Oh, gotta love Android for this! Another paid app I would like to tell you about is Juice Defender. There is a night mode which you can use. As an added benefit, it also saves you battery, by turning on data in frequencies that you can set. The free version can only choose between 15m and 30m. With the paid version can also set location specific power settings.
If you just want to turn it off during the night, you can just set the phone to Airplane Mode during the night.
But you might forget to unset it in the morning. Another app, which is primarily a funky power widget, also has a night mode. Its called Battery Widget? Reborn! Yeah, the exclamations are part of the name.
Tasker and others might be a tad overkill for what you are looking for, but yeah, once you realize the possibilities, you wont use anything else.
Welcome to the symbiotic Android ecosystem :)