Author: Franck

Starlink is a project by the American company SpaceX, which aims to provide high-speed Internet connection across the globe through a myriad of specially designed satellites.

To reduce latency, these small satellites, weighing less than 260 kg, are placed in low Earth orbit at just a few hundred kilometers in altitude. At term, this constellation will consist of more than 42,000 satellites!

This project is a disaster for astronomers who fear that their measurements will be seriously affected by the increasing number of these intruders. This pollution will not only impact deep-sky photography but could also harm radio telescopes that observe the sky in other regions of the electromagnetic spectrum. The frustration grows as professional and amateur astronomers begin to notice the initial effects of these constant passes in the field of view of their instruments.

However, Elon Musk’s company is not the only one seeking to exploit low Earth orbits. OneWeb and Amazon are already developing competing projects that, in a few years, will fill the sky with hundreds of thousands of bright points impossible to remove.

This will result in a radical transformation of the sky as we know it, making astrophysics research impossible from Earth. This natural heritage, accessible to everyone and already severely damaged by chaotic suburban lighting, will disappear forever.

Unfortunately, it seems difficult to fight against these multinationals that decide with impunity to deprive humanity of this common good. Every month, they obtain authorization to launch new satellites from organizations such as the International Telecommunication Union or the Federal Communications Commission, taking advantage of the current legal vacuum and outdated rules caused by this space race. Moreover, these mega-constellations of satellites significantly increase the risk of collisions and could saturate near-Earth space with debris of all kinds.

Astronomers are left with no choice but to protest and can only try to alert public opinion and governments to the dangers of these uncontrollable projects.

To see the extent of the damage, the latest version of WinStars displays the real-time position of the Starlink constellation satellites.

Simply go to the “Objects” field in the “Solar System/Satellites” menu and select, one by one, all satellites whose names begin with Starlink.

The occlusion mapping technique plays with shadows and lights to simulate roughness on the surface of an object.

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

Thanks to tessellation, the number of polygons used to represent an object’s details increases considerably. Hollows and bumps are now represented in three dimensions and are no longer merely simulated.

The much more complex mesh of the surface is visible in wireframe mode. The triangles here are counted by the thousands.

The advantage of tessellation lies in the fact that the addition of these new triangles is carried out internally by the graphics processor during rendering.
There is therefore no problem of bandwidth reduction between the CPU and GPU during the geometric complexification phase. Since this technique is highly optimized, its impact on the software’s fluidity is limited.

This Gamoniac video explains the benefits 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 Mars’ surface is not as good as the Moon’s due to the significantly lower texture quality. I am searching for better textures to provide a similar rendering.

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

We know that Betelgeuse is the closest candidate for a future supernova explosion in our galaxy. For this reason, it has been observed for about fifty years in the hope of learning more about the processes at play during the agony of stars. Although several scenarios can explain the abnormal decline in its brightness, we obviously cannot rule out the possibility that it is, perhaps, on the verge of exploding.

With each launch of WinStars, the program will consult AAVSO data to take into account the evolution of Betelgeuse’s magnitude. We can already see that the star is hardly brighter than its neighbor Bellatrix in the constellation of Orion.

The 3.0.104 version also includes a slightly redesigned “Animations” dialog box. The slider has been replaced with a simple field in which the user can enter a multiplicative factor to speed up or slow down the normal flow of time.

In addition, a new icon appears in the menu on the right side of the screen. It replaces the “point in a direction” icon, which didn’t have much use and wasn’t implemented yet. This new icon allows you 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: wikipedia.org)

Finally, the Android version contains optimized executable files for the arm64-v8a and x86 architectures. A dedicated version for x86 64-bit processors is currently in preparation.

By clicking on the telescope and selecting the “Space telescope live” option, you can also access the instrument’s schedule, the name of the astronomer responsible for the ongoing observation, as well as the instrumentation parameters (camera used, filters, field value).

We would like to thank the STScI Web Team for their prompt response and for making the numerous findings of this exceptional telescope available to the general public!

