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IDProjectCategoryView StatusLast Update
0001529SkyChart1-Softwarepublic16-11-27 17:39
ReporterSasa Assigned ToPatrick Chevalley  
PrioritynormalSeveritytrivialReproducibilityalways
Status resolvedResolutionfixed 
PlatformLinux 64-bitOSKubuntuOS Version14.04
Product Version3.11 SVN 
Target Version4.0Fixed in Version3.11 SVN 
Summary0001529: Details form - some suggestions
DescriptionFor some trivial calculations I use following site use approximate methods:
http://www.esrl.noaa.gov/gmd/grad/solcalc/

According to that, the value for "Hour angle" in CDC is at least not divided by 15 ( it is shown in h:m:s format).

Distance from Earth in AU is shown up to 4 decimals, which is too small, at least for Sun. As well, additional value in km may be useful to show (for accuracy testing at least).

Angular diameter value perhaps may be with 2 decimals at least.
TagsNo tags attached.

Activities

Patrick Chevalley

16-04-06 13:45

administrator   ~0003348

Hi Sasa,

Hour Angle is show in hours, so degree divided by 15.
I not find this value in the mentioned web page, can you be more explicit?

Agree to improve the distance display. The AU value require 9 digits for a precision of 1 km. But I also thing it is good to display the km value and maybe in this case it is not valuable to show the AU value with more than 5 digits.

For the planets 0.1 arcsec precision on the diameter is probably sufficient.
For the Moon and Sun I can replace the display in minute by mm'ss.s"

Sasa

16-04-06 16:13

reporter   ~0003351

Last edited: 16-04-06 16:19

Sorry for being unclear...

Hour angle value is a bit weird to me. Upper NOAA link use javascript low precision methods for calculation (main.js) and values calculated for sunset and sunrise hour angle are definitely different than CDC shows in these specific moments of times. As well, Stellarium show significantly different value than CDC.

All upper indicate some problem or my misunderstanding...

Regarding distances. I would suggest displaying AU with precise 9 decimals as well as precise value in km (with 3 decimals). There is plenty of space to display it precisely it can be. NASA JPL live simulator show live distance from Earth to tracked planet in km only, which I though is interesting feature for CDC.

I have forgotten as well to suggest to display more precision for magnitude value.

In general, there is no reason to truncate values in this form if they are calculated with precise methods.

Patrick Chevalley

16-11-27 17:39

administrator   ~0003446

Revision 3332 increase the display precision for the planet distance:
https://sourceforge.net/p/skychart/code/3332/

I not increase the precision for the planet magnitude because this is a very crude estimate that not take account for the planet feature albedo.

The hour angle of an object is simply the local sidereal time minus the object right ascension.
It is 0 when the object is at the meridian and increase to the west.

To compare rise or set time you must be very careful on how the refraction is counted by each software.

Issue History

Date Modified Username Field Change
16-04-05 22:13 Sasa New Issue
16-04-06 13:45 Patrick Chevalley Note Added: 0003348
16-04-06 13:45 Patrick Chevalley Assigned To => Patrick Chevalley
16-04-06 13:45 Patrick Chevalley Status new => feedback
16-04-06 13:45 Patrick Chevalley Target Version => 4.0
16-04-06 16:13 Sasa Note Added: 0003351
16-04-06 16:13 Sasa Status feedback => assigned
16-04-06 16:19 Sasa Note Edited: 0003351
16-11-27 17:39 Patrick Chevalley Note Added: 0003446
16-11-27 17:39 Patrick Chevalley Status assigned => resolved
16-11-27 17:39 Patrick Chevalley Resolution open => fixed
16-11-27 17:39 Patrick Chevalley Fixed in Version => 3.11 SVN