A Secondary Saga Southbound Sextant Adventure .. "Seeking Sally"

[salt_air]

No rest for the weary, but no worse for the wear ....

Ransom note tacked to the headboard of the room I'm stowed away in at Salta says:

"Bring the goods to Isla Rey Jorge in exchange for Sally"



I've secured an abandoned DC-3 ... older model ... paint removed and renumbered US markings, but with only the earliest of navigational equipment .... none of which is of any use in this part of the world.


Attachment 44793


There's a volunteer mercy mission headed that way soon ... recruiting pilots now.

I'll have to learn how to navigate with a sextant .... should be no problem as the lead pilot in the mission (Dil52) is well seasoned and very handy with the Bubble Sextant.

I'm in! ...

Cargo flights out of Salta to begin soon headed to S C De Baniloche (SAZS) ... Ushuaia Int'l Malvine Is. (SAWH) ... and finally to Isla Rey Jorge (SCRM) on Antarctica.




Sign up here if your interested in joining the mission ....

[Dil52]

Thanks salt_air,

This should be great!

If anyone is interested in joining the flight, I'll post some some pics and text to explain, as best I can, the settings, lines of positioning, timelines and links to the UNSO (United States Naval Observatory) Data site so everything will be hands on for each and everyone without reading and studying too much.

The flight legs will be about 1000 miles if that's OK. If not we can make them shorter if anyone's opposed to the lengh of the legs.
Personally I'm still tying to get over the PlanG learning curve, but have managed to make a crude map for the 1st leg so far.

I'll post it up here with some explainations once I get everything compiled.

Can't wait to find out who the surprise guest might be....but I think I have an idea.....

Dil

[Dil52]

Note: Mark Beaumont and Dave Bitzer articulate the use of the sextant in their tutorials far better than my more simplified version here for this exercise.

The big picture:

1. When navigating, using the sextant, we must first plan our route using average speeds and times and LOP (lines of position) by (fixed points) spread out at about 250nm to 300nm apart. Anything over 300nm using the sextant would give us erroneous readings.

2. The sextant is not like a DME or GPS, which gives us the distance to a waypoint, rather we must first determine a fixed point by using Latitude and Longitude, then set the sextant up for that point. The closer we get the smaller our (distance too our predetermined fix point) is.

3. The result is that we determine how close we are to that fixed point using data from the data tables provided by Celestial Navigation tables for an assumed position and time.

4. Once we determine that we’ve reached that particular fixed point, we then set the sextant up for the next fixed point, or LOP near our destination.

5. We can determine our airspeed by taking frequent timed readings such as every 5 or 10 minutes, then simply do the calculations. If we traveled 25nm in 10 minutes our TAS would be 150 knots. R = (d25 * t60)/10 or 150nmph.

6. Sextant readings using Sun calculations are more accurate to determine longitude than latitude as the angle of the sun is determined mostly by the azimuth at any given time. It stands to reason the early in the morning and late in the afternoon are the best times for sextant readings when the tangent angle is most acute. That goes for reading the stars as well.

7. The most accurate longitude and latitude readings are gotten by reading two or three star positions and crossing the angles. For instance, when flying in the north, we’d use a star located as close to east or west for longitude and Polaris (the north star) for latitude. Since we’re flying during the day we’ll only use the sun. The data charts and times will give us a pretty good estimation of our position. If we knew our exact location at 12 noon local time we could get the most accurate reading for latitude using the sun. Since aircraft are much faster than ships this is a bit more difficult when flying than when sailing.

Sextant 101

This might help you to understand the logic and see the sextant at work for what it is in FS vs what it would be in real life. (shhhh the big secret) J First we’ll simplify it by cutting to the chase. We can build our reality skills from there.

1. For starters go to KJFX R/W 9 on the first day of spring, March 21 (close enough), (any year), time 7:21 AM local time (12:21 UTC), which is sunrise. http://aa.usno.navy.mil/data/docs/RS_OneDay.php Use Jasper, Alabama for city.

Logic: Jasper, Alabama in on the Agonic line which the true heading is close to the compass heading (the magnetic declination is close to zero). The page is from the menu on the left - Data Services/Complete Sun and Moon Data for one Day. From here: http://aa.usno.navy.mil/

For illustration purposes, (only) for now: Let’s look at a chart: From the menu go to Data Services/More/Celestial Navigation/Celestial Navigation Data, which brings us here: http://aa.usno.navy.mil/data/docs/celnavtable.php

2. When looking at the panel hit Shift/Z to bring up the latitude and longitude of this location. We’ll see N33° 54.13’ W87° 19.29’

3. Enter into sextant:
LAT: 33 DEG 55 MIN (plus values for north of equator).
LON: -87 DEG -20 MIN (minus values for west of prime meridian)

4. Play with the sextant to learn the logic.
a. Note that: On the left of the eye piece set bubble size to (3) (biggest)
b. Set azimuth to 90 degrees which is not relevant to the aircraft heading but to the star position. The sextant is dumb. It doesn’t know which direction we’re heading.
c. On the right side of the eye-piece there are two ‘course’ and ‘fine’ adj. wheels which adjust the elevation on the work pad. (leave the elevation set at zero for now)
d. Click on the eye piece and watch the bubble dance for 60 sec.
e. Read: N. Miles = 0 It’s telling us we are where we are. Cool!
f. Once we get our reading we can click on the graph...star 1 (blue line) star 2 (green line) or star 3 (red line) for a graphical reference. Clicking again erases the lines. This comes in handy when taking timed readings of one star as well to figure TAS.

