With + Noun + adverb

Have you ever wondered if a full moon is larger when it’s on the horizon than when it’s high in the sky? Here’s a simple experiment you can try. On a night when there’s a full moon, take a ruler and hold it at arm’s length to measure the moon. Do this twice: once when the moon is in the open sky, and once when it’s on the horizon. You’ll find that even though the moon seems to change size, your two measurements will be the same. In fact, the difference in size that your eyes see is an optical illusion. With the moon high overhead, there’s nothing nearby to compare it to. But when it’s lower, seeing it in comparison to the small trees, buildings, or hills on the horizon makes it look bigger.

'With the moon high overhead' can be changed into the followings ? Which one is more suitable?

- When the moon is high overhead (?)

- If the moon is high overhead (?)