Blog – Page 2 – WinStars 3

Tessellation in WinStars

With version 3.0.118, WinStars uses tessellation to improve the rendering of planetary surfaces. This technique, introduced with the OpenGL 4.0 standard, adds a large number of triangles to an object to make its 3D appearance more complex.
Previously, WinStars simulated the relief of a planet by playing with shadows and illusory perspectives. The textures modified by occlusion mapping were then applied on simple geometrical shapes (typically about ten triangles).

Occlusion mapping technique that plays on shadows and lights to simulate roughness on the surface of an object.

Here, wireframe rendering has been activated.  In reality, the surface remains very simple geometrically..

With tessellation, the number of polygons used to represent the details of an object becomes massive. Depressions and bumps are now represented in three dimensions and are no longer simulated.

The significantly more complex surface mesh is visible in wire mode. Triangles are counted here by thousands

The advantage of tessellation lies in the fact that the addition of these new triangles is done internally by the graphics processor during the rendering phase.
Therefore, there is no bandwidth reduction problem between CPU and GPU during this geometric complexification phase. This technique being very optimized, the impact on the fluidity of the software is limited…

This video from Gamers Nexus explains very well the interest of this technique in the video game industry:

Tessellation is enabled for Mars and the Moon and currently only works with desktop versions (Linux, MacOS and Windows). The rendering of the surface of Mars is not as good as for the Moon, the textures quality being much inferior. I’m looking for better textures to offer a comparable rendering.

What’s going on with Betelgeuse ?

Have you noticed that Betelgeuse1, the star forming the right shoulder of the legendary hunter Orion, has recently lost its luster?

The light curves available on the American Association of Variable Star Observers (AAVSO) website confirm a change in magnitude from 0.5 to 1.3 in the space of few weeks. These changes in brightness are not so surprising for this red supergiant, twelve times more massive than our Sun, known for its variability and irregularity. But it is the brutality of this evolution that intrigues astronomers today.

We know that Betelgeuse is the closest candidate for a future supernova explosion in our galaxy. For this reason, it has been observed attentively for the last 50 years with the hope of learning more about the processes at work in the stars’ agony. Even if several scenarios can explain the abnormal decline of its luminosity, we obviously cannot exclude the fact that it is, perhaps, about to explode.

Each time WinStars starts, the program will consult the AAVSO data to reflect the evolution of the magnitude of Betelgeuse. We can already note that the star is not much brighter than its neighbour Bellatrix in the constellation of Orion.

Version 3.0.104 also features a slightly redesigned Animations dialog box. The slider has been replaced by a simple field in which the user can enter a multiplicative factor to speed up, or slow down, the normal rate of time flow.

A new icon will also appear in the right hand menu. It replaces the “point in a direction” icon which was not really needed and was not yet implemented.
It makes it possible to reverse the course of time…

1. The traditional name Betelgeuse is derived from either the Arabic إبط الجوزاء Ibṭ al-Jauzā’, meaning “the armpit of Orion”, or يد الجوزاء Yad al-Jauzā’ “the hand of Orion” (Sources:


Apollo 11, processor optimizations and Russian translation

On the occasion of the 50th anniversary of this historic event that captivated the world, the “Apollo 11” module honours the man’s first steps on the Moon.
A 3d model of the LEM and control module is just placed between the Earth and the Moon. No trajectory is calculated. The date is not taken into consideration.

As a coincidence of timing, this new version also offers a Russian translation of the site and software. Thanks to Sergey Telukhin for doing this huge job.

Finally, the Android version contains executables optimized for arm64-v8a and x86 architectures. A specific version for 64-bit x86 processors is in preparation.



Version 3.0.86 is online: close-up of the Hubble Space Telescope

It is now possible to monitor, in real time, the position and orientation of the Hubble Space Telescope.

The telescope changing target

By clicking on the telescope and choosing the “Space telescope live” option, you can also access the instrument’s schedule, the name of the astronomer who initiated the observation and the instrumentation parameters (camera used, filters, field value).

And thank you to the STScl Web Team for responding me so quickly and making available to the public the innumerable benefits of this telescope!

NICER Maps the X-ray Sky

NASA has just published a new map of the sky. It represents what we could see if our eyes were sensitive to x-rays. It was obtained thanks to the NICER instrument (“Neutron Star Interior Composition Explorer”) which has been performing measurements on board the International Space Station since June 2017.

The main mission of Nicer is to learn more about the inside of neutron stars, very compact and dense stars formed after the explosion of an end-of-life star. One of the objectives is to measure their diameter “with an accuracy of 5%”, says NASA.

To carry out these surveys, NICER scans the sky by moving from one target to another. It is these movements that are at the origin of the arcs that are visible on the final image.