5. Enter into sextant:
LAT: 33 DEG 55 MIN (same as above)
LON: -85 DEG -20 MIN (same as above)
c. same as above (click eyepiece and watch bubble dance for 60 sec)
d. instead of trying to center the bubble set ELEV. DEG to 2 by adjusting the fine wheel.
e. Read: N. Miles = 100 (each 1° degree of equal to about 60nm on earth). Cooler

6. Now repeat step 5 only ‘center the bubble’ as best we can.
d. above N. Miles = 100 or near that (keep in mind the sextant isn’t exact) we're centering the bubble for the degrees longitudinal distance at this latitude which is about 50nm per 1°.

The Logic: If we were at the equator an offset of 2° longitude would be 120nm. The lines of longitude get closer as they approach the poles. Note that circles of latitude are parallel and are always truly 60nm apart.

As stated in 5 above, each 1° degree is equal to 60nm on earth. 60 x 360 – 2160nm, 24,856.8 statue miles, or 40003.2 km.

7. This time, before clicking the eyepiece, use the course adjustment to set in an elevation of 20° 5’. Notice what happening to the ELEV. DEG below.
c. same as above (click eyepiece and watch bubble dance for 60 sec)
d. above N. Miles = 100 or near that (keep in mind the sextant isn’t exact)
Logic: The reading + or - the elevation setting is still the same.

8. Set the Lon. back to -87 DEG -20 MIN and this time move the Lat to 35 DEG 55 MIN instead. Notice Polaris on the navigational data chart we brought up earlier. Set the azimuth to (0° or 360°) or 180° for this excersize.

Keep in mind we’re now locating (latitude) which is a point north or south of our location.

We now know how to use the sextant. You can play with it for awhile to get oriented

*******************************
Summery: When West of the Prime Meridian or South of the Equator the sextant is in a minus environment. When East of the Prime Meridian or North of the equator the sextant is in a plus environment. So, as in mathematics, a minus plus a minus is a plus. Also a plus and a minus is a minus.

To make it easier to understand I place the terms “more” and less” in front of the direction of travel.

Example: More west is plus in the west and more south is plus in the south.

To Quote Dave Bitzer: “The USNO web site has information on what the Altitude Corrections are, and how to apply them. These Corrections are generally much smaller than the intrinsic error in the jittery environment of a fast moving aircraft, and may be ignored.”

************************************************** ***
Sextant 102

Sextant 101 Review: or drop down to New Sextant 102 below.
You may start here or review Sextant 101. Once again execute the following steps as in Sextant 101.

1. For starters go to KJFX R/W 9 on the first day of spring, March 21 (close enough), (any year), time 7:21 AM local time (12:21 UTC), which is sunrise. http://aa.usno.navy.mil/data/docs/RS_OneDay.php Use Jasper, Alabama for city.
Logic: Jasper, Alabama in on the Agonic line which true heading is close to compass heading (magnetic declination is close to zero). The page is from the menu on the left - Data Services/Complete Sun and Moon Data for one Day. From here: http://aa.usno.navy.mil/
For illustration purposes, let’s now look at a chart: From the menu go to Data Services/more/Celestial Navigation/Celestial Navigation Data, which brings us here: http://aa.usno.navy.mil/data/docs/celnavtable.php

2. When looking at the panel hit Shift/Z to bring up the latitude and longitude of this location. We’ll see N33° 54.13’ W87° 19.29’

3. Enter into sextant:
LAT: 33 DEG 55 MIN (plus values for north of equator).
LON: -87 DEG -20 MIN (minus values for west of prime meridian)
Note that: On the left of the eye piece set bubble size to (3) (biggest)
This is just telling us we are where we are once again.
End Review:
*************************

NEW Sextant 102
Reading and understanding the navigational data charts

1. From the charts notice two things: Zn and Hc: The azimuths and elevations for our particular location and the sextant.
GHA Dec Hc Zn | Refr SD PA Sum
Quote from the USNO Site: The almanac data consist of Greenwich hour angle (GHA), declination (Dec), computed altitude (Hc), and computed azimuth (Zn). (For reasons of simplicity, we will not use declination here). It is used for atmospheric refraction which is way too complicated and scares people (at it does least me).
The stars we are looking for should be under the columns labeled:
Zn : Azimuth of stars (example) = North 0°, East 90°, South 180°, West 270° and everything in between, which are readable (in blue) at the time of the data request.
Hc : Elevation of the stars in regards to a level plain at sea level at the time of reading. Hc should be between above 15 degrees and 65 degrees to avoid atmospheric refraction (distortion).

2. When flying in the northern hemisphere, it makes sense to use Polaris, at night, to check the latitude as it’s (zenith) is located almost directly above the North Pole. If we were to point a camera at Polaris and take a time delay photo shot, say 3 or 4 hours with the lens open, we would see that Polaris does not move however the other visible stars form arcs around it.

