Circumstances: Those data were acquired during the practical phase of an Astronomy course delivered by the Côte d’Azur University (Diplôme Universitaire d’Astronomie Observationelle (https://www.oca.eu/fr/duao-oca#:~:text=Le%20DUAO%20(Dipl%C3%B4me%20Universitaire%20d,th%C3%A9orique%20et%20pratique%20en%20astronomie) Data acquisition: Date: Sunday, January 15th 2023, 1st image 18:56; 84th and last image: 21:55 Location : C2PU/Calern Observatory (IAU_010), France [long.: +6.92277, lat.: +43.75377, alt. 1260 m] Telescope: Epsilon, Focal length 9.36m, Aperture diameter: 1.04m Focus configuration: Cassegrain, + Focal reductor F/9 Science camera: QSI 632, temp.: -20° Weather: 1st image: temp.: 2.6° (dome+outside), pressure: 864 mbar/hPa, wind: 4.4m/s, hum.: 62% 84th and last image: temp.: 2.3° (dome+outside), pressure: 863 mbar/hPa, wind: 5.3m/s, hum.: 44% Observers: Serge DURAND, Paris (serge.deuxieme@hotmail.com) Alain ESCAFFRE (alain.escaffre@gmail.com) Data processing: Serge DURAND, Paris (serge.deuxieme@hotmail.com) Note about pictures : They were taken in a defocalised mode. Important note : there is another star very near HAT-P-20 : UCAC3 229-88754 other name 2MASS 07273963+2420171. This star is fainter than HAT-P-20 by 1.36 mag (R). Therefore the Real depth (in flux) is the observed one multiplied by 1.3