That’s why he has to take their CelNav course.
- To learn how to properly hold a sextant.
- can’t take a sun line without a clear horizon.
That dude is the instructor.
[QUOTE=Flyer69;122873]https://www.facebook.com/Northeast.Maritime.Institute/posts/601517356574389:0[/QUOTE]
Ok, ok, funny picture, but in all seriousness there’s this:
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In Buzzards Bay where Northeast Maritime is there are places where you can get a good sun line from shore. I know because I’ve done it.
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He’s bringing the horizon up to the sun instead of brining the sun down to the horizon. Not a great system for shooting the sun, more of a star procedure, but it works.
Don’t really see what is wrong with how he is holding the sextant. You can absolutely do celestial without a full sea horizon. There is a table in Bowditch that will give you dip for a short sea horizon. It will give you dip for a horizon that is as close as 0.25NM away. I used a bank of the Mokelumne River in the California delta that was 0.25 NM away and got a LOP within 2 NM of my position. That was with the cheapest Davis plastic sextant (mk 3) with a index error of 1 degree 15 minutes.
Take another look at the pic.
Specifically the filters.
The horizon glass is about a 30 degree angle up in the air.
Still think the guy holding the sextant has a clue?
Well you would certainly want the filters if shooting the sun. Otherwise I would say he he is sighting the body and bringing it down to the horizon
No idea why you’d bring the horizon up to the sun. pretty simple and easy to find, if i may say so. done many a sight using a radar range for ‘dip of the short sea horizon’ though, particularly in training situations.
Maybe shooting the moon to explain the filters!
Assumptions based on scanty information are what? Lets face it you guys are critiquing a photo of antiquated piece of equipment that no one uses except for hobby. If the GPS system ever goes out drive east or west. Eventually you’ll hit land just in time to watch the world fall into eternal chaos.
If you’re within sight of land though there’s really no reason to shoot a sun line. For training purposes of course. We’re all just kidding around though I’m sure he’s a great instructor and probably a heck of a lot better at celestial than me.
Indeed.
I posted the pic more for the entertainment value I knew would ensue in the discussion here.
Yes, to me it seems he is bringing the sun down to the horizon. A common practice really. As far as shooting a sun line from shore, done than many times myself. In fact I used to head out to the beach and practice sun lines years ago.
Deep sea professionals still use the sextant. While gps is great, I’d not sail with a deep sea licensed mate or master than didn’t still know how to use a sextant and practice it. It’s a mark of a professional standard that I doubt is going away anytime soon.
As much as I love celestial navigation I would just like to caution against the next big “C-Nav is obsolete” debate. We’ve been down this road countless times before, it’s always exhausting, and the outcome is always the same: no one’s opinion is ever changed from what it was to begin with.
[QUOTE=“PaddyWest2012;122960”]As much as I love celestial navigation I would just like to caution against the next big “C-Nav is obsolete” debate. We’ve been down this road countless times before, it’s always exhausting, and the outcome is always the same: no one’s opinion is ever changed from what it was to begin with.[/QUOTE]
Your right there
Of course we all keep horses in our back yard… just in case our cars break down.
May as well keep the ABs too just in case the autopilot breaks.
How many times in your career did you take a lunar to verify your chronometer was keeping accurate time?
How often did you do longhand calculations to verify the nautical almanac was correct?
Did you keep canvas in the sail locker just in case the engines quit?
I’m sure you noticed ABs don’t drive anymore with the exception of MSC where we dogmatically stick to outdated tradition - just in case.
[QUOTE=DeckApe;122991]How many times in your career did you take a lunar to verify your chronometer was keeping accurate time?
How often did you do longhand calculations to verify the nautical almanac was correct?
Did you keep canvas in the sail locker just in case the engines quit?
I’m sure you noticed ABs don’t drive anymore with the exception if MSC where we dogmatically stick to outdated tradition - just in case.[/QUOTE]
Please, no more, I beg you… I’m not offering any rebuttal, I’m just saying let’s not do this again… Please?
Actually ABs steer when with MSC to maintain their proficiency for alongside work, something not generally seen in the commercial world.
As far as traditions go, it’s simply a personal choice. Personally I don’t and would not sail with anyone that was willing to toss the tried and true out for the newest toy. Goes not only for nav gear, Ecdis ( tossing paper charts and the like ), but other sea going details as well. It’s not an arguable position, just a position some people hold. I also mount my own motorcycle tires, balance them myself and load my own ammo. Yea, I don’t need to do either but I prefer to as its a personal choice.
I also maintained the magnetic compass onboard by checking deviation via azimuth swings using a shadow pin. But I’m sure some would deem that is not needed, after all we have a gyro.
In short, I relied on myself and my knowledge of seamanship when at sea… Seems to have served me well given a long and safe career. I’ve seen new mates come and go. Some would balk at the use of a sextant. The same ones generally needed a calculator to figure a simple time speed and distance calculation. But to each his own to find the level of professionalism he or she is comfortable with in their careers. It really doesn’t matter to me… Unless of course the person in question sailed with me.