(In the southern hemisphere use GACRUS or ACRUS (Crus or Crux meaning Cross) located in the Southern Cross. Sigma Octantis is the South Pole’s star but is not very bright, so Crux offers a better guidepost. From the top of the cross Gacrux (gamma crucis) trace a line south to Acrux (alpha crucis) and continue about 4.5 times that distance and we will get near the celestial south pole……not necessary for sextant readings…just some info for understanding)

3. If we look at records chart next to sextant we can see that the maximum distances for both latitudinal and longitudinal readings is 180nm or 3 degrees or 180 minutes since each 1 degree = 60nm of latitude and 60 nm of longitude (only at the equator).
For this lesson we’ll be looking at the Sun in the east and Polaris in the north or a star in the east (near Zn 90°) or west (near Zn 270°) for our longitudinal readings
Go to http://aa.usno.navy.mil/data/docs/celnavtable.php

For Time information use 12:21 UTC/7:21AM local. To bring up a Navigational Data chart by entering the date and time then choose: North 33° 54.1’ and West 87° 19.3’ or longitude W87.3, latitude N33.8 the

Get Data…
The navigational data charts are color coded. The red for celestial bodies within our solar system (the Sun moon and planets) The Blue stars are those located between an
(Hc) elevation of 15 to 65 degrees, suitable for navigation, or in this case, for sextant readings. The ones in back are other known stars outside but visible at this time of observation. If known can help to locate the ones we’re looking for. The green are for Polaris and the GHA of Aries. (great pole stars for latitude verification).

Notice the Zn of the sun 93.2 and the Hc is + 5 11.3. Due to atmospheric refraction we wouldn’t want to read the sun or a star this low on the horizon. Hc should be at least about 15-20° or higher and no more than 65° elevation.

4. Now Enter 17:56:30 UTC for time and observe data chart readings. The suns Zn (zenith) at sunrise here is 180.0° and the Hc elevation is 56° 24.3’.
Also notice that the Zn of Polaris is 0.5° and the HC is +34° 25.2’. This is a great Zn and Hc for a good reading….IF IT WERE DARK!

5. For this location, we can determine that at exactly 17:56:30 UTC the sun is at its highest point, 12 noon local time when the Zn of the sun is exactly 180°….read as sun transit here.http://aa.usno.navy.mil/data/docs/RS_OneDay.php Keep in mind that each time zone has a center and since there are 24 time zones and if they were divided equally would be 15° each or 900nm each at the equator. So if we were 45 degrees north or south latitude the time zones about 620nm miles apart. (explained later)

NOTE: This is the one and only time of day which we can use the sun to determine our latitude. To determine that exact point, we must first determine our present location……by reverse mathematics.
a) determine distance to next way point.
b) subtract 60nm for each degree and 1nm for each minute

6. Now Enter 23:00 UTC for time and observe data chart readings. The suns zenith here is 262.3° and the Hc is +11° 53.5’.
Since the Hc (elevation) is less than 20 degrees this is not a good time to take a reading from the sun, as was it NOT at dawn, either.
Summery: So we must observe both the Zn (azimuth) and Hc (elevation) to assure we’re getting a good reading.

Logic. Imagine the stars as if we were inside a huge dome. It stands to reason that a reading of HC +20 and to perhaps +50 would be best for a reading. The closer to a +20 reading the better as the angle is more acute (flatter).

By now I’d say we’re ready to read Navigational charts and know what to look for.

7. AT NIGHT, in order to get accurate readings, we would choose two or three stars for a location. At least two of them should be at 90 degrees of one another so we can verify longitude and latitude.

8. Let’s do some readings of stars. We’ll start by setting our time to midnight 00:00:00 or 6:00:00 UTC. With our location set in above (where we are) lets bring up the chart.
The first thing we see is that there’s nothing in red. BTW we’re doing 2011 here for the year.

First of all, as usual at night, my favorite is Polaris (the North Star) at ZN .07°and Hc of 33° 32.9’ above the horizon. The 2^nd one I like is ALPHECCA which is located with a Zn of 272.8° and an acceptable Hc of 49° 15.7’. Even though it’s behind us, we have the RD4 DC-3 sextant observatory window above the flight deck.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Summery:
each 1° degree is equal to 60nm on earth.
each 1’ (minute) is equal to 1nm on earth.
each 1” (second) is equal to 88’/26.8224m on earth. NOT PRACTICLE FOR SEXTANT READINGS> The best we can hope for is accurate to within about 5nm.
Since we are reading latitude and longitude in degrees and decimal degrees each .1 degree of course is .6nm.

However it must be remembered that:

each 1° “line of latitude” is equal to 60nm anywhere on earth.
And:
each 1° “line of longitude” is equal to 60nm only at the equator.
As the latitude increases and decreases toward the poles the longitudinal lines become closer together until, at the poles, it could be one step or one foot or one inch.

Pleasant navigating to all!
Dil

PS Yikes, I thought this would be short

[mickj300]

I don't have the patience to get my head around this sextant stuff but I'd love to make the trip. Truth is, my Englishness rather stands out here in Salta and I figure it's only a matter of time before the locals start to question if I had anything to do with an earlier delivery to what they consider Argentinian territory. Last year Flightsim.com teamed up with Simaviators to fly Vulcans and Victors to 'deliver' some heavy ordnance to Port Stanley in the Falkland Islands. The problem being that this cargo was not unloaded on the ground but from 10,000ft!

I'll be carrying on with C-46, let's see what this baby can do when she's lightly loaded.

[salt_air]

I don't have the patience to get my head around this sextant stuff but I'd love to make the trip. Truth is, my Englishness rather stands out here in Salta and I figure it's only a matter of time before the locals start to question if I had anything to do with an earlier delivery to what they consider Argentinian territory. Last year Flightsim.com teamed up with Simaviators to fly Vulcans and Victors to 'deliver' some heavy ordnance to Port Stanley in the Falkland Islands. The problem being that this cargo was not unloaded on the ground but from 10,000ft!

