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Often I look at NASA's Eclipse Web Site. More specifically, I often look at the Index to Five Millennium Catalog of Lunar Eclipse. How can I tell if an eclipse results in a "blood moon"? I know not all lunar eclipses result in a blood moon, but I do know that some do. So how can I know if one is from looking at it? A blood moon is the phenomenon whereby the moon in total eclipse appears reddish in color as it is illuminated by sunlight filtered and refracted by the earth's atmosphere. (Google)

Edit:

James K says this question may be a duplicate of another question. I want to know how to identify "blood moons" from looking at NASA's reports. The other question is more general. However the answer may be the same.

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  • $\begingroup$ @JamesK I want to know how to identify "blood moons" from looking at NASA's reports. The question you linked to above is more general. However the answer may be the same. $\endgroup$ – A Child of God Apr 3 '17 at 12:26
  • $\begingroup$ Your edit hasn't addressed the main issue with the question, which is that the term "blood moon" is not clearly defined. I suggest you edit your question to remove all references to "blood moon". It is further unclear whether you want to know about historical eclipses, recent eclipses or future eclipses. Some context might be useful - why are you interested in the brightness of an eclipse? $\endgroup$ – James K Apr 3 '17 at 16:33
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"Blood moon" is not a term used scientifically. Therefore look for total lunar eclipses.

As some light is diffracted by earth's atmosphere, the moon is not entirely black but appears red. (Blue light is scattered, see why is the sky blue).

All total lunar eclipses will show a reddish colour. The brightness may vary according to the state of the atmosphere but the moon will never be black, or any other colour.

(James K contributed equally to this answer)

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  • $\begingroup$ Is that the case for all total eclipses? $\endgroup$ – A Child of God Apr 2 '17 at 20:18
  • $\begingroup$ All total lunar eclipses will show a reddish colour. The brightness may vary according to the state of the atmosphere but the moon will never be black, or any other colour. "Blood moon" is not a term used scientifically. $\endgroup$ – James K Apr 3 '17 at 1:57
  • $\begingroup$ Basically same answer I gave last time this question was asked $\endgroup$ – Carl Witthoft Apr 3 '17 at 13:20
  • $\begingroup$ @CarlWitthoft what question are you referring to? $\endgroup$ – A Child of God Apr 3 '17 at 19:05
  • $\begingroup$ @AChildofGod your post: astronomy.stackexchange.com/questions/19071/partial-blood-moon/… $\endgroup$ – Carl Witthoft Apr 4 '17 at 12:06

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