* * * * * C/2015 ER61 (PANSTARRS) * * * * *

Year Mn Day MM Mag Ref Scope Pwr coma DC tail p.a. Obs Site 2017 9 1.07 S 10.8 TK 20.3T 100 3 1/ GON Alcuetas - Villabraz, León 2017 9 1.022 S 13.1 AQ 30.5T 102 0.8 1 DIJ Burlage 2017 9 1.019 S 12.7 AQ 30.5T 102 1.5 1/ BOU Burlage, Germany 2017 8 30.71 S 13.1 AQ 25.0L 83 1.1 2/ WYA Walcha, NSW (Close to faint star. Coma diffuse, weak central condensation.) 2017 8 25.17 S 10.6 TK 20.3T 100 3 2 GON Puerto del Pando - Prioro, León 2017 8 23.069 S 12.2 AQ 25.4J 88 1.4 2 BOU Sint Annen 2017 8 21.08 S 10.5 TK 20.3T 100 3 2 GON Alto del Castro - Aralla, León 2017 8 19.72 S 12.5 AQ 25.0L 83 1.5 2 WYA Walcha, NSW (Coma diffuse, on edge of Pleaides star cluster. Close to star but distinguishable.) 2017 8 17.69 S 12.1 AQ 25.0L 83 1.2 2 WYA Walcha, NSW (Coma very diffuse. Comet on edge of Pleiades star cluster. Low altitude 12.1°.) 2017 8 17.02 S 10.2 TK 20.3T 77 3.5 2/ GON Alto del Castro - Aralla, León (Before moonrise. Altitude 17°.) 2017 8 12.77 S 10.7 TA 40.0L 144 1.5 3/ YOS Kita-karuizawa, Gunma (Fading. Hard to see in the moonlight. Near Pleiades.) 2017 8 1.83 S 11.5 AQ 40.6L 76 3.0 3 CAM Katherine, NT (Enhanced in Swan Band filter.) 2017 8 1.75 M 11.6 AQ 25.0L 39 3.8 4 WYA Walcha, NSW (Coma diffuse, brightening to centre, moderately condensed. Does not enhance in Swan Band filter.) 2017 7 30.82 S 11.5 AQ 40.6L 76 2.0 3 CAM Katherine, NT (Enhanced in Swan Band filter.) 2017 7 27.81 S 11.5 AQ 40.6L 76 3.0 2 CAM Katherine, NT (Enhanced in Swan Band filter.) 2017 7 25.78 M 11.2 AQ 25.0L 39 3 3/ WYA Walcha, NSW (Coma enhances slightly in Swan Band filter.) 2017 7 24.82 S 11.5 AQ 40.6L 76 1.5 1 CAM Katherine, NT 2017 7 24.77 S 11.2 AQ 25.0L 39 2.8 3 WYA Walcha, NSW (Coma enhances in Swan Band filter.) 2017 7 23.12 S 10.0 TK 20.3T 100 3.5 3/ GON Alto del Castro - Aralla, León 2017 7 22.84 S 11.0 AQ 40.6L 165 2.0 3 CAM Katherine, NT 2017 7 5.80 M 9.6 TK 25.0L 39 5.6 6 0.33 258 WYA Walcha, NSW (Inner coma elongated and opaque. Small stellar central condensation. Fragment B not visible. Combined light observation.) 2017 7 2.10 S 9.5 TK 20.3T 77 4 4 GON Alto del Castro - Aralla, León 2017 6 30.75 M 9.7 TK 25.0L 39 4.4 5 0.33 253 WYA Walcha, NSW (Inner coma elongated in tail direction. Combined light from fragment B in coma although fragment B not visible.) 2017 6 24.82 S 9.4 TK 8.0B 20 6 3 CAM Katherine, NT 2017 6 24.33 S 8.9 TK 10.0B 20 4 3/ GOI Araçatuba 2017 6 22.76 M 9.3 TK 25.0L 39 4.1 5 0.18 260 WYA Walcha, NSW (Coma dims slightly in Swan Band filter. Inner coma appears elongated to the South-West approximately. Fragment B just noticeable as a diffuse smudge behind the central condensation in the coma. Magnitude refers to total combined light of the pair.) 2017 6 21.82 S 9.0 TK 8.0R 36 4 4 CAM Katherine, NT 2017 6 21.10 S 8.0 TK 10.0B 25 4 4 GON Puerto de Aralla, León 2017 6 21.09 S 8.2 TK 20.3T 77 3 4/ 0.2 260 GON Puerto de Aralla, León 2017 6 18.82 S 8.8 TK 40.6L 76 2.5 4 CAM Katherine, NT (Moonlight.) 