I'll be carrying on with C-46, let's see what this baby can do when she's lightly loaded.

Great News!!

One of my best mates along for the whipping ... uh, I mean schooling.

Confident we'll "get it" this time Mick as Dil is very handy with it's operation and use applied to MSFS and equally as proficient with wordage.

With that, the encouragement and support I have received from both Dave Bitzer and Mark Beaumont via email, and our own two noggins beating together like cymbals in a marching band .... this will be like free Sextant College rather than school.

We can finally get a grip on this then take it back to our knucklehead buddies and spoon feed them as well as help the newbies as time goes by.



This is a milestone for me!




Now's the time to turn the page Mick ... I hope more folks will saddle up.

To me personally ... slaving A/C to GPS's or FSNav FP's is nowhere near the fun of not really knowing exactly where you are during the flight ... pretty good idea ... but that's about it.

If your lucky an occasional land mark confirmation, but scrambling around ... using what instruments are available ... reaching across the desk from time to time for the calculator or pencil and paper .... never sure until you arrive ... that's a huge part of FS that is missing with all the "new school" bells and whistles.





Ah yes! ... what a brilliant event that was .... you and Barry put that mission back together in a beautiful recreation of Operation Black Buck.

[Dil52]

I don't have the patience to get my head around this sextant stuff but I'd love to make the trip. Truth is, my Englishness rather stands out here in Salta and I figure it's only a matter of time before the locals start to question if I had anything to do with an earlier delivery to what they consider Argentinian territory. Last year Flightsim.com teamed up with Simaviators to fly Vulcans and Victors to 'deliver' some heavy ordnance to Port Stanley in the Falkland Islands. The problem being that this cargo was not unloaded on the ground but from 10,000ft!

I'll be carrying on with C-46, let's see what this baby can do when she's lightly loaded.

Yes Sir Mick,

Welcome!!!!!
You can load the sextant in your aircraft of choice and run the flights with us using it.
Don't worry, no one will be left in the dark. We'll give a step by step process of the settings, how to take the readings, and the USNO web site so you can do it all hands on as well.....includeing screen shots of the sextant settings.

After the first couple of flights you'll be a pro. It's not as difficult as the Sextant 101 and 102 recipe looks. That's packed full of a lot of details that will make sense as we go.

salt_air,
(and all who are interested)

I'd like to shoot for the first flight to begin on Saturday, August 6th 2011 at 8AM Salta time, if that sounds good for everyone? That will allow the people who don't get that much time in the evenings to have some time.......it's not a multiplayer, I'll just post my first experimental flight before then.

I'll be working one the details early this week and post them before Saturday.

I mean, depending on everyone's approval of course.

Dil

[salt_air]

06 of August at Noon Zulu ... sun shots ... sounds good to me.

Also if your not going to be online then folks can follow along in the posts ...



If the "Good to Go at 0800 Local/Noon Zulu" list populates to any degree I can host (FSHost) an online session.



Teamspeak Dil? .... asking because even if one or all fly along off line we can still relate if we've synched up our sims time and date .... crucial with what I have read so far ... and there will be questions and revelations made that will need to be confirmed on the fly ... so to speak ... best handled live if possible.



Would really like a better idea of crowd size ... if it's just the two of us come Saturday morning ... for whatever reason ... then none of that would matter.




Next ... we will need a schedule or plan set up as to when we make the shots .... any quick and dirty sheets need to be set up prior or just run off the chart gauge attached to the sextant?





Not much on breakfast around here ... these folks better hope Jimmy Dean doesn't show up raising the devil about that ... "a typical breakfast in Argentina is a cup of coffee with milk (café con leche), a few croissants (medialunas), and a shot glass of carbonated water. Not exactly gut-busting, or even filling."


So I'll be ready for lunch when we're done ...



First leg is 980 nm? (SASA - SAZS) that's Six hours (or so) in A DC-3 ... any plans to stop enroute?




Just observations and suggestions mate ... it's on you how things are run.




Another thought is the "dangle the carrot" method whereby you make a flight with instruction and commentary as you fly ... could be posted after you're done ... and we then try to mimic everything and post questions to that.


Then on to the next leg ... sorta like leap frog.

[Dil52]

OK salt,

Sorry, I don't have teamspeak. I have not flown on line since back in the FS2000 days when we typed everything. I made one on-line flight and a controller was abrasive and left me hanging so i never returned. I was so nervous I could hardly fly and type at the same time....Oh well, I've been thinking about it again as the people who are on now days are a lot nicer than many in those days.....or so it seems. This site, SOH, is the greatest thing I've come across, as everyone participates and is so encouraging. They're also nice at DC-3 Airways and I've been thinking about it, but never seem to know what I'm doing three hours from now, let alone a particular date and time. I guess, in my working days, it was on call 24/7/365-6 for years. It became a firmly implanted lifestyle and it seems I've never been able to plan life well since.
Having said all that, I'm not completely negative and am open to suggestions as to how to download, and use teamspeak, even before Saturday's theoretical or actual start time.

I've also been thinking about shortening the legs. I believe that more people will come if we fly legs that are 3 to 4 hours rather than 6 or more hours. For instance instead flying from SASA to SAZS we could make the first flight from SASA to SAME, which is about 500nm and around 3 hours or less, depending on how well we do with the LOP once we reach SAME.

