B2_1520p31-20210418-S001-R001-B-021523.fts
Only less than 50 stars was detected


B2_1520p31-20210418-S001-R001-I-021912.fts
Only less than 50 stars was detected


B2_1520p31-20210418-S001-R001-R-021756.fts
upper limit SN vs magnitude graph from USNO-B1 catalog
UT upper limit
2021-04-18 17:17:57
16.111 +/- 2.399 (3sigma)
15.503 +/- 2.403 (5sigma)
14.678 +/- 2.412 (10sigma)


B2_1520p31-20210418-S001-R001-V-021641.fts
Only less than 50 stars was detected