The open star cluster NGC 6633 (mag 4.6) in Ophiuchus will be well placed in the evening sky in coming weeks. On 28 June it will reach its highest point in the sky at around midnight local time, and on subsequent evenings it will culminate four minutes earlier each day.
From Cambridge , it is visible all night. It will become visible at around 21:52 (EST), 38° above your south-eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 00:41, 54° above your southern horizon. It will be lost to dawn twilight at around 03:39, 36° above your south-western horizon.
At a declination of 6°30'N, it is visible across much of the world; it can be seen at latitudes between 76°N and 63°S.
At magnitude 4.6, NGC6633 is too faint to be seen with the naked eye from any but the very darkest sites, but is visible through a pair of binoculars or small telescope.
The position of NGC6633 is as follows:
| Object | Right Ascension | Declination | Constellation | Magnitude | Angular Size |
| NGC6633 | 18h27m10s | 6°30'N | Ophiuchus | 4.6 | 0'00" |
The coordinates above are given in J2000.0.
The sky on 29 Jun 2025
| The sky on 29 June 2025 | ||||||||||||||||||||||||||||||||||
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21% 4 days old |
All times shown in EDT.
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Source
The circumstances of this event were computed using the DE430 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.
Image credit
© Digitised Sky Survey (DSS); Second Palomar Observatory Sky Survey (POSS-II)