View Issue Details
ID | Project | Category | View Status | Date Submitted | Last Update |
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0001714 | SkyChart | 1-Software | public | 17-05-19 02:58 | 18-10-09 17:35 |
Reporter | Sasa | Assigned To | Patrick Chevalley | ||
Priority | normal | Severity | minor | Reproducibility | always |
Status | resolved | Resolution | fixed | ||
Platform | Linux 32-bit | OS | Lubuntu | OS Version | 17.04 |
Product Version | 4.1 SVN | ||||
Target Version | 4.2 | ||||
Summary | 0001714: Julian date conversion - rounding bug | ||||
Description | If convert Julian date near midnight, it will switch to 0h, however day will not turn over. | ||||
Steps To Reproduce | For instance: 2299160.49999 = 1582-10-04 23:59:59 2299160.499999 = 1582-10-04 00:00:00 instead 1582-10-15 00:00:00 2457893.49999 = 2017-05-20 23:59:59 2457893.499999 = 2017-05-20 00:00:00 instead 2017-05-21 00:00:00 | ||||
Tags | No tags attached. | ||||
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Of course when round correctly, JD should be changed to integer part + 0.5. Or, if do not allow fraction of seconds, JD should be limited to 5 decimal points on input. |
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I cannot reproduce the problem. Both my 32bit and 64bit Linux version do the following: 2299160.49999 = 1582-10-04 23:59:59 2299160.499999 = 1582-10-04 24:00:00 2299160.4999999999 = 1582-10-15 00:00:00 2457893.49999 = 2017-05-19 23:59:59 2457893.499999 = 2017-05-19 24:00:00 2457893.4999999999 = 2017-05-20 00:00:00 I agree the 24:00:00 is not very nice but not wrong, this is only a formating problem in function TimToStr(). Can you confirm two point: - Is 2457893.49999 really show as 2017-05-20 on your system, not 2017-05-19 ? - To be sure it is also a text formating problem (not jd conversion problem) on you system can you zoom the map on the Moon with date set to 2457893.49999, then change date to 2457893.499999 and look if the Moon jump one day back or not. |
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To be more clear, this is tested with latest .deb version SVN 3586 Attached screenshots for: 2457893.49999 2457893.499999 2457893.5 The Moon apparently does not move position on any of these values. I do not mind 24:00:00 value in label, however, comparing date and time on label, edit fields and the chart show the problem exists. It doesn't matter it is pressed Enter, Apply or save config on exit and reopening. When reopening, TrackEpoch in .ini file is exactly entered in JD edit field. It is highly unlikely anyone will ever enter such JD, however for such border values it show wrong date and time, even calculation seems to be proper regarding entered JD. |
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Furthermore. Entering 2457893.499999 and entering 1 second (or click on UpDown) will change JD value to 2457892.500012 (!!! one day off), then back to zero will keep 2457892.500000 (still one day off). Doing the same with Day edit field will simply add or subtract current JD value, leaving fractions the same and JD consistent. This as well demonstrate Julian date conversion bug due unhandled fraction values and rounding. I had similar problem working on artificial satellite orbit prediction and to obtain maximum precision I kept whole 11 decimal points for JD and to keep datetime displayed as close possible with 3 decimal points for seconds, avoiding rounding when display. |
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This is fixed by truncating the JD input to five decimal place. This is less than one second so it make no sens to want more digits here. https://github.com/pchev/skychart/commit/88aa8b8bafda11a1a94ddc962914c464d1bdf7b2 |
Date Modified | Username | Field | Change |
---|---|---|---|
17-05-19 02:58 | Sasa | New Issue | |
17-05-19 03:13 | Sasa | Note Added: 0003810 | |
17-05-19 03:14 | Sasa | Note Edited: 0003810 | |
17-05-22 15:30 | Patrick Chevalley | Assigned To | => Patrick Chevalley |
17-05-22 15:30 | Patrick Chevalley | Status | new => feedback |
17-05-22 15:30 | Patrick Chevalley | Note Added: 0003813 | |
17-05-22 17:05 | Sasa | File Added: 2457893.4999.png | |
17-05-22 17:05 | Sasa | File Added: 2457893.49999.png | |
17-05-22 17:06 | Sasa | File Added: 2457893.5.png | |
17-05-22 17:26 | Sasa | Note Added: 0003814 | |
17-05-22 17:26 | Sasa | Status | feedback => assigned |
17-05-22 17:28 | Sasa | Note Edited: 0003814 | |
17-05-22 17:32 | Sasa | Note Edited: 0003814 | |
17-05-23 06:45 | Sasa | Note Added: 0003815 | |
17-05-23 06:46 | Sasa | Note Edited: 0003815 | |
17-05-23 06:46 | Sasa | Note Edited: 0003815 | |
17-05-23 06:47 | Sasa | Note Edited: 0003815 | |
17-05-23 06:51 | Sasa | Note Edited: 0003815 | |
17-05-23 06:58 | Sasa | Note Edited: 0003815 | |
18-10-09 17:35 | Patrick Chevalley | Status | assigned => resolved |
18-10-09 17:35 | Patrick Chevalley | Resolution | open => fixed |
18-10-09 17:35 | Patrick Chevalley | Target Version | => 4.2 |
18-10-09 17:35 | Patrick Chevalley | Note Added: 0004935 |