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 Post subject: Crepuscular Astronomy
PostPosted: Tue Mar 13, 2018 6:49 am 
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Location: Portslade, Sussex Lat 50deg 51min Long 0deg 13mins West
Crepuscular Astronomy by E.Kim
Some people imagine that if you do astronomy as a hobby, you spend every clear night outside looking up at the stars. However, for me, that is far from the truth. This is also true for many aging astronomers who now dislike the cold and feel unhappy about the safety of operating telescopes in the dark. The spread of lighting from houses and streets has become more of a problem too and traveling by vehicle to darker locations and carrying large telescopes becomes problemmatic in itself.

Having done the dark-sky observing when younger and bolder, some just give up. However others look for some observing that can be done in the daytime, and many go for solar observing. Light pollution is irrelevant and if the Sun is out, it is likely that you will feel its warmth.

For me the best solution is crepuscular skywatching. “Crepuscular” derives from the Latin word “crepusculum” which means “twilight”, that is the pale light of “ dawn or dusk”. It is used in nature-study to refer to creatures that are not active during day - “diurnal ones”, nor during the night - “nocturnal ones”, but those that are out and about at dawn and dusk. You may also have come across it in the term, “crepuscular rays”, when the sunlight shining through holes in the cloud produce a pattern of rays in the sky.

Observing the sky at twilight really is my favorite time. The colours of the sunset, sundogs, the conjunction of the bright planets, like Venus and Mercury and crescent Moon with earthshine, either “new” in the evening or “old” in the early morning. The rising Full Moon at dusk or setting the in dawning sky can be a lovely sight.

Sometimes, if one is very lucky, a bright comet might hang low in the sky. Quite often crepuscular observing can be done from indoors, even through the window! For most of those targets, a spotting scope, a small monocular or even a hand-held binocular will do nicely! (March 2018)

[NB. I wrote this short essay- under my nom de plume for the local astronomy group's newsletter but thought that it may be relevant and of interest to readers here.)


Last edited by mike a feist on Tue Mar 13, 2018 9:23 pm, edited 4 times in total.

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PostPosted: Tue Mar 13, 2018 11:42 am 
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Sorry hard to read one long sentence.

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Last edited by skyhawk on Fri Mar 16, 2018 10:50 am, edited 1 time in total.

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PostPosted: Tue Mar 13, 2018 9:17 pm 
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I do not understand your reply, Skyhawk.

It is not one long sentence but a series of well-constructed, proper sentences with capital letters at the start of each one and full stops at the end, plus commas inserted as appropriate.

It is one long paragraph though, and I have broken it down into a number of separate smaller paragraphs for your convenience.

Your reply however is not even a proper sentence as it has no capital letter at the beginning, nor a full stop at the end.

regards maf


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PostPosted: Tue Mar 13, 2018 10:07 pm 
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Very interesting read, Mike. I’m certainly with you on the crepuscular astronomy. Twilight is definitely my favourite time to observe, for all the reasons you state. At this time of year it fits in well with when I’m out and about on my commuting to work. I’m thinking about carrying a lightweight binocular with me on my travels.

Best wishes, Jeff.


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PostPosted: Wed Mar 14, 2018 12:42 pm 
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Hello Jeff: Yesterday morning I popped over to the papershop just after sunrise and on the way back noiced that, although the Sun was somewhat hidden in the clouds, above it was the most fine & fancy piece of ice-cloud (cirrus).I ran home, threw the newspaper and other purchases in the door, grabbed the camera and managed to capture another absolutely spectacularly -coloured piece of iridescence! That really started the day well! Crepuscular skywatching at its best regards maf


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PostPosted: Wed Mar 14, 2018 2:13 pm 
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Mike, I haven’t seen an occurrence of iridescent cloud for some time. I bet it looked impressive. I do still recall the colour and effect being very captivating.

Best wishes, Jeff.


