Planetary Nebula "Dumbbell" (also known as Messier object 27, M 27, or NGC 6853) is an object in the constellation Vulpecula. 07.06.2025

Here you can only enter in seconds. So I looked up online how many seconds 45 minutes of total integration would be, and that's 2700s.

Everything is correct, 2700" is the total integration time. But you have written 68x2700, which makes it seem like 68 frames of 45 minutes each, totaling 51 hours. If you had 68 frames with a total exposure of 45 minutes, you should have written 68x40" That is, 68 frames of 40 seconds each, which would add up to exactly 45 minutes ;)

I wrote simply 45 seconds for 68 frames. Probably that will be clearer)