Air Navigation

[JDavHouston]

Well, Earhart did one very important thing that still lasts to this day, the creation of the 99s. Sometimes the legacy we want isn’t the legacy we get. Sadly, Noonan is unknown in most aviation circles these days, with the exception of discussions of the Earhart disappearance.

As far as being difficult to learn, I’m no CW (continuous wave, the ham name for morse code) operator, but I don’t think it’s any more difficult than learning celestial navigation. It’s all about having the willingness to do some paperwork and exercises that most do not do because there is ‘no need’ anymore.

VOR is VHF Omni Range. It allows you to find your relative position to any of 360 ‘radial’ courses from a station – this allows you to navigate fairly easily from one station to another without any specialized equipment. ILS is the ‘instrument landing system’ that allows an aircraft to follow a signal down through the clouds and fog right to the runway. Both systems transmit a repeated identification in Morse that the pilot uses to make certain they are receiving the right signal before using it to navigate.

LORAN was a totally different system, and has been turned off and unavailable since February 2010. Aviation navigation is all either VOR stations (the backup) or GPS (the main system) now. Of course, pilotage and dead reckoning are still taught, but are fast becoming a lost art themselves it seems.

I’m considered an extreme oddity for considering air celestial navigation.

I have some rare(ish) wrenches on the way for my sextant which should allow me to adjust the calibration, per some videos I watched. We’ll see how it goes, I’m going to have to “get creative with some lasers” to build a collimator to adjust this thing.

[manxcat]

To: JDavHuston,
Well, you’re right, A.E. was the first president of the 99s… who are still going strong… like the Lady’s ‘Tail-Draggers’ flying club. One time I talked to this old guy who used to be a woodwind player during the Big Band era in the 1940s. Once I asked him which is the hardest woodwind to learn to play: the sax or clarinet? He sounded a little-bit put out with me, and he sharply answered: “What does it matter to you which is the hardest to play if you’re the one playing them?” If people had to learn Morse code and celestial navigation they would get over the hump and just do it without wasting time worrying about the ‘difficulties’. Once you wrote me that you’re working on getting within ten miles of your targeted destination. I hike in the foothills around Cool, California with a Garmin GPSMAP66sr… and to be off by ten miles is a big deal when you’re on foot in the mountains, especially if it’s getting dark (maybe life or death). In celestial navigation there is an ‘acceptable’ area-of-uncertainty that grows with the greater distance traveled from the last solid position. That’s why few people bother with celestial–it’s not reliably accurate and there is no need for it, and it’s hard to learn. If the Red Chinese gobble-up our GPS satellites or successfully jam them, it would be a different story. I understand that the Air Force Blackbird bombers had computerized sextant-like devices that can take sites on up to eleven astral bodies and do all the math every 2 seconds twenty-four hours a day except when it’s cloudy. Yes, it saw stars and planets during the daylight hours. You probably knew about that already? If they take down our orbiting GPS sphere on a cloudy day we’re all screwed. ha,ha, LOL
Celestial Navigation might come in handy for deep-ocean mariners in an emergency but they’ll have to actually know what they’re doing with it. The rest are people who take up celestial as a hobby-horse. The best one of these hobbyists that I’ve read is the physicist John Karl, who wrote “Celestial Navigation in the GPS Age.” You can buy it used on Amazon if you’re interested. The book is oriented to mariners using traditional sextants. I think he has got his chops down pat. The one thing that really put me off from trying celestial is John Karl’s statement that a person with poor eyesight will get poor results using a sextant… my eyes aren’t great.
As far as how celestial navigation went for Earhart and Nonoon back in 1937 goes… even the coordinates they had for the ‘correct position’ of Howland Island was proved wrong by GPS to be about 5 to 8 miles off.
I like what you’re trying to do with your A-12… it’s a living part of history. I want you to succeed and become good at it. I like your grit too.

