June 2025 promises a mesmerising array of celestial events for skywatchers in Delhi. As the region transitions into the heart of summer, the night sky over the capital comes alive with spectacular astronomical phenomena—from meteor showers to rare planetary alignments. Though the days grow hotter, Delhi’s relatively clear summer nights offer ideal opportunities for viewing the heavens. These cosmic events not only offer a visual treat but also reflect centuries of astronomical tradition and cultural significance. Whether you're a curious newcomer or a passionate astronomer, here are five unmissable celestial events to witness this May.
The Great Globular Cluster in Hercules (M13, NGC 6205; mag 5.8) will be prominently visible in the evening sky over the coming weeks. From Delhi, it will be visible all night, becoming apparent around 20:18 IST at 39 degrees above the north-eastern horizon as dusk fades. On 2 June, it will reach its highest point at approximately 00:20, standing 82 degrees above the northern horizon, and will remain visible until about 04:16, when it is lost to dawn twilight at 40 degrees above the north-western horizon. On following nights, it will culminate around four minutes earlier each day.
The globular cluster M92 (NGC 6341; mag 6.5) in the constellation Hercules will be well placed in the evening sky in the coming weeks. From Delhi, it will be visible all night, first appearing around 20:23 IST at 41 degrees above the north-eastern horizon as darkness sets in. On June 11, it will reach its highest point in the sky at approximately 00:20, 75 degrees above the northern horizon, and remain visible until about 04:14 when it fades into dawn twilight at 41degrees above the north-western horizon. Positioned at a declination of 43°08'N, M92 is best observed from the northern hemisphere and is not visible from locations much south of 26 degrees South. Although faint at magnitude 6.5 and not visible to the naked eye, the cluster can be spotted using binoculars or a small telescope.
The Butterfly Cluster (M6, NGC 6405; mag 4.2), an open star cluster in the constellation Scorpius, will be well placed in the evening sky in the coming weeks. From Delhi, it will be visible from approximately 21:45 IST, when it rises to 18 degrees above the south-eastern horizon, until around 03:02 when it drops below 18 degrees above the south-western horizon. On June 16, it will reach its highest point in the sky at about 00:24, standing 29 degrees above the southern horizon. With a declination of 32°15'S, M6 is more easily observed from the southern hemisphere and is not visible from locations north of 37°N. At magnitude 4.2, the cluster may be challenging to spot with the naked eye unless under very dark skies, but is clearly visible through binoculars or a small telescope.
The Ptolemy Cluster (M7, NGC 6475; mag 3.3), a bright open star cluster in Scorpius, will be well placed in the evening sky over the coming weeks. From Delhi, it will be visible from around 21:45 IST, when it rises to 16 degrees above the south-eastern horizon, until approximately 02:58 when it drops below 16 degrees above the south-western horizon. On June 20, it will reach its highest point in the sky at about 00:21, standing 26 degrees above the southern horizon. With a declination of 34°47'S, M7 is best observed from the southern hemisphere and is not visible from locations north of 35°N. Though faint to the unaided eye except from dark sites, it is easily visible through binoculars or a small telescope.
The June Bootid meteor shower will be active from June 22 to July 2, peaking around June 27. From Delhi, the radiant point in the constellation Boötes remains above the horizon all night, making the shower visible throughout the hours of darkness. The radiant culminates before nightfall, at approximately 21:00 IST, so the best displays are likely just after dusk when it is still high in the sky. This timing allows for optimal viewing conditions as Earth’s rotation positions Delhi favourably to receive meteors descending nearly vertically, producing bright but short trails. As the night progresses, meteors will appear less frequently and more obliquely, often creating longer trails across the sky. Peak activity is expected around 17:00 IST on June 27, 2025, making that evening an ideal time to observe the shower.