Moon Shadow on Earth captured from satellite during Total Solar Eclipse of 16thFeb1980 AA

  

After every solar eclipse we see reports with photos  of Moon masking the Sun disk.

Another 'must' image in every report is that of   that moment when the bright Sun just starts shining after the totality causing a diamond Ring effect also called  Baily's beads.  

This post narrates my unique experience of an unusual view during Total Solar Eclipse of   16th Feb 1980.

  Of course the reason why others could not see this is that  it involved highly complex equipment which was actually being used, albeit for a totally different purpose. Moreover it was purely a chance viewing culminating through several coincidences. 

 My job involved receiving Earth photos taken by satellites and record the data on magnetic tapes. These satellites were moving around Earth at about 850 Kms height and were transmitting data as a radio signal. 

On that day, we ( 4 or 5 of us ) were on shift duty.  Our data receiving and recording station  is  about 70 Kms South of Hyderabad, India.

Earlier, the Newspapers had said that for Hyderabad there will be only a partial (about 99% occulation by Moon ) eclipse. Projected times were 2:28 PM to 4:55 PM with a Maximum at 3:46 PM.

Obviously,  While travelling from Hyderabad to Station ( 3 Hrs minimum in those days to cover 70 kms ) the discussion was centered around the Total Solar eclipse that day afternoon and what to observe during that period like : Total darkness for 2 minutes, Seeing Stars in daytime, Birds chirping after eclipse end, Corona around moon during total period, Diamond Ring  and so on. But it was also expected  that  due to partial coverage we may experience these phenomenon with less intensity.  

The  satellites   make one revolution around Earth in about 102 minutes and our station could see a part of that revolution for about 13 to 15 minutes ( called Satellite Pass ). During this period the data is received  and recorded

 on magnetic tapes. During recording we can see the data  ( like the one on right ) of the ground, water and other features seen by satellite based cameras.  ( Note: This image is a recent one and so it is a high resolution type ..  in those days the images were 1km*1km resolution ). 

Those were the days prior to Internet, Google and Maps, even the PC had not arrived (It came a year later ). Hardly anyone knew that Satellites could take images of Earth.

On reaching the station we were disappointed:  exactly during  eclipse period we would have been busy with our work because there was a satellite pass we had to track (from 3:30PM to 3:45PM )

Reluctantly we took our respective positions in front of our workstations.

From about 3:00PM we noticed the reduced sun light  and it started getting dark and also the temperature started falling. Shadow bands started appearing on ground. At 3:20 we returned to our workstations, disappointed that we missed the REAL fun part of eclipse and got ourselves busy with recording the data.

 Disappointment was deepened further when we did not see any ground image on video display ( White image seen on left ) which always used to show the nice ground details being acquired.

Anyway the pass was over by 3:42 and as the darkness was still seen outside we ran out to experience the eclipse  we noticed that the eclipse was still deepening and it became still darker but what was baffling was the fact that the eclipse was now TOTAL ..   unexpectedly it turned out to be a total eclipse. We cursed the newspapers that said it would be a partial eclipse.

We were ready with darkened film negatives so we saw the corona , followed by  the Diamond ring and then as it started to brighten up we REALLY heard the birds chirping and the Cocks crow in nearby fields thinking that it was dawn.

After spending some more time we returned to our work. We ran the recorded tape again to see if we can see the image.  Still nothing was seen. Only blank screen. 

So as per routine procedure we were going to recycle the tape by Erasing the data.  Each tape costed several dollars and those days dollar was a very scarce so each tape was precious. 

At that moment I had a spark in my mind..  is it possible that there IS a data but it is very weak ..  because of darkness due to eclipse the image is very feeble???   [ I am not ashamed to use I ( instead of WE ) in earlier sentence.  Facts are facts. ]

We decided to give it a try. We raised all the display controls to maximum ..  Maximum Contrast, Highest gains etc.  

This time we saw a grainy image. AND THERE IT WAS:  an unexpected treasure, a goldmine.

There in front of us was the image of India with a dark patch over Goa, Hubli area.

That Dark Egg shaped Patch is the real shadow of Moon falling on Earth during eclipse!!!!  

 

Perhaps the FIRST time ever an eclipse was  captured by a Satellite!!!

Later we analyzed that the reason for 'no image' in the first place was because of the fact that for full duration of pass the area was in penumbra shadow so the amount of sunlight reaching the Earth surface was  very small and not enough to activate the camera sensor fully to generate the regular image. 

For writing this post I have used modern tools to model that solar eclipse and this has thrown light on some points raised above.

Hyderabad was in Partial zone but the Station where we received data from satellite was in Total Zone so we could see the full range of eclipse effects while Hyderabad did not because it was in 90% eclipse region.

Google search revealed that after this 1980 image of shadow, next reported image  is from Russian station MIR  on 11th August 1999:

  :  https://www.space.com/ring-of-fire-solar-eclipse-moon-shadow-photos-from-space.html )  

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