Sextant box found on Nikumaroro
When Gallagher did a thorough search of the area near where the skull was found, he discovered an empty sextant box with two numbers on it--3500 and 1542. The British saw no significance in the numbers; in 2008, TIGHAR found an intriguing pattern of dual numbers (maker's number and U.S. Naval Observatory numbers assigned when the instruments were inspected there).
The Brandis sextant boxes pictured here are approximately 10" x 10" x 5".
- 1 Notes from the bones file
- 2 Tofiga's recollection
- 3 What might 3500 and 1542 mean?
- 4 The Pensacola Sextant Box (3547 and 173)
- 5 Sextant Box Numbers: Suggestive Patterns
- 6 Photo Gallery
- 7 Links
- 8 References
- 9 Related articles
Notes from the bones file
- Telegram No. 71 from Gallagher to Jack Barley, Resident Commissioner, Ocean Island, Sept. 23, 1940
- Sextant box has two numbers on it 3500 (stencilled) and 1542--sextant being old fashioned and probably painted over with black enamel.
- Typed note in file 4439-40 (23) from Vaskess to Sir Harry, April 11, 1941
- The sextant box with its contents is now with me. Perhaps Captain Nasmyth might be willing to examine this with a view to ascertaining the origin?
- Letter – circled 14. Vaskess to Commander G.B. Nasmyth, F.R. Met. Soc., Suva. June 6, 1941.
- Dear Commander Nasmyth,
- With reference to our telephone conversation relative to the identification of a sextant and box which I mentioned as having been found and which you were so good as to say you would examine, I regret to state that on further examination it was discovered that no sextant had actually been found but only a box thought to have contained a sextant.
- I am forwarding the box to you with this letter and His Excellency would be grateful if you would examine it with a view to determining its use and origin if possible.
- Secretary to the High Commission
- Typed note to file 4439-40 in red ink (39). Sir Harry to Vaskess. August 8, 1941.
- Sec., H.C.,
- I return the sextant box which I had retrieved from Captain Nasmyth in order to show it to Mr. Gatty who has expert knowledge of such matters. Mr. Gatty thinks that the box is an English one of some age and judges that it was used latterly merely as a receptacle. He does not consider that it could in any circumstance have been a sextant box used in modern trans-Pacific aviation. 2. What was Captain Nasmyth's opinion of it?
- Note to file 4439-40 (40). MacDonald to Vaskess (passed along to Sir Harry)
- The Secretary
- Mnt (39), para. 2, I have spoken to Captain Nasmyth who replied as follows:- "As the sextant box has no distinguishing marks, & since it was discovered that no sextant had been found, all I have been able to find out is that the make of the box – that is – the dovetailing of the corners – makes it appear to be of French origin."
Dovetailed sextant boxes
"Dovetail joints for the corners had by the 1920s given way to comb (finger) joints, but as some later American aircraft cases used corner rebates, which are much easier to make without special machinery."
Tofiga said he had seen a sextant box on Vaskess' credenza. Tofiga was not taken into the confidences of the WPHC officers who examined the materials sent to Fiji from Gardner Island, but it seems very likely that the box he saw was the one Gallagher sent to Suva.
What might 3500 and 1542 mean?
The sextant box found on Nikumaroro and shipped to Fiji in 1941 had two numbers on it: 3500 and 1542. TIGHAR has recently found a plausible explanation for those two numbers. The first is likely to be the maker's number; the second a number inscribed on the instrument when it was inspected at the U.S. Naval Observatory.
Fred Noonan loaned a naval sextant to a student of his prior to the fatal flight. That sextant box is extant and also has two numbers handwritten on the bottom of it: 3547 and 173. But the sextant inside the box is a Ludolph with a different serial number.