2017 6 6.81 S 8.6 TK 8.0B 20 5 4 CAM Katherine, NT 2017 6 5.81 S 8.5 TK 8.0R 36 5 4 10m 252 CAM Katherine, NT 2017 6 3.33 S 8.6 TK 10.0B 20 5 4/ GOI Araçatuba 2017 5 24.81 S 7.8 TK 8.0B 20 4 4/ CAM Katherine, NT 2017 5 24.12 S 7.9 TK 10.0B 25 4 5 GON Puerto de Aralla, León (Altitude 9°. In 20cm SCT AT 77x, tail 0.4-deg in p.a. 260 deg. Beginning of astronomical twilight.) 2017 5 23.81 S 7.7 TK 8.0B 20 5 5 CAM Katherine, NT 2017 5 7.76 S 7.9 AA 10.0B 25 6.0 0.2 255 SEA Cowra, NSW (Marginally brighter using Swan Band filter.) 2017 5 7.35 S 7.6 TK 10.0B 20 6 4/ GOI Araçatuba 2017 5 6.77 M 7.8 TK 5.0B 7 8.5 6 WYA Walcha, NSW (Star-like central condensation surrounded by a diffuse haze, appears circular. Strongly enhances in Swan Band filter. Slight interference from zodiacal light and glare from Venus.) 2017 5 4.75 S 7.8 TJ 40.0L 36 5 5 YOS Kita-karuizawa, Gunma (Well condensed and easy to see.) 2017 5 3.15 S 7.5 TK 10.0B 25 5 5 GON Puerto de Aralla, León (Altitude 9°. In 20cm SCT at 77x, tail 0.6-deg in p.a. 250 deg. Beginning of astronomical twilight.) 2017 5 1.78 S 7.8 TK 8.0B 20 5 4 CAM Warners Bay, NSW 2017 4 30.79 S 7.5 TK 8.0B 20 6 5 CAM Warners Bay, NSW 2017 4 30.31 M 7.4 TK 10.0B 20 6 5 GOI Araçatuba 2017 4 29.77 S 7.5 TK 8.0B 20 5 4 CAM Warners Bay, NSW 2017 4 28.77 M 7.8 TK 5.0B 7 8.2 6 WYA Walcha, NSW (Coma diffuse. Stellar centre enhances strongly in Swan Band filter. Tail visible, in 25-cmL at 39x, and traced to 23.5 in length in p.a. 253 deg. Slight interference by zodiacal light.) 2017 4 28.76 S 7.5 TK 8.0B 20 5 5 CAM Warners Bay, NSW 2017 4 28.16 S 7.4 TK 5.0B 10 5 5 GON Puerto de Aralla, León (Altitude 10°. In 20cm SCT at 77x, tail 0.5-deg in p.a. 250 deg. Beginning of astronomical twilight.) 2017 4 25.80 S 7.4 TK 8.0B 20 6 5 CAM Warners Bay, NSW 2017 4 22.79 S 7.4 TK 8.0B 20 8 4 CAM Warners Bay, NSW 2017 4 22.29 M 7.4 TK 10.0B 20 4 5 GOI Araçatuba (Moonlight, clouds.) 2017 4 21.17 S 7.0 TK 10.0B 25 5 5 GON Puerto de Aralla, León (Altitude 12°. Astronomical twilight. Moonlight interference.) 2017 4 17.80 S 7.0 TK 8.0B 20 6 5 CAM Warners Bay, NSW 2017 4 16.27 S 6.9 TK 10.0B 20 7 4/ GOI Araçatuba (Moonlight, clouds.) 2017 4 15.25 S 6.7 TK 5.0B 7 8 4 GOI Araçatuba (Moonlight. Comet altitude 11°.) 2017 4 10.34 S 6.5 TK 5.0B 7 12 4/ GOI Araçatuba (Moonlight, clouds.) 2017 4 7.76 S 6.5 TK 8.0B 20 8 5 CAM Warners Bay, NSW 2017 4 7.18 S 6.2 TK 5.0B 10 8 5/ GON Puerto de Aralla, León (In evolution after the recent outburst. The comet shows a wider coma diameter and brighter m1 estimate in comparison with my previous Apr. 4.17 observation. Altitude 12°.) 2017 4 6.78 S 6.3 TK 8.0B 20 8 6 CAM Warners Bay, NSW 2017 4 5.74 M 6.4 TK 5.0B 7 7.3 6/ WYA Walcha, NSW (In outburst. Inner coma bright and aqua-blue in colour, enhances strongly in Swan Band filter.) 