Time descrepancy in Cumulus

[The hooded Claw]

I have run this program ... http://www.marcopiccone.it/iphone/iEphemeris_Guide.html for many years (Since Iphone first came out) I have noted some time/sunrise/set descrepancies in cumulus are as much as 4 minutes out, I wonder if Steve could utilize this program within Cumulus to obtain a "More accurate" time/sunset/rise function within the cumulus program

The Ephemeris program is run thru JPL/NASA .............(For a link just drop the "i" off the front )

[steve]

You probably have a problem with your co-ordinates. Every time someone says that the sunrise and sunset times are out I spend ages checking up and they always agree with the 'usual' places e.g. http://aa.usno.navy.mil/data/docs/RS_OneDay.php (the 'problem' is invariably down to user error - wrong co-ordinates etc). The moon rise and moon set times do tend to be a couple of minutes out - I don't propose to do anything about that.

[TNETWeather]

Just give the moon a little shove Steve... that will fix it.

[sjukmidlands]

So far I've always found the sunrise/sunset times in Cumulus correspond exactly with the other programs I use to obtain this, for my own co-ordinates.

Oh, and nudging the moon sounds like a good idea we all ought to get together sometime as a team to try it....

Steve

[The hooded Claw]

You probably have a problem with your co-ordinates. Every time someone says that the sunrise and sunset times are out I spend ages checking up and they always agree with the 'usual' places e.g. http://aa.usno.navy.mil/data/docs/RS_OneDay.php (the 'problem' is invariably down to user error - wrong co-ordinates etc). The moon rise and moon set times do tend to be a couple of minutes out - I don't propose to do anything about that.

I don't have a problem with my co-ordinates ...iemphemeris GPS locates me EXACTLY as I entered it into Cumulus yet the Sun rise/set on Cumulus is 3 minutes out between each

[steve]

I put the co-ordinates from your web site into here: http://www.srrb.noaa.gov/highlights/sun ... nrise.html

Cumulus gives sunrise 0823 sunset 1619
NOAA gives sunrise 0823 sunset 1620

The stated accuracy of the NOAA calculator for latitudes less than 72 degrees is one minute.

I did the same at http://aa.usno.navy.mil/data/docs/RS_OneDay.php and got the same result as NOAA.

I did the same at NOAA's improved solar calculator here: http://www.esrl.noaa.gov/gmd/grad/solcalc/ and got exactly the same answer as Cumulus.

The Cumulus calculation is correct, to the nearest minute.

[The hooded Claw]

Cheers.................. I THINK I've worked this out now ...................According to iempheris I'm 68 Meters (or 223 feet) above sea level......Now, as My House fronts onto the beach & I KNOW my front drive is 20 feet above Sea level ( coz I measured it!!!) ..... Iempheris is WRONG...................

& to prove it I just walked down to the waters edge............& it STILL said I was 52 meters above sea level We are now 33 minutes AFTER High Water here (Measured on Newlyn) ..............so if the tide is/was 52 meters I'd be wearing Scuba gear in my lounge right now!!!!!...............How can a GPS be so inaccurate with regards to altitude???

[sjukmidlands]

I have found my GPS on my HTC Touch HD is inaccurate regarding altitude.

For example, whilst in Wales last year, (we have a caravan at Porthmadog) whilst parked next to Bangor harbour, I set the GPS altitude on one of the GPS programs I was trying at 10ft ASL (a bit of a guess as it depends on the tide etc), then drove back over the mountains to Borth-y-Gest a small harbour village next to where our carvan site is. I parked again on the harbour front at a similar elevation from the sea and the program said we were over 130ft BELOW sea level! Tried this out many times in various GPS based applications and the altitude is always suspect and varies a lot - even when stationary.

Hopefully when the Galileo project is up and running in about four years we will have much more accurate GPS system and thus more accurate altitude readings. In the meant time therefore don't trust altiude via some GPS applications.

Steve