Askaniy @askaniy.bsky.social · 08/09/2026There’s a big difference here. The channels I synthesize actually exist, and based on their data, I derive a formula for converting between photometric systems. If a channel doesn’t exist, there’s no reference result from which to derive the formulas. Any estimate of a nonexistent channel is rough. 010
Askaniy @askaniy.bsky.social · 08/09/2026Example coefficients obtained using the least squares method based on a sample of one million pixels from all OPAL maps: F467M(F395N, F502N) = 0.18 + 0.80 a - 0.58 b - 0.65 a² - 0.37 ab + 2.16 b² + 5.87 a³ - 9.09 a²b + 4.84 ab² - 1.73 b³ The root mean square deviation σ = 0.01206. [3/3] 130
Askaniy @askaniy.bsky.social · 08/09/2026For example, OPAL Cycle 22 maps of Jupiter (Jan. 2015). Rotation A has all the necessary filters for high-quality spectral reconstruction: F395N, F467M, F502N, F547M, F658N. Rotation B missed F467M and F547M. These were synthesized from F395N, F502N, and F658N. [2/3] 130
Askaniy @askaniy.bsky.social · 08/09/2026I'm working on a true color processing of the outer planets maps, projected by the HST team. The selection of filters varied from year to year, resulting in slightly inconsistent spectral reconstructions, so I tried to recreate the data for the missing filters using synthetic maps. It worked. [1/3] 282
Reposted by AskaniyCelestia @celestiaproject.bsky.social · 18/08/2026It's been more than 20 years since Celestia's iconic splash screen was created. Celestia has come a long way since then. Time for a refresh! @askaniy.bsky.social made the skeuomorphic version of the Celestia wordmark seen on the new splash screen, paying homage to the old splash. 082
Askaniy @askaniy.bsky.social · 26/07/2026What I can do quickly is remove the background from the data in bands with fixed polar cap and reprocess the colors: 110
Askaniy @askaniy.bsky.social · 26/07/2026Thank you for the explanation and the suggestion! I'd be happy to reprocess the data using your results, but because of the polar cap correction, that will take some time, which I don't have right now. I'll definitely contact you if I return to the Psyche data! 110
Askaniy @askaniy.bsky.social · 26/07/2026Thanks! I kept the background on the photo by Psyche for aesthetic. But I just couldn't find any bias images or metadata, and they are definitely necessary for proper processing. Were they somewhere? I thought this was preliminary "raw" data, and that the actual raw data would be released later? 110
Askaniy @askaniy.bsky.social · 26/07/2026Bluesky's image compression is highly lossy, see on Flickr: Hubble: flic.kr/p/2srj5Kb Psyche: flic.kr/p/2srdtgzflic.krMars by Psyche, May 2026Ten years apart, Hubble and Psyche captured roughly the same region. You can see Sinus Sabaeus, with Arabia Terra above and the South Polar cap below. Psyche raw images on solarsystem.nasa.gov/psyche... 150
Askaniy @askaniy.bsky.social · 26/07/20263. HST Proposal ID=14499, "MARS-OPPOSITION-2016". 4. By "true color processing", I mean spectral cube reconstruction and transformation to the sRGB color space with chromatic adaptation for illuminant E white point. 110
Askaniy @askaniy.bsky.social · 26/07/2026Details: 1. Psyche raw images on solarsystem.nasa.gov/psyche-raw-i... don't have flux (color) calibration, so the HST photo was used for this purpose. 2. The high-SNR dataset from Psyche has the polar cap overexposed. I fixed it by mixing it with low-exposure images. 110
Askaniy @askaniy.bsky.social · 26/07/2026True color processing of Mars: ten years apart, Hubble and Psyche captured roughly the same region. You can see Sinus Sabaeus, with Arabia Terra above and the South Polar cap below. 16314
Askaniy @askaniy.bsky.social · 10/07/2026Current color table for some featured data (including Torifune and Kamoʻoalewa this time). More options can be found here (github.com/Askaniy/True...) or generated for different categories. 021
Askaniy @askaniy.bsky.social · 10/07/2026TrueColorTools v4.6 is out! The changelog is dominated by new and updated spectral data. Thanks to @lunathesilly.bsky.social, Pedro J. Garcia, @geobica.com, and SevenSpheres for their contributions! github.com/Askaniy/True... 142
Reposted by AskaniyExtrema @extrema207.bsky.social · 31/05/2026Little dump of processed images from the Cassini spacecraft #cassini #saturn #jupiter #solarsystem #titan #mimas 072
Askaniy @askaniy.bsky.social · 04/07/2026Designed and rendered in Blender updated wordmark for @celestiaproject.bsky.social After some modifications, it will be used for the new splash screen that the community is currently working on 073
Reposted by AskaniyCelestia @celestiaproject.bsky.social · 20/06/2026Celestia mobile 1.9.18 for Android devices has been released. This update fully releases the new PSF star renderer, which can be enabled by going to Settings > Renderer > Star Style! Download from GitHub 063