2017 4 5.35 M 6.2 TK 5.0B 7 7 6/ 0.7 255 GOI Araçatuba 2017 4 5.34 M 6.4 TK 10.0B 20 6 7 0.7 255 GOI Araçatuba 2017 4 4.17 S 7.4 TK 5.0B 10 4 6 GON Puerto de Aralla, León (Possible outburst. The comet shows a higher DC, appearing significantly brighter than expected in comparison with my previous Apr. 1.18 observation. Altitude 9°. In 20cm SCT at 77x, m2=10.5:. Dust tail 0.2-deg in p.a. 260 deg.) 2017 4 3.73 M 8.6 TK 25.0L 39 4 6 29m 253 WYA Walcha, NSW (Faint tail. Coma centre stellar and aqua-blue in colour.) 2017 4 2.28 M 8.4 TK 10.0B 20 6 5 0.3 260 GOI Araçatuba 2017 4 1.71 M 8.1 TK 7.0B 11 6.8 4 WYA Walcha, NSW (Diffuse coma, moderately condensed centre, enhances in Swan Band filter.) 2017 4 1.18 S 8.2 TK 10.0B 25 6 3 GON Candanedo de Fenar, León (Altitude 10°.) 2017 3 30.33 M 8.5 TK 10.0B 20 6 5 0.3 260 GOI Araçatuba 2017 3 29.33 M 8.5 TK 10.0B 20 6 5 0.3 260 GOI Araçatuba 2017 3 28.19 S 8.7 TK 10.0B 25 4 3 GON Collado del Fresno, Asturias (Altitude 12°. In 20-cm SCT at 77x, dust tail 0.2-deg in p.a. 260 deg.) 2017 3 27.75 S 8.2 TK 8.0B 20 5 4 CAM Warners Bay, NSW 2017 3 27.74 S 8.6 AA 10.0B 25 SEA Cowra, NSW (Little change using Swan Band filter.) 2017 3 27.71 M 9.0 TK 25.0L 39 3.6 5 16.5m 259 WYA Walcha, NSW (Coma enhances in Swan Band filter. Inner coma opaque.) 2017 3 26.75 S 8.4 TK 40.6L 76 4 5 CAM Warners Bay, NSW 2017 3 25.33 S 9.5 TK 22.0L 60 5 4/ GOI Araçatuba (Enhanced image with Swan band filter.) 2017 3 9.23 S 9.1 TK 10.0B 25 5 2/ GON Cea, León (Altitude 16°. Astronomical twilight.) 2017 3 9.22 S 9.3 TK 20.3T 77 5 2 GON Cea, León (Elongated coma.) 2017 3 8.68 M 10.4 TK 25.0L 39 2.3 4 & 5m 272 WYA Walcha, NSW (Faint tail visible.) 2017 3 6.69 M 10.0 AQ 25.0L 39 2.8 4 5.4m 235 WYA Walcha, NSW (Transparent coma enhances in Swan Band filter. Slight interference by star in coma, approximately 1 from the central condensation.) 2017 3 3.80 S 10.7 AU 40.0L 144 1.1 3/ YOS Mt. Hanadate, Ibaraki (Much smaller than expected and I felt it was very faint, probably due to the low sky condition.) 2017 2 28.31 S 11.3 AU 22.0L 160 1 3 GOI Araçatuba 2017 2 23.76 S 10.6 AQ 40.6L 76 2.0 4 CAM Warners Bay, NSW 2017 2 23.67 M 10.9 AQ 25.0L 39 3 4 3.6m 286 WYA Walcha, NSW (Coma enhances well in Swan Band filter.) 2017 2 22.73 S 11.3 AQ 40.6L 76 1.8 3 CAM Warners Bay, NSW 2017 2 21.21 S 9.5 TK 20.3T 77 4 2 GON Alto de la Camperona, León (Very faint and diffuse outer coma. Altitude 14°. Field stars checked in DSS. Some moonlight interference.) 2017 2 20.72 S 10.8 AQ 40.6L 76 1.5 3 CAM Warners Bay, NSW 2017 2 20.67 S 11.0 AQ 25.0L 83 1.4 2/ WYA Walcha, NSW (Moonlight. Enhances slightly in Swan Band filter, opaque centre.) 2017 2 19.70 S 10.5 TK 40.6L 76 1.5 3/ CAM Warners Bay, NSW 2017 2 17.68 S 11.0 AQ 25.0L 83 1.4 3 WYA Walcha, NSW (Moonlight. Slightly enhances in Swan Band filter.) 