[JDavHouston]

This jumped out at me: “The one thing that really put me off from trying celestial is John Karl’s statement that a person with poor eyesight will get poor results using a sextant… my eyes aren’t great.” Mine are so bad that my prescription glasses cause severe chromatic aberration!

Also, I really love this quote: “What does it matter to you which is the hardest to play if you’re the one playing them?” I will be using that one!

I do appreciate the encouragement, it’s proving to be a bit of an adventure nonetheless, and it’s given me a new appreciation for the stars and world around me, and improved my regular flying navigation. Sometimes, you just gotta turn off the GPS and navigate by seeing landmarks, good ol’ pilotage.

I’d heard of the Airforce’s automatic systems, and I’m told they could even locate planets in a good amount of haze as well.

[manxcat]

To JDavHouston,
I think you’ve busted me: The poor eyesight and sextant connection was a great excuse for me not to get too involved with celestial navigation with all its math, astronomy, and mechanical [sextant servicing] challenges. Not to mention all the Celnav software for computers and handheld scientific-calculators. I chickened out. The view from the sidelines is most relaxing.
When you wrote about ‘good ol’ pilotage’ I thought of a show that I saw on the TV awhile back, like something that you would see on the “Mayday air disasters” series. Well, this private pilot along with his entire nuclear family were flying VFR to someplace and he was closely following the major freeway he needed to reach his destination safely. Everything was totally under control, except he was following the wrong freeway. The freeway that he actually was following ran right towards a major International airports restricted airspace. He inadvertently crossed the path of a landing jet airliner that was full of passengers. The accident investigators surmised afterwards that the private pilot was concentrating on looking to his right… where the freeway was located… and the jet airliner’s crew were looking to their left… where the International airport was located. The prop on the small plane hit the jet’s tail elevator and opened it up like a can-opener, with a series of nasty gashes along its length. The top of the small plane’s cabin was completely torn off (the TV show didn’t say if the family all had their heads cut off or not) The jet airliner was uncontrollable and shortly crashed killing everybody on board. So much for pilotage. I don’t like the feeling of getting lost in the countryside, especially when I am out of cellphone range. If GPS fails, it’s mini-pilotage for me–but I’ll be wondering: “Was this trip necessary?”
What is your flying experience? Tell me about it… I am interested.

[JDavHouston]

That sort of accident is just… sad. I always recommend ‘Flight Following’ to my students. You get radar services from Approach and Center controllers to avoid that sort of problem.

As for my experience, I’m a Commercial Single Engine Land and Multi-Engine Land pilot, instrument rated, and a certified flight instructor for single engine airplanes and for instrument airplane operations. It probably sounds far more impressive than it is. About half the industry has those ratings, and I don’t fly any jets or such.

[manxcat]

To: JDavHouston
I think most of those flight disaster TV shows are depicting accidents that have occurred years ago. In some cases decades ago. After each of those accidents there were supposedly corrective measures and new policies & procedures instituted. Hopefully, flying has gotten safer for all of us since then.
I was meaning to mention something that I read on an Internet post awhile back. Somebody posted on a flying forum that there was a flight simulator that pilots could use. It was the usual mock-up of an airplane cockpit but this one was under a planetarium dome. As I understood it, There was a bubble octant or sextant setup as part of the simulator. I assume that the device was the mounted periscope type. The person that had used it said it was great practice, and that he learned a lot about celestial navigation from his simulator sessions. I am sorry, I can’t remember much of the details, it has been too long ago. I don’t know if you’ve ever heard of this kind of simulator before. But if you haven’t, it might be worth doing an Internet search for it?
I think you should look into the Gary LaPook postings if you haven’t already. He is an Amelia Earhart buff, but otherwise, he is right in there with what you’re trying to do with you’re your A-12. He is not some kind of A.E. nut… he is just interested in the celestial navigation part of it. As far as I know LaPook is still alive. I’ve tried to contact him before, but I didn’t try very hard. You might try going to the Stratus Project site of which he is / or was a contributor.: http://www.stratusproject.com/
Also, I can’t imagine that you don’t already know about the Stellarium astronomy site. But if somehow you don’t, It’s a great tool for locating astral bodies and then being able to find them in the real night sky. It’s free. Stellarium

[JDavHouston]

Yep, I’ve been using LaPook’s information to shore up some of the ‘what does this mean’ questions I’ve had while going through the last edition of the Flight Navigator’s Handbook. I’ve heard of those types of simulator, but I don’t know of one that exists at present. I should look for one.

