Hubble Space Telescope images of Titan's surface

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NEW! A revised map including 1995 images. Can you guess which features are the clouds?

Approximate-color image of Titan Atmospheric component of HST image HST F850LP image of Titan Surface component of image


Titan as it appeared in October 1994 to the Hubble Space Telescope's Wide Field / Planetary Camera. The first image is an approximate color composite made from red (F673N), green (F547M + F588N), and blue (F439W) filter images. The same haze that was seen by Voyager is seen here, except that the asymmetry has changed with the season, so that the north is slightly brighter than the south. The next three images illustrate the proceedure of seeing the surface with the F850LP filter. The first is an average of all 14 images with this filter -- the atmospheric component remains, but the surface has been essentially removed. It has been tilted so that north is 15 degrees to the right of straight up in order to match the next image. The second shows the final HST image from 18 October 1994, after it has been deconvolved to bring out the small scale features. The original PC pixels can be seen. The final image shows the derived map of Titan projected into the same viewing orientation. The continent-like feature is coming into view from the left.

The Titan imaging project:

From October 4 to 18, 1994, the Hubble Space Telescope Planetary Camera took 53 images of Titan at wavelengths ranging from the ultraviolet to the near-infrared. Fourteen of those images have been used to make the first albedo map of Titan's surface, at 0.94 microns; 8 others show Titan's surface near 1.08 microns. A paper (abstract) has been prepared and submitted for publication by Peter Smith, Mark Lemmon, Ralph Lorenz, John Caldwell, Larry Sromovsky, and Michael Allison.

Latest news:

HST 95:

There is a project by Caldwell, Smith, and Lemmon to obtain images of Titan between 28 September and 8 October 1995. These images will, a) observe the surface features again, b) fill in gaps in coverage from 1994, and c) extend the baseline of observations at shorter wavelengths, where seasonal changes in the haze are known to occur.

MMT 95:

A ground based project by Lemmon, McCarthy, and Smith will attempt to use the Multiple Mirror Telescope to image Titan at 2 microns 11-15 October 1995. At the longer wavelengths, the haze is much more transparent, and the surface is easily available. However, the possible resolution (for a given telescope) is much worse due to the diffraction limit, and HST does not currently have the capacity to image at 2 microns. (Wait for NICMOS!) We will use the MMT as a phase array imaging interferometer -- in English, we'll use it as a 6.9-m telescope to obtain images comparable in resolution to those taken by HST at shorter wavelengths.

Titan images at DPS:

Online abstracts of talks to be presented at DPS in October:

Available images

Image: F673N (red continuum) F850LP (0.94 micron window) F1042M (1.07 micron window)
Color (table): map map map
Black and white: No map map map
Two HST images of Titan

A view of the "four faces of Titan"

Average image of Titan for each wavelength

An animation of Titan is available thanks to SEDS

Links to other sites

Future studies with the HST Titan data set:

The HST images with the 850LP filter as well as other filters that are thought to probe Titan's lower atmosphere but not to be sensitive to the surface will be analyzed to find any cloud features that could be tracked. If there are some, the direction of Titan's strong winds will be known. This information is rather important, as it will determine how long the Cassini Orbiter will stay in contact with the Huygens Probe. During its 2.5 hour descent, the Probe will drift a considerable distance (as much as 11 degrees of longitude) -- if the winds are prograde, Huygens could land 1000 km from where it might land if the winds are strong and retrograde.

HST images at methane continuum wavelengths from ultraviolet to red, as well as images through methane band filters in the red and infrared will be used to study the variation of the north-south asymmetry with time. The asymmetry will likely tell us about the haze distribution in the atmosphere, which in turn will tell us about large scale dynamical processes in the atmosphere.

The HST Titan imaging team included Smith and Mark Lemmon, both of the University of Arizona, John Caldwell of York University, Larry Sromovsky of the University of Wisconsin, and Michael Allison of the Goddard Institute for Space Studies. We should thank NASA here -- not only did they pay for it, this project would not have been possible before the repair mission. We have Titan images with the original WF/PC -- we know.

Questions, suggestions, etc., about this information should be directed to Mark Lemmon,