Celestial Navigation

[AKA-None]

Star charts can belated to an iPad, iPod or iphone. I use the iPad version with my telescope. You can hold it up and see the stars labeled to match your current view from where er you are if your device includes the GPS chipset.

[goboatingnow]

why do you need star charts for celestial navigation ?


dave

[thomm225]

Originally Posted by goboatingnow

why do you need star charts for celestial navigation ?


dave

A guy earlier was interested in planet and star locations etc on an earlier post.

Although you can use things like Orion's belt to locate due east and west when he rises and sets. This was in the book Barefoot Navigator..........he gives the actual stars to look for in the Constellation Orion

[gjordan]

I would not recommend the lowest cost Davis (lifeboat sextant ) to learn with. I used the lifeboat sextant and an Ebbco plastic sextant on several passages in the Pacific, and the slightly more expensive Ebbco would work for any celestial body, because it had a telescope. Telescopes have light gathering characteristics that make star and planet sights workable, where the Davis only had a sight tube, and I could never get a clear horizon, and star at the same time. My eyesight was very good back then, so I imagine the problem would be worse now. The Davis will work for what it was designed for (emergency sun only shots) but if you are serious about learning celestial, I would recommend going for the next model up, or buying a metal sextant from Craiglist or Ebay. Many people are selling unused ones for a good price. Maybe other people have had good luck doing twilight shots with the small Davis, but I sure could not. Good Luck ____Grant.

[RonRock]

I just want to say thanks dacust for the link. I just got started reading the book, but so far it makes celestial navigation interesting and understandable enough to keep me going.

Thanks Dan.

Ron

[jasonk]

Sending my thanks to nigel1 for posting the links to the celestial nav info. Also, thanks to everyone else who responded. Love these forums.

[jkindredpdx]

For learning stars, I really enjoy the Star Walk iPhone app (free or really cheap)... point your phone up, open shutter, and the star maps overlay the sky.

Slightly off topic, I want a telescope. I was thinking about a 6" reflector. Does anyone have experience using one on board? Is a Dobsonian style mount adequate?

[Celestialsailor]

I saw that from a crew member coming down the Ca. coast...Impressive. Thanks to his higher tech thinking than mine, I'm going to "Tablet" next year with things like that app and open CPN. They have built in GPS's now and work great for Navigating and Internet. Still, I will never surrender my paper charts.

[jkindredpdx]

Originally Posted by Celestialsailor

I saw that from a crew member coming down the Ca. coast...Impressive. Thanks to his higher tech thinking than mine, I'm going to "Tablet" next year with things like that app and open CPN. They have built in GPS's now and work great for Navigating and Internet. Still, I will never surrender my paper charts.

Didn't you read the other thread Martin? . . . paper charts are dead!!! Good thing I have mine on life support I bought my notebook (has GPS and OpenCPN) just a few months before the Tablet explosion, now I have serious tablet envy but I'm too cheap to switch-out a perfectly acceptable computer.

[Celestialsailor]

Luckily my laptop is 7 years old...you know...antique. Started looking at the Windows Surface 2. but do not have enough info yet if it will suit my needs, which are simply Open CPN, has GPS and does Internet and able to plug my Island Time bullet antenna into. Maybe someone will read this and chime in with their experience.

[dacust]

Originally Posted by gjordan

I would not recommend the lowest cost Davis (lifeboat sextant ) to learn with. I used the lifeboat sextant and an Ebbco plastic sextant on several passages in the Pacific, and the slightly more expensive Ebbco would work for any celestial body, because it had a telescope. Telescopes have light gathering characteristics that make star and planet sights workable, where the Davis only had a sight tube, and I could never get a clear horizon, and star at the same time. My eyesight was very good back then, so I imagine the problem would be worse now. The Davis will work for what it was designed for (emergency sun only shots) but if you are serious about learning celestial, I would recommend going for the next model up, or buying a metal sextant from Craiglist or Ebay. Many people are selling unused ones for a good price. Maybe other people have had good luck doing twilight shots with the small Davis, but I sure could not. Good Luck ____Grant.

Thanks for that assessment. I had not heard comments just like this, and I will keep them in mind next time I post recommendations.

I had heard people say they had good luck with it, but I think they were only doing noon sights.

-dan

[goboatingnow]

Originally Posted by thomm225

A guy earlier was interested in planet and star locations etc on an earlier post.

Although you can use things like Orion's belt to locate due east and west when he rises and sets. This was in the book Barefoot Navigator..........he gives the actual stars to look for in the Constellation Orion

If you have a sextant , and you need to find the navigation stars , use your DR position , look up the stars azimuth and altitude , preset the sextant and the star will appear somewhere in the view finder

Dave

[jkindredpdx]

Originally Posted by Celestialsailor

Luckily my laptop is 7 years old...you know...antique. Started looking at the Windows Surface 2. but do not have enough info yet if it will suit my needs, which are simply Open CPN, has GPS and does Internet and able to plug my Island Time bullet antenna into. Maybe someone will read this and chime in with their experience.

We probably should start another thread instead of hijacking this one... but I looked for a friend recently. Don't know about reliability of ASUS transformers, but they have some nice looking tablets in Andriod and Win8. This one average performance has a nice price point Asus 10.1 inch Tablet with 32GB Memory T100TA-B1-GR - Best Buy. I tried to help a friend with Win8 and was frustrated, but then I'm often baffled by Android devices also.

[Andrew B.]

Originally Posted by jkindredpdx

For learning stars, I really enjoy the Star Walk iPhone app (free or really cheap)... point your phone up, open shutter, and the star maps overlay the sky.

Slightly off topic, I want a telescope. I was thinking about a 6" reflector. Does anyone have experience using one on board? Is a Dobsonian style mount adequate?

Thanks for the app tip !
FYI, It's $2.99, and looks to be well worth the price.

[gjordan]

Dacust, I am going to again open up an old argument on CR by recommending that you DONT learn to do a noon sight. What I saw in the Pacific was too many sailors that once they learned how to do a noon sight, never went any farther. Learning to do a noon sight is an accomplishment , and too many folks sat back and said GOOD ENOUGH, when for only a few steps more you can learn to do a proper LOP,( line of position). One of the problems with doing a noon sight in the tropics, is that you are nearly under the sun. High angle sights are very difficult. At 80 degrees or so, it is very hard to get any accuracy by bringing the sun down to the horizon. The only way to check your accuracy is to wait 24 hours and do it again. If it happens to be cloudy the next day, you are SOL. I also never used the method of pre-calculating the position of stars since when you come out to the cockpit at twilight, you never know what will be visible. Usually Venus was the first viable sight, and it is a planet, not a star, so a couple of extra(or just different) steps. Then you look around to see if there are any of the 6 or 8 nav stars that are clear for a shot(I am assuming HO249). Once a proper sun sight is learned, the stars , planets, and moon are only a little more difficult. Good Luck, Just my 2 cents worth. _____Grant.