Betelgeuse supernova would not be good for deep sky observers. Currently Betelgeuse shines at a -5.4 absolute magnitude. Typical supernova can peak at an absolute mag of -15 to -19 meaning that Betelgeuse would increase in apparent magnitude to about -10 to -15. Bright as the Full Moon and an intense pin point of light. If it followed a light curve similar to SN1987A it would take 2-3yrs to return to its current brightness. You might need you put your Herschel Objects list away for a while