Total Lunar Eclipse Images and superstitions associated with eclipses

On December 10, 2011 we were fortunate enough to be in Shegaon to be able to watch the total lunar eclipse from completely non-polluted area of Anand Sagar. Air pollution and lights in the cities often deteriorate the quality of viewing such events. 

I tried to capture that beauty into the camera, but that wasn't easy since I do not have DSLR camera. I had to do some experiments in different modes in my digital camera. I used full 40x zoom (10x optical and 4x digital) and finally selected Shutter Speed Priority mode rather than Auto mode. Also at 40x zoom,  if you do not have the tripod, with even a slightest of handshake, the distant object goes out of focus quickly. So I sat on the floor and kept my camera on a bench so as to provide the support to the camera from beneath.  Even I needed to hold the breath for a while so as to reduce the body shake. With all these efforts, I could finally capture that beauty. 

Lets have a look at the clicks now.

Just before the start

In the last picture, moon is hardly visible. 


I always get amazed to see the celestial bodies moving in tandem and in perfect synchronisation. Equally fascinating is the fact that Indians had that knowledge, thousands of years ago and were able to do the precise calculations of timings for these events. 


At the same time, its not a happy feeling that in modern times people are more superstitious and deny themselves the opportunity to view such a spectacular event. And that is the case even with a highly educated class with a science background as well. 


Actually all these eclipses are just the game of shadows. Still people have some beliefs and do some acts, some of which are cited below:


1) Some monsters like Rahu, Ketu swallow Moon and the Sun at the time of eclipses. 


2) It is harmful for health to eat or drink during eclipses, even before actual eclipse gets visible and just the First Contact starts.


3) Taking a bath after the eclipse is over. (bathing is good otherwise for hygiene, but there is no necessity to do that after the eclipse)

4) Covering drinking water and eatables at home (now this we do in normal practice as well for maintaining hygiene, but people are more keen to do this during eclipses) 


5) Keeping Tulsi leaves on drinking water and eatables at home. 


6) Making donations so that eclipse comes to an end (donations are even good otherwise, but eclipse is certain to come to an end at a pre-defined precise time, whether you donate or not)


7) Keeping themselves immersed in holy river till the time eclipse is there.  


8) Its bad for eyes to see with naked eyes. ( It is true for Solar Eclipse, since the Sun being the brightest source of light is behind the moon and its rays are harmful for naked eyes. But in lunar eclipse, its purely the shadow of Earth on the moon and the intensity of light is actually even dimmer than the normal full moon. So it is perfectly safe to see the Lunar Eclipse with naked eyes)


9) The strength of evil spirits increases during eclipse and there are bad omens everywhere. Does that even need a comment here? 


10) One should not travel during the eclipse. 


11) Air is polluted during the eclipse. 


12) Pregnant women should not come out of the house during eclipse. 


Personally speaking I don't believe in any of these superstitions. I enjoyed the view with my complete family and we did that while eating as well.


Detailed post on our Shegaon visit is here: www.parkhi.net/2012/01/shegaon-gajanan-maharaj-anand-sagar.html

Why Moon rises 50 minutes later everyday?

Have you ever got curious to know why moon rises approximately 50 minutes later everyday as compared to the previous day?

For understanding this, first we need to understand how celestial bodies like earth, moon etc. rotate (around itself) and revolve (around some other planet or star). Its so wonderful to know how these celestial bodies move in tandem and that too for millions of years in perfect synchronisation. 

Its a well known fact that earth completes one rotation in 24 hours. And also moon completes one revolution around its parent earth in approximately one month. Now this approximate period of one month is calculated in two ways. 

First one is Sidereal Month which is equal to the time taken by moon to complete one revolution around the earth, but with respect to the background stars which we see from the earth. This period is equal to 27.32 days.

Second one is Synodic Month. Even though, moon completes one apparent revolution in one Sidereal Month, we won't be able to see the new moon just after one sidereal month is complete. This is because moon revolves around the earth and at the same time earth also revolves around the Sun. As a result, moon has to travel some extra distance so as to reach at the same place, with respect to the Sun and we get new moon again. So the total time taken, also called as a Lunar Month is equal to 29.53 days.

Visit http://www.sumanasinc.com/webcontent/animations/content/sidereal.html for nice animated presentation explaining Sidereal and Synodic Months.

Now lets understand why moon rises 50 minutes later everyday. 

Here for us, the relevant time taken by moon to complete one revolution around the earth is Sidereal Month, since we want the exact moonrise time i.e. the time when moon first appears on the horizon. Hence the position of the moon which is apparent from the earth with respect to the background is what matters for us rather than its position with respect to the Sun. 

Let is assume that in a figure beside, on Day 1, a person is standing at a point A on earth and he sees the moonrise exactly at 07:00 pm. 

Exactly 24 hours later, on Day 2, the man is standing at the same point A on earth at the same time i.e. at 07:00 pm expecting to see the moonrise again. But in those 24 hours, moon also has revolved around the earth. Now as we have seen, one sidereal month is 27.3 days. So moon completes 360 degrees revolution in 27.3 days. So in one day of 24 hours, it moves by 360/27.3= 13.18 degrees. So for a man standing at point A on the earth on day 2 at 07:00 pm expecting to see the moonrise, moon is still 13.18 degrees below the horizon. So he has to wait for the earth to rotate 13.18 degrees to see the moonrise again. So now the moon will rise for him when the point A on earth travels further to reach point B. As we know, earth rotates 360 degrees in 24 hours i.e in 1440 minutes. So it rotates 1 degree in 4 minutes. So to rotate 13.18 degrees, it takes 13.18 x 4 = 52.72 minutes. This is the delay in moonrise everyday.

This delay would have been same at all places on earth, if earth's plane of rotation around itself and moon's plane of revolution around the earth would have been co-planer with each other. Had the planes been like that, we would have seen solar eclipse on every dark moon day and lunar eclipse on every full moon day. But they are at a angle of almost 29 degrees with each other. So this delay calculated above is not the same at all places on earth and depends on the latitude of the place from where we see the moonrise but it averages out to be around 50 minutes per day.