Sunrise & Sunset

[rolly]

Anyone having a clue why sunrise shows at 22:10 and sunrise 07:20 ? Yes sir, my offset is set correctly i.e. GMT+1 since I live in Belgium.



Best regards

Rolly

[Kram]

I've noticed that for at least the past few days GPSAssist has been switching TTN to night colours at very silly times of day. I didn't think too much about it because I already switch between day and night manually due to the bug where GPSAssist insists on being in GMT+1.

[rolly]

Thank you Kram. I was not aware there was a bug. Any idea if this will be fixed soon.



Best regards

Rolly

[Kram]

Rolly,



no idea on when a fix might be available. When I reported it a few months ago I was told it would be in the next release "on Sunday", but as far as I'm aware there hasn't been another release since then.



Cheers,



Mark.

[3GGG]

I was about to post on this subject today. I have noticed that Sunset and Sunrise are reversed up here in Scotland GMT =0.

Finally registered my version yesterday as it had timed out, I must say they give very generous testing time for the shareware. finding it very useful, but really would like the sunrise/set times fixed please.
_________________
David

[devulderj]

All,



this is fixed in version 1.3.3. Check http://www.autoreplying.com/gpsassist.htm for the download.



PS: your unlock codes will as always still work.



Cheers,

Jo.

[3GGG]

Quote: Originally posted by devulderj on 08 April 2003

---

All,



this is fixed in version 1.3.3. Check http://www.autoreplying.com/gpsassist.htm for the download.



PS: your unlock codes will as always still work.



Cheers,

Jo.

---

Jo, The calculations are still wrong . At my location in Southern Scotland the approx Sunrise sunset today is 06:25 / 20:08 local time (GMT-1 hour)



GPS Assist says 06:07 16:24



Something not quite right yet
_________________
David

[Kram]

Jo, thanks for the update but there are still problems. It does remember the offset from GMT now, which is great thanks, but it doesn't seem to calculate sensible sunset times and thinks that they are much earlier than in real life. I haven't checked sunrise as I don't very often see one of those.



At least with the offset working I can now manually tune the sunset time by selecting a higher offset from GMT so it is at least partially useable now.

[Malcolm]

Jo and guys



I echo Mark's comments. It sorts out the offest but seems to take no account of Latitude. Thus although you can move the times by changing the offset, there seems to be no allowance for the longer daylight hours the further north you go. Tonight it changed at c.1830 when it fact it isn't getting dark until nearer 2000.

Also, as an aside, any ideas for stopping TTN2 overriding the Assist mapping keys? - very annoying!

[ekapco]

HI,



Jo is working on these problems with the incorrect settings for day and night.

He has used a special calculation that was made by somebody else, but now seems to be off.



He's trying to find a better one and that is very difficult.



So this will take some time.

[3GGG]

Quote: Originally posted by ekapco on 13 April 2003

---

HI,



Jo is working on these problems with the incorrect settings for day and night.

He has used a special calculation that was made by somebody else, but now seems to be off.



He's trying to find a better one and that is very difficult.



So this will take some time.

---

Can I suggest the following page for some good sunrise/set calculation programs that you may want to adapt.

http://www3.edgenet.net/lingling/x10-sun.html
_________________
David

[3GGG]

Quote: Originally posted by ekapco on 13 April 2003

---

HI,



Jo is working on these problems with the incorrect settings for day and night.

He has used a special calculation that was made by somebody else, but now seems to be off.



He's trying to find a better one and that is very difficult.



So this will take some time.

---

The first program in that link above works very well, I tried it tonight in a small BASIC program on my Macintosh. It outputs the time in decimal parts of a day, but can easily be converted to output in HH:MM:SS

It will certainly be accurate enough for our purposes here.



If you need any help in understanding or modifying it just let me know and I will be only to happy to assist.





Private Sub ComputeDawnDusk(ByVal DateFor As Date, Dawn As Date, Dusk As Date)

Dim MonthFor As Integer

Dim DayFor As Integer

Dim N As Integer

Dim LO As Double

Dim C As Double

Dim C2 As Double

Dim SD As Double

Dim CD As Double

Dim SC As Double

Dim C3 As Double

Dim TimeZone As Integer

Const Latitude = 45.07 '45 degrees 4 minutes

Const Longitude = -93.3 '93 degrees 20 minutes

Const RadiansPerDegree = 0.017453293

'see http://tycho.usno.navy.mil/srss_comp.html (US Naval Observatory) for definitions, etc.

TimeZone = 6

If DaylightTime Then TimeZone = TimeZone - 1

MonthFor = Month(DateFor)

DayFor = Day(DateFor)

N = Int(275 * MonthFor / 9) - 2 * Int((MonthFor + 9) / 12) + DayFor - 30

LO = 4.8771 + 0.0172 * (N + 0.5 - Longitude / 360)

C = 0.03342 * Sin(LO + 1.345)

C2 = (1 / RadiansPerDegree) * (Atn(Tan(LO + C)) - Atn(0.9175 * Tan(LO +C)) - C)

SD = 0.3978 * Sin(LO + C)

CD = Sqr(1 - SD * SD)

SC = (SD * Sin(Latitude * RadiansPerDegree) + 0.0145) / (Cos(Latitude * RadiansPerDegree) * CD) 'this one calculates true astronomical sunrise and sunset

C3 = (1 / RadiansPerDegree) * Atn(SC / Sqr(1 - SC * SC))

Dawn = DateFor + (6 - TimeZone - (Longitude + C2 + C3) / 15) / 24

Dusk = DateFor + (18 - TimeZone - (Longitude + C2 - C3) / 15) / 24

REM Dawn and Dusk are in decimal parts of a day.



End Sub
_________________
David

[ekapco]

I forwarded your link to Jo

Thnx David

[NigelJ]

As I posted elswhere V1.3.3 does not fix the sunrise/sunset problem and i repeat what I posted elsewher for information.



I tried this again today and with adjustment I could get sunset to agree at 1830hrs. I know that this is correct as from my front window I look out over the Irish Sea and can see the sun dip below the horizon, BUT this leaves sunrise set at 0830hrs. Although I am retired I am usually up at 0730hrs to take my dog for a walk on the beach and the sun was visible at this time over the hills in the East. Therefore the fix is not working!!!!



Hopefully the next edition will fix this and make a reasonable program excellent.



Nigel

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