C/2021 A1 (Leonard) is an inbound long period comet discovered by G. J. Leonard at the Mount Lemmon Observatory on 3 January 2021 when the comet was 5 AU from the Sun. The comet will make its closest approach to Earth on 12 December at around 34.4 million kilometres (0.23 astronomical units).The comet has an orbital period of around 80,000 years and it will not be returning anytime soon.
If you point your telescope or binoculars at M3 on 3rd Decmeber 2021 at around 5 a.m., you will find the comet just above it. You will also be able to fit M3 and the comet in the same field if you have a low-power binocular. The comet will be visible to the naked eyes too (under dark skies).
Location of C/2021 A1 (Leonard) on 3rd December 2021 at 5 a.m IST from Chennai facing East
The comet will be at its brightest on 12th and 13th December but will be below the horizon.
The comet has been already updated on star chart apps like Stellarium, Sky-safari etc. If you are unable to find it on Stellarium (PC), this video will help you to add it to the database.