Also, for learning purposes, perhaps we could fly the first let without wind, so as not to throw everything at the beginners all at once with WCA's, magnetic variations, etc. Once we get down into the S40s latitudes (roaring 40s), S50s and S60s, we'll be dealing with some pretty hefty trades (crosswinds) coming off the Pacific. We're still at a mild -2 degrees magnetic varation up here at SASA. It will get to over 10 degrees and the longitudinal lines pretty close together nearer the south pole. (not that it's a big deal, we have some great pilots here as proven by the cargo flights)..just call me crash!

Also, I believe that the first flight is crucial for the explanation of each and every setting of the sextant, especially for those who are new to it. I'm hoping to post the first leg by mid week so that folks can do a trail run at their convience. It will also allow some time for specific questions and answers.

BTW all, there's an excellent tutorial written by Dave Bitzer on using the charting gauge in the dc3_bbsxa folder. I'm actually learning something every day, so don't be afraid to be critical about any of my instructions or explainations.....that means everyone. I expect I'll learn from each and every pilot on the flights. That 's just how it works.

What say you to all that sir?

[mickj300]

We're actually going away for a week or so, I'll catch up when I get back.

[salt_air]

Controllers? ... we don't need no stinkin' Controllers ... if you want to be able fly online (recommended) including Teamspeak you came to the right place.

SOH uses a FSHost server that we can use for any or all of this Odyssey to the Land of Penguin ... and there are close to 200 more servers running 24hrs on any given day including one that I can boot up if you don't want anybody else "on".

If I can't get it done for some odd reason (and there are some of those) then Dangeroousdave26 is the guy I ask for help ... and he's right here ... Hey Dave!!

No disrespect to the rest of the crowd Dil .... there's a bunch of online help right here in this forum ... I guarantee you can get "on" if you want with nobody hasslin' you either.

But that's a different subject ... just raise your hand if you want to pursue that ... happy to help.




As far as the flight(s) are concerned you will find no one with the exception of me (just guessing) that will want to get into a 6+ hour vigil in a DC-3.

An hour or two is about all most folks can set aside at one time for FS ... maybe three.

Also thrown in to the soup ... I have had 3 or 4 occasions that I tried to spend some time with the sextant while I was running the duenna on some flights that were over a thousand miles, but the real weather I was running got me every time ... visibility is key to making any kind of shots ... I don't have to tell ya.





Now back to the show .... if it's easier to fly this solo offline ... then make a post with specific tips and instruction for that particular flight .... null of any weather ... then go for it anytime you want.

Running clear skies is not as good for screenshots, but that's not why we're here.

Also puts everyone on the same page as far as wind and atmospheric conditions.

Go with that if you want to ... we'll follow along as time allows and bring up the questions as we go ... may need to look back and make sure folks are following okay.




I'm personally interested in everything that you do before you even start the engines with respect to planning.

I think the next time you'll "see" me sit down and shut up is when you tell us what to do with the info or readings from the shots.




Keep in mind that there is and will be a huge silent following to our antics and education (in no particular order) along the way.




[Mick, this should fit your schedule just right mate.]




Take it away Dil ...

[Dil52]

sum Updayts n Umer n fax n stuph... ha ha.... Cun u reed this? It's not hieroglyphics, it's written in teen text message style!

We had compiled and drafted a step by step procedure and lost everything without saving the document.....so back to the drawing board...... all's not entirely lost as the hand scribbled notes have survived, and the short term memory is.....ah. oh, well.... what was I saying??.....Oh yes, as good as usual!

I don't know why but it seems that sometimes we do our best work at around 2AM.

No problems, we should have the first flight documented and ready for everyone to follow by tonight. Actually as we rewrite this it gets better.....perhaps?

Just to let everyone know.....

We now have added a "Sextant Orientation" section that is guaranteed to make everyone who flies the first leg "instant experts" on sextant navigation. It’s sort of a reverse engineering approach and methodology thingy!

dil

[salt_air]

Sounds great ... well that last line anyway about the new section.


That Orientation gizmo ... :mixedsmi:

[teson1]

I've got no time to fly, but be sure we'll be following along on your sextant adventures.
And all the best freeing Sally. Make good use of the sextant there as well - hit the bastards on the head.

[cputters]

I'd love to mate, but I might wait for a more novice one to begin with.

I'll be following it closely though.

good luck.

[salt_air]

I'd love to mate, but I might wait for a more novice one to begin with.

I'll be following it closely though.

good luck.

This is it! ... cputters

We are in no hurry at all ... give it a whack and ask questions just like the rest of us mate ... you'll be in good company!


Do you need any help getting the sextant in the plane you want to use?

I've got no time to fly, but be sure we'll be following along on your sextant adventures.
And all the best freeing Sally. Make good use of the sextant there as well - hit the bastards on the head.

You know they're dead meat teson1 ....


I hope you do follow along and please chime in when you have something to share.


I can already see a bunch of copy and pastin' in my future.

[Dil52]

OK ladies, gentlemen, pilots, navigators, attendents, mechanics, cargo loaders, agents and observers,

Trust me when I say this is for novices as well as seasoned pilots.

We've completed the flight from SASA to SAME.
It's not picture perfect, but we believe everyone will come away a bit more knowledgable once they've read and followed along.

We've accumulated 15 screen shots and 6 pages in MS Word that we need to edit, check, and figure out where the picturess will best fit in.
I should have all compiled by late tonight.
The early to bed sleepers will have something to chew on in the AM or after work tomorrow.

I wonder whether we shouild move down to the regular section or stay here in the sticky section.


