The Sun Was Walking His Dogs During Sunset!

These pictures were taken at about 5:30 on Sep. 3, 2007 in Kaohsiung, Taiwan. The Sun was flanked by two sundogs.

Sundog, also called parhelion or mock sun, is an atmospheric optical phenomenon. It forms when sunlight is refracted by horizontally oriented hexagonal plate ice crystals with diameters larger than 30 micrometers.

The following links provide two more sundog pictures from NASA:
APOD: 2006 September 23 - Triple Sunrise

APOD: 1999 August 23 - Sundogs over the VLA

For more deeper information, please visit the following websites:
Sundogs: mock suns or parhelia
Sundogs (parhelia)

太陽溜狗

2007/9/3下午大約5:30時高雄西方天空突然出現異象。太陽兩旁約22度位置與太陽同高處出現兩個彩色光點，右邊光點維持約3分鐘後消失，左邊光點則持續到日落。這個大氣光學現象稱為「幻日」，又稱「假日」，英文俗稱「日狗」。

「幻日」是由於陽光被六角形扁平冰晶的垂直面折射所致。產生幻日的冰晶直徑要大於30微米，下落時像落葉因空氣阻力使得扁平面保持水平。

下列「幻日」圖片是成功大學翻譯的NASA每日一圖中文網頁：

APOD: 2006 September 23 - Triple Sunrise
APOD: 1999 August 23 - Sundogs over the VLA

更詳細的英文解說請看：
Sundogs: mock suns or parhelia

Sundogs (parhelia)

相關中文解釋請看：
大氣光象
大氣的光與色彩

(Photos by author)