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PostPosted: Wed Mar 14, 2018 7:04 pm 
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Mike
I found your "Crepuscular" astronomy post intriguing. It being one of many words, I think I've occasionally come across over the years, but never really knew what they mean. However, with regards "Crepuscular", I do not like the actual word itself.
That said, I have really enjoyed many dawns and evenings in my time.
I was half joking to a friend about another word I don't like. I told him if I did athletics I'd always finish towards the bottom of any event because I hate the word "Podium". Of course TV sports presenters only spout off about athletes who are likely to get in the first three and stand on it.
Best wishes from Cliff


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PostPosted: Fri Mar 16, 2018 10:49 am 
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mike a feist wrote:
I do not understand your reply, Skyhawk.

It is not one long sentence but a series of well-constructed, proper sentences with capital letters at the start of each one and full stops at the end, plus commas inserted as appropriate.

It is one long paragraph though, and I have broken it down into a number of separate smaller paragraphs for your convenience.

Your reply however is not even a proper sentence as it has no capital letter at the beginning, nor a full stop at the end.

regards maf


Remember some people have problems, aspergers, reading etc, it should be made "readable" for all not just as you say "I have broken it down into a number of separate smaller paragraphs for your convenience.", it is grammatically poor to write everything as one paragraph anyway

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PostPosted: Fri Mar 16, 2018 10:50 am 
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mike a feist wrote:
I do not understand your reply, Skyhawk.

Your reply however is not even a proper sentence as it has no capital letter at the beginning, nor a full stop at the end.

regards maf


Bad as each other then. :)

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PostPosted: Fri Mar 16, 2018 3:03 pm 
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Location: New Farnley, Leeds lat 53.8N long 1.6W
Dear Mike, What an interesting and well written piece. You've hit on a great title - Crepuscular Astronomy - for the kind of observing that many of us find most comfortable and engaging these days. I can't help thinking of TS Eliot's metaphor in "The Wasteland" for that in-between time. He called it "the violet hour", a phrase full of (unpleasant) implications in its literary context, but somewhat out of context I find it a brilliant encapsulation of the strange, changing conditions of light and colour at twilight. Please write more of your thoughts and experiences in this area. Interesting and perfectly expressed. Kind thoughts, Bob


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PostPosted: Fri Mar 16, 2018 4:48 pm 
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Thank you Bob for your kind words.
You may not be aware that I resigned from the SPA when my subs became due BUT I intend to continue here at this forum, and hope that we can share many more crepuscular observations. regards maf


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PostPosted: Fri Mar 16, 2018 5:21 pm 
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Quote:
What an interesting and well written piece.


Indeed. Over the years I've always found Mike's posts to be interesting, well written, and correctly punctuated!

Regards :D


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PostPosted: Sat Mar 17, 2018 9:14 am 
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Mike
I agree with Hippy. You covered the subject of "C" astronomy very nicely and indeed other related things as well.
I think I was lucky to get interested in astronomy when I was a boy, ironically at a time of the Black Out (although it was a sad time for many people). Our house was even on a hillside just above the worst pollution of many cotton mills chimneys in our area.
I was a loner stargazer then - getting as far away as M31. But didn't see my first comet until I was 40 (by incredible luck) out hill walking on the Pennines. I had thought astronomical societies were for "mad professors" and the likes, so didn't join one till my mid-50s. I subsequently joined 7 UK astro organisations (though only 6 at any one time). Eventually that seemed over the top and I am now only a member of ONE organisation & only stargaze one star. I don't think any of the organisations I left are bothered about my loss but I've saved a few bob. I feel a bit sad that light pollution here increased surprisingly drastically here recently - It seems someone is mocking me and is yet more proof humankind is DOOMED.
Mike I think you still enjoy meeting up with people of your own local group - which may well be enough. Good luck to you - sorry I didn't write the "C" word earlier, but I still don't like it ! but that doesn't mean I don't like what the word relates to - it's just the actual word itself that's my problem.
from Cliff


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PostPosted: Sat Mar 17, 2018 9:51 am 
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Of course Cliff, we could call it "Twilight Astronomy" or "Twilight Skywatching"!!
regards maf or even regards E.Kim.
(It took members of the FTAG ages to figure out who this member E.Kim was who was writing the book reviews for "Towering Sky"! I finally explained it to a member called "I Moan", sorry, Naomi !)


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