Askaniy @askaniy.bsky.social · 07/06/2026Teamwork in action! Limb darkening was primarily implemented by Hleb Valoshka, @astrochara.bsky.social calibrated the star textures, while Pedro J. Garcia and I helped in fixing. The animation also shows seamless transition to the resolved star rendering mode, which was developed by Levin Li and me. 263
Askaniy @askaniy.bsky.social · 05/06/2026The radio sources were rendered using CelestiaStarRenderer I developed and redesigned last month: github.com/Askaniy/Cele... You can download the map and see more details on Flickr and DeviantArt: flic.kr/p/2rThKWw www.deviantart.com/askaniy/art/... 010
Askaniy @askaniy.bsky.social · 05/06/2026I used GSM2016 model available in PyGDSM library to map diffuse radiation (with some patched parts) and SPECFIND V3.0 to map radio sources. Sources: ui.adsabs.harvard.edu/abs/2017MNRA... github.com/telegraphic/... ui.adsabs.harvard.edu/abs/2021A%26... cdsarc.u-strasbg.fr/viz-bin/cat/... 100
Askaniy @askaniy.bsky.social · 05/06/2026Wavelengths of monochromatic primaries were scaled by a factor of ~500,000 so that R, G, B channels correspond to 89.90, 110.25 and 130.61 MHz (3.34, 2.72 and 2.27 meters). The saturation (overexposure) flux density corresponds to 30 Jansky per pixel (1.2e-26 W / (m² nm)). 100
Askaniy @askaniy.bsky.social · 05/06/2026What would the night sky look like if we could see it in radio waves? This synthetic false color map, which was created as a byproduct of my work with radio data, illustrates this hypothetical scenario. Simple cylindrical projection, center right ascension 0° (increases to the left). 1184
Askaniy @askaniy.bsky.social · 01/06/2026You can import `RenderEngine` class from `CSR.py` to draw a star on a NumPy array canvas. Cylindrical maps are also supported. 020
Askaniy @askaniy.bsky.social · 01/06/2026Details about the rendering method and examples of its implementation in Python are available here: github.com/Askaniy/Cele... Last month, I revised the formulas to make them much closer to the original PSF. Thanks to Levin Li for implementing the method in Celestia! 161
Reposted by AskaniyExtrema @extrema207.bsky.social · 15/04/2026Crescent Mercury #mercury #solarsystem #space #astronomy 051
Askaniy @askaniy.bsky.social · 06/04/2026The texture map is more suitable for visualization than for scientific purposes. Also, I made a true color version (16-bit color depth). Details: - Simple cylindrical projection, planetocentric coordinate system, center longitude 0°. - sRGB color space with chromatic adaptation for illuminant E. 031
Askaniy @askaniy.bsky.social · 06/04/2026Last week, I processed a global contrast-enhanced false color map of asteroid Ryugu by painting a mask to fill regions of unknown or corrupted data. The RGB values correspond to Hayabusa2's x, v, b filters. Original map: jlpeda.jaxa.jp/en/product/a... Yokota et al. (2021): doi.org/10.3847/PSJ/... 131
Askaniy @askaniy.bsky.social · 16/03/2026Done: github.com/Askaniy/True...github.comAdded support for saving in JPEG and TIFF with selectable color depth · Askaniy/TrueColorTools@b7e969a 110
Askaniy @askaniy.bsky.social · 16/03/2026I'm thinking of using TIFF instead, adding the options "PNG int8", "TIFF int16" and "TIFF float32" using `tifffile` library, small and available in PyPI. Are you ok with it? 111
Askaniy @askaniy.bsky.social · 16/03/2026The library I use (Pillow) has historically not supported 16-bit RGB color: github.com/python-pillo... Other libraries for saving PNG files either overloaded with dependencies (affect the size of the compiled file) or are slow and require changes in the installation method. 110
Reposted by AskaniyBjörn Jónsson @bjornjonsson.bsky.social · 14/03/2026(1/3) Another set of Jupiter test renders from the Voyager 2 map I'm working on. Here I used True Color Tools (TCT) to correct the color. This is a great set of tools by @askaniy.bsky.social to compute realistic colors (see github.com/Askaniy/True... ) 1368
Askaniy @askaniy.bsky.social · 20/02/2026Great work! I'm also looking towards a cylindrical map. Earlier, I wanted to ask for a cylindrical map for your processing of Pluto. Would that be okay? 110
Reposted by AskaniyExtrema @extrema207.bsky.social · 06/02/2026Uranus during equinox #space #astronomy #solarsystem #uranus #hubble 162
Reposted by AskaniyExtrema @extrema207.bsky.social · 31/01/2026Saturn #astronomy #space #solarsystem #planets #saturn #hubble 081
Askaniy @askaniy.bsky.social · 24/01/2026The method can be easily extended to cases where smoothness depends on wavelength, or where a characteristic spectral scale is specified instead of smoothness. Unfortunately, a different method is required to use a reference spectrum. 020
Askaniy @askaniy.bsky.social · 24/01/2026You're right, it was a typo... We need to maximize smoothness = minimize derivatives 110
