View allAll Photos Tagged multiband
Saturn's moon Titan is one of the most difficult objects to figure out true colors. To begin with, its surface is simply impossible to observe in the visible range because of the haze. Sufficiently transparent spectral bands begin only in the infrared, which means that only for the infrared it is possible to create a global map. Fortunately, we have Huygens landing probe, whose data was processed by Erich Karkoschka and Stefan E. Schröder [1]. The figure 6 was run through my program TrueColorTools (requiring some modifications along the way). The multiband images were interpolated and extrapolated (to blue range) there to a spectral cube and then convolved with the sensitivity of the human eye.
Having surface panoramas with a known color processing, all that is left is to extend that color to some infrared map. The best available option was a map from B. Seignovert et al. [2], which was first rid of artifacts and manually cleaned of pixilization. The Huygens landing site was selected from this map and matched to a previously processed projection of it in visible colors.
Now we need to find an unknown transformation over a piece of the infrared map so that it produces something as close as possible to the corresponding piece of the visible map, and then apply the found transformation to the entire infrared map. Assuming linearity of the transformation, it can be written in the form IR · X + C = VIS, where IR is a known 3-vector of some pixel color, X is an unknown 3x3 color transformation matrix, C is an unknown 3-vector and VIS is the resulted visible color 3-vector. The linearity assumption can be justified if the surface spectra in the visible and infrared are highly correlated with each other (which is true), but the infrared map used [2] contains nonlinear color transformations to highlight geologic features. Therefore, it was renormalized as follows before processing: R′ = G · B = 2.03/1.08 μm, G′ = R · B = 1.59/1.08 μm, B′ = B = 1.27/1.08 μm.
It turns out that we do not know the 3x3+3=12 parameters of X and C responsible for color conversion. They were found in 12-dimensional space as a result of optimization over all the landing site pieces pixels by the MNC method in Python. There was an attempt to add another matrix with quadratic form, but it failed: the result was too optimized and unrealistic.
Unfortunately, Huygens was only able to capture a small region of the surface, only one of two variations in the coloration of the dunes. Therefore, the unknown color of the second type of dunes had to be handpicked based on the assumption that there were no sharp brightness gradients on the surface, and run the optimization with this patch of handpicked influence. The color of the lakes is also handpicked, no suitable theoretical data has been found. Without these assumptions, the texture map cannot be completed. That's about as close to maximum color realism as we can achieve right now.
Lake delineations were obtained separately using radar data [3], which had noise and missing data. These regions were manually reconstructed from infrared data from Cassini, and the infrared map [2] itself was pre-warped to match the radar data (reprojected from the polar stereographic projection with another Python script).
Thanks to Pedro J. and Chara for their help and support!
History
August 2025: the Titan color map series was updated in accordance with the color processing updates in TrueColorTools (Tikhonov regularization for spectral reconstruction, color spaces management).
Contrast is slightly increased due to the darker presumed visible color of the second type of dunes.
January 2026: Did a little research on the color of liquid methane and ethane under Titan surface conditions. Turns out they're likely transparent, see this paper. The spherical albedo color was calculated from the refractive index "n" from [4] by integrating the Fresnel equations. The script makes the average color of the lakes calculated taking into account map distortions.
Info
Simple cylindrical projection, center longitude 0°.
Gamma corrected, albedo corrected.
Sources
[1] Karkoschka et al. (2016). Eight-color maps of Titan’s surface from spectroscopy with Huygens’ DISR
[2] B. Seignovert et al. (2019). Titan's global map combining VIMS and ISS mosaics (1.1). CaltechDATA
[4] Martonchik & Orton (1994). Optical constants of liquid and solid methane
Related
Digital Antenna’s new 9dB gain global cellular antenna is designed and manufactured for all cellular systems, including third generation (3G) and WCDMA technology. It improves signals on all cellular bands (850, 900, 1800, 1900 and 2100 MHz), offering excellent performance in a compact design. Ideal for many land and marine applications, including boats, RVs, homes and offices. Includes stainless steel L-bracket and U-bolts for mounting to a wall or pole.
Contact us at 1877-259-4629 or www.quantum-wireless.com/store/index.php/manufacturers/di...
Digital Antenna's completely unique multi-band directional cellular antenna covers the entire spectrum from 800 MHz to 2.5 GHz. It can be used for all cellular frequencies, including North American standard 850 and 1900 MHz bands, Euro/Asian standard 900 and 1800 MHz bands, WCDMA at 2.1 GHz, Nextel 800 MHz and the 2.5 GHz WiFi band.
Contact us at 1877-259-4629 or www.quantum-wireless.com/store/index.php/manufacturers/di...
Fourth annual Irish Sound, Science and Technology Convocation (ISSTC 2014) at Maynooth University, 28-29 August 2014.
The infrared portrait of the Small Magellanic Cloud, taken by NASA's Spitzer Space Telescope, reveals the stars and dust in this galaxy as never seen before. The Small Magellanic Cloud is a nearby satellite galaxy to our Milky Way galaxy, approximately 200,000 light-years away..
.
The image shows the main body of the Small Magellanic Cloud, which is comprised of the "bar" and "wing" on the left and the "tail" extending to the right. The bar contains both old stars (in blue) and young stars lighting up their natal dust (green/red). The wing mainly contains young stars. The tail contains only gas, dust and newly formed stars. Spitzer data has confirmed that the tail region was recently torn off the main body of the galaxy. Two of the tail clusters, which are still embedded in their birth clouds, can be seen as red dots..