I'm not sure I'm going to post this in several stages or one long post. Due to detailed instructions this will be the longest post of all and can be referred to for learning as well a review later on.


Let me know what you think staff?

I'm excited, I think we'll get a lot of swimmer-simmers who'll stick their toe in to test the waters and others who'll jump right in!!!!

dil

[salt_air]

"Let the Good Times Roll"


Still early enough in this thread to let it go ....

If they start to pile up later then we'll start a new thread as prompted.

You'll get an automatic error if an individual post is to big ... then just split it up.



This is one of the best moderated forums there is ... steady as she goes.

We'll get notified of what to do when ... until then ...


"Carry on My Wayward Son"

[salt_air]

I'd keep the screenies to a minimum just for illustration purpose ... and you can hit the "insert" between paragraphs to place them as you go.


As you insert files (screenshots) in the manage attachments screen they will be assigned a number that will show up on the compose window.

You can copy and paste those just like text if that's easier.

[salt_air]

Another thought is to write the text in a notepad file that can be saved and then attached like a screen shot.

Just watch the size per page and you should be able to post either eight or ten files less than the size limit to a single post.

Followers could simply d/l the text files and not to copy anything ... unless they want it in another format.

[Dil52]

OK I think?

I'd like to post it in the format here instead of text then I can add bold, highlights, and links.

I'm going to give it a shot at one post. if not we'll break it up.

dil

[Dil52]

sorry all, we'll post in the morning...........found an error in the sequence and not really satisfied with the format.......

no sense in buggering it up now...the cranium is shutting down.

[Dil52]

Please Read and follow:
Orientation Exercise:
1. Go to SASA, RW 19, our departure airport, for this adventure

2. Settings to start: Time 11:55 UTC or 7:55AM local time
The sextant setting for our first LOP will be our starting location:
Set the following into the sextant by using the + and – hot spots under Assumed Position. It may take some getting used to, but once you have gotten the concept of entering degrees and minutes, it will become easy after a few times.

3. Set into the sextant under ASSUMED POSITION:
The location of SASA (Aircraft) (LOP)
LAT/ DEG= -24 and MIN= -50
LON/ DEG= -65 and MIN= -30

4. Go to: http://aa.usno.navy.mil/data/docs/celnavtable.php
Set the coordinates S24° 50.0’, W65° 30.0’ and the time as Aug 6, 2011 Hour: 12, Minute: 0, and Second: 00 UT then Get Data chart.

Attachment 45093
On the data chart notice that the sun’s Zn (azimuth) is 64.6°.
The sun’s Hc (elevation above the horizon) is +12° 39.3’.

5. Set into the sextant under STAR:
The location of SUN’s Zenith at this time.
Set AZIMUTH: 65° (note that we do not use minute settings in the sextant for AZIMUTH settings)
Set ELEVATION: 12° 40’ (which rounded off the closest 5 minutes)
Use the Course and Fine Elevation adjustment wheels, located to the right of the eye piece on the sextant to set the elevation. Once again, it may take some getting used to setting these in, but once you’ve gotten the concept of entering degrees and minutes, it will be simple.
Before taking a reading, set the bubble wheel, located on the left side of the eye piece, to Size 3.

We’re now ready to take our first shot of the sun: (For the best accuracy, always start the shot exactly 1 minute before the data chart time): In this case start the shot at 7:59:00 AM local time.

6. Double Click on the eye piece and let the bubble dance for one minute until it goes out (No need to move the Fine adjustment wheel while we are here at SASA) Once the shot has completed notice that, under DISTANCE N. MILES, the result is 0. Now, at the top left of the graph click on the Star 1 hot spot and there will appear a slanted blue crossing directly over the small green circle (our location is the center of the graph). This is telling us that we are where we are.

Attachment 45092
Now that we know how to navigate around the settings and how to take a reading, let’s make some sense of it all.

Without changing our ASSUMMED POSITION

7. Set AZIMUTH to either 0° (360°) or 180° and take a reading then hit the Star 2 hot spot. Notice we now have a straight horizontal green line across the graph, no matter which azimuth we chose. (Directly North or South)

8. Next set AZIMUTH to 90° or 270° and take a reading then hit the Star 3 hot spot. Notice we now have a straight vertical red line across the graph, no matter which one you chose. (Directly East or West)

The graph should look exactly like this.
Attachment 45095

You can turn off the lines on the graph by hitting the Star 1, 2 and 3 hot spots.

9. MOVE the AIRCRAFT to SANT
Repeat steps 7 and 8 but this time, by using the fine adjustment wheel on the right, center the dancing bubble into the circle.

The graph should look exactly like this.
Attachment 45094

You can turn off the lines on the graph by hitting the Star 1, 2 and 3 hot spots.

10 . MOVE the AIRCRAFT back to SASA

Logic: As we all know, the sun comes up in the east (approximately) and sets in the west (approximately). So during the course of the day in the morning the sun will be somewhere in the eastern half of the compass (Zn) until noon and in the afternoon and evening the azimuth of the sun will be on the west side of the compass (Zn)…..thus represented by the red line (exactly east) and the blue (approximately east). So the blue and red (vertical lines) are east and west readings. That is how the graph is oriented and we can look at it as reading LONGITUDE.
The horizontal green line is the LATITUDE reading (north and south).
Of course every star or the sun reading will NOT be located exactly north south east or west, which is illustrated by the blue line which is oriented diagonally across the graph.

To sum it up simply: We now know that the horizontal lines on the graph represent latitude and the vertical lines represent longitude.

