Calculating sunrise and sunset between two points

close
more_vert
bawn79 B
bawn79 Dec 3, 2008 17:23:45
Replying to tiompan

tiompan wrote:
bawn79 wrote:
tiompan wrote:
bawn79 wrote:
Sorry all,

I've been checking out a passage tomb and I was wondering if I have an ordnance survey reference for the tomb and an ordance survey for the hill which can be seen from the passage, could anyone on here calculate if any significant sunrise / sunsets are linked to this passage?

Its just a rough estimate I need.

Hi Bawn , I took a guess and checked the Kilmacow wedge wedge tomb to Knockfeerina .It's very imporatnt to have the altitude of both sites but I think I managed to get them from the archaeology ie website .I have assumed that the sighting is to the highest point on the hill which gives a declination of -23.71 very close to winter solstice sunset which is ideally -24 . I'll double check everything tomorrow but I think it's ok .
Hi Tiompan,
It was actually Shrough (http://www.themodernantiquarian.com/site/8350/shrough.html) in Tipp and Knockfeerina for sunset (http://www.themodernantiquarian.com/site/7901/knockfeerina.html) and Shrough and Sliabh na mBan (http://www.themodernantiquarian.com/site/1530/slievenamon.html) for sunrise. Im not sure which way this passage is oriented but I think it actually may be faced to the west.

I was at the passage grave for sunset two days ago and it is a long way from setting in the passage at the moment.
Does the sun set 'move' very much this time of year (as in position of setting)?

Hi Bawn , double checked the Knockfeerina figures and if anything they are even closer to the solstice .
Shrough - Sliabh na mban (why is it spelt like that ?, surely Sliabh nam Ban ?) is almost due east to west i.e. 89 .7 degrees , have I missed something ?
Sun set around solstice appears to stay pretty still as it is reaching it's max then returning , hence the number of days Newgrange has it's light show .
Tiompan,

Sorry Im a bit confused (thats why I always have to ask people on here about where the sun is likely to set and rise).
When you say the Knockfeerina figures do you mean the Kilmacow figures that you gave already or the Shrough figures?
Because as far as I know Kilmacow is to the North of Knockfeerina so it wouldnt set over it at all.
Shrough to Sliabh na mBan was for sunrise, I was just curious if that was a possible alignment.

Thanks for checking again and hopefully that makes more sense.

T tiompan
tiompan Dec 3, 2008 17:54:57
Replying to bawn79

bawn79 wrote:
tiompan wrote:
bawn79 wrote:
tiompan wrote:
bawn79 wrote:
Sorry all,

I've been checking out a passage tomb and I was wondering if I have an ordnance survey reference for the tomb and an ordance survey for the hill which can be seen from the passage, could anyone on here calculate if any significant sunrise / sunsets are linked to this passage?

Its just a rough estimate I need.

Hi Bawn , I took a guess and checked the Kilmacow wedge wedge tomb to Knockfeerina .It's very imporatnt to have the altitude of both sites but I think I managed to get them from the archaeology ie website .I have assumed that the sighting is to the highest point on the hill which gives a declination of -23.71 very close to winter solstice sunset which is ideally -24 . I'll double check everything tomorrow but I think it's ok .
Hi Tiompan,
It was actually Shrough (http://www.themodernantiquarian.com/site/8350/shrough.html) in Tipp and Knockfeerina for sunset (http://www.themodernantiquarian.com/site/7901/knockfeerina.html) and Shrough and Sliabh na mBan (http://www.themodernantiquarian.com/site/1530/slievenamon.html) for sunrise. Im not sure which way this passage is oriented but I think it actually may be faced to the west.

I was at the passage grave for sunset two days ago and it is a long way from setting in the passage at the moment.
Does the sun set 'move' very much this time of year (as in position of setting)?

Hi Bawn , double checked the Knockfeerina figures and if anything they are even closer to the solstice .
Shrough - Sliabh na mban (why is it spelt like that ?, surely Sliabh nam Ban ?) is almost due east to west i.e. 89 .7 degrees , have I missed something ?
Sun set around solstice appears to stay pretty still as it is reaching it's max then returning , hence the number of days Newgrange has it's light show .
Tiompan,

Sorry Im a bit confused (thats why I always have to ask people on here about where the sun is likely to set and rise).
When you say the Knockfeerina figures do you mean the Kilmacow figures that you gave already or the Shrough figures?
Because as far as I know Kilmacow is to the North of Knockfeerina so it wouldnt set over it at all.
Shrough to Sliabh na mBan was for sunrise, I was just curious if that was a possible alignment.

Thanks for checking again and hopefully that makes more sense.

Bawn ,
the Kilmacow -Knockfaeerina is a bit of surprise because the hill must appear quite close (355 m) and high but it works out perfectly , the sun sets in the SSW at winter solstice but because of the height and proximity of Knockfeerina it will be seen setting even more to the south . If the passage is aligned 210 degrees then it would be an even greater sign of intentionality .
Shrough - Sliabh is spot on for equinox sunrise but more difficult to prove intention there ,unless there is something to indicate Sliabh e.g. an outlying stone or passage .
You seem to have struck lucky with both .