Telescopic optical images of comet C/2020 F3 (NEOWISE) on 21.9, 26.9 July, and 6.9 August 2020 UT, close in time to the IRAM observations. North is to the top and the field-of-views (fov) are 40 × 40′. Corresponding estimates of Afρ (red band) were 10 000, 4300, and 1600 cm, respectively. The 20–40 s exposure at the focus of a 407 mm diameter telescope (F = 1750 mm) from Eure-et-Loire (France). ©N. Biver.