All this may not make sense at this time, but keep in mind that the that little green circle in the center of the graph is the ASSUMED POSITION of the our aircraft’s LOP, which is located at SASA. By moving the latitude or longitude under ASSUMED POSITION a couple of degrees one way or the other will give us an ASSUMED POSITION of the aircraft LOP AWAY from the present location. For each degree we move the latitude it will represent 60nm away from the aircraft. For each degree of latitude, read here at S24°50’ a degrees of longitude is about 54nm since the longitudinal lines are getting closer as we move toward the pole from the equator. We can try different settings to get the idea if you’d like at this time. We’ll need to move the elevation to center the bubble in the bubble circle while taking the reading if we do this.

NOTE: Think of looking at the stars as if we were inside a planetarium (dome) and the stars were on the ceiling of the dome. If we were standing looking straight up at a star, at that moment in time we would be at that star’s Zenith. Or if we were to draw a line from a star straight down to the earth that point on earth is at that star’s zenith. Enough of this…….Orientation is over.
Perhaps you’ve noticed something here by now? We were not actually looking at the sun when taking readings were we? However a star was visible each time we took a reading. So, by this time, you have probably realized that we don’t really NEED to use the charts in FS to navigate. We can get latitude and longitude readings anytime night or day. Of course there are many ways to cheat in FS using map followers, when flying using Guenna, and other means such as the GPS, looking at map view, etc.

As always, the idea for these flights here is to do it honestly. J

END ORIENTATION

[Dil52]

SASA to FIX # 1 LOP

Start of the Antarctica Adventure

We’ll try to avoid using Shift Z at all costs when flying, but you may use it to compare the settings, explained below, before takeoff.

First we can check the weather, especially the winds aloft, at various altitudes.
In case you don’t know how to do this in FS, here is my method.

Go to Weather/User Defined/Specific Weather Station/Choose Station./Salta, Salta, Argentina….retrieve the weather then choose the Wind Tab and click on the various yellows lines up to 18,000 to get the existing winds aloft conditions. You can now return to weather updated every 15 minutes. At least we know what it’s doing now. Better info than the navigator pioneers had used the sextant. You’ll find that by using the sextant, we can check our TAS or TGS by taking exact timed readings.

First leg: SASA-SAME (NO WEATHER THIS TIME> Set to clear all weather). When setting up a flight plan in Plan G I set in a fixed point between the two airports at S29° 30’ and W67° 21’ LOP reference. Each leg shows a heading of 198 degrees. This is a slightly off the great circle route, but the difference isn’t that critical when navigating using the sextant.
Attachment 45114

1. Settings to start: Time 11:55 UTC or 7:55AM local time for an 8:00AM TO.
The sextant setting for our first LOP will be our starting location:


2. Make sure that the ASSUMMED POSITION of SASA’s LOP


3. OK were ready to go. Again if graph is not cleared, turn the lines off on the graph by hitting the Star 1, 2 an 3 hot spots and let’s be on our way.

We’re going to start rolling and take off on the RW at exactly 11:59:30Z or 8:59:30 local time or close. This is not critical, but we realize some folks are perfectionists. I guess, once the wheels leave the ground we’re flying. Is that a reasonable thing to assume? I believe that’s when Duenna time begins. Also, on the RR_41 DC-3, I’m going to start the stop watch when at rotate.

Our course will be set to a heading of about 197 or 198°. We’ll climb and use the 17,000’ ceiling on this leg. The default load will be OK this time, we’ll pick up out produce or whatever supplies for Antarctica later. For those who may be flying the DC-3 RR_41, 1940 edition, be sure to keep the CHT below 323C.


4. Go to: http://aa.usno.navy.mil/data/docs/celnavtable.php
Set in the same coordinates and time of Aug 6, 2011 hour=12, minutes=30, and seconds=0 UT
We’ll take a sun shot when the clock or stop watch reads 8:29AM local time. We’ll leave our ASSUMED LOP at: LAT/ DEG= -24 and MIN= -50 and LON/ DEG= -65 and MIN= -30…….SASA

ON the sextant, set the AZIMUTH to 61° and the ELEVATION to 18° 40’ as read from the charts and we’ll now be ready to take our first LOP shot.

Our first LOP shot will be a reading behind us at SASA.
Notice the sun’s Hc (elevation above the horizon) WILL BE +18 degrees and 42.1 minutes. (Note that at that time the sun is above +15 degrees above the horizon. So in the real world it would be a good shot.
Attachment 45115
We’ve traveled 50nm in 30 minutes at an average ground speed (GS) of R= D*T or 50*60/30=100nmph for the climb out and 1^st half hour.

5. Next we’ll change our NEW ASSUMED POSITION LOP to FIX # 1, which is S29° 30’ W67° 21’

On the sextant below “ASSUMED POSITION” set:
LAT/ DEG= -30 and MIN= -30
LON/ DEG= -67 and MIN= -20

Again we’ll set at the USNO site: Go to: http://aa.usno.navy.mil/data/docs/celnavtable.php

Set in the NEW coordinates and change the time to Aug 6, 2011 hour=13, minutes=0, and seconds=0 UT
South 29° 30’ and West 67° 30 min then Get Data tables.

This will give us the position of the sun in the future, or in one hour after take-off. Notice that at this time the sun’s Zn (azimuth) will be 55.7 ° and the suns Hc (elevation above the horizon) will be +29° 30.9’

SET IN under STAR:
Location of SUN’s Zenith at this time.

