ASASSN-15an: bright overlooked (likely) superoutburst in May

In the field of RR Pic. Previous long outburst (but fainter) in 2018 Nov.-Dec. + precursor.

YYYYMMDD(UT) mag observer 20230427.0321 <18.022g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230428.8108 <15.932g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230428.8108 <15.952g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230428.8108 <16.039g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230429.0297 <17.929g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230502.7112 15.295o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230502.7146 15.314o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230502.7198 15.325o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230502.7305 15.310o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230502.8203 14.941g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230502.8203 14.946g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230503.7953 14.869g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230503.7953 14.873g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230503.7953 14.875g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230503.7953 15.222g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230504.7783 14.844g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230504.7783 15.132g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230505.0544 14.970g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230505.7373 15.264g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230505.7373 <15.135g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230505.7373 <15.139g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230505.7373 <15.141g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230505.7532 15.583o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230506.8011 14.462g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230506.8011 14.464g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230506.8011 14.471g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230506.8011 15.584g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230507.0282 15.903o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230507.0315 15.930o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230507.0413 15.817o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230507.0571 15.807o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230507.0619 16.042g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230507.8108 15.447g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230508.0505 15.690g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230508.7199 15.897g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230508.7199 15.942g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230508.7599 16.115o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230508.7633 16.099o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230508.7696 16.039o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230508.7822 16.022o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230509.0563 15.934g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230510.0256 16.033g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230510.0256 16.040g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230511.7321 16.039c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230511.7422 16.033c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230511.7523 16.119c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230511.7551 16.118c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230511.7614 16.200c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230511.7646 16.118c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230511.7709 16.005c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230511.7828 16.138c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230512.0190 16.245g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230512.0190 16.247g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230513.0050 16.407o (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230513.0084 16.284g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230516.0037 <18.077g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230517.9956 <18.095g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230518.9990 <17.419g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230519.9949 <17.696g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230519.9961 <17.205g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230520.9946 <18.234g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230523.7015 19.459c (ATLAS Forced Photometry (Tonry+2018; Shingles+2021)) 20230523.9798 <17.983g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230524.9797 <17.872g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230526.9712 <17.517g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230527.9700 <16.951g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014))