Sat, 22 Jul 2017
Bright new Russian 'star'
Sky-watchers might notice a strange, new and very bright object in the sky over the coming weeks. Predicted to be as bright as magnitude –10, which is as bright as the first-quarter Moon, this is a new Russian spacecraft named Mayak, launched on 14 July.
The satellite carries a tetrahedral reflector, with each face being four square metres in area. The aim is not to create a bright object, but in due course to test the possibility of aerobraking satellites to deorbit them. However, as with the Iridium satellites, this also has the side-effect of possibly making it one of the brightest objects in the sky.
Mayak is in an almost north–south orbit, unlike the west–east orbit of the International Space Station. It is due to be visible from the UK around midnight during the next few weeks, as this orbit brings it over the same part of the Earth at roughly the same time on each orbit. After about a month the satellite may do what it’s designed to do and come out of orbit.
So far there have been few reports of the object, leading to suspicions that the reflectors may not have deployed as intended. However, as the reflectors are arranged in a tetrahedron, there is only a limited chance that one of them will reflect sunlight directly at an observer rather then black space. This could account for the disparity in brightness. One observer in Germany has reported it at its full brightness, while MalcolmP, observing from SW England, reports that ‘I was able to observe this object from SW England at 01:26 BST on 23/07/17 and found it to be between mag 1.2 and mag 2.2: brighter than Gamma Draconis, not as bright as Deneb – best guess therefore at about mag 1.5.’
You can get predictions of its passes at Heavens-above.com. If you are unfamiliar with using this website, read our help file on using it to observe the International Space Station. The ISS will also be visible in the evenings over the coming few weeks. On 23 July around midnight BST the two objects will be in the sky together, though their paths are not predicted to cross. Notice from the predicted tracks that many of the Mayak passes are quite low in the eastern sky, so you'll need a good eastern horizon.
Please report any sightings or, even better, photos, to firstname.lastname@example.org. But if you want to know more about the satellite itself, try this news story from Sky and Telescope.
Added by: Robin Scagell