* * * * * 174P/Echeclus * * * * *

Year Mn Day MM Mag Ref Scope Pwr coma DC tail p.a. Obs Site 2017 12 23.58 S 13.8 AQ 25.0L 83 1 2 WYA Walcha, NSW (Coma diffuse.) 2017 12 19.86 S 13.2 AQ 20.3T 133 0.8 5 GON Puerto de Aralla, León (Post-outburst. Possible faint and diffuse outer coma. Field stars checked in DSS.) 2017 12 19.43 S 14.3 UV 40.0L 257 0.7 0 YOS Mt. Hanadate, Ibaraki (It became completely diffuse with no condensation only within one week.) 2017 12 13.59 M 14.0 AQ 25.0L 83 1 5/ WYA Walcha, NSW (Coma diffuse, uniform brightness across coma with faint stellar centre visible in good seeing.) 2017 12 12.02 M 13.0:AU 22.0L 160 0.5 7 GOI Araçatuba 2017 12 11.83 M 13.6 AQ 20.3T 222 0.3 8 GON Villacintor, León (In outburst. Field stars checked in DSS.) 2017 12 11.37 S 13.2 TA 40.0L 144 0.5 7/ YOS Kita-karuizawa, Gunma (Very bright! Easily visible. It is 4 days after the outburst, and it looks already cometary.) 2016 9 1.72 M 15.0 HS 40.0L 257 0.3 4 YOS Kita-karuizawa, Gunma (Lucky that it brigthened in outburst on Aug. 28, just before my observation trip. I could see the comet again after 10 years. Near limit. I felt it was somewhat diffuse. However, the diameter and DC are very uncertain because the comet is too faint.) 2016 8 31.77 I 15.0 AQ 40.6L 260 0.1 8 CAM Warners Bay, NSW 2016 8 30.998 S 15.3 AQ 30.5T 139 8 DIJ Burlage 2016 8 30.993 M 14.9 AQ 30.5T 139 8/ BOU Burlage, Germany (Field checked in DSS. Object softer than nearby stars of similar magnitude. During moments of good seeing hint of some surrounding nebulosity.) 2016 8 30.09 I 14.8 AQ 20.3T 133 9 GON Pandorado, León (In outburst. Stellar appearance. Field stars checked in DSS.) 2011 6 4.01 S 14.3 HN 20.3T 206 0.4 6 GON Alto del Castro - Aralla, León (Nearby field stars checked in DSS. Comparison stars taken from Henden photometry - SA132 and V818 Sco fields. Limiting star magnitude near comet : 15.3 [GSC]. Mountain location, very clear sky.) 2006 2 4.21 S 14.3 HN 20.3T 133 0.6 4 GON Pobladura de Luna, León (Mountain location, very clear sky. Limiting stellar magnitude: 15.5. Comparison stars taken from Henden photometry near HS Vir.) 2006 1 8.78 S 14.4 AU 40.0L 257 0.5 3 YOS Ibaraki, Japan (This object has been revealed to be a comet just before I left home for observation. It was reported as 17.5 mag in IAUC 8656, but I received a report by Ken-ichi Kadota that this comet is much brighter actually, 14.8 mag on Jan. 7.85 (UT). So I hurriedly added it to my target list. This comet is farther than 13 A.U., but surprisingly, it is visible visually! Maybe it is the farthest comet observed visually, isn't it? Before the observation, I have imagined that it would be sharply and strongly condensed like 29P just after an outburst. However, on the contrary, it is very diffuse actually. Round diffuse object like a planetary nebula, similar to Owl Nebula. Kadota reported that the condensation became somewhat weaker on Jan. 8. Maybe the outburst has been already cooling down?)