The Pensacola Sextant Box (3547 and 173)
The National Museum of Naval Aviation has a sextant box with "dovetailed corners, the number 116 handwritten on the front, and the numbers 3547 and 173 handwritten on the bottom." The box contains "a sextant manufactured by W. Ludolph of Bremerhaven, Germany, in 1919, with the serial number XIX 1090, painted black." The box was donated by W. A. Cluthe, a retired Pan Am captain, who said that he had borrowed the Ludolph sextant from Fred Noonan. The box is listed in the table below as Brandis (theoretical) because the box contains modifications that may have been made to accommodate a Brandis bubble sextant.
Sextant Box Numbers: Suggestive Patterns
This chart is organized in the order of the Navy number given to the instruments by the Naval Observatory when they were sent there for calibration. Two entries are theoretical; the rest are actual pairs of numbers obtained from various sources. Two of the boxes in TIGHAR's possession have Naval Observatory numbers stamped on the box along with Brandis maker's numbers stenciled on the box.
In the engraving on the sextants, there is a symbol for the Naval Observatory between "U.S. Navy" and the number issued by the Naval Observatory. The symbol is an "N" superimposed on a square "O". The symbol is relatively clear in this photograph.All the nautical instrument repair and calibration work was shipped off to Norfolk in the early 1950s.
"Important though this work was, the Observatory was open to the criticism, especially from astronomers, that navigational instruments should be no part of the work of an astronomical observatory. This was undoubtedly part of the reason that the chronometer function was transferred in 1951 to the Norfolk Navy Yard, leaving only a small group of instrument makers who repaired and constructed the Observatory’s telescopes and other instrumentation, rather than navigational instruments."
Any sextant marked "FE Brandis" is definitely a pre-1925 or so product.
|Maker||Maker No.||Navy No.||Inspection date||Comments||Bubble||N.O. # on box||WB/WS|
|W&S (stamped into box and on plate) Warner & Swasey||69||34||Flying Fish Trading Co.||?|
|Keuffel & Esser||14279||330||1931-06-11||Live Auctioneers. Class: H.G. Stylized N+O. Unusual inlaid U.S. Navy shield with N+O and N+O 330 on it.||Unusual engraved brass plaque on top.||
|Brandis||2763||348||Dovetail joints on box.||Yes, on brass plaque.|
|Brandis||2734||362||1943-04-18||ebay #350401896246; re-inspected 1965-11-12||no||yes (die-punched)|
|Keuffel & Esser||18446||405||Smithsonian; K&E date: 1908||yes|
|Keuffel & Esser||4940||415||1936-01-29||Flying Fish Trading; K&E date: 1901; in W&S box||no||
|Keuffel & Esser||470||0107||1942-12-31||Manufactured 1887/1888? Class: survey. Lacks stylized N+O.||Engraved in two places on instrument. Punch-stamped twice on hingeline of box. Class: Survey.||
|Keuffel & Esser||5418||575||1918-04-16||Mystic Seaport; K&E date: 1901||no|
|Keuffel & Esser||31475||616||1941-09-29||Private collection. Sextant described by owner in e-mail to TIGHAR (2013-06-04).||no||Yes, on inlaid shield, outside lid of the box.|
|Keuffel & Esser||33839||664||K&E date: 1916|
|Brandis||3249||836||ebay||no||"3249" in pencil inside box lid and in ink on box top|
|Brandis||3239||850|| Dominic Winter Book Auctions; "circa 1918."
"Brandis & Sons Mfg. Co. Brooklyn."
