Been monitoring HT-Cas star several nights ( 12"F4 + Starlight MX716 ccd + Baader IRcut 90sek exp.) When making measures, i,d take star 172 (AAVSO Chart 12645FMI ), as chek star to see how accurate my measures is in low SNR. Seems to mee that star 172 is varying slightly. I compared star 172 to as bright star USNO-A 1500-01193693 (Chk 3) and it show no trace of such wobbling.
I'm right or is it my error?