Over the years, some stars in the AAVSO database proved not to be variable. These "constant" stars are no longer of interest, astrophysically speaking, but they are convenient targets to check the quality of your photometry. Thirteen northern stars are listed below (southern "constants" are harder to come by). All are in the master list of PEP targets. Since these stars are still in the AAVSO system, you can submit and examine data for them. The greater the B-V difference, the more strongly the calibration of your system will be challenged.
Note: This campaign is the subject of the AAVSO Spectroscopy discussion forum thread: https://www.aavso.org/p-cyg-monitoring-intrinsic-h%CE%B1-flux
Also, spectroscopy reports should be submitted to the AAVSO Spectroscopy Database (AVSpec, https://www.aavso.org/apps/avspec/). - Elizabeth O. Waagen, 20 May 2020
CONTINUED THROUGH 2020 AT LEAST
AAVSO observer Raymond Winslow (Win) Jones passed away on 28 February 2007 at age 98.