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* * * * * C/2010 X1 (Elenin) * * * * *
Year Mn Day MM Mag Ref Scope Pwr coma DC tail p.a. Obs Site 2011 11 24.57 S[10.6 TJ 40.0L 75 ! 4 YOS Kita-karuizawa, Gunma (I assumed a very large diffuse object. Actually, it is very near by Pleiades and there are many bright stars. So the observation is very hard. Several 14th magn. stars exist near by the position, which affected if something diffuse exists. Therefore, if the remnant of the comet still exists at 11-13 mag, I could not recognize it.) 2011 11 24.16 S 9.5 TK 20.3T 77 7 1/ 0.2 270 GON Alto del Castro - Aralla, León (The tail-like comet's remnant was observable for 0.2 deg along the major axis. The m1 estimate refers to the area of diameter 7' on the sunward end. Nearby field stars checked in DSS. Mountain location, very clear sky.) 2011 11 17.87 S 9.5 TK 20.3T 77 7 1/ 0.3 300 GON Angliru - Sierra del Aramo, Asturias (The tail-like comet's remnant was observable for 0.3 deg. along the major axis. The m1 estimate refers to the near-circular area of diameter 7' on the sunward end, showing a slightly higher degree of condensation. Nearby field stars checked in DSS. Mountain location, very clear sky.) 2011 10 30.14 S 9.3 TK 20.3T 77 9 1/ 0.6 300 GON Alto del Castro - Aralla, León (The tail-like comet's remnant was observable for 0.6 deg. along the major axis, showing a near-circular area of a slightly higher degree of condensation and 9' of diameter, located at the sunward end of the remnant. The m1 estimate refers to this area on the sunward end, as on the previous Oct. 9 and Oct. 21 observations. The dense starfield didn't allow for a more detailed study of the remnant's length and morphology. The motion was followed for 5 hours, being consistent with the ephemeris. Nearby field stars checked in DSS. Mountain location, very clear sky.) 2011 10 24.10 15.5L 29 DIJ Burlage (Very faint remnant, some 5x20' wide, seen near expected position, and followed over 90 minutes.) 2011 10 24.094 15.5L 29 BOU Burlage, Germany (A very diffuse pathch of roughly 5x12' [elongated towards p.a. 290 deg.] was observed near the expected position [some arcminutes north of the ephemeris position of C/2010 X1.]. A further check of the field about 75 minutes later confirmed the observation both re shape and expected motion. A very rough magnitude estimate showed that the object could have been as bright as 10.5 for a [supposed] 5' coma, but this number is probably meaningless, because actually we were not seeing a coma but just [part of] a tail remnant.) 2011 10 21.00 S 10.2 TK 20.3T 77 7 1/ 0.4 310 GON Alto del Castro - Aralla, León (The comet's remnant appears visually like a very diffuse tail-like morphology, observable for 0.4 deg along the major axis, showing two near-circular areas of similar brightness with a slightly higher degree of condensation and 7' of diameter. One of this areas, with geometric center located approximately at R.A.=8h00m.5, Decl.=+28o26'.0 [Oct. 21.00 UT], was close to the ephemeris position. The other area's center was located at R.A.=7h59m.5, Decl.