THEMIS FAQ

Are THEMIS images copyrighted?

All THEMIS images on the website are in the public domain, and should be credited to NASA/JPL/Arizona State University.

Acknowledgment of the THEMIS website and its resources will help ensure the continuing support necessary for the validation, archiving, and distribution of the Mars work at ASU. See Data Citation hints for more example references.

Can I do my own data processing of THEMIS images?

Yes! The THEMIS standard processing is described in the documents here, but you are, of course, always welcome to ingest the published products into your favorite image processing tools. However, we also have created an online processing tool which allows you to complete your own specialized processing using the THEMIS toolset and the ASU-MARS computers. Many exciting and new features for this tool are being developed based on feedback from users like you.

Can the public target a THEMIS image?

Currently the only way for the public to target a THEMIS image is through the MSIP education project. The MSIP project is open to groups of students in grades 5 through college sophomore.

Can THEMIS detect water or ice?

Yes. Both water and ice are easily detected in the wavelength bands of the IR camera.

Can THEMIS see through dust?

THEMIS can see through a small amount of atmospheric dust; however, even a small layer of surface dust (~100 um) will obscure any underlying thermal IR signatures. Diurnal thermal conductivity can occur through several centimeters of dust, but will only change the temperature of the dust on top.

How do I download multiple THEMIS images at a time?

Use one of the following methods to access the THEMIS data and documentation directories:

HTML Data Access (lower left on Search THEMIS page)
Browser access to the THEMIS Virtual Volume directory
Suitable for Wget data retrieval
FTP Data Access
FTP Server Address: pdsftp.mars.asu.edu
Login Name: anonymous
Password: your complete email address

How do I subscribe to get announcements about new THEMIS data?

JPL provideds a subscription service that will notify you weekly of the new THEMIS daily images and quarterly of new data releases. You may also select to receive Press Releases for a variety of other NASA space topics. You can sign up for the service through http://www.kintera.org

How do you make THEMIS "true color" VIS images?

The five color filters of the THEMIS VIS camera do not span the full range of colors available to the human eye, so extensive processing, and an artistic touch, is applied to convert a raw image into an approximately "true color" image. Several of the THEMIS Team members are experts in VIS spectroscopy and have used their experience with the Hubble Space Telescope (HST) observations of Mars to generate a limited number of VIS color images. Their multi-step process:

How does the "Search THEMIS" tool find images within the latitude/longitude box that I define?

The "Search THEMIS" tool is supported by a database that contains the coordinates for at least six points (usually significantly more) outlining the edges of each available THEMIS image. The image will be included in the results table if any of these outline points falls inside your latitude/longitude box, and your remaining criteria are also met.

Note that the previous THEMIS query tool relied only on three coordinates per image; therefore, this new method may return more positive results for the same latitude/longitude box.

What bands does THEMIS use?

The IR bands (1-10) used by THEMIS are centered at the following wavelengths (in microns):
6.78, 6.78, 7.93, 8.56, 9.35, 10.21, 11.04, 11.79, 12.57, 14.88
(Yes, the first two filters have the same spectral center.)
The VIS bands (1-5) used by THEMIS are centered at the following wavelengths (in microns):
0.425, 0.540, 0.654, 0.749, 0.860