  Four observations of Starlink's LEO communication satellites, Darksat and
STARLINK-1113, were conducted on two nights with two telescopes. The Chakana
0.6\,m telescope at the Ckoirama observatory (Chile) observed both satellites
on 5\,Mar\,2020 (UTC) and 7\,Mar\,2020 (UTC) using a Sloan r' and Sloan i'
filter, respectively. The ESO VISTA 4.1\,m telescope with the VIRCAM instrument
observed both satellites on 5\,Mar\,2020 (UTC) and 7\,Mar\,2020 (UTC) in the
NIR J-band and Ks-band, respectively. The calibration, image processing, and
analysis of the Darksat images give r\,$\approx$\,5.6\,mag,
i\,$\approx$\,5.0\,mag, J\,$\approx$\,4.2\,mag, and Ks\,$\approx$\,4.0\,mag
when scaled to a range of 550\,km (airmass $=1$) and corrected for the solar
incidence and observer phase angles. In comparison, the STARLINK-1113 images
give r\,$\approx$\,4.9\,mag, i\,$\approx$\,4.4\,mag, J\,$\approx$\,3.8\,mag,
and Ks\,$\approx$\,3.6\,mag when corrected for range, solar incidence, and
observer phase angles. The data and results presented in this work show that
the special darkening coating used by Starlink for Darksat has darkened the
Sloan r' magnitude by 50\,\%, Sloan i' magnitude by 42\,\%, NIR J magnitude by
32\,\%, and NIR Ks magnitude by 28\,\%. The results show that both satellites
increase in reflective brightness with increasing wavelength and that the
effectiveness of the darkening treatment is reduced at longer wavelengths. This
shows that the mitigation strategies being developed by Starlink and other LEO
satellite operators need to take into account other wavelengths, not just the
optical. This work highlights the continued importance of obtaining
multi-wavelength observations of many different LEO satellites in order to
characterise their reflective properties and to aid the community in developing
impact simulations and developing mitigation tools.
