We analyzed 99 of the tweets by @彗星機構(呼び方彗、すいでも良いです) and here's what we found.
Note Timezone shown is UTC+0. Current UTC time is 19:02:55 +0000. The world clock can help you compare different timezones. If the tweets are spread evenly across the full 24 hour span, chances are that it's been set up to tweet automatically.