|Brandis||3268||882 (?)||ebay; 882 is stenciled on front of the box.||no||882 stenciled on front; box only; contains 3657||WS
|Brandis||3667||889||ebay.||no||yes. Box only; contains 3703/936.||WS
|Brandis||3703||936||ebay.||no||Yes, but box is for 3667/889.||WB
|Brandis||3738||945||ebay; In box for 3268.||no||WB|
|Buff & Buff||11778||1065||1918-05-12||eBay||no|
|Brandis||5851||1110||Purchased on ebay by Lee Paynter, a TIGHAR member.||no||no, but Maker number is stenciled on edge||
|Brandis||5756||1114||1937-08-02||ebay; box containing Brandis 5981 / N.O. 1142 with certificate of inspection for 5756/1114||WS
|Brandis||5727||1127||1921-08-20||email to TIGHAR headquarters||
|Brandis||5981||1142||in box for Brandis 5756 / N.O. 1114||WB|
|Buff & Buff||11949||1144||eBay||no|
|Buff & Buff||13069||1248||ebay.||n/a||
|Buff & Buff||13135||1365||La Timonerie Antiquities. Manufactured 1908? Maker number and NO number on instrument.||
|Brandis||3331||1421||Land and Sea; in box for 4551||No||No.||WB|
|Brandis||3360||1446|| in box for 4131, which is stamped in ink above right hinge. Also stamped in ink:
|Brandis||3444||1461||eBay.||no||No, box is for a Buff & Buff||
|Brandis||4129||1530||eBay.||In box for 4483||WB
|Keuffel & Esser||37548||1555||1919-10-24||Mariner's Museum; K&E date 1918||no|
|Brandis||3483||1567||1932-01-27||ebay; box only.||no||WS|
|Brandis (sextant only)||3511||1585||TIGHAR (sextant only)||no|
|Keuffel & Esser||37508||1595||ebay; USN number 161-USN-252194||n/a|
|Brandis||3527||1599||1933-05-04||TIGHAR; large box; box only||yes|
|Brandis||4521||1648||no||no; 58281 in pencil inside the lid on what looks like a repair or addition|
|Brandis||4551||1762||ebay; box only; contains B. 3331 / N.O. 1421||no||yes||WS|
|Brandis||4297||1880||1939-09-18||TIGHAR - McKenna||no||yes|
|Brandis||4522||1868||1918-11-07||Brandis & Sons; survey; "H.K."; Capt. J. H. Klein||no|
|Brandis||4672||1889||eBay (reported 11/17/2011 on AE Forum by D.P.Cotts)||no||In Box for Brandis 4667.||WB|
|Brandis||4345||1914||ebay. metal tag: 61071 000065. Inside edge: (pencil) serial 1914; Brandis stamp: 4001.||no||no||WB|
|Brandis||4319||1960||ebay||no||(in box for 3483/1567)||WB|
|Brandis (sextant only)||4279||2531||1941-07-23||Flying Fish Trading Co.; box is for B. 4234||no||
|Brandis||4244||2561||Moinat SA, "Sextant 'US NAVY N° 2551 par Brandis & Son." I read "2561" in the photo.||"4244" (?) is in ink on the hingeline. Not visible on photos of instrument.||
|Brandis (sextant only)||4834||2564||1941-06-28||ebay||no||yes||
|Brandis||4836||2607||ebay||no||no. In box for 4798.||WB
|Brandis||4919||2659||1919-02-18||ebay. NO 2659 etched on arc. Brandis 4919 on the arc and the inspection certificate.||no||no. Serial number is stenciled on the box.||
|Brandis (sextant only)||4934||2687||ebay, sold 12/30/2014 $132.50||no||yes|
|Brandis||5015||2693||1945-06-05||LiveAuctioneers.These two numbers are on the collimation certificate. They have not been cross-checked with the instrument in the box.||??|
|Brandis||5071||2696||1939-09-18||U. of Illinois Observatory||no|
|Brandis||4994||2741||1942-05-25||eBay (reported 12/05/2011 on AE Forum by D.P.Cotts)||no|
|Brandis||4440||2743||eBay; box number 4902||no||no||WB|
|Brandis||2539||2827||eBay; "161 - USN - 252222" by hand on arc; "U.S. Navy" stamped on arc||only on box; Brandis 2539 on arc|
|Brandis||4182||2868||eBay; (no box)||N/A|
