It says in Lech Lecha that Hashem took Abraham outside and asked him to count the stars. And from the word "habet" we learn it was during the daytime.
Why would it be during the daytime when stars cannot be seen?
Rashi explains that because it was a nevua, he did not have to physically see the stars in the sky. Indeed, if he had seen the stars in the sky, then it would have been impossible to see the stars that were below the horizon.
Pasuk Lech Lecha 15:5
And He took him outside, and He said, "Please look heavenward and count the stars, if you are able to count them." And He said to him, "So will be your seed."
And He took him outside: According to its simple meaning: He took him out of his tent, outdoors, to see the stars. But according to its midrashic interpretation, He said to him,“Go out of your astrology,” for you have seen in the signs of the zodiac that you are not destined to have a son. Indeed, Abram will have no son, but Abraham will have a son. Similarly, Sarai will not give birth, but Sarah will give birth. I will give you another name, and your destiny will change (Ned. 32a, Gen. Rabbah 44:10). Another explanation: He took him out of the terrestrial sphere and lifted him above the stars. This explains the expression of הַבָּטָה, looking down from above (Gen. Rabbah 44:12).