Can I rephrase the original sentence as:
"The observation is only done during the day, from 10 AM to 03 PM."
Numbers aren't generally preceded with 0 when telling time. But other than that, the sentence is normal.
But you are giving a general range of "done during the day", which usually suggests "during daylight hours". It's common knowledge that 10 AM to 3 PM is "daytime" (on most of the planet). So this is redundant, and mentioning "during the day" really just raises questions... such as "why not 4 PM?" and "why not 9 AM?"
So you might just say:
- "The observation takes place from 10 AM to 3 PM."