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Dave Chapman
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Reged: 01/27/07

Loc: Halifax, Nova Scotia, Canada
Earthshine observing project—any interest? new
      #5633301 - 01/20/13 02:08 PM

Is anyone on this forum interested in a project to observe enhanced Earthshine at predictable Sun-Moon elongations?

This would be a great activity regardless of your observing experience, and it can even be carried out from an urban backyard.

There is theoretical and observational evidence that earthshine is enhanced by a "fogbow" effect for about 8 hours around the time that the crescent Moon is 41º elongated from the Sun (more or less 3.4 days). In essence, from the Moon's perspective, the bright gibbous Earth is at the same angle from the anti-solar direction that forms rainbows here on Earth, however the water droplets in the clouds are so small it is a white-light bow, not a coloured bow. When the Earth is within the bow range, there is enhanced illumination of the Moon, hence enhanced earthshine.

The enhancement was observed here in Nova Scotia last Monday, and there is already a small group interested in following it up.

On LPOD there was a wonderful photo: http://tinyurl.com/aruvp9f

If there is interest, I will post the computed predicted dates and times for 2013. Because it is a short-lived effect, it may not be visible from a fixed location during successive lunations, so a "longitudically dispersed" observing group would be an asset.

Dave XVII Chapman

Edited by Dave Chapman (01/22/13 01:20 PM)


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Tim2723
The Moon Guy
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Reged: 02/19/04

Loc: Northern New Jersey
Re: Earthshine observing project—any interest? new [Re: Dave Chapman]
      #5633531 - 01/20/13 04:41 PM

Sounds like fun. I look up every time I leave the house anyway, so what's one more thing to pay attention to?

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RobDob
sage


Reged: 04/10/10

Loc: Brentwood (East Bay Area), CA
Re: Earthshine observing project—any interest? new [Re: Tim2723]
      #5633867 - 01/20/13 08:13 PM

Very interesting. I've seen this phenomena before. Just hope prediction times match with observing time and conditions... But, yes. sounds like a fun project!

Rob


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Dave Chapman
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Reged: 01/27/07

Loc: Halifax, Nova Scotia, Canada
Re: Earthshine observing project—any interest? new [Re: RobDob]
      #5634508 - 01/21/13 08:53 AM Attachment (40 downloads)

Here is a photo by Phillipe Tosi (France), who gave me permission to use it. Take on January 15, 2013, it gives a good idea what we are looking for, should people need an incentive!

Dave


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Quinn
member


Reged: 03/19/12

Loc: California, Los Angeles
Re: Earthshine observing project—any interest? new [Re: RobDob]
      #5634509 - 01/21/13 08:53 AM

Sound interesting. If you could point me to where I can find the calculations for this would be great.

Alway looking for something new to wrap my head around

Quinn


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NeilMac
Carpal Tunnel


Reged: 09/25/10

Loc: MedHat, AB, Canada
Re: Earthshine observing project—any interest? new [Re: Quinn]
      #5634793 - 01/21/13 11:57 AM

Sounds like fun, have seen that effect, will depend on the clouds

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Carol L

*****

Reged: 07/05/04

Loc: Tomahawk, WI 45N//89W
Re: Earthshine observing project—any interest? new [Re: Dave Chapman]
      #5634883 - 01/21/13 12:39 PM

Sounds great, Dave - count me in too.
Just wondering - would a Moonglow filter make the enhanced Earthglow vanish?
It'd be interesting to experiment with, provided the cloudgods cooperate in the first place.


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Dave Chapman
sage
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Reged: 01/27/07

Loc: Halifax, Nova Scotia, Canada
Re: Earthshine observing project—any interest? new [Re: Quinn]
      #5634891 - 01/21/13 12:42 PM

Quote:

Sound interesting. If you could point me to where I can find the calculations for this would be great.

Alway looking for something new to wrap my head around

Quinn




Thanks for your interest, Quinn. The following are the Universal Time dates and times we expect to notice enhancement of earthshine, based on the Moon being elongated from the Sun by 41º

For your location, it would be helpful to use a desktop planetarium program such as Stellarium to determine your local observing circumstances: times of sunset, end of twilight, moonset, etc.

The duration of the event is expected to be +/- 3h, so only a fraction of the events may be observable from a fixed location. There may be 2–3 lunations (or even more) between opportunities.

EXPECTED DATE AND TIMES (UT) OF EARTHSHINE ENHANCEMENT

Waxing Crescent

Jan 14 20h
Feb 13 12h
Mar 15 06h
Apr 14 00h
May 13 18h
June 12 09h
July 11 23h
Aug 10 11h
Sep 8 21h
Oct 8 06h
Nov 6 14h
Dec 5 22h

Waning Crescent

Jan 8 21h
Feb 7 07h
Mar 8 16h
Apr 7 01h
May 6 11h
June 4 23h
July 4 13h
Aug 3 05h
Sep 1 22h
Oct 1 15h
Oct 31 07h
Nov 29 23h
Dec 29 13h

The possibility of the observation was documented in a paper by C. R. Benn, The Observatory, Vol. 114, 115–117 (June 1994).

cielos claros

Dave


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cphk96
member


Reged: 11/01/07

Loc: North Hollywood, CA
Re: Earthshine observing project—any interest? new [Re: Dave Chapman]
      #5648242 - 01/28/13 01:50 PM

I want to participate! THis sounds like fun.

What exactly will I be reporting?
Will I be reporting what Lunar features I can see in the Earthshine portion of the moon?

Chris


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Dave Chapman
sage
*****

Reged: 01/27/07

Loc: Halifax, Nova Scotia, Canada
Re: Earthshine observing project—any interest? new [Re: cphk96]
      #5648647 - 01/28/13 04:34 PM

Quote:

I want to participate! THis sounds like fun.

What exactly will I be reporting?
Will I be reporting what Lunar features I can see in the Earthshine portion of the moon?

Chris




Thanks, Chris! We are sort of making this up as we go along. Ideally, we want to observe the Moon over 3 days, to see if the Earthshine changes in luminance. Tricky, to be sure, but noting what features can be seen on "the dark side" could be part of that.

clear skies

Dave


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Tom and Beth
Post Laureate


Reged: 01/08/07

Loc: Tucson, AZ
Re: Earthshine observing project—any interest? [Re: Dave Chapman]
      #5652791 - 01/30/13 05:10 PM

What the heck, I'm game for learning more on this.

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rookie
Good Night Nurse
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Reged: 01/14/06

Loc: St. Petersburg, FL
Re: Earthshine observing project—any interest? new [Re: Tom and Beth]
      #5656672 - 02/01/13 04:18 PM

Dave,
I'd like to take part in this too. It seems a good way to develop and learn more observing skills. The waning crescents will be harder for me to observe.


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ursamajor
sage


Reged: 07/24/07

Re: Earthshine observing project—any interest? new [Re: rookie]
      #5794128 - 04/12/13 10:36 AM

The evening of Saturday April 13 is perfect for North America. There will be ideal conditions to look for a bright Earthshine. The weather here in Ontario doesn't look promising but I'll be checking anyways.

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NeilMac
Carpal Tunnel


Reged: 09/25/10

Loc: MedHat, AB, Canada
Re: Earthshine observing project—any interest? new [Re: ursamajor]
      #5794244 - 04/12/13 11:39 AM

Weather forecast does not look promising here either

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