Askaniy @askaniy.bsky.social · 24/01/2026In brief, I write the filter profiles as a matrix and the photospectrum as the result of multiplication by the spectrum. I then solve the inverse problem by minimizing the smoothness, a combination of the first and second derivative (in the current implementation). 120
Askaniy @askaniy.bsky.social · 24/01/2026This is my development, on which I'm currently writing a research paper, for some time 😅 I've reviewed the literature, but it doesn't seem to have been used before. The current implementation is in TCT and is about to be modified after some experiments. 120
Askaniy @askaniy.bsky.social · 24/01/2026Simple cylindrical projection, center longitude 0°. Gamma corrected, albedo scaled. Color space: sRGB, while point: Illuminant E. Links for the full resolution (11K, 2 km/pix): www.flickr.com/photos/19356... www.deviantart.com/askaniy/art/... [3/3] 011
Askaniy @askaniy.bsky.social · 24/01/2026The original paper by Michael et al. (2024): www.sciencedirect.com/science/arti... The data archive used: psaftp.esac.esa.int#/Guest-Stora... TrueColorTools: github.com/Askaniy/True... A related article: www.esa.int/Science_Expl... [2/3] 110
Askaniy @askaniy.bsky.social · 24/01/2026Map of Mars in true colors: images from Mars Express were projected by Michael et al. (2024) and post-processed with TrueColorTools. TCT used the Tikhonov regularization to reconstruct a spectral cube from four High Resolution Stereo Camera (HRSC) channels and simulated human perception of it. [1/3] 2248
Askaniy @askaniy.bsky.social · 13/01/2026GitHub repository: github.com/Askaniy/Cyli... In the last update, the GUI became three-column and the mean color/brightness output was added. Processing is no longer limited to cylindrical maps, and a major part has been rewritten using the OOP paradigm. (Not vibe coded). [5/5]github.comGitHub - Askaniy/CylindricalTextureCalibrator: GUI application for preparing space texture mapsGUI application for preparing space texture maps. Contribute to Askaniy/CylindricalTextureCalibrator development by creating an account on GitHub. 020
Askaniy @askaniy.bsky.social · 13/01/2026Cyclic longitude shift function uses a Fourier transform. Alpha channel represents a mask. Bowring's formulas and the curvature tensor are used to derive weights for map pixels. Oblateness is taken into account. The pictures show the main formulas and a comparison of weight maps. [4/5] 100
Askaniy @askaniy.bsky.social · 13/01/2026Although they are both "simple cylindrical projections", the difference in the latitude systems is significant. For example: PIA07782. In software, the planetographic system is often assumed. However, this map uses the planetocentric system, and I've never seen it rendered correctly before. [3/5] 200
Askaniy @askaniy.bsky.social · 13/01/2026The main goal is to simplify specific image processing operations. CTC can (re)color textures, taking into account cylindrical projection distortions. It can reproject maps from planetocentric (and Lambertian) latitudes to planetographic ones. The sRGB gamma correction can easily be applied. [2/5] 100
![A clump of gas in front of a hot Jupiter
An attempt to (relatively) realistically paint a hot Jupiter with a quasi-closed type of atmosphere, according to [1][2].
For hot Jupiters, the Lagrange points L1 and L2 are just within a few planetary radii, so it's easy for the atmosphere to escape outward and inward of the orbit. With a lower semi-major axis, the speed of the leaked atmosphere is higher, so it goes in the direction of motion. But solar wind (and light pressure) can stop the leak and form a quasi-closed configuration.
The color of the photometric surface is blue according to modeling ([3] for example) and measurements ([4] for example), but mostly overexposed here. The color of the upper atmosphere is blue due to Rayleigh scattering.
In reality there may be the following differences: smaller photometric radius relative to the outer atmosphere, the planet may not have a clear boundary, the photometric properties of the outer atmosphere are not clear. The brightness balance has also not been calculated.
[1] Gas envelopes of exoplanets - hot Jupiters: https://ui.adsabs.harvard.edu/abs/2021PhyU...64..747B/abstract
[2] Types of Hot Jupiter Atmospheres: https://www.researchgate.net/publication/269725888_Types_of_Hot_Jupiter_Atmospheres
[3] Albedo and Reflection Spectra of Extrasolar Giant Planets: https://ui.adsabs.harvard.edu/abs/2000ApJ...538..885S/abstract
[4] The Deep Blue Color of HD189733b: Albedo Measurements with Hubble Space Telescope/Space Telescope Imaging Spectrograph at Visible Wavelengths: https://ui.adsabs.harvard.edu/abs/2013ApJ...772L..16E/abstract](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:xbjs5d6srll42cljj3kqpdrr/bafkreiclm5qkucfbkj2k56feryg5jtrn724fqhcevfp5m7lio4sfnppzne)