NICER’s main mission is to study the interiors of neutron stars, extremely compact and dense celestial bodies formed after a star explodes. One of the specific objectives is to measure their diameter with a precision of 5%, according to NASA

To carry out these measurements, NICER scans the sky by moving from one target to another. These movements create the arcs visible in the final image.

If some curves appear brighter than others, it is simply because the instrument has followed the same path multiple times between certain targets. These curves intersect at bright points that are powerful sources of X-rays.

Among these sources are the Cygnus Loop, a supernova remnant, and the MAXI J1820+070 source, suspected to be a black hole in reality.

By activating the NICER module in WinStars, you can replace the usual sky background with the image that NASA has just published on the mission’s website (you also need to disable the Brunier module for the image to appear correctly).

The original NASA annotations have been intentionally preserved in the final image.

Version 3.0.84: The RA/Dec and Azi/Alt coordinate grids now have labels!

The program now displays objects from the OpenNGC catalog (https://github.com/mattiaverga/OpenNGC) whose positions and data are much more reliable than those contained in the old SAC catalog.

This catalog was built using several sources: NASA/IPAC Extragalactic Database, HyperLEDA, Simbad, and HEASARC. It contains around 15,000 objects.

You can find details about its creation here: https://github.com/mattiaverga/OpenNGC/blob/master/README.md

Launched on August 4, 2018, the Parker Solar Probe (PSP) has the mission of studying the Sun for 7 years. Placed in a elliptical orbit, with its perihelion located at less than 0.17 astronomical units (AU) and its aphelion at the orbit of Venus, this NASA mission is full of achievements. Equipped with an efficient thermal shield that protects its structure from the flux emanating from the Sun and will raise the temperature to 1400 K at times, the probe is equipped with four instruments that will study the solar corona.

Indeed, the corona remains poorly understood even today. We know almost nothing about the accelerating mechanisms of the particle flux escaping from the upper atmosphere (the solar wind), nor about the origin of the high temperatures of the corona (1 million degrees K), which are a hundred times higher than those observed at the surface of the star.

A wide-angle coronagraph will capture three-dimensional images of the corona and the inner 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 about the characteristics of particles present in the solar atmosphere and the inner heliosphere, 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.

On April 4, 2019, the probe ventured to within 25 million kilometers of the Sun, moving at a relative speed of 343,000 km/h with respect to it, making it the fastest object in human history. In 2023, PSP will come within 6 million km of the Sun.

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

As a reminder, the Gaia mission aims to map a portion of the Milky Way (1%) in 3D by assessing the proper motion of the celestial bodies listed. This colossal task is carried out by a satellite positioned at the Lagrange 2 point, which performs 500 million measurements daily.

The previous catalogs, such as Sky2000, UCAC4, and I/280B, have been replaced to make way for the 1.7 billion stars featured in this second edition, published in April 2018, one year ago.

Since it is not reasonable to retrieve all of the data from DR2, WinStars only uses right ascension, declination, parallax, proper motion, and G magnitude for objects with a magnitude lower than 13. Beyond this limit, the program only retrieves hourly coordinates and magnitude.

A version 3 in 2022

The Gaia mission’s measurement campaign continues, and a version 3 of the catalog is expected in 2022 with increased data accuracy.

We are only at the beginning of the mission. In the long run, the entire structure of our galaxy, its dynamics, and evolution will be better understood through the analysis of this vast amount of information.

Scientific data freely accessible thanks to the CDS

I would like to conclude by acknowledging the work of the Centre de Données de Strasbourg, a true virtual memory of the sky, which makes available to everyone the data collected by the largest observatories and collaborations like Gaia. This is how measurements from a satellite located two million kilometers from Earth can be found in WinStars just a few months later.

To learn more:

• https://www.cosmos.esa.int/web/gaia/dr2
• https://m.esa.int/Our_Activities/Space_Science/Gaia/Frequently_Asked_Questions_about_Gaia
• Gaia Data Release 2- Summary of the contents and survey properties