|Brandis||5310||2919||1946-03-07||eBay; Survey; box only|
|Keuffel & Esser||36961||3227||1937||K&E date: 1918||
|Keuffel & Esser||37305||3277||1940-09-20||Cloudy Nights. "1919 K&E Sextant." Class: Survey.||
|David White Co.||3954-41||1948-12-11||Craigslist||NO 3954 on plaque. Other numbers and signs written on the top of the box: "X9773-" and "R1" on top.|
|Brandis||5156||4017||eBay; in box for UNSO 4717/1982||no||WB|
|Brandis||4193||4161||1919-04-02||ebay. Problematic.||no||Pictures show 4193 stamped on arc and inked on the box. N.O. 4161 also on arc, according to the text. Maker's number 5317 on the inspection certificate. So there is quite a discrepancy!||WB
|Brandis||4765||4267||1938-11-15||ebay||no||Appears to be 4765.|
|Brandis||4750||4296||In box for NO 4572||4572||WB|
|Brandis||4762||4334||eBay||?||plate on box says 1844||WB|
|Brandis||5524||4374||ebay. In box for Brandis 4065 (inked on hingeline).||no||no||WB|
|Brandis||5577||4485||1941-03-14||ebay. A note made in pen on the margin of the N.O. certificate reads, "Use cigarette ashes to wash."||no||Not stenciled or stamped. Gillespie: "Interesting that the box has no stenciled serial number or stamped-in N.O. number. Apparently, at some point, they stopped doing that." The collimation (calibration) certificate glued into the box matches the serial number and N.O. number on the sextant.|
|Brandis||3596||4510||ebay; 7.5" radius||no||no box|
|Brandis||3920||4516||Fleaglass.com||no||seller says "yes"|
|Brandis||3893||4569||1941-03-14||ebay; sold in 1946 as war surplus||no|
|Brandis||4029||4572||Numbers from box; contains NO 4296.||4572||WS|
|Brandis||3826||4603||eBay||no||Brass plaque on box: "248 US Navy 101009"|
|Brandis||3946||Box only. Holds Brandis 5670.||No.||WS|
|Brandis||4097||4657||1937-09-30||eBay; class: Survey||no||in pencil inside|
|Brandis||4313||4665||Bruce Thomas||no||No box. In display case from USS Hancock.|
|Brandis||5670||4705||Smithsonian; offered for sale on ebay in 2017. Identified as Brandis 5670. Curator confirms number is 5670.||no||No. The box is for Brandis 3946.||WB|
|Brandis||1982||4717||ebay; holds USNO 4017/5156||yes; box only||WS|
|Brandis||3336||4773||eBay (no box)||no|
|Brandis||3320||4799||eBay (reported 11/22/2011 on AE Forum by D.P.Cotts)||no||no|
|Brandis||3985||4826||eBay (reported on AE Forum 6/30/2012 by Walter Runck)||no||No|
|Brandis||3898||4842||1941-04-18||Last digit in inspection year uncertain: 194? ebay||no||3898 on box; no NO No. seen in ebay pictures.|
|Brandis||3806||4879||purchased by TIGHAR member Jim Linder||no|
|Brandis||5628||4954||1932-12-23||eBay (McKenna). "DD 359" (US Destroyer USS Winslow?) written in pencil twice in the box.||no||No numbers on the box (neither Brandis nor N.O.).|
|Mergenthaler||5083-44||1945-03-27||Only the box; ebay.||n/a|
|Mergenthaler||5223-44||1945-01-04||MK. I. Mod. 0; ebay||no||Note on box for 5878-44|
|David White (1943)||11949||5508||eBay||no|
|David White (1941)||5273||USNO Historical Committee Inv|
|Mergenthaler||5878-44||MK. I. Mod. 0; ebay||no||In box for 5223-44|
|David White (1941)||9746||eBay (reported 10/15/2011 on AE Forum by A.McKenna) was used on USS Hector||no||13692 stamped on brass plate affixed above lid latches|
|David White (1943)||17649||17649-43||1946-07-19||eBay||no|
|No Navy numbers or not known|
|Brandis||1844||?||eBay; plate on box containing 4762||WS|
