Comet C/2015 V2 (Johnson) 要到最亮時間了

[peter]

core 12等
那太暗

[peter]

c/2015 V2  核心應該不是12 等應該是 8.x 等左右

阿勇昨天去寶2 有跟同好拍同頂

等看是否有彗星圖就知道亮度應該多少 .



==

http://www.skyandtelescope.com/online-gallery/comet-c2015-v2-johnson-on-may-12th-from-the-davis-mountains-of-west-texas/




Comet V2 Johnson takes center stage
May 19, 2017 by David Dickinson, Universe Today




May 19th: passes near +3.4 magnitude Delta Bootis.
June 5th: Closest approach to the Earth at 0.812 AU distant.
June 12th: Perihelion 1.64 AU from the sun.
June 15th: Crosses into the constellation Virgo.
June 21st: Crosses the celestial equator southward.
June 26th: Passes near the +4 magnitude star Syrma.
July 1st: Passes near (30″!) the +4.2 magnitude star Kappa Virginis
July 3rd: The waning gibbous moon passes two degrees north of the comet.
July 5th: Crosses the ecliptic southward.
July 17th: Crosses into the constellation Hydra.
July 22nd: Passes 2.5 degrees from the +3.3 magnitude star Pi Hydrae.
July 28th: Crosses into the constellation Centaurus.


Read more at: https://phys.org/news/2017-05-comet-v2-johnson-center-stage.html#jCp

[Daniel Guo]

c/2015 V2  核心應該不是12 等應該是 8.x 等左右

http://www.cobs.si/recent
C/2015 V2 (Johnson)
Total-magnitude and coma-diameter estimates:
2017 May. 21.96, 7.9, 6' (C. Harder, Jeersdorf, Germany , 0.252-m Newtonian reflector; 7.0' tail in p.a. 320)
2017 May. 21.95, 7.8, 6' (U. Pilz, 7x50 binoculars)
2017 May. 21.15, 8.4, 3.4' (S. Aguirre, Sonora, Mexico, 0.2-m Schmidt-Cassegrain)
2017 May. 21.00, 7.9, 12' (A. Scholten, Eerbeek, 8x56 binoculars)
COBS 8等的觀測紀錄全部都是整體 (total magnitude), 不是核心.

IAU資料庫最新的觀測紀錄:
C/2015 V2 (Johnson)                 2017 05 21.00  12.0 N  K87
核心12等.

核心亮度看第一張Sky&Telescope的照片就很明顯.
Description:
... Brightest stars in this image are around 10th magnitude, faintest around 13th
照片中的星點亮度介於10~13之間. 和核心比有亮有暗, 因此核心亮度介於10~13.

[peter]

希望不會難拍 只希望好拍 ,  先前寶二拍  8等間 好暗好暗   如果 12等應該 曝不出來 .
不過阿勇說昨天有拍到 V2  . 

上週去 苗栗聯大洪大哥要我 goto  V2  , 不過 我覺得 核心太暗 應該是望遠鏡要看也很難  .  那天看 M3 都還可以
 不過 M6 還有 6~7等間 .  天頂那邊 V2 應該不可能就沒 GOTO 過去 .

 

[Daniel Guo]

目視觀測的話, 因為整體亮度算亮, 用低倍率的話應該不難看到, 近期記錄中有人用7x50雙筒看到 (不知光害如何). 核心部分12等曝半分一分應該就可以看到, 要照彗尾的話就要疊圖了.

可惜我家陽臺只能照西邊天空, 上週末本來要在戶外照 (順便照2017eaw超新星), 但設置搞太久. 看看這周末star party有沒有機會.

[peter]

http://www.itelescope.net/sky-alerts/2017/5/22/comet-c2015-v2-johnson-heads-for-closest-approach-to-earth-j.html

[peter]

我說錯拉  我指的是 m1   整個彗星頭部的亮度估計  . 看m1 才能知道拍不拍到

目前 C/2015 V2
目視說是  2017 May 18.88 UT: m1=8.1

不過 好像 到底實際多亮要以那單位發表當標準 ?
不同目視好像都不同

[peter]

2017/04/03_0300

https://www.facebook.com/photo.php?fbid=10158543251705012&set=p.10158543251705012&type=3&theater

[peter]

20170521@寶二 單張180s(別人拍的)

https://www.facebook.com/photo.php?fbid=10158543255745012&set=p.10158543255745012&type=3&theater

[peter]

http://spaceweathergallery.com/indiv_upload.php?upload_id=135786&PHPSESSID=chfj2i3f7a8mh4lmjdc95lggu1

Taken by rolando ligustri on May 28, 2017 @ from New Mexico , ITelescope.net


開叉 ..

[Daniel Guo]

5/28拍的, 120s x 15, 60D, CFF 105mm f/6.

http://www.astrobin.com/298511/

[peter]

 Comet C/2015 V2 跟130P comet 交會了嗎??

http://astrogeoguy.tumblr.com/



 Comet C/2015 V2 (Johnson)  


http://www.aerith.net/comet/catalog/2015V2/2015V2.html


  130P comet


http://www.aerith.net/comet/catalog/0130P/2018.html
BUT 130P 很暗吧