Stellarium is great software. I’m using it to help calibrate the sextant I have – which is a frustrating endeavor, but at least I have the required bristol wrenches now.

[manxcat]

To JDavHuston,
I’ve attached links to a AOPA [Aircraft Owners and Pilots Association Foundation] 2003 celestial navigation article that mentions Gary LaPook [Third paragraph down as well as elsewhere] Also be sure to open the link to profession astronomy software that is recommended in this article.
You may be very modest about your flight training and skills, but I’ll tell you one thing that is for sure: Your instrument training would have come in pretty damn handy for John Kennedy Jr on his way to Martha’s Vineyard!!!

https://www.aopa.org/news-and-media/all-news/2003/april/pilot/celestial-navigation

http://www.starrynight.com
Let me know if you have any trouble opening those two links, because I’ve been having a lot of trouble sending them
–Joseph

[mcaminos]

In my case, I have been using a regular marine sextant for a couple of years and a few months ago I got an A12 and recently a Mark V both with artificial horizons. (the Mark V have both artificial and natural horizons)

I have tested both on land taking sights of the sun, moon, planets and starts in different location in Florida, Spain and Argentina. The A12 worked fine with errors between 3 and 8 miles, and the Mark V worked even better with errors between 2 and 6 miles compared to the real GPS positions.

Considering that both the A12 and the Mark V were built in the 1940’s, I would say that the results were quite satisfactory.

The great thing about a sextant with artificial horizon, comes at night because you can take sights of the moon, planets and stars (and a combination of them for a more accurate fix), any time at night and not necessarily during nautical twilight.

[manxcat]

To Mcaminos
Well, I am interested in celestial navigation as it relates to the abortive Amelia Earhart World Flight of 1937. If you’ve read my previous posts [above], you know where I am coming from. Your post answered my question about bubble-octants / sextants in that they can be used at night, but can they be used throughout the entire dark of night? Can the traditional aeronautical and maritime almanacs & reduction tables be used with sites taken at any time in the dead-of-night with a bubble-octant/sextant?
I did a quick google search for Mark V sextants… and is yours as heavy to hold as I read they were?
By-the-way, ‘Mark V’ was also the designation for the “new-improved” version of the standardized Navy deep-sea “hard-hat” diving helmets that were in use for generations.
–Joseph

[mcaminos]

To Manxcat
Hi Joseph:

Bubble octants can be used anytime of the day you cannot see the horizon for meteorological reasons, or anytime at night that is convenient for you based on the starts, planets and moon available.

This is the great advantage of the bubble octants over regular marine sextants. However, if you are on a ship in the middle of mid to heavy weather (day or night) when the ships rolls and pitch all over, it would be quite a challenge to take a sight with the bubble moving all over the display. The same would apply for a plane under heavy turbulence. In relative calm seas or on the ground, that problem is gone and you can use the octant anytime, anywhere in the world.

The nautical almanac and sight reduction tables are 24 / 365, so you can use them anytime, with the respective interpolation when need it. The main difference between the nautical and the aeronautical almanacs, is that the nautical almanac gives the data by hour (from zero to 24 hs) and the aeronautical gives the every ten minutes, every hour, so it is easier to interpolate when need it.

Regarding the Mark V octant, it was designed in the 1930’s and weights around 4.5 pounds. It is a little heavy, but no problem to handle with both hands. This model, also has a natural horizon option, so you can also use it as a regular marine sextant.

