*May* be the earliest colour photograph of an astronomical expedition according to an article by Paul Sutherland titled 'Earliest colour photo of astro event' on the SkyMania website.
From the article:
Sergey Prokudin-Gorsky does not appear to have recorded the eclipse itself. But his image offers a fascinating glimpse of how scientists headed into the snowy peaks in the depths of winter to observe totality.
Two refracting telescopes on equatorial mounts stand proudly outside the team’s yurt – a traditional tent-like but wooden structure that nomads typically used in this part of the world. The photographer himself stands, second from the left, in a fur hat.
Prokudin-Gorsky’s notes tell us they were at Cherniaevo Station in the Tian-Shan mountains above the Saliuktin mines on Golodnaia Steppe. That is in the east of what is today Uzbekistan, near its eastern border with Tajikistan.
Here is the uncropped original colour photograph from the Library Of Congress collection of Sergey Prokudin-Gorsky photographs -
And here are the two 'I CAN HAS CHEEZBURGER?' LOLcats style photos that I could not resist creating -