There is an eclipse on the calendar for 18 July 2027, and there is nothing to see. NASA’s catalogue lists it as a penumbral eclipse, the smallest in the whole 21st century, with a magnitude of 0.0014. That means the edge of the Moon just reaches the edge of the Earth’s faint outer shadow and then leaves again about twelve minutes later. Nothing changes in the Moon’s brightness that an eye or an ordinary camera can pick up. The website timeanddate.com does not call it an eclipse at all, but an almost eclipse, and no city in the world sees anything.
Why it is on this page
Almanacs and lists of eclipses sometimes include it because the geometry technically allows it, and readers do ask about it. It falls on Guru Purnima, a major day in the Hindu calendar. This page exists to say plainly that nothing is going to happen to the sky, and that you do not need to alter anything for the day.
Times
The Moon touches the faint shadow at about 15:57 UT, is closest to the centre of the shadow at 16:02 UT, and has left it by 16:09 UT. In India that is the evening, from about 21:27 to 21:39 IST, with the greatest at 21:32. The full Moon rises in New Delhi at about 19:17, so it is up for the whole grazing. A list of these times for every city would only repeat that nothing is seen, so the table on this page shows just that no city sees a change.
Not a grahan
The traditional rules count a lunar eclipse from the moment the Moon enters the Earth’s dark inner shadow, and a penumbral eclipse of any size is generally not counted. This one does not even reach the point at which a penumbral shading can be made out. There is no sutak, no closing of temples and no change to the Guru Purnima puja. The festival is described on the Guru Purnima page, with its dates and the tithi timings for 49 cities, and the general Purnima observances are on the Purnima page.
In the Hindu calendar
At the middle of the near eclipse the Moon is in Makara, the sidereal Capricorn, about 1.7 degrees into the sign, in Uttara Ashadha nakshatra, with the Sun opposite in Karka. These are Lahiri positions, worked out to within a few hundredths of a degree. Because the eclipse is so slight, astrologers who watch eclipses closely do not treat this one as a significant event.
What to do instead
Guru Purnima is a good night for what it is already meant for, which is honouring a teacher, and the full Moon will be bright and unshadowed. If you enjoy watching eclipses, the one to look for in 2027 is the total solar eclipse of 2 August 2027, which is partial in India. The calculator tells you its times for your town.
No city sees any change in the Moon at this eclipse. All times are local to each city and cut to the whole minute. For any other place use the eclipse visibility calculator.
How the lunar eclipse times are worked out
The time of greatest eclipse, the magnitude and the lengths of the penumbral, partial and total phases are taken from NASA's catalogue of lunar eclipses (Fred Espenak, eclipse.gsfc.nasa.gov, public domain). A lunar eclipse starts and ends at the same instant for everybody on the night side of the Earth, so what changes between cities is the clock time and whether the Moon is above the horizon. This site works out the Moon's height for each city at each stage, and the table gives the first and last moment you can see the eclipse.
Times are the local clock time of the city, with daylight saving where it applies, cut to the whole minute. For eclipses with a dark umbral stage the table lists that stage, when the Moon enters the dark core of the Earth's shadow, because the traditional rules count it. The faint penumbral stage is the one listed only for eclipses that have no umbral stage.
Sutak. By Hindu tradition the period of caution before a lunar eclipse, sutak, begins nine hours before the eclipse and ends when it ends. This page counts it from the first umbral contact, and only for a city where the eclipse can be seen. A penumbral eclipse is not counted as a grahan in most almanacs and has no sutak. Families follow their own rules for what is avoided during sutak, so follow your own family or temple. Children, the elderly and the unwell are generally excused from fasting.
Frequently asked questions
↳ Is there a lunar eclipse on Guru Purnima 2027?
Technically yes, but the Moon only grazes the faint outer shadow for about 12 minutes and nothing can be seen. It is not treated as a grahan, so Guru Purnima is kept in the usual way.
↳ Does sutak apply on 18 July 2027?
No. There is no sutak for a penumbral eclipse, and this one is not even visible. Temples stay open and the puja timings are unchanged.
↳ Why do some websites call it an eclipse and some not?
NASA's catalogue gives a penumbral magnitude of 0.0014 and counts it as the smallest penumbral eclipse of the century. Timeanddate.com calls it an almost eclipse because the Moon is barely touched. The two agree on the facts and differ only in what to call a near miss.
↳ Could a camera pick up any change in the Moon?
It is very unlikely. The dimming at the greatest moment is a tiny fraction of what a penumbral eclipse such as the one in February 2027 produces, and ordinary cameras cannot record it.