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.
| Star* | V | Comparison | V | Δ(B-V) | Check |
|---|---|---|---|---|---|
| alf Cas | 2.225 | HD 5395 | 4.629 | 0.212 | HD 9927 |
| RU Cas | 5.558 | HD 6960 | 5.551 | -0.025 | HD 5015 |
| RR Ari | 5.75 | HD 13174 | 4.989 | 0.853 | HD 13363 |
| NSV 16300 (Ori) | 5.695 | HD 34658 | 5.34 | -0.626 | HD 36134 |
| niu Aur | 3.96 | HD 38656 | 4.51 | 0.182 | HD 41357 |
| 1 Gem | 4.158 | HD 38751 | 4.877 | -0.192 | HD 43039 |
| NSV 2877 (Aur) | 4.338 | HD 40588 | 6.19 | 0.939 | HD 42471 |
| SY UMa | 5.28 | HD 82328 | 3.175 | -0.392 | HD 82621 |
| alf Com | 4.318 | SAO 82650 | 5.99 | 0.064 | SAO 82692 |
| NSV 6687 (UMi) | 4.275 | HD 136726 | 5.013 | 0.065 | HD 142105 |
| VW Dra | 6.319 | SAO 17360 | 6.7 | 0.494 | SAO 17312 |
| NSV 24912 (Aql) | 5.118 | HD 185018 | 5.978 | -0.33 | HD 188310 |
| 51 Peg | 5.467 | HD 218235 | 6.157 | 0.215 | HD 215510 |
* These are the PEP designations. NSV 16300 is HD 35299, NSV 2877 is HD 43039, NSV 6877 is HD 127700, NSV 24912 is HD 187691, and niu Aur is the PEP id for η Aur (HD 39003).