TIGHAR

Amelia Earhart Search Forum => General discussion => Topic started by: Scott C. Mitchell on January 12, 2020, 07:57:19 PM

Title: Night sky at Nikumaroro
Post by: Scott C. Mitchell on January 12, 2020, 07:57:19 PM
Curious what the night sky looked like from Nikumaroro on July 3 and July 4, 1937.  The attached data was compiled by SkyTools (a software used by amateur astronomers), in which you input location by latitude & longitude, and date selection.  If this data is accurate, it was interesting how late the waning crescent moon rose in the evening at this particular date (about 11 p.m.) and how early sunrise came (3:46 a.m.).  Perhaps those of us who have been on the island can test this with their own night observations.

Scott
#3292
Title: Re: Night sky at Nikumaroro - table to save downloading attachment
Post by: Scott C. Mitchell on January 12, 2020, 08:06:18 PM
Here's the table of celestial positions of moon, sun & planets from Nikumaroro on July 3, 1937.  The top two lines have the most relevant impact on our castaways.  The other attachment is just an overhead skychart at the same date & time. / Scott

Sunset 15:38, Twilight ends 16:52, Twilight begins 02:32, Sunrise 03:46, Moon rise 23:17, Moon set 11:31
Completely dark from 16:52 to 23:17. Waning Crescent Moon. All times local (GMT+10).
Listing All Classes after 20:12 and before 06:48.
Cls Log Status Primary ID Alternate ID Con RA (Ap) Dec (Ap) Mag Size Rise Transit Set Begin Optimum End Alt Az S.A. U2000 PSA Optimum EP
MSS Y Jupiter Sgr 19h43m24.6s -21°39'05" -2.7 47"x 44" 16:28 22:37 04:46 18:40 22:37 02:34 +73°01' +180°07' 22 II-342 66 Nagler 7mm 2.0x
MSS Y Mars Lib 15h06m25.9s -20°04'57" -1.3 16" 11:49 18:01 00:09 16:05 18:01 22:00 +54°25' +241°27' 21 II-333 57 Nagler 7mm 2.0x
MSS Y Mercury Gem 06h25m51.3s +24°08'00" -1.8 5.2" 03:23 09:19 15:09 05:40 08:58 12:50 +43°33' +049°56' 5 I-137 25 X-Cel 5mm 2.0x
MSS Y Moon Ari 02h31m27.9s +18°21'58" -7.9 33.2' 23:17 05:24 11:31 01:32 05:24 09:15 +66°57' +000°15' 10 I-130 4 Super Plössl 40mm
MSS Neptune Leo 11h12m04.5s +06°17'39" 8.0 2.2" 08:04 14:07 20:06 16:16 16:47 18:03 -02°03' +276°09' 13 I-191 34 Super Plössl 40mm
MSS Pluto Cnc 08h01m57.5s +23°10'51" 15.0 0.1" 05:00 10:54 16:51 - - - +62°09' +000°00' 6 I-140 24 X-Cel 5mm
MSS Y Saturn Psc 00h21m56.5s -00°08'26" 0.9 18"x 16" 21:13 03:15 09:16 23:16 02:31 03:17 +78°15' +067°36' 17 I+II-216 7 Nagler 7mm 2.0x
MSS Y Sun Gem 06h49m52.2s +22°57'09" -26.8 31.5' 03:46 09:42 15:38 06:04 09:42 13:21 +39°24' +055°00' 5 I-138 25 Super Plössl 40mm
MSS Y Uranus Ari 02h41m58.3s +15°17'35" 5.8 3.5" 23:38 05:34 11:31 01:45 02:40 03:09 +42°24' +064°20' 10 I-175 4 Nagler 7mm 2.0x
MSS Y Venus Tau 03h36m53.5s +16°10'38" -4.3 22" 00:33 06:30 12:27 01:01 02:41 03:18 +29°49' +068°21' 11 I-177 15 Nagler 7mm 2.0x
Title: Re: Night sky at Nikumaroro
Post by: Christophe Blondel on January 13, 2020, 09:43:33 AM
But Nikumaroro, at longitude 174°32' west, is not 10h late with respect to Greenwich, rather 11h 38 min. So your sunrise time of 3:46 has to be revised to something like 5:24, local time. Except if local authorities have decided another local legal time, but local authorities were curiously absent from the island on July 3, 1937...
Nothing so extraordinary. So you can go back to sleep quietly another 1 h and 38 min. Except if you want to contemplate the crescent moon.
Best wishes
Christophe
Title: Re: Night sky at Nikumaroro
Post by: Scott C. Mitchell on January 13, 2020, 05:50:51 PM
Thanks for those updates, Christophe.  So sunset would be not 15.38, but more like 17:20 (5:20 PM) and moonrise would be not 23.17 but more like 24.00 (midnight).  Sunrise, as you say, would be 5:24 a.m.  If the aircraft landed on the western side of Nikumaroro, then the trees and bush would, to some degree, block the light of the moon rising toward the east even further.  Referring to the Tides & Credible Signals report prepared by Bob Brandenburg in Volume 28 #1 of Tighar Tracks, the radio signals started about 7:00 pm and continued to about 11 pm (July 2-3), from about 9:00 pm to 1:00 am, with another scattering at about 5:00 a.m. (July 3-4).  and from about 7:30 pm to about 3:00 am (July 4-5).  So these were essentially moonless dark nights in which they would have to make their way across the reef to find the aircraft.  Just getting to the aircraft to make these radio calls could not have been easy. / Scott #3292
Title: Re: Night sky at Nikumaroro
Post by: John Klier on January 15, 2020, 08:04:44 AM
The website timeanddate.com shows sunrise at 5:46 am and sunset at 5:37 pm.  Here's a link to the whole month of July in 1937.

https://www.timeanddate.com/sun/@-4.67791,-174.52?month=7&year=1937

...and here's the moon data.

https://www.timeanddate.com/moon/@-4.67791,-174.52?month=7&year=1937
Title: Re: Night sky at Nikumaroro
Post by: Ross Devitt on February 26, 2020, 05:53:58 AM
Quote
So these were essentially moonless dark nights in which they would have to make their way across the reef to find the aircraft.  Just getting to the aircraft to make these radio calls could not have been easy. / Scott #3292

Someone, somewhere on the forum has  etrapolated tide data for Gardner based on known data for Hull or some other island in the vicinity on those dates.

It is unlikely that Fred and Amelia would have tried to cross the reef on a moonless night. Tropical reefs are treacherous even if the water is shallow.  Usually patches of slime on the rocks, and little crevices everywhere just waiting to snap an ankle.
It's much more likely that they would have started making their way out as the tide fell, so they could have maximum time in the Electra.  If they had already worked out the tide times (both should have had watches) they should have been fine and worked out they would have about two, maybe three hours at the Electra and within the third they had to head back pretty smartly.

If the tide was rising quickly, they would have slept in the Airplane rather than trying to tiptoe through the biteys to get back to land.