then, pass it to the [https://irsa.ipac.caltech.edu/applications/TblValidator/ IPAC Table Validator] and ask it to " Apply name resolution/coordinate transformation." Save the resulting file, which will be a 100% compliant IPAC table file.

Go to IRSA's Finder Chart. Upload the IPAC table you just created uner "Multiple positions." Ask for all images, but no catalogs. Make a sensible choice for the image size -- you will find that you need vastly different image sizes for different objects.

==Just a few Messier objects==

Pick one Messier object of each broad category -- globular cluster, galaxy, star-forming region, planetary nebula, etc. If you're only doing a few, you don't need the source list above. 

Go to IRSA's Finder Chart or IRSA Viewer (more data and bigger images available here). Make a sensible choice for the image size -- you will find that you need vastly different image sizes for different objects.

=Looking at (and thinking about) the images=

Which types of objects look the same in the visible and IR? Why is this the case? 

Using IRSA Viewer, you have access to relatively high resolution images across broad swaths of sky up to wavelengths of about 70 microns; longer wavelengths are also available through IRSA, but are lower spatial resolution. Which objects change appearance from near-IR through mid-IR into far-IR? Why is this the case? 

Make three-color images to highlight similarities and differences among objects.

=Relevant topics from the rest of the wiki=
(e.g., these are the "Lego bricks" to go investigate in order to build this "Lego kit.")
*[[FITS format]]
*[[Finding FITS files]]
*[[Viewing FITS files]] 
*[[All ds9 information in one place]]
*[[Light beyond the visible]]
*[[Astronomical imaging]]
*[[Image artifacts]]
*[[Filters]]

=Related links=
*[https://old.ipac.caltech.edu/2mass/gallery/messiercat.html 2MASS Messier Catalog Image Gallery]
*[https://www.youtube.com/watch?v=kh83EfB_uZ4 Video from IRSA's YouTube feed] on doing a "Dustier, Messier Messier Marathon," using the WISE Image Service rather than Finder Chart or IRSA Viewer.