I'm facing some major issue on My Samsung galaxy m51. From 2-3 days my phone screen automatically going turn off. Not only 1 or 2 time it's happening again and again. Please suggest me what should I do now?

Need more slow shutter count in pro mode of Samsung Galaxy M51. It's important for astro photography. @22900 phone we can expect at least proper pro mode. Plz provide us more seconds at least 20-30 in pro mode through updates.Thank youSudipta Karmak...

Samsung galaxy M51