.
In addition, the image contains a galactic globular cluster in the lower left (blue cluster of stars) and emission from dust in our own galaxy (green in the upper right and lower right corners)..
.
The data in this image are being used by astronomers to study the lifecycle of dust in the entire galaxy: from the formation in stellar atmospheres, to the reservoir containing the present day interstellar medium, and the dust consumed in forming new stars. The dust being formed in old, evolved stars (blue stars with a red tinge) is measured using mid-infrared wavelengths. The present day interstellar dust is weighed by measuring the intensity and color of emission at longer infrared wavelengths. The rate at which the raw material is being consumed is determined by studying ionized gas regions and the younger stars (yellow/red extended regions). The Small Magellanic Cloud, and its companion galaxy the Large Magellanic Cloud, are the two galaxies where this type of study is possible, and the research could not be done without Spitzer..
.
This image was captured by Spitzer's infrared array camera and multiband imaging photometer (blue is 3.6-micron light; green is 8.0 microns; and red is combination of 24-, 70- and 160-micron light). The blue color mainly traces old stars. The green color traces emission from organic dust grains (mainly polycyclic aromatic hydrocarbons). The red traces emission from larger, cooler dust grains..
.
The image was taken as part of the Spitzer Legacy program known as SAGE-SMC: Surveying the Agents of Galaxy Evolution in the Tidally-Stripped, Low Metallicity Small Magellanic Cloud.
The NASA CE318-N Sun Sky photometer at the Mesa Lakes Ranger Station. The multiband photometer operates at daytime and takes optical measurements to provide quantification and physical-optical characterization of the aerosols.
This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye.
The nebula, located about 700 light-years away in the constellation Aquarius, belongs to a class of objects called planetary nebulae. Discovered in the 18th century, these cosmic butterflies were named for their resemblance to gas-giant planets.
Planetary nebulae are actually the remains of stars that once looked a lot like our sun.
When sun-like stars die, they puff out their outer gaseous layers. These layers are heated by the hot core of the dead star, called a white dwarf, and shine with infrared and visible-light colors. Our own sun will blossom into a planetary nebula when it dies in about five billion years.
In Spitzer's infrared view of the Helix nebula, the eye looks more like that of a green monster's. Infrared light from the outer gaseous layers is represented in blues and greens. The white dwarf is visible as a tiny white dot in the center of the picture. The red color in the middle of the eye denotes the final layers of gas blown out when the star died.
The brighter red circle in the very center is the glow of a dusty disk circling the white dwarf (the disk itself is too small to be resolved). This dust, discovered by Spitzer's infrared heat-seeking vision, was most likely kicked up by comets that survived the death of their star. Before the star died, its comets and possibly planets would have orbited the star in an orderly fashion. But when the star blew off its outer layers, the icy bodies and outer planets would have been tossed about and into each other, resulting in an ongoing cosmic dust storm. Any inner planets in the system would have burned up or been swallowed as their dying star expanded.
The Helix nebula is one of only a few dead-star systems in which evidence for comet survivors has been found.
This image is made up of data from Spitzer's infrared array camera and multiband imaging photometer. Blue shows infrared light of 3.6 to 4.5 microns; green shows infrared light of 5.8 to 8 microns; and red shows infrared light of 24 microns.
Credit: NASA/JPL-Caltech/Univ. of Ariz.
The infrared portrait of the Small Magellanic Cloud, taken by NASA's Spitzer Space Telescope, reveals the stars and dust in this galaxy as never seen before. The Small Magellanic Cloud is a nearby satellite galaxy to our Milky Way galaxy, approximately 200,000 light-years away..
.
The image shows the main body of the Small Magellanic Cloud, which is comprised of the "bar" and "wing" on the left and the "tail" extending to the right. The bar contains both old stars (in blue) and young stars lighting up their natal dust (green/red). The wing mainly contains young stars. The tail contains only gas, dust and newly formed stars. Spitzer data has confirmed that the tail region was recently torn off the main body of the galaxy. Two of the tail clusters, which are still embedded in their birth clouds, can be seen as red dots..
.
In addition, the image contains a galactic globular cluster in the lower left (blue cluster of stars) and emission from dust in our own galaxy (green in the upper right and lower right corners)..
.
The data in this image are being used by astronomers to study the lifecycle of dust in the entire galaxy: from the formation in stellar atmospheres, to the reservoir containing the present day interstellar medium, and the dust consumed in forming new stars. The dust being formed in old, evolved stars (blue stars with a red tinge) is measured using mid-infrared wavelengths. The present day interstellar dust is weighed by measuring the intensity and color of emission at longer infrared wavelengths. The rate at which the raw material is being consumed is determined by studying ionized gas regions and the younger stars (yellow/red extended regions). The Small Magellanic Cloud, and its companion galaxy the Large Magellanic Cloud, are the two galaxies where this type of study is possible, and the research could not be done without Spitzer..
.
This image was captured by Spitzer's infrared array camera and multiband imaging photometer (blue is 3.6-micron light; green is 8.0 microns; and red is combination of 24-, 70- and 160-micron light). The blue color mainly traces old stars. The green color traces emission from organic dust grains (mainly polycyclic aromatic hydrocarbons). The red traces emission from larger, cooler dust grains..
.
The image was taken as part of the Spitzer Legacy program known as SAGE-SMC: Surveying the Agents of Galaxy Evolution in the Tidally-Stripped, Low Metallicity Small Magellanic Cloud.