During the last few days Spectrum-RG spacecraft was observed by many Russian optical telescopes. These observations are needed to improve SRG orbit parameters measurements. The improved orbital solution will allow to apply more accurate orbit correction, which is planned on July 22. More accurate orbit correction will allow to save fuel aboard SRG spacecraft during its fly to the second Lagrange point (L2) of the Sun-Earth system. In future it will help to extend the mission lifetime.
These optical observations were done with Russian-Turkish 1.5-m telescope, Zeiss-1000 of Special Astrophysical Observatory of RAS, 1.6-m Sayan observatory telescope of Institute of Solar-Terrestrial Physics of SB RAS, 0.6-m telescope of Institute of Astronomy of RAS at Terskol observatory, telescopes of Crimean Astrophysical Observatory and others.
The SRG spacecraft is now located at the distance about 700 km from the Earth, in the direction of Aquila constellation and is moving to the Lagrange L2 point with the velocity around 800 m/s relative to Earth.