此当是乾元二年七月在秦州作，故有"伴月落边城”之句。王柏曰：天河，从北极分为两头，至于南极，随天而转入地下过，水之气也。《广雅》：云汉、星汉、河汉、银河、绛河、天津、汉津，皆天河名。

杜甫·《天河》

常时任显晦，秋至辄分明。

纵被微云掩，终能永夜清。

含星动双阙，伴月照边城。

牛女年年渡，何曾风浪生。

The River of Heaven

Du Fu

The moon forever turns obscure or bright,

But clearest in the autumn, though sometimes

A floating cloud may darken it a while,

Keeps purely shining through the endless night.

The stars that move through the gates of night and day

Companion the moon down frontier walls:

The Spinning Girl1 and the Cowboy year by year

Have met nor wind nor wave upon the Milky Way.

1. The star Vega in the constellation of Lyra.

2. Herd-boy, stars in Aquila. The union of their constellations occurs on the 7th of the 7th lunar month.