Over the last few years, with the evolution of sensor localization technologies on our smartphones, applications for the exploration of constellations and planets have become more and more precise. They are simple but extremely powerful tools, which allow you to orient yourself in the night sky even to those who are completely starved of astronomy. We have selected some of the best, almost all with a free version (or with in-app purchases and subscription) that you can try in the next few days to discover three spectacular alignments between the Moon and other planets.
The upcoming alignments
It starts on April 24, 2022 with the conjunction between the Moon and Saturn. Starting at 10:56 pm, our satellite and the planet will be positioned at 4.6 ° from each other. The Moon will shine with an apparent magnitude of -11.5 while Saturn will be fainter, but still visible with a magnitude of 0.6 (nb: the apparent magnitude is a logarithmic scale and negative values indicate greater brightness). The best way to observe the conjunction is with binoculars or with the naked eye.
On the night between 25 and 26 April the Moon will be close to Mars, in the constellation of Aquarius. The Red Planet will have an apparent magnitude of 0.9 and will be 4.1 ° away from our satellite. The event will be visible from 00:06 on April 26 and the conjunction will last about three hours. Night owls can then try to observe the nocturnal dance between the Moon and Venus, scheduled for April 27 at 03:51. The Moon will be waning and will approach Lucifer, as Venus is historically called the “light bearer” when it rises in the sky before dawn. The planet will be bright enough, with a magnitude of -4.1.
Apps for observing the sky
Whether you have an iPhone or an Android smartphone, it will not be difficult to find an app to help you discover the starry sky. They all work more or less the same way, that is, they use GPS and gyroscope inside the smartphone to show the stars in the direction the smartphone is pointing. Some, like Night Sky on iOS, also offer an augmented reality feature that turns the ceiling into a virtual planetarium (with varying results). Net of advanced functions and the difference in the interface, they all allow you to easily identify constellations, single stars, planets and in many cases also the trajectory of the International Space Station, comets (even those not visible to the naked eye) and of satellites.
Star Walk 2 is one of the most popular apps: it is available both on the App Store and on the Google Play Store. The free version is called Star Walk 2 Ads + and contains advertising, which can however be removed thanks to in-app purchases (or by downloading the paid app).
Link: iOS / Android
For iPhone users, Night Sky is another interesting option. The app is well done and fast. Here we have been using it for years in the free version: it allows you to observe the sky, identify celestial bodies and obtain information on stars, planets and much more. There is also a paid version but it is a subscription and costs a little too much (around € 30 a year). The peculiarity compared to the others is that it is available for all Apple devices, including iPad, Mac and Apple TV. In the case of the latter two it is only possible to “navigate” the constellations and planets without the AR functions overlapping with the starry sky.
Link: iOS
Star Tracker is a cross-platform app that allows you to observe and recognize up to 88 constellations and more than 8000 stars. All functions are also available offline, a very useful feature for those who want to use the app while camping, in the mountains, on a boat or in many situations far from the light pollution of the city as well as from LTE connectivity. Otherwise the functions are very similar to those of Star Walk and Night Sky X.
Link: iOS / Android
SkySafari it is free for all Android users, while it costs € 1.99 in the version for iOS, which however adds some features and is also compatible with Mac and iPad. The concept is always the same: once opened, just point it towards the sky to find out which stars and planets we are observing. Two in-app purchases for iOS also allow you to observe the trajectories of the Apollo moon missions or to discover the history of the cosmos thanks to special audio guides.
Link: iOS / Android