Problematic Discoveries

[Springhead]

Tiompan,

Check my last post for the winter solstice sunrise saddle comment.

[Tiompan]

Tiompan,

Check my last post for the winter solstice sunrise saddle comment.

Spring head ,

I missed it while replying to your earlier one .

I hadn't seen a mention of the mouth being mentioned as 670 feet etc.,maybe that's in the book .

Btw the ,the actual time of the solstice is the time that it takes place at the site ,whilst it might be earlier or later than another viewed elesewhere , it's still the
actual time, and azimuth , from that site , and that is what would have mattered to anyone seeing it and anyone calculating data realted to it .
It's a common mistake , people look up the time and azimuth of an event and think it applies to the area as a whole .Whilst it might do , if there are hills on the horizon, it will vary , depending on their height and proximity to the obesever .

[Springhead]

Tiompan,

The incorrect 670' observation for the Spout Run mouth was mistake from the book. There is a knoll feature on my mountain site where I suspected the winter solstice sunset was exactly in the cleft between two mountains. I drew it up on GE with the vantage point at the crest of the knoll. The vector from there to the cleft did not have the exact solstice degree reading, but when I carried the sun path to the actual horizon, the nine degree adjustment to the west put the numbers right on. On the actual winter solstice I was pleased to be on site and view a perfectly centered sunset in the cleft.

[Tiompan]

Tiompan,

The incorrect 670' observation for the Spout Run mouth was mistake from the book. There is a knoll feature on my mountain site where I suspected the winter solstice sunset was exactly in the cleft between two mountains. I drew it up on GE with the vantage point at the crest of the knoll. The vector from there to the cleft did not have the exact solstice degree reading, but when I carried the sun path to the actual horizon, the nine degree adjustment to the west put the numbers right on. On the actual winter solstice I was pleased to be on site and view a perfectly centered sunset in the cleft.

This is what I mean Springhead . "The vector from there to the cleft did not have the exact solstice degree reading," The only exact solstice azimuth is the one from the observer to the event on the horizon , not a generalised one for the area that fails to consider the local horizon .

When we look at the point point on the horizon from from ancient monument on a solstcie orientation e.g. Stonehenge , Newgrange it is rarely to anything striking ,the peaks and troughs are not where the alignments occur on the horizon but on non descript points of the horizon . The same applies to stone circles that don't have accepted alignments , when we calculate the horizon points of the events they still avoid the peaks and troughs .
Google castlerigg .This is a famous stone circle encircled by hills but every one of the solstcies and equinoxes are on non descript slopes .
Of course there is no reason to believe that any of these events had a bearing on the siting of the monument , but it is surprisng how people do associate and imagine there was an association .

[Tiompan]

Wow!
Enlightening screenshots, guys!

Maybe a wee thought experiment will work .
Imagine you are at the bottom of the grand canyon , your experience of the sunrise will differ dramatically from someone at almost exactly the same latitude and longitude , at the rim directly above you .
The bearing of the sunrise on the horizon for your companion will be nothing like your bearing .
What matters is not simply the bearing /azimuth but the altitude of the horizon (in your case the height of the canyon walls ) as well as the latitude ,and if it is considering earlier experiences , knowledge of obliquity in the period under consideration .That value is the declination which incorporates all the other values .
The problem is that the bearing is often considered minus the other all important factors .

[Springhead]

Tiompan,

With the frequent need to analyze site dynamics in archaeology, it seems that a formula could be developed (if it hasn't been already) to calculate the perceived and actual bearings of the equinox and solstice on any given site, not to mention calculating positions relative to sites of various heavenly bodies. As long as the vantage point location and altitude and the local horizon location, altitude, and distance from the vantage point are known, the values could be plugged in to formulas for each event. It could follow that allowances for the passage of time at the studied site could also be calculated to understand ancient heavenly body locations. I suspect these calculations are routine these days, but perhaps it would be helpful to have formulas that could be used quickly on site. This may all be moot if the software has been developed already.

[Tiompan]

Tiompan,

With the frequent need to analyze site dynamics in archaeology, it seems that a formula could be developed (if it hasn't been already) to calculate the perceived and actual bearings of the equinox and solstice on any given site, not to mention calculating positions relative to sites of various heavenly bodies. As long as the vantage point location and altitude and the local horizon location, altitude, and distance from the vantage point are known, the values could be plugged in to formulas for each event. It could follow that allowances for the passage of time at the studied site could also be calculated to understand ancient heavenly body locations. I suspect these calculations are routine these days, but perhaps it would be helpful to have formulas that could be used quickly on site. This may all be moot if the software has been developed already.

