Technical question needing a proper old almanac

[Tomahawk]

Does anyone have a set of solar elevations and can answer a simple question?

What is the solar elevation at mid day on mid winters day at 51.80 degrees north?

Ta muchy in advance of someone helping

 

[B27]

I'm probably wrong on this but the obvious answer would seem to be 90 - 51.8 - 23.4 = 14.8 degrees?
23.4 being the tilt of the earth's axis.

 

[DJE]

I thought the same but I made the subtraction come out as 14.8 degrees.

Is this any use?

 

[B27]

I thought the same but I made the subtraction come out as 14.8 degrees.

Is this any use?

Doh!

 

[john_morris_uk]

Except the dec of the sun on midwinters day this year max’s out at 23 degrees 26.3

Depends how accurate you want to be.

 

[Tomahawk]

Except the dec of the sun on midwinters day this year max’s out at 23 degrees 26.3

Depends how accurate you want to be.

You using dictate? Because I can't make sense of that..

Do you mean "expect the declination of the sun on midwinters day to be 23 degrees and 26.3 minutes"

 

[Tomahawk]

Doh!

It sems to give me New York and nothing else

 

[DJE]

It sems to give me New York and nothing else

You should be able to pan and zoom the map then click on the point you want to use. Set the date and time in the relevant boxes above the map.

 

[B27]

You using dictate? Because I can't make sense of that..

Do you mean "expect the declination of the sun on midwinters day to be 23 degrees and 26.3 minutes"

I think the tilt of the earth's axis varies a bit, so the answer will be slightly different from year to year.
As he said, how accurate do you want to be?

It will also vary a smidge from place to place because the earth is in a different point of its orbit at a different local 'middays'.

If you are looking for precision, then you need to take care over the definition of everything,
I would need to revise a bit!
Is the 'elevation' the reading on the sextant, or is it after you corrected it for altitude and all that sort of thing.

 

[Tomahawk]

Thanks everyone..

The sun dial site has given me what I need... Min elevation is about 16degrees.. It relates to overshadowing and loss of sun light that has nothing whatsoever to do with sailing.. but as they say, I know a man who can

 

[john_morris_uk]

You using dictate? Because I can't make sense of that..

Do you mean "expect the declination of the sun on midwinters day to be 23 degrees and 26.3 minutes"

Yes. Sorry but I’m at Birmingham Airport on my phone with a delayed flight etc. I wasn’t proof reading very well.

 

[john_morris_uk]

I think the tilt of the earth's axis varies a bit, so the answer will be slightly different from year to year.
As he said, how accurate do you want to be?

It will also vary a smidge from place to place because the earth is in a different point of its orbit at a different local 'middays'.

If you are looking for precision, then you need to take care over the definition of everything,
I would need to revise a bit!
Is the 'elevation' the reading on the sextant, or is it after you corrected it for altitude and all that sort of thing.

I imagined he meant true altitude.
The varying/wobbling of the earths axis has a nice name. ‘Precession’ IIRC.
There are others who are more expert than me at this stuff.
It appears the OP doesn’t need precision after all.

I’m going to guess a planning enquiry/objection?

 

[jdc]

At 11:57:57 on 21 Dec 2023 the altitude of the sun when observed from 51° 48'N (51.80°), 0°00'W will be 14° 46'. The lower limb will be 14° 33' above the horizon, assuming pressure = 1010 mB and atmospheric temp = 5°C.

Is that what you meant? The solstice is later, at around 3am on the 22nd, but unless you're somewhere around China (correction - Siberia) you won't observe it!

See sextant.html

 

[john_morris_uk]

At 11:57:57 on 21 Dec 2023 the altitude of the sun when observed from 51° 48'N (51.80°), 0°00'W will be 14° 46'. The lower limb will be 14° 33' above the horizon, assuming pressure = 1010 mB and atmospheric temp = 5°C.

Is that what you meant? The solstice is later, at around 3am on the 22nd, but unless you're somewhere around China (correction - Siberia) you won't observe it!

See sextant.html

True: the OP didn’t say what longitude he was at.