Summer Triangles over Japan . ... Credit Copyright: Shingo Takei ( TWAN ) Explanation: Have you ever seen the Summer Triangle? The bright stars Vega , Deneb , and Altair form a large triangle on the sky that can be seen rising in the early northern early spring during the morning and rising in the northern fall during the evening. ... Featured here, the Summer Triangle asterism was captured last month from Gunma , Japan . ... NASA Web Site Statements, Warnings, and Disclaimers . ...