A timelapse of NICER aboard the ISS.

If some curves appear brighter than others, it is only because the instrument has made the same path many times between specific targets. The curves intersect on bright points which are powerful sources of X-rays.

Among these sources can be found the Cygnus Loop, a supernova afterglow, or the MAXI J1820+070 source which is suspected to be actually a black hole.

By activating the NICER module in WinStars, you can replace the usual background of the sky with the image that NASA has just published on the mission site (it is also necessary to disable the Brunier module to display the image normally).

The original NASA annotations were deliberately left on the final image.

The map that NASA has just published as it appears in WinStars


New catalogue concerning the deep sky objects

The program now displays objects from the OpenNGC catalog ( whose positions and data are much more reliable than those contained in the old SAC catalog.

This catalogue was built by merging information from NASA/IPAC Extragalactic Database, HyperLEDA, Simbad and HEASARC and includes about 15,000 objects.

More information on its creation can be found here:

Parker Solar Mission: Learn more about the solar corona

Launched on August 4, 2018, the Parker Solar Probe (PSP) is designed to study the Sun for 7 years. Placed in an elliptical orbit, with a perihelion less than 0.17 AU and an aphelion at the level of the Venus orbit, NASA’s mission is the mission of all exploits. Equipped with a powerful heat shield protecting the structure from the flow emanating from the Sun and which will raise the temperature up to 1400 K in some moments, the probe has four instruments to study the solar corona.

PSP in WinStars

Indeed, the corona is still very poorly known today. We know almost nothing about the accelerating mechanisms of the flow of particles escaping from the upper atmosphere (the solar wind), and about the origin of the high corona temperatures (1 million degrees K), which are a hundred times higher than those observed on the surface of the star.

A wide-angle coronograph will take three-dimensional images of the corona and the internal heliosphere. The FIELDS instrument will measure electric and magnetic fields, radio wave emissions and plasma waves.
ISIS (Integrated Science Investigation of the Sun) will provide more information on the characteristics of particles in the solar atmosphere and the internal heliosphere that are accelerated to high energies (from 10 keV to 100 MeV).
Finally, the SWEAP (Solar Wind Electrons Alphas and Protons) instrument will study the electrons, protons and helium ions that make up the solar wind.

In April 4, 2019, the probe adventured less than 25 million kilometers from the Sun, travelling at a relative speed of 343,000 km/h, making it the fastest object in human history. In 2023, PSP will be close to the Sun at a distance of only 6 million km.

By installing the Parker Solar module in WinStars, it is possible to view the position of the probe in real time and follow the 24 orbits planned to reveal the secrets of the atmosphere of our star.

Gaia Data Release 2

After several weeks of work, the second catalogue of the Gaia mission is now integrated into WinStars.

As a reminder, the Gaia mission is designed to map in 3D a part of the Milky Way (1%), with an evaluation of the proper velocity of the celestial bodies identified. A herculean task made by a satellite located at Lagrange 2 point that performs 500 million measurements every day.

The old Sky2000, UCAC4 and I/280B catalogues have therefore been abandoned to be replaced by the 1.7 billion stars (!) contained in this second edition published in April 2018, just one year ago.

Since it is not reasonable to get all the data from the DR2, WinStars only uses right ascension, declination, parallax, proper motion and magnitude G for objects with a magnitude less than 13. Beyond this limit, the program only retrieves positions on the sky and magnitude.

A version 3 in 2022

But the Gaia mission’s measurement campaign continues. A version 3 of the catalogue is planned for 2022 with increased data accuracy.

We are only at the beginning of the mission. In the long run, it is the entire structure of our galaxy, its dynamics and evolution that will be better understood by analyzing this gigantic mass of information.

Scientific data freely accessible through CDS

I would like to conclude by acknowledging the work of the Centre de Données de Strasbourg, a virtual memory of the sky, which makes available all the data collected from the largest observatories and from Gaia-type collaborations.
Thus, the data coming from a satellite located at two million km from Earth can be included in software such as WinStars a few months later.

In an age of fake news and other conspiracy theories, access to knowledge obtained through the disinterested work of thousands of scientists dispersed throughout the world has never been, paradoxically, so simple.

WinStars uses the Gaia DR2 catalogue to display stars up to magnitude 20. Here, the globular cluster Messier 13.

To go further:

Changes regarding the Android version of WinStars

On March 7, Google suspended WinStars for non-compliance with the program update method. Indeed, Google requires developers to use two files to download data and update applications.

I had chosen to keep the update method developed for the desktop version, which is less expensive in terms of download volume, which seemed to me to be a good idea for a mobile version.

Also, if you want to continue using the Android version of WinStars, you must uninstall the program and reinstall the application using this pack: