My toons (one: Astro 20R / Recog 10R, another: Astro 19R / Recog 12R, the other: Astro 19R / Recog 14R) could pull this map. All toons had Boston "Astronomer's Growth 1" skill.
I also tried with 3 toons.
1: Recog:11/Astro:13
2: Recog:11/Astro:12
3: Recog:15/Astro:18
None of them had
Astronomer's Growth 1
I would asume it works like other maps, the highest skill in the fleet is used, so if one has Astronomy 18 then the other toons in the fleet dont even need to have Astronomy at all in order to pull the map (if the toons can communicate with each other, which means they share a lang).
I also got the disc without
Astronomer's Growth 1 and Recognition 15, but it took me 3 nights, so if you can get to a higher Recognition then i would recommend doing that.