Offline jim22

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Star in the sky closer to the earth than the moon
« on: October 03, 2019, 09:34:25 PM »
 :-B Hi guys! What do you think?

Today we were watching the moon at night, and it caught our attention that a star that was close to the moon, seemed to be closer than the moon of us, that star fell with time about half an hour and disappeared. Any theory about that? I have some fotos but i can't upload because max. 192KB..

Offline ChrisTP

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Re: Star in the sky closer to the earth than the moon
« Reply #1 on: October 03, 2019, 09:57:14 PM »
Could well have just been a satellite. You can see them bright in the sky sometimes a bit like a fast moving star.
Tom is wrong most of the time. Hardly big news, don't you think?

TheScientist

Re: Star in the sky closer to the earth than the moon
« Reply #2 on: October 03, 2019, 10:03:47 PM »
Looking a this entirely from the point of view of an experienced amateur astronomer, I'm pretty sure you are describing a simple lunar occulation.  The Moon moves eastwards w.r.t to the stars and so the eastern side of the lunar disk will cover up stars to the east of the Moon periodically.  When the Moon is a waxing crescent as it is at the moment his will make stars disappear behind the part the Moons disk which is not illuminated.  The length of an occultation, or the time before the star reappears on the western side of the Moons disk (as we look at it) will generally be less than a hour. Your description of 'fell with time about half an hour' doesn't entirely make sense but I could interpret that as the length of the occulation.

I'm sure that others on this site will offer you a different version of your observation but I can tell you without any element of doubt that the star would not be closer than the Moon. Anyone who tells you otherwise doesn't understand the physical nature of stars.

I would agree with ChrisTP if your observation as made entirely with the naked eye.  Satellites look exactly like stars and I guess your description of 'falling' could be applied if the 'star' was moving from the Moon towards the horizon.
« Last Edit: October 03, 2019, 10:06:05 PM by TheScientist »

Offline jim22

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Re: Star in the sky closer to the earth than the moon
« Reply #3 on: October 03, 2019, 10:23:20 PM »
Thanks guys for the replies, ChrisTP it was an object bright enough not to be a satellite, I've seen many stars at night and I don't think it was that and too big to be able to see it with my eyes.  ::)
TheScientist  the star was far enough from the moon more than the diameter, and I think that to be a occulation it should be closer.

TheScientist

Re: Star in the sky closer to the earth than the moon
« Reply #4 on: October 03, 2019, 10:28:25 PM »
What you saw tonight was the planet Jupiter...  read through the following link under Sunset Conjunction.

www.spaceweather.com

At mag -2 the planet Jupiter outshines all the stars in the sky but the brightest satellite (the ISS) can reach -4 magnitude which is approaching Venus brightness.
« Last Edit: October 03, 2019, 10:33:14 PM by TheScientist »

Offline jim22

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Re: Star in the sky closer to the earth than the moon
« Reply #5 on: October 03, 2019, 10:44:52 PM »
thank TheScientist you but here in this case the star or planet was to the left of the moon not to the right..  :-\  8)

TheScientist

Re: Star in the sky closer to the earth than the moon
« Reply #6 on: October 03, 2019, 10:52:22 PM »
Whether Jupiter was seen to the left or to the right of the Moon would depend on your location and local time.  This simulation of the event taken 45 minutes after sunset from my location shows the Moon and Jupiter almost exactly matching the appearance and position in your photo.

Offline jim22

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Re: Star in the sky closer to the earth than the moon
« Reply #7 on: October 03, 2019, 11:03:53 PM »
I don't know if this data is interesting the sunset here was at 20:05 UTC / GMT +1. The picture was taken at 23:07. The location would be in Cadiz Spain. It's too late here and I fall asleep. Thanks.. See you soon

TheScientist

Re: Star in the sky closer to the earth than the moon
« Reply #8 on: October 04, 2019, 05:42:54 AM »
Regardless... the 'star' you saw near the Moon was definitely Jupiter.

TheScientist

Re: Star in the sky closer to the earth than the moon
« Reply #9 on: October 04, 2019, 03:55:31 PM »
Jim22...

I have set Starry Night to the date, time and location you specified and this is what I got.  You can see the position of Jupiter relative to the Moon at the time you were observing, along with the labelled positions of Saturn and Pluto.

Hopefully this is similar to what you saw.  The landscape is just simulated and there are a number of different ones to choose from.  It has no impact whatsoever on what is shown in the sky.

Offline jim22

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Re: Star in the sky closer to the earth than the moon
« Reply #10 on: October 04, 2019, 06:25:37 PM »
 ;D ;D Very very interesting, good job! thanks for simulation :) what I would have to say is that I am surprised that it was so bright and it seemed that it was closer than the moon of us and the distance between the moon and Jupiter in our photo appears much larger.
but I guess it will be normal due to the movement of the planets  :P

TheScientist

Re: Star in the sky closer to the earth than the moon
« Reply #11 on: October 04, 2019, 06:51:13 PM »
Why would you be surprised at the brightness of Jupiter? It is always around the magnitude -2 mark.  I guess it only appears so bright to people who are not used to spotting planets in the sky.

It is only when you have a bright marker like Jupiter than you come to notice how quickly the Moon moves in the sky. That is because the Moon is so much closer to us than any other celestial body. Compare its position in the sky tonight for example, several degrees east of Jupiter now.