|Brandis||2539||166 - USN 25222 (?)||ebay; "U.S. Navy on one end of arc; "161 - USN - 25222" hand-engraved; in box with 2827 die-punched on it||2827 die-punched (not inked) on wood. Because of the two different kinds of numbers, I have entered this sextant number twice in the table. Here as 166 - USN 25222; elsewhere as Navy No. 2827.||
|Brandis||2679||Brandis sticker identifies this as an octant manufactured on 1/19/1911. There does not seem to be any Navy number or collimation certificate. The box has "dovetail joints." ebay.|
|Brandis||3657||883 (?)||box holding sextant 3692; ebay||no; 883 stenciled on box||WS|
|Brandis||2864||none||"F. E. Brandis, Sons & Co." and serial number in center of the arc.||none|
|Brandis||3692||none||ebay||no; in box for 3657||WB|
|Brandis||3702||none||e-bay. Large "916" stenciled in gold on box.||no||"916"?|
|Brandis||4001||?||eBay; box for 4345||no||WB|
|Brandis||4037||?||eBay; stencil on box for 4487||WS
|Brandis||4234||?||stencil on box||
|Brandis||4234||?||stencil on box||
|Brandis||4483||1918-11-30||Box contains #4129, NO # 1530.||None on box nor on Navy collation certificate.||WS
|Brandis||4798||1919-01-30||ebay||no||no. Contains sextant 4836/2607.||WS
|Brandis||5360||?||eBay; stencil on box for 3987||
|Brandis||5687||Plate on box says "Fiala Outfits, Inc. ..."|
|Brandis||5953||184 imprinted twice on lens bracket||184?||
|Brandis||5996||1920-10-08||Live Auctioneers. Maker's No.: 5996 crossed out on inspection certificate. 6006 written in green ink.||5996 punch-stamped on box in large numbers near hasp. "Weems 805W" in upper-right corner of certificate--pencil? different ink? Class: Aviation. Sticker: "Directional Laboratory Instrument Service, Nautical - Aeronautical - Industrial, Ivanhoe, Baltimore, MD."||
|Brandis||6006||5996?||Live Auctioneers. In box for 5996? Quadrant?||Yes? Wired with on/off switch, light.||5996 punch-stamped on box in large numbers near hasp. "Weems 805W" in upper-right corner of certificate--pencil? different ink? Class: Aviation. Sticker: "Directional Laboratory Instrument Service, Nautical - Aeronautical - Industrial, Ivanhoe, Baltimore, MD."||
|Buff & Buff||13024||1919-04-24||La Timonerie Antiquities. Manufactured 1908? Class: Survey||13024 on box & inspection. Inlaid shield--seems to be blank.|
Looking for patterns in the data
There seems to be some correlation between the dates of calibration by the Naval Observatory and the number given to the sextant by the Observatory.
The numbers issued in 1919 seem to be in ascending order by date, but they are out of sequence compared to the rest of the table.
With the 1919 numbers removed, most of the rest of the numbers are in ascending order by date. Two of those sextants (2977 and 2975) are bubble mods for the Navy transatlantic flight in May of that year.
|Maker||Maker No.||Navy No.||Inspection date|
|Keuffel & Esser (in W&S box)||4940||415||1936-01-29|
|Keuffel & Esser||5418||575||1918-04-16|
|Buff & Buff||11778||1065||1918-05-12|
|Keuffel & Esser||37548||1555||1919-10-24|
|David White (1943)||17649||17649-43||1946-07-19|
Brandis production eras
- John Kada, Forum (19 Oct 2012)
- According to a brief history of Brandis given on the Smithsonian web site, Brandis slightly changed its name three times during its existence, and therefore the way the Brandis company name is marked on a sextant can potentially tell us something about when it was manufactured.
