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When the sun is fully eclipsed the sky darkens and the stars appears as if it was night. Obviously, when this happens in the middle of the day, and the process of the moon slowly moving to occlude the sun is clear, then it is no different than dark clouds in the sky.

The question here is if the sun is fully eclipsed following sunset but before Tzes HaChochavim. In this circumstance, the cause of the early darkness is not apparent because the sun in below the horizon. When the stars disappear early they will not reappear again until the following dawn. Night has, by all appearances, to any witnesses observers, fallen early.

Does this early darkness and early appearance of stars meet the halachic requirements of 'Tzes HaChochavim'?

(Please provide sources, pre-500CE, i.e. on the direct authority of Sanhedrin or higher, only.)

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Can you source scientifically that eclipses post sunset affect the ambient light strength? –  Double AA Nov 3 '13 at 18:25
I don't see anything in the above comments that clarifies or seeks to clarify the question (except what I just edited into it). I'm therefore deleting the comments. If you wish to discuss the view expressed at the end of the question, or have any other discussion, please do so not here but in chat. –  msh210 Nov 4 '13 at 7:37
My edit was not malicious, and, although I figured it would prejudice some readers, I didn't think you'd mind, since you wrote the same text yourself (in a now-deleted comment) as I included into the question. Moreover, my edit was necessary for clarifying what you're seeking. I still maintain my edit was a good one, but we can see what others think. –  msh210 Nov 11 '13 at 18:59
@Jonathan, I don't think msh210 intended an objectionable edit. I urge you to try to judge others favorably. There have been a lot of comments here, many of them heated, and it appears that some of you are not understanding each other. Can we please agree that everybody has good intentions and focus on making the question say what you want it to say? Thank you. –  Monica Cellio Nov 11 '13 at 19:35
@Jonathan He added what you wrote to the question. If you don't agree with what you wrote, then don't write it. –  Double AA Nov 11 '13 at 20:25

2 Answers 2

up vote 0 down vote accepted

Based on your statement "In this circumstance, the cause of the early darkness is not apparent" it would seem that an eclipse during the day is not considered "night" because the cause IS apparent. Now, why should knowing the cause or not knowing the cause define night? IOW either it should be night by both or by neither.

Now to try to answer your question: in Gemara Shabbos in the Sugya of Bain Hashmoshos (from 34b - 35b) Rav Yehudah in the name of Shmuel gives 3 definitions of "night"; 1) (both Rabbah & Rav Yosef agree) when the upper horizon is pale and the same (equal) as the lower it is night. 2) Rabbah says the amount it takes to walk 3/4 of a Mil after sunset, Rav Yosef says 2/3 of a Mil. 3) 3 stars is night.

From the above we see that the definition of night is by 2 factors (the 3rd definition is only an indication as to when in time it happens in Yerusholayim on the days of the equinoxes) and not just by the visibility of stars.

In addition the stars that appear in the beginning of the night will reappear after it becomes dark again after the eclipse (and not wait till 24 hours later) like they would have if there were no eclipse (because if they won't show up again tonight because they're only above the horizion (let's say) 10 minutes after sunset, then they won't appear (to the naked eye) tomorrow night either.

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Maybe the third is the Ikkar reason, but we don't know what an "average star" is? –  Shmuel Brin Nov 3 '13 at 20:45
@Shmuel Brin his question was if we were to know. I don't know what you call the 3rd reason so please explain TY –  Meir Zirkind Nov 3 '13 at 22:48
3 "average sized" stars is ikkar night, but what defines an "average sized" star? The Alter Rebbe said they have to be both "visibly" medium and "really" medium in size. –  Shmuel Brin Nov 3 '13 at 23:55
@Shmuel Brin Are you telling me that Shmuel couldn't make up his mind C"V? ALL 3 are true and they are all from Shmuel! –  Meir Zirkind Nov 4 '13 at 3:47
no, CH"v. It's simanim for us. We (laymen) don't know what an average star is. –  Shmuel Brin Nov 4 '13 at 4:19

The question presupposes that tzeis is determined by the ability to see the stars, thus, an eclipse at the right time would make the stars' visibility earlier. But, according to a summary of the issue here indicates that the gemara's view was that tzeis was a mathematical construct, not a function of simple visibility so regardless of the lighting, tzeis would be reckoned the same way. To wit:

"In Shabbos (34) R' Yehuda says that from suntil until צאת הכוכבים is 3/4 of a mil (we will define how long a mil is later). The gemara in Pesachim (94) states that according to R' Yehuda there are 4 mil from sunset until צאת הכוכבים. "

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How do you know that stars are an indicator of time and not that time is an indicator of stars? –  Double AA Nov 3 '13 at 20:35
I don't. I only know that, as per the limitations of the question, a source pre-500CE answers the question in a way which would not be affected by eclipses because it makes a blanket statement about time. –  Danno Nov 3 '13 at 20:38
But there are also sources from pre500E which give blanket statements about stars –  Double AA Nov 3 '13 at 20:39
Maybe it's an argument. One opinion says that it's about time, the other says that it's about stars? –  Shmuel Brin Nov 3 '13 at 20:39
Maybe that mathematical construct was only when one couldn't see stars (if it was cloudy, for example). Otherwise stars always win? –  Shmuel Brin Nov 3 '13 at 20:40

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