Set these readings into the sextant’s AZIMUTH 56° and ELEVATION DEG= 20 and MIN= 30 using the Course and Fine adjustments on the right side of the sextant’s eye piece.
Now we’re ready to take our second reading at 1300 UTC or 9:00 AM local time. Notice the sun is up to 20 degrees above the horizon so there the atmospheric refraction will not affect our readings. (not that it would in FS, just to make it clear if you were doing this in real life)

Hmm, looks like we’re going to need to do some ridge dodging as well.
Attachment 45116
Notice where the blue line and the horizontal lines cross at 120nm on the graph. Also note the once you record the distance on the graph, the DICTANCE N. MILES reading changes. I don’t know why, but this happens….with the sextant and graph gauge.
We’ve traveled 70nm in this 30minutes at cruise so our average speed GS has been R= D*T or 70*60/30=140nmph at cruise speed. We should be over the FIX #1 at about (120/140)*60=51.4minutes or at 9:51AM local.

We’ll take another shot in 25.4 minutes at or 9:25:45 (1 minute before we should be AT 60nm for Fix #1).


6. Again Go to: http://aa.usno.navy.mil/data/docs/celnavtable.php and set the time for the sun readings and set them into AZIMUTH and ELEATION. For 51° and 24°55’ respectfully as read on the data chart.
SET IN under STAR:
Location of SUN’s Zenith at this time.

By now I’d be willing to bet we have several sextant pros!!!! J
Attachment 45118
Shot taken at 25.4 minutes at or 9:25:45 (1 minute before we should be AT 60nm for Fix #1). The Green line shows us that we're traveled another 60nm which was our projected time and distance in 25 3/4 minutes.


7. Again Go to: http://aa.usno.navy.mil/data/docs/celnavtable.php and set the time for the sun readings and set them into AZIMUTH and ELEATION at For 46° and 29°10’ respectfully as read on the data chart.
Start the shot at 9:50:15 (again 1 minute before reading time)
Attachment 45119
Bubble is looking good!!!!! (This is a shot of the bubble before the reading).

One minutes has passed.

Attachment 45120
Wala! We've reached Fix #1 LOP right on time!


The next post will be from Fix#1 to SAME

dil

[Dil52]

Flight from SASA-SAME continued from Fix#1 to SAME.

Next we’re going to set the coordinates for SAME, which, according to our calculations is located at:
On the sextant below “ASSUMED POSITION” set:
LAT/ DEG= -32 and MIN= -50’
LON/ DEG= -68 and MIN= -50’


While writing here I’d run out of fuel in the Mains and discovered I’d lost 2000' so this is going to take a toll on our average speed……or should I say mine. J

At this time we should change our heading about 10 degrees or so to one side or the other of SAME. We need to do this because we don’t really have an accurate way of determining latitude and longitude without a two or three star reading. We only have the sun.

8. Again Go to: http://aa.usno.navy.mil/data/docs/celnavtable.php and set the time for the sun readings and set them into AZIMUTH and ELEATION. For 46° and 29°10’ respectfully as read .

We’re going to set in the time as 14:30:00 at the UNSO site.

(Anyone can feel free to take as many shots as they may desire now) Don’t forget to set in the coordinates for SAME before GET DATA
Also make sure to have an accurate Zn and Hc for each time a reading is taken!


Attachment 45127
Notice that the AZIMUTH of the sun is on 37° (and behind us in the souther hemisphere), which is less than 40° from "noon" which would be a Zn 0 or 360° giving us more of the latitudinal reading than longitudinal accruacty. For this reason we're going to rely more on the horizontal lines of the graph thanvertical lines. Looks like about 75 nm to SAME LOP.

9. At about 60 nm we’re going to start a slowly descent down to where we can get a visual once we turn 90 degrees onto our LOP. In this case since I turned to 188 degrees I believe we’ll be east of SAME so we’ll turn right to heading 278 or 198+90 degrees to the airport.

Attachment 45128
Found out that if we resize the screen, while flying we loose all our settings in the sextant. Thus we had tor reset the ASSUMMED POSITION and STAR in the sextant. thus the lost prior reading. Not important just to let everyone know why we have only one LOP line after the 2nd SAME LOP reading.
Again writing while flying has got me. I’d forgotten to start a descent at 60nm, so we’re heading down now at 25 LOP. We learn from our mistakes. We’re not doing this flight over. What we see is what we have got.


Attachment 45129
8. LOP 5nm....It's time to turn right 90 degrees to heading 278° and begin searching for the airport. We'd turned 10 degrees left back about 70nm out, which gave us a right turn once the LOP was reached. If anyone turned more left to intentually MISS on one side of SAME then they should turn right one the LOP is reached. Stands to reason.

I had a nice shot when we first got the airport and accidently deleted it.
I'm sure we'll get some great shots from others who make this flight.

After a procedure turn to loose altitude we located the airport once again and landed sucessfully.

Attachment 45130
Final approach to Mendosa, Argentina SAME.

This completes the first leg to Antarctica. We’ll keep this detailed flight for reference. There’s no need to post subsequent flights with such detail and screen shots. Everyone who’s completed this flight will have a good idea how the sextant works.
The challenges from here on out will increase as we’ll use real world weather on the next legs..

Please join us all who can!!!

dil

[Dil52]

We’re going to start rolling and take off on the RW at exactly 11:59:30Z or 8:59:30 local time or close.

On the first leg post (SASA to Fix #1) time should have read 7:59:30 local time.