=+28o34'.5. The motion of both areas was followed for 40 minutes, being consistent with the ephemeris. Observation made before moonrise, from mountain location with very good seeing , under slightly better conditions than twelve days ago [Oct. 9]. Nearby field stars checked in DSS. Altitude: 16 deg.) 2011 10 9.20 S 10.7 TK 20.3T 77 6 1/ 0.2 310 GON Alto del Castro - Aralla, León (The coma appears large and very diffuse, without central condensation. Observation made from mountain location under very good seeing conditions. Nearby field stars checked in DSS. Zodiacal light. Altitude: 23 deg.) 2011 10 8.80 S[10.9 TA 40.0L 144 !1.5 YOS Kita-karuizawa, Gunma 2011 10 7.81 S[10.0 TJ 40.0L 144 !2.2 YOS Kita-karuizawa, Gunma (This comet had been disintegrated until mid September. Now it is appearing in the morning sky after a long time blank. I found nothing at the predicted position. But the condition to see a diffuse object was poor, the background sky was bright due to the low altitude. A 13.2-mag star was visible.) 2011 9 1.93 S 8.9 TK 22.0L 60 5 2/ GOI Araçatuba 2011 8 21.37 S 8.1 AA 10.0B 25 5 3 SEA Cowra, NSW (Did not seem as condensed as previous observation. A little brighter through Swan Band filter, but did not seem to be more condensed through filter. Nevertheless, central regions were more enhanced, making the comet appear smaller [but slightly brighter] through filter.) 2011 8 19.36 S 8.4 AA 10.0B 25 4 4 SEA Cowra, NSW (Appeared more condensed than on Aug. 16, but this may have been due to clearer conditions. A little enhanced through Swan Band filter. Condensation seemed sharper through filter, as if central condensation was enhanced more than the larger coma.) 2011 8 16.94 S 8.9 TK 10.0B 20 4 4 GOI Araçatuba 2011 8 16.38 S 8.4 AA 10.0B 25 5 SEA Cowra, NSW (Somewhat brighter using Swan Band filter. Low elevation and thin high cloud, though brief clearing at time of observation.) 2011 7 24.94 S 10.4 TK 22.0L 160 2.5 2/ GOI Araçatuba 2011 7 21.94 S 10.5 TK 22.0L 160 2 2/ GOI Araçatuba 2011 7 20.38 S 9.9 GA 10.0B 25 4 SEA Cowra, NSW 2011 7 20.38 S 9.9 GA 25.4L 71 4 SEA Cowra, NSW (Close to star but easily visible in both instruments.) 2011 7 18.38 S 10.0 GA 25.4L 71 4 SEA Cowra, NSW (Little if any change thro' Swan Band filter. Possibly appeared very slightly smaller and marginally brighter toward centre with filter.) 2011 6 25.93 S 10.5 TK 20.3T 77 2.5 3 GON Alto del Castro - Aralla, León (Brighter than expected. 2'.5 coma with faint outer region. The comet was also observed the previous day [24.93 UT], but a close star interfered with the estimate. Nearby field stars checked in DSS. Mountain location, very clear sky. End of astronomical twilight. Altitude: 12 deg.) 2011 6 19.94 S 12.6 AU 22.0L 160 1.5 4 GOI Araçatuba 2011 6 4.93 S 14.2:HS 40.7L 135 1.0 3 BIV Versailles 2011 5 25.93 S 14.1 HS 25.6L 97 0.8 3 BIV Versailles 2011 5 22.94 S 13.2 HN 20.3T 100 1.2 5 GON Sierra de Penouta - Boal, Asturias (Nearby field stars checked in DSS. Comparison stars taken from Henden photometry - G2681005 field. Mountain location, clear sky.) 2011 5 1.935 S 13.5 AU 31.0J 155 0.4 4 DIJ Burlage 2011 5 1.931 S 13.7 AU 31.0J 155 0.6 4/ BOU Burlage, Germany 2011 4 26.89 S 13.7 HN 20.3T 100 1.3 5 GON Alto del Castro - Aralla, León (Obviously brighter than three weeks ago, showing a well developed coma. Nearby field stars checked in DSS. Comparison stars taken from Henden photometry - G2681005 field. Mountain location, very clear sky.) 2011 4 26.83 S 13.8 UD 25.4L 150 0.5 3 IVA Saratov 2011 4 5.04 I 14.9 HN 20.3T 133 0.3 7 GON Alto del Castro - Aralla, León (Strongly condensed object, observed from mountain location under very good seeing conditions. Nearby field stars checked in DSS. Motion checked over a 100-min period. Comparison stars taken from Henden photometry - G2681005 field.)