- “Frederick Ernest Brandis (1845–1916) was born in Germany, came to the United States in 1858, worked for Stackpole & Brothers for a few years, and then opened his own instrument shop in 1871. The firm became F. Brandis & Co. in 1875, F. E. Brandis, Sons & Co. in 1890, and Brandis & Sons Mfg. Co. in 1916. The Pioneer Instrument Company purchased control of Brandis in 1922, and sold it to the Bendix Aviation Corporation in 1928. The manufacture of Brandis instruments ceased in 1932.”
- So, we have three Brandis eras:
- - The ‘F. Brandis & Co.’ era, from 1875 to 1890;
- - The ‘F. E. Brandis, Sons, & Co.’ era, from 1890 to 1916;
- - The ‘Brandis & Sons Mfg. Co.’ era, from 1916 to 1932.
- Art Rypinski
- In the late 1920s, the Navy changed their serial numbering scheme, just about the time aircraft octant became avialable. . Later serial numbers took the form XX-YY, where YY is the year of acquisition. If the octant that Fred Noonan took on the world flight originated with the Navy, it would probably would have had an XX-YY serial number, where the year element would fall between 27 and 38. However, Noonan might have bought his own octant, or scrounged it from Pan Am, in which case the form of the serial number is anyone's guess. (Army Air Corps also used YY-XXXX serial numbers from 1940 and perhaps earlier). Octants and octant boxes have a distinctive and peculiar shape. We can be pretty certain that the 3500/1542 box was not an octant box.
- The 3500/1542 inscription is particularly interesting because it is consistent with a particular moment in time (1918-1921), a particular institution (the US Navy and USNO), and a particular make of sextant (Brandis). During this period, we know that the Navy modified a number of Brandis sextants in aviation/bubble/"Byrd" sextants, and we know that Noonan's friend Cmdr. Weems owned several modified Brandis sextants because he much later donated them to the Smithsonian.
- We also know that Noonan carried a nautical sextant on the China Clipper flight, and we have a contemporary photo showing a Brandis sextant box sitting next to an octant on the navigator's shelf of the China Clipper. We do not have any direct evidence that Noonan carried a sextant on the world flight, nor any direct evidence of the make or serial number of any hypothesized sextant. So, there are still some links missing in this chain of evidence.
- However, it would very interesting to demonstrate that the Navy once owned a Brandis sextant with the serial numbers 3500/1542, and even more interesting if it could be shown that this particular sextant had been modified as an aircraft sextant. It would be yet more interesting if this sextant could be linked to Weems, Pan Am, or Noonanj. It would also be interesting (in a negative way) if the sextant turned up in an inconvenient location (like aboard a ship) in July 1937.
- Some things to look for:
- Listing of sextants surplused, with serial numbers.
- Listing of sextants sent or received for modification as byrd or bubble or aviation sextants;
- listing of sextants calibrated by USNO, with serial numbers.
Keuffel & Esser production dates
- John Kada, Forum, 4 October 2012.
- In the table below I list the N.O. number, Keuffel & Esser serial number, date of manufacture as indicated by the table from Surveying Antiques, and date of the eccentricity certificate we have for the sextant. The last sextant in the table is the sextant that I mentioned in reply #99, whose N.O. number we don't have.
N.O. # K&E # K&E year E.C. year 405 18446 1908 N/A 415 4940 1901 1936 575 5418 1901 1918 664 33839 1916 N/A 1555 37548 1918 1919 3227 36961 1918 1937
- The dates of manufacture would of course be the earliest the sextants could have appeared at the Naval Observatory, while the eccentricity certificate dates may represent re-certifications rather that the first certification of the sextant.
- The K&E sextant with an N.O. number 1555 is only a few removed from our holy grail sextant, N.O. #1542; if we have a correct date for the K&E sextant then it would seem that the sextant with N.O. #1542 passed through the Naval Observatory for the first time in 1918 or 1919. It is interesting to note that the Ludolph sextant that Noonan gave to a fellow Pan Am pilot, has a manufacture date of 1919 (as indicated by the Roman numerals XIX).
