21日云蒙山的Q4——2

焦点不好的一张。曝光178秒。

彗尾呈扇形，好美哦！

能否说一下拍摄器械参数

2004 May 20.19 UT: m1=4.2, Dia=12', DC=6...10x50 B...Charles S. Morris (Fillmore, CA) [Tails ~5 deg. in PA 104 (gas), ~2 deg. in PA 146 deg. (part of dust fan) & ~3 deg. in PA ~170 (leading edge of dust fan). Comet faintly visible to naked eye.]
这是http://encke.jpl.nasa.gov/RecentObs.html#01Q4上的数据。
拍摄设备1DS+400/2.8  时间3分钟

*2004 May 21.18 UT: m1=4.3, Dia=12', DC=6, Tails ~5 deg. (gas) & ~3 deg. (dust fan)...10x50 B...Charles S. Morris (Fillmore, CA) [Tails are similar to last night.]
这是最近的观测报告，请注意[Tails are similar to last night.]  彗尾在变小。

2004 May 16.39 UT: m1=3.5, Dia= 8', DC= 6/7...10x50B...Mariano Ribas (Planetario de Buenos Aires, Argentina)[Coma is a little brighter and bigger than early May. Comet only 12 degrees over East horizon in deep twilight at dawn, and marginally visible to nake eye in Buenos Aires, where mag. limit is 4.5. There´s a hint of tail only with binoculars]
2004 May 17.36 UT: m1=3.3, Dia=10', DC=5, tail: 0.5 deg in PA 220...7x50B...Alexandre Amorim(Florianopolis,Brazil)[alt. 5 deg.]
*2004 May 17.87 UT: m1=3.5,Dia=5', DC=5, tail 0.2 deg in p.a. 185deg...11x80B...Willian Souza (Sao Paulo,Brazil)[comet altitude ~ 6deg.]
*2004 May 18.89 UT: m1=3.4, Dia=10', DC=5,...7x50B...Alexandre Amorim(Florianopolis,Brazil)[alt. 10 deg.]
*2004 May 19.34 UT: m1=3.5; Dia=10', DC = 5 ...7x50 B ... Luis Alberto Mansilla (Rosario, Argentina) [Morris method used; naked eye; ref. stars: Delta and Zeta Leporis]
*2004 May 19.35 UT: m1=3.5; Dia=10', DC = 5 ...20x80 B ... Julio Nardón (Alvarez, Argentina) [Morris method used; naked eye; visual limiting magnitude = 4.2 ]
*2004 May 20.34 UT: m1=2.8, Diam=30’, DC=8, Tail ~3deg in PA 160deg...7x50B...Peter Conde (Stokers Siding, NSW): [Comet clearly visible to naked eye some 3deg west of Beta Lep.  Observation made 15 min before end of astronomical twilight.  Very similar to Q4!]
*2004 May 20.68 UT: m1=2.8, Dia. =9', DC=6, Tail:1.6 degrees in P.A. 110 degrees...10x50 B..David Pringle-Wood (Harare, Zimbabwe) [A very decent naked eye object viewed in the evening sky for the first time.]
*2004 May 20.69 UT: m1=2.8, Dia. =25', DC =7, Tail: 1.6 degrees in P.A. 150 degrees...7x50 B...Mike Begbie (Harare, Zimbabwe) [Perfectly spherical blue-green coma. Faint but clearly discernible tail. 20.68 UT: m1=2.8, Dia. =25' DC=7...NE Slightly hazy conditions.]
这是C/2002 T7最近几天的观测报告。