Springhead ,
Yes the formulae are pretty basic trig .
Alexander Thom ,was the first I was aware of in highlighting them .
Declination is what matters ,in those terms .

sin declination =sin latitude sinaltitude + cos latitude cos altitude cos Azimuth

A progammable calculator helps for speed ,failing that it's not too awkward .

There are some additions that make for more accurate if minor adjustments e.g. the addition of refraction to the altitude etc .

[Tiompan]

Mod Note: Edit. Fixed that link for you, T.

Min

[Tiompan]

Mod Note: Edit. Fixed that link for you, T.

Min

Thanks M.

[Springhead]

[img][/img]

Tiompan,

This is similar to the image I used to calculate the winter solstice sunset location in the area of the mountain site. The red "x" (rather faint for some reason) is at the crest of the central knoll and the saddle or cleft (apparent horizon) is above and slightly to the right of the "x." With the measuring tool providing vector degree readings it is handy in doing seasonal sunrise and sunset estimations. Though my methods are seat of the pants, one can be accurate enough to get the general idea. If one can't be on site on the appropriate day, this armchair method can be useful until real accuracy is desired.

[Tiompan]

[img][/img]

Tiompan,

This is similar to the image I used to calculate the winter solstice sunset location in the area of the mountain site. The red "x" (rather faint for some reason) is at the crest of the central knoll and the saddle or cleft (apparent horizon) is above and slightly to the right of the "x." With the measuring tool providing vector degree readings it is handy in doing seasonal sunrise and sunset estimations. Though my methods are seat of the pants, one can be accurate enough to get the general idea. If one can't be on site on the appropriate day, this armchair method can be useful until real accuracy is desired.

Springhead ,
if you give me the co-ordiantes I'll calculte the point on the horizon where the sun will be seen to rise /set on solstices etc , for today so
you can see the accuracy and also for a period when there was a more significant change in obliquity , e.g. neolithci or earlier .
Or as a test of methods choose a spot anywhere that can be verified for any date and astro event .
A hillier area will usually provide a bigger strain on an ad hoc methods accuracy .
At sea or level horizons are safer ground .

[Springhead]

Tiompan,

Thanks. I have kept the mountain site location private for security reasons at this time, but I do have a potential site on the coast near where I live that might be a good spot as it is at sea level and on the water with minor land elevations shore side. I'll call it Tom's Island. 34 degrees 16' 03.48" N
77 degrees 46' 08.23" W

Thanks for this. It will be useful now and in reference later. There is no doubt that my seat of the pants method lacks accuracy in the mountainous terrain of Virginia. I was lucky to get so close there which was affirmed by the actual sunset event on winter solstice.

[Tiompan]

Tiompan,

Thanks. I have kept the mountain site location private for security reasons at this time, but I do have a potential site on the coast near where I live that might be a good spot as it is at sea level and on the water with minor land elevations shore side. I'll call it Tom's Island. 34 degrees 16' 03.48" N
77 degrees 46' 08.23" W

Thanks for this. It will be useful now and in reference later. There is no doubt that my seat of the pants method lacks accuracy in the mountainous terrain of Virginia. I was lucky to get so close there which was affirmed by the actual sunset event on winter solstice.

Got it Springhead . Three miles east of Ogden ?
What events and what dates are you interested in and from what point of the Island ?

[Springhead]

Tiompan,

Yes, that's the spot. The island is so small that the coordinates will suffice at this point as the vantage point. I am interested in three dates, but they are approximate, especially the second and third: 539 AD, 1250 AD, and 3500 BC. Are these specific enough? Initially the solstices and equinoxes would be good. I am trying to relate the site to local topography and features if in fact it has any authenticity. The first two dates correspond to possible ocean strikes by comets, and the third is related to the shell mound culture of the southeast coast.

Thanks Lily,

A picture is worth a thousand words.

[Springhead]

Lily,

I believe there was a comet or asteroid strike on that date near the Bahamas that caused a mega tsunami that may have destroyed southeastern US coastal cultures and drove possible survivors inland and upland. Tsunami debris may have added to or created a ridge inland which runs from Richmond Va to northern Florida. In Georgia that ridge is still 60'-80' in height.