8 Sights on New Year's Day...

I celebrated arriving into 2017 by taking an hourly set of Sun Sights through the course of the day - and losing out out with a Moon and Venus Sight. All this to get cracking on using a new 2017 Nautical Alamanc. I have previously referred to my back yard approach to Celestial Navigation as Guerilla CelNav, because of dealing with clouds, trees, overhead wires, squirrel nests and other manner of things that get in the way of a clear limb or body to get a sight on. I have tried to imagine getting a photo that would show some of the interesting viewing challenges that occur which lead to a lot of guessing of where the bottom or top of the limb might be because it is hidden behind something.

Here is a photo of what a good part of my 'clear' sky looks like...

View of the Sky from the Stone Frigate

Anyway, during yesterday's sights I wasn't expecting to get a good round of results because of visual obstruction through the trees for some Sun Sights, and particularly the Moon. For the Moon I was shooting through tree branches and waiting for a gap so that I could see the LL.

Amazingly, I got 8 sights on the day that had LOP's that were either spot on or within 1.5 nm of actual - just lucky I guess.

And the plots...

1 January 2017 Plots

All In A Day's Work Aboard The Stone Frigate...

Yesterday was a very busy day with the first clear sky in a while. Got up early, sun was out during the day and had a clear sky in the early evening. So what did I shoot?

In day's order...

- Jupiter
- Sun x 4 (could have had more but the tree branches got in the way)
- Venus
- Moon (could have had more but it got too high into the canopy of the nook)

It was exciting to get Venus and Jupiter as they are not always around and visible. The past few evenings Venus has been visible - low and getting lower in the early evening sky.

The good news is that the Stone Frigate is firmly where it is supposed to be and not moving out of position.

Worksheet for the Moon...

Worksheet for Moon - 9 December 2016

See Plot following...

Stone Frigate Plots for 9 December 2016

The MIRRORS Are EVERYTHING!

Setup of the mirrors are everything. Since I have been able to accurately determine IE with my sextants I have been able to knock the SUN and MOON out of the sky everytime!

Sure - I don't have a long distance horizon from my house and therefore unable to eliminate IE - knowing IE as accurate as possible makes all the difference. Under perfect condition and even less than, I have been able to get absolutely brilliant sights. Can't wait to do it on the water again.

The Mistakes That I Have Made...

This could be a pretty long list with new ways being added all the time I am sure. But just thinking about the kinds - big and small - will probably be longer than all the ways to do things right.

Yesterday I took a couple of Moon Sights and one of them was a little out which was curious as there was a nice Moon out. Then looking a little more close I saw that I had forgotten to apply the correct azimuth rule. Once corrected the sight was bang on. Now, would I have done the same thing if I had no actual GPS location feedback to challenge the result? Definitely not, unless it had been a really big and different azimuth.

Anyway, now the fun begins...

- applying the incorrect azimuth without using logic to realize it was incorrect - Moon was in the wrong part of the sky!!!
- using the wrong numbers for Assumed Longitude
- reading along the wrong line or column
- not differentiating between SAME and CONTRARY
- making SIMPLE math mistakes while adding or subtracting
- using the wrong scale when measuring intercepts on plots
- misreading the scale
- using longitude scale instead of latitude scale
- forgetting to account for DST
- adding when I should be subtracting and vice versa
- reversing numerals this way and that without reason
- mixing up lower limb with upper limb (w. artificial horizon)
- just LOTS and LOTS of little mental mistakes

More to come.

1978 Cassens & Plath Sextant

Great news! After a bit of a cleanup that even consisted of complete removal of the Index Mirror - gasp!!! And a session out on the deck to determine current IE - I have been getting near perfect accuracy on some sun sights.

1978 Cassens & Plath Sextant

And the illumination light now works too!

One thing that I need to do is find some ammonia so that I can gice the arc a good clean-up.

A few things that are contributing are as follows...

- correct filter application (and placement relative to horizon mirror) for sun sights
- application of IE correction before halving of Hs (thanks Alan!)
- IE determination from Bruce Bauer book - The Sextant Handbook - and comments by Frank Reed

Because I am currently shooting from my nook on the back deck, I don't have a long distance horizon that will allow me to zero out IE as professed by Frank Reed. Rather I am easily able to determine current IE by using the Bruce Bauer method as modified by Frank Reed.

To determine IE - set your sextant to 0 deg 0.0', turn the micrometer to 25.0' OFF the arc - put shades on and sight the sun. Bring the upper body down to kiss the sun - record the value and correctly read the micrometer from zero - not the other way around. Then move the body to the bottom of the sun, kiss the sun and record the value. Subtract the smaller from the larger and divide the difference by 2. Whichever value is the larger becomes the sign - ON or OFF.

As Frank Reed says - it is not necessary to hold the sextant horizontally as Bruce Bauer professes.

After determining IE this way - I have been able to get 3 near perfect sights! Way to go Bruce and Frank.

3 Sun Sights from the Stone Frigate - 27 November 2016

Toronto Boat Show 2017 Seminar

I have just received my dates from the Boat Show folks for my seminar titled...

A Practical Primer for Celestial Navigation

The dates are:

- Monday, 23 January 2017 at 5:30pm, Salon 107
- Thursday, 26 January 2017 at 2:00pm, Presentation Theatre
- Saturday, 28 January 2017 at 2:00pm, Presentation Theatre
- Sunday, 29 January 2017 at 4:00pm, Presentation Theatre

Seminar Synopsis is...

How to apply Celestial Navigation for practical on the water application for the purposes of emergency backup navigation, or for the fun of it. Celestial Navigation, once the basics have been learned and understood, can be an easy and fun way to navigate larger waters - to locate yourself and achieve landfall from these open waters with great accuracy. Learn how to easily develop and obtain navigational fixes using celestial bodies such as the Sun, Moon, some Planets and selected Stars. Gain an understanding and be amazed by the workings of the natural universe. Be surprised by how easily you can use these celestial bodies, that are in some cases incomprehensible distances away from us - to locate yourself on a big ocean. It is all highly practical and also quite magical.

Two New (Used) Sextants!!!

I have just closed a deal to acquire two used sextants from a fellow in Kingston, ON. They are a German Cassens & Plath made in 1978 and another German one, a Freiburger made in 1977.

These are both classic metal sextants and I will be delighted to take possession in about a week's time.

Cassens & Plath

Freiburger

They appear (from my distance and photos studied) to be in good and very good condition. Mirrors appear to be in a very good.

They both have split horizon mirrors, something that I am not used to but better to see dimmer stars. Can't wait to give them a try.

UPDATE - 9 November 2016

I took possession on the weekend. They are exactly as advertised. I have been using the Freiburger exclusively for the last few days and yesterday after getting the mirrors adjusted and Index Error sorted out - 2 sun sights gave me a fix that was spot on to my location. First time ever.

2 Sun Sights - Spot On to Actual Location

I have a new approach to determining IE which is to hold the sextant horizontal with shades, look at the sun with index 30' off the arc, sight the sun, adjust limb to sun - record the setting - then move the image to the other limb - record the setting, then subtract the difference and divide by 2. Whichever of Hi of becomes On or Off.

The split horizon mirror takes some getting used to - will be interesting with a real horizon.

The C&P is next for use and close handling.