It is a lost art, but was very essential back in the day. I have a slight correction to your post and that is the ability to take Polaris shots during daylight hours. Yes it can be done and have done it many times. The great advantage obviously is surveying at night is not generally very efficient. The disadvantage is being able to find that little light easily. One drawback is that the sky must be perfectly clear with no haze or pollution. This was usually the condition in the middle of nowhere in Wyoming & Montana where I did a great deal of my surveying back in the 60's & 70's. The method requires pre-calculating the position of Polaris in the sky relative to Astronomic North, as it rotates around it with an approximate 3/4° radius. The method is to determine when the star is nearing elongation. At these times, the apparent movement of the star is nearly vertical with very little lateral movement for around 20 minutes making the ability to methodically turn a set of angles a casual procedure instead of a frantic race trying to chase a celestial object across the sky. This method is not nearly as time critical as using the sun and much more precise and accurate. Once the star position has been determined, a search in the bright daylight will shortly reveal an extremely small but very bright star smiling down on you. The star is so small that it can be hidden by the crosshairs, making for a wonderfully reliable target. Once the initial sighting has occurred, the star is easily recaptured when the set of angles is being turned. Post-calculations determine the angular distance from the observation data to Astronomic North. Give it a try...you will be amazed at how well it works. Practice on a station that you already have an accurate azimuth to another station to make the acquisition of Polaris less time consuming, as it does sometimes take quite a while to initially find that little dot, but once you do, you will be impressed with your new found ability. Happy surveying from a dinosaur.
This Content Originally Published by a land surveyor to Land Surveyors United Network
Hi Ron, Glad to talk to you, I have never sighted Polaris in the day , but have read about it before. yes on the clear skies and the City lights hurt also. I did not get into details on Polaris, Dr. Elgin, Knowles and Senne go over every thing in the hand book. on the when ,where and how to do a Polaris observation, I have many books on this subject with star maps on the Eastern,Western,Elongation and Upper and Lower Culmination, good to hear other views, Very good description on your day light observation, I had a friend who had worked in Saudi Arabia, and they did both night and day but i have never been able to find Polaris in the day,so i did not mention it, you know the dangers of pointing Skyward in the day with a Total Station. So i did not mention it. But Glad to talk to someone else who has done it . My Friend and you are the only two people I have ever talked to that has done it. I have only read it in book. I feel like this is something missing from Surveying and Earth science. Old surveyors never die, they just lose their Bearings.
Hi Ron, Thanks for sparking my interest in a day time observation again, I had gave up on it. That was the main reason why i did not mention it. Because it seem impossible to me. I have also talked to others that were also unable to do it. For whatever reasons, sky not clear, instrument magnification not strong enough,or not being able to locate a Star. But with all my star charts , and i think my Gun is strong enough to do this. Do not know if the sky here is clear enough, only at some times, But I will try once again. I have always liked a challenge , When i mention the city light ,of course i was talking about night, I never had a problem at night, when possible and most of the time i had Tower lights as BS, Plus Night rods or Targets,if no Towers.
Polaris or any other Star you can use is easy to find at night. But this is a subject that young surveyors know nothing about, that is why i started this discussion, My fear in this that someone, that does not know the dangers of Day time observations. But these precautions should be taken every day at work, no matter Star, Sun shots or not. So do not look at the Sun
without a filter.To all, who do not know. Some may ask what is a FILTER, you need it to look at the Sun.And today they do not come with the Instrument. Also you have a different Focus Optical eye sight for the Telescope.This one is a prism, to view at a steeper angle. So thank you again, Ron for being so educational with your experience. My friend i told you about loves to talk about his Polaris observation in the Saudi Arabian desert. Night and day. He is a retired PLS.
Hi Everyone, This link pages and files ,contains Sun and Polaris Ephemerii for the year of 2016 for the use by land Surveyors.If just for fun, give it a try.
Sun and Polaris Ephemerii for the year of 2016 .
Home Page This also has a link for 2017 Sun and Polaris Ephemerii .
and for those who like to try Day time Polaris, just be careful,
do not turn the scope toward the Sun at any time. are look at the sun
without a Filter. This is explained below,more data may be required.
Hi Everyone, I have been using this site,for quite some time,I first found it in Chrome Web store. I wanted it just for my love of Star Science and star locations. This is neave .com. This site has a on line Planetarium, It is also interactive with you. If you are not familiar with star locations and like to learn the Night Shy, this is a good place to Start. It is also very Cool. In this you can see how to located Polaris, because it will produce, your night or day sky , from your Location. so you see the sky not just view of it , but a view from where ever you are at or located. At real time, so how Cool is that. so get this, Not for just to help you survey , but if you like. So here is some links. this is very neat. There is also many other things at,
neave .com ,Games and also Zoom Earth, Nasa Satellite, Taken and updated every day.
also Live maps,Satellite, Earth Map, Aerial Maps. by Google, Enjoy!
also available on chrome web store, Go there i could not get there link to work , it has a Info page on how it works also you can install there for Chrome users