- Ric Gillespie
- If we throw out the 1919 numbers as an anomaly, along with K&E #4940, we can say that the assignment of N.O. number 1542 (on the Niku box) might have occurred circa 1930/31 and that the instrument was still in the Navy inventory at that time. Noonan went to work for Pan Am in 1930. Pan Am acquired the landing rights to Honolulu, Midway, Wake and Guam in 1934 and began assembling its Pacific Division with Noonan as the lead navigator.
- In other words, Noonan's acquisition of Brandis 3500/N.O. 1542 as surplus sometime between 1934 and 1936 seems possible.
- Art Rypinski
- Keep in mind that Brandis made thousands of sextants during the period 1918-1920 or so, which left the peacetime Navy with far more sextants than they could ever use. The Naval Observatory Annual Reports for the period describe surplusing of large number of instruments. According to the Smithsonian, Brandis was acquired by the Pioneer Instrument Co. in 1922, and "the manufacture of Brandis instruments ceased in 1932." I think it would be reasonable to believe that almost all of the Brandis sextants in circulation were actually manufactured in 1918-1920, and that none were manufactured after 1932. Further, the Naval Observatory appears to have changed its numbering plan (at least for aviation octants) in the late 1920s, and begin issuing NO numbers with the form XXXX-YY, where YY was the year of original calibration. Therefore, I believe that all of the post-1930 calibration dates are recalibrations of sextants that were originally calibrated and issued their NO numbers in 1918-1920. Hence, I hypothesize that neither the maker’s number nor the NO number of sextants calibrated after 1930 has any relationship with the calibration date.
- 3500/NO 1542 could have been surplused and put into private hands at any point after 1920. If 3500/1542 was a Byrd Sextant, however, I speculate that it would have been relatively rare and would have been kept in service until aviation octants became relatively plentiful--say, early 1930s?
Sextants, Octants, Quadrants
- P. V. H. Weems, Air Navigation, 1938, second edition, p. 301
- Since an arc of 45 degrees is one-eighth of a circle, instruments of this general type, having a maximum angle of 45 degrees between the two reflectors, are known as octants. Instruments having an arc or limb of 60 degrees, or one-sixth of a circle, for measuring the angle between reflectors are called sextants, and those having arcs of 90 degrees, or one-quarter of a circle are called quadrants. Either octants or sextants are suitable for aerial use, but the quadrant is too bulky. For a great many years practically all instruments used by marine navigators for measuring altitudes have been sextants, and the term sextant has become so generally used that it is now applied to all instruments for measuring altitudes of heavenly bodies whether they are actually quadrants, sextants, or octants.
- Left-handed Brandis aeronautical octant, 206C-145.
- Sextants at Greenwich: a catalog by W.F.J. Mörzer Bruyns and Richard Dunn.
- The Nautical Sextant by Bill Morris.
- Numbers Game in TIGHAR Tracks, Volume 24, October 2008
- "Update on Byrd Aircraft Sextant."
- Shoes p. 232.
- Ibid. p. 233.
- Sky and Ocean Joined: The U.S. Naval Observatory, 1830-2000, by Steven J. Dick, Cambridge University Press, 2003; p. 507.
- Model #5227, manufactured about 1915/16, with K & E serial number 31475.
- There was an earlier Naval Observatory "Cert" card that had been glued inside the lid, but there is no written information left on its remains, and only just enough paper and printing to tell with certainty that is what it was. So this confirms that it had been "Certified" by the Naval Observatory at a much earlier date, most certainly in the "teens" when it was still quite new, but sadly the actual date of that earlier inspection, and any of its results. have been lost to us.
- The collimation label gives the Maker No. as 2919. 5310 is stamped in ink on the box while 2919 is impressed in the wood.
- Andrew McKenna: If "DD 359" does indicate service aboard US Destroyer USS Winslow, it is interesting that they were still issuing 1920s sextants to ships being commissioned as late as 1937.
- "How To Date Your Keuffel & Esser (K&E) Instruments."