Skip to main content

Occultation of Mars by Moon, 17 April, 2021

An occultation of the planet Mars by Moon or lunar occultation of Mars occurred on the evening of April 17, 2021. Occultation is an astronomical phenomenon in which a large angular sized body obscures a much smaller angular sized body. A waxing crescent Moon passed in front of Mars, obscuring it as observed from most of the Indian region. Since  the sun was still above the horizon for most of India except the eastern region, when the occultation started (immersion), it could not be observed. Other than the extreme western parts of Gujarat, sunset had already occurred for nearly the whole country by the time Mars started coming out at the end of the occultation (emersion),  so it was observed in nearly the whole country. The timings different regions in India can differ by few minutes to nearly an hour as compared to Nainital. It was only a grazing occultation at Jammu and there was no occultation as observed from the areas north of Jammu.

As observed from Nainital region where ARIES is located, the occultation would have started around 18:12 and ended around 19:05, lasting just over 50 minutes. However due to the presence of clouds and rain for most of the time, the occultation could not be observed. The clouds cleared only a couple of minutes after the occultation ended.

Occultation of Mars

Simulated view of the occultation just before 'immersion' and after 'emersion' from ARIES, Nainital in Stellarium software.

ARIES had arranged an introductory talk on the Occultation of Mars by Moon at 5 pm by Dr. Virendra Yadav, followed by the live streaming of the telescopic view of the occultation on ARIES's Facebook page and YouTube Channel. A digital camera was attached to a 6 inch refracting telescope for this purpose. This event was a part of activities commemorating "75 years of India's Independence: Azadi ka Amrit Mahotsav" at ARIES.

Event Poster


The following are a few images from the live streaming from ARIES.

Clear Moon









Glimpse of Moon in the clear sky before the occultation.                                                                                       Clouds hiding the Moon.

Occultation Ends 1

Occultation Ends 2








Mars just below Moon on the right side about 2 minutes after emersion.                                                       Increasing angular separation between Moon and Mars post occultation.



Event Date