2017 2 6.81 S 11.4 AU 40.0L 144 1.2 3 YOS Mt. Hanadate, Ibaraki (Diffuse, but well visible.) 2017 2 5.72 S 11.5 AQ 40.6L 76 1.5 4/ CAM Warners Bay, NSW 2017 2 1.71 M 11.2 AQ 25.0L 39 2.5 5/ WYA Walcha, NSW (Outer coma very diffuse, brightening to a moderately condensed inner coma with a sometimes stellar central condensation. Coma slightly elongated to the West.) 2017 1 31.70 M 11.5 AQ 25.0L 83 1.2 5 WYA Walcha, NSW (Outer coma diffuse, elongated to West approximately. Gradual brightening to a small and opaque but moderately condensed centre, faintly stellar in good seeing.) 2017 1 30.71 M 12.0 AQ 25.0L 83 1 4 WYA Walcha, NSW (Coma appears slightly elongated to the West approximately. Transparent outer coma brightening to a moderately condensed and opaque centre. Does not enhance in Swan Band filter. Bright star of mag 7.8 [TK] 2.1 away.) 2017 1 29.72 S 12.5 AQ 40.6L 165 1.0 3 CAM Warners Bay, NSW 2017 1 29.70 S 12.0 AQ 25.0L 83 1.1 3/ WYA Walcha, NSW (Outer coma diffuse and transparent, brightening slightly to centre. Coma slightly elongated to the West approximately. Does not enhance in Swan Band filter. Background star of mag 12.5 in coma, 0.2 away. At 166x the inner coma appears small and opaque.) 2017 1 24.83 S 12.2 AU 40.0L 144 1.1 3/ YOS Mt. Hanadate, Ibaraki (Much fainter and harder to see than expected, probably due to the low sky condition.) 2017 1 24.22 S 9.3 TK 20.3T 77 6 1 GON Collada de la Cobertoria, Asturias (Very faint and diffuse outer coma. Altitude 13°. Field stars checked in DSS. Several stars in coma, the brightest being mag 12.5 [GSC]. 2017 1 23.69 S 12.5 AQ 25.0L 83 1 2/ WYA Walcha, NSW (Moonlight. Coma diffuse, slight brightening to centre. No enhancement in Swan Band filter. Motion detected after 15 mins.) 2017 1 7.21 S 10.1 TK 20.3T 77 4.5 1/ GON Alto del Castro, León (Very faint and diffuse outer coma. Altitude 11°. Zodiacal light. Field stars checked in DSS.) 2017 1 1.25 S 10.2 TK 20.3T 77 4.5 1/ GON Puerto de las Señales, León (Very faint and diffuse outer coma. Altitude 17°. Zodiacal light. Field stars checked in DSS.) 2016 12 29.72 S 13.0 AQ 25.0L 83 0.6 2/ WYA Walcha, NSW (Coma small and diffuse, difficult to see due to zodiacal light and twilight interference.) 2016 12 26.25 S 11.2 TK 20.3T 133 2.5 1/ GON Les Retuertes - Sierra del Aramo, Asturias (Very faint and diffuse outer coma. Altitude 16°. Some moonlight interference. Field stars checked in DSS. Limiting star magnitude near comet: 13.9 [AQ].) 2016 12 10.25 S 10.3 TK 20.3T 100 3 1/ GON Les Retuertes - Sierra del Aramo, Asturias (Very faint and diffuse outer coma. Altitude 14°. Zodiacal light. Field stars checked in DSS. Limiting star magnitude near comet 13.5 [AQ] - 14.0 [HS].) 2016 12 6.25 S 10.4 TK 20.3T 100 2.5 2 GON Les Retuertes - Sierra del Aramo, Asturias (Diffuse outer coma. Altitude 13°. Zodiacal light. Field stars checked in DSS. Limiting star magnitude near comet: 13.5 [AQ].)