By the way, in case you do not know why the bubble ones are called octants and the marine versions sextants, here goes the explanation:

it is because in the case of octants, the altitude range you can measure goes from 0 to 90 degrees but the range of the scale only moves 45 degrees (because of the double reflection principle). 360 degrees / 45 degrees range = 8 (octant).
The marine sextants can measure altitudes with a range from o to 120 degrees, but the range of the scale only moves 60 degrees (same principle of reflection): 360 degrees / 60 degrees range = 6 (sextant).

If you measure any celestial body with an altitude higher than 90 degrees (only with a sextant), it would mean that body is actually “behind you back” respect to the natural horizon you are using as a reference. Why you would do that ? In case the natural horizon on the same side of the body your are taking a sight of is not visible for any reason (weather or even the coast), you can use the opposite side horizon as a reference, as long as the body is at least with an altitude of 60 degrees or higher to respect to the body same side horizon.
With a bubble octant, you do not need to take any angle higher than 90 degrees, because you always have an artificial horizon as a zero reference for altitude. It the altitude of the body is higher than 90 degrees, just turn around towards the azimuth where the body is located. That is another great advantage of the octants.

I hope my explanations are clear enough, and please let me know if you have any questions.

Best regards, Martin

[JDavHouston]

It’s also worth noting that the sextant will allow one to measure the angles between the moon and stars at greater than 90 degrees, which is required when doing ‘lunars’ to determine GMT. Lunars permit a navigator to determine the time with precision, and then do sight reduction for that time – removing the requirement for a highly accurate chronometer.

[JDavHouston]

Also, sorry I’ve been absent a lot lately. Work has really picked up. (I’m not complaining, that means more money for me.)

[mcaminos]

Thanks JDavHouston for your comments.

I tried a couple times to do “lunars”, but the tables available with the angles between the moon and the stars and planets are not very clear to me. If you can recommend any publication to learn more about the technique, I would appreciate it.
As you probably know, the nautical almanacs stop publishing the lunar tables back in the 1910’s

On the other hand, with the bubble octant, I have tried a couple of time the meridian passage sight of the moon, using the same technique you would use with the sun to calculate latitude and longitude. I did it both when the moon crosses the local meridian during the day and also during the night, and worked pretty well.
In both cases, the sights were taken at from my home’s backyard in Miami.

The next challenge is to try the meridian passage sights of the planets and some of the navigational stars.

By the way, I also have a commercial, instrument single and muti engine pilot license. I only fly for fun around Florida and I have around 500 hours of experience.

[manxcat]

To Mcaminos from manxcat,
Martin, Your post to me [above] answered some of my basic questions about bubble-octants / sextants vs. marine sextants. Thanks. It’s just that this subject is difficult to explain in writing. It would more understandable in person using a bubble or natural horizon sextant to demonstrate. This of course, would be the preferred instruction technique (incidentally, the face-to-face, hands-on method is the only way I personally would attempt to learn celestial navigation). In my reading on this subject I understand that the natural horizon marine octant was an earlier, more primitive, version of the later more-advanced marine sextant[?]
Your comments taken on the whole make the bubble versions seem far superior to the standard natural horizon marine sextant[?] I would’ve thought the same thing. However, also in my celnav reading, I came across the vintage book, “The Wilderness Route Finder: The Classic Guide to finding Your Way in the Wild”, by Calvin Rustrum [University of Minnesota Press, Minneapolis 1967 & 2000]. In this book, the author states that the natural horizon, whenever it is visible, is much preferred to the bubble horizon; and apparently, even the maritime sextant using the two pots of reflective liquid placed on the ground–are preferred to the bubble-octant / sextant’s horizon which is the least preferred method for land navigation. When navigating on land there are permanent landmarks that enable triangulation using surveyor’s instruments (i.e. transits). This would be a big issue for me, because I live in the mountains, and don’t have easy access to nautical horizons. I am going to keep referring to the explanation in your previous Email regarding the angles of degrees in octants and sextants, and see if I can get it straight.
Thanks Again,
Joseph

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