<div dir="ltr">Hi Robert,<div><br></div><div>Oh!! I am working on this bug now. I'm not getting anywhere with it so far. I use JPL Horizons system to check the orbital parameters: <a href="https://ssd.jpl.nasa.gov/horizons.cgi">https://ssd.jpl.nasa.gov/horizons.cgi</a></div><div><br></div><div>I am calculating all orbital elements and comparing it with JPL values starting from Mean Anamoly, then True Anamoly..etc. Here are JPL values from Horizon:</div><div><br></div><div>JPL Heliocentric Orbital Elements</div><div><pre style="color:rgb(0,0,0);background-color:rgb(238,238,238)">$$SOE
2457998.500000000 = A.D. 2017-Sep-02 00:00:00.0000 TDB
EC= 4.232744439134506E-01 QR= 1.020269859137170E+00 IN= 2.215206298911301E+01
OM= 3.360953610775869E+02 W = 2.784196493952410E+01 Tp= 2458020.936332046986
N = 4.188758125005247E-01 MA= 3.506019631843183E+02 TA= 3.348867725600903E+02
A = 1.769073432535834E+00 AD= 2.517877005934499E+00 PR= 8.594432747284709E+02
2457999.500000000 = A.D. 2017-Sep-03 00:00:00.0000 TDB
EC= 4.232901835419896E-01 QR= 1.020263438440515E+00 IN= 2.215145437416221E+01
OM= 3.360952684752951E+02 W = 2.784456004960867E+01 Tp= 2458020.938336936291
N = 4.188626190102440E-01 MA= 3.510202820436723E+02 TA= 3.359645930024024E+02
A = 1.769110580961994E+00 AD= 2.517957723483473E+00 PR= 8.594703457918157E+02
$$EOE</pre><div>JPL Heliocentric Ephemeris<pre style="color:rgb(0,0,0);background-color:rgb(238,238,238)">**********************************************************************************************************************************************************
Date__(UT)__HR:MN R.A.__(a-apparent)__DEC hEcl-Lon hEcl-Lat r rdot delta deldot ObsEcLon ObsEcLat Tru_Anom
**********************************************************************************************************************************************************
$$SOE
2017-Sep-02 00:00 22 56 46.97 +08 13 17.0 338.6177 1.0264 1.049795367593 -4.4410821 1.04979536759279 -4.4410821 338.6176978 1.0264441 334.8811
2017-Sep-03 00:00 23 00 48.31 +08 38 34.4 339.6187 1.4332 1.047281909825 -4.2622642 1.04728190982466 -4.2622642 339.6187413 1.4332183 335.9589
$$EOE</pre></div><div>JPL Vector Data (Rectangular Heliocentric Coordinates):</div><div><br></div><div><pre style="color:rgb(0,0,0);background-color:rgb(238,238,238)">$$SOE
2457998.500000000 = A.D. 2017-Sep-02 00:00:00.0000 TDB
X = 9.774013251109912E-01 Y =-3.825877896251375E-01 Z = 1.884479352236287E-02
VX= 4.155441472803211E-03 VY= 1.801646315290931E-02 VZ= 7.391156829632851E-03
LT= 6.063034210721955E-03 RG= 1.049781831306806E+00 RR=-2.564399485651484E-03
2457999.500000000 = A.D. 2017-Sep-03 00:00:00.0000 TDB
X = 9.814311564582442E-01 Y =-3.645229326093622E-01 Z = 2.623313001987751E-02
VX= 3.903753134260795E-03 VY= 1.811258715727221E-02 VZ= 7.385185521988751E-03
LT= 6.048521037259282E-03 RG= 1.047268953218673E+00 RR=-2.461117456681675E-03
$$EOE</pre><pre style="color:rgb(0,0,0);background-color:rgb(238,238,238)"><br></pre></div>They precess all values while we don't precess anything in asteroid class. In comets we precess OM, so I added that back into asteroid class to precess OM (Longitude of the Ascending Node). Here is KStars values for Sep 2nd 00:00:00:</div><div><br></div><div>EC = 0.4233003617604261</div><div>W = 27.84698664318219</div><div>MA = 350.5485275538136</div><div>E = 343.7697842874328 (Not shown in JPL above, the Eccentric Anamoly)</div><div>TA = -25.252507942167078 = 334.747492057832922</div><div>IN = 22.1507826948212</div><div>A = 1.769132449016887</div><div>OM = 336.095126120893 (After I precessed it, it's not in code yet)</div><div>r = 1.0510131460163505</div><div><br></div><div>You can see we have some differences in the true anamoly and by extension sun distance. There are small differences in other elements, but these two stand out leading to inaccurate heliocentric ecliptic coordinates and eventually to wrong geccentric J2000/JNow coords. At first glance it appears that the eccentric anamoly value might be inaccurate, but we use the same iterative algorithm we already use in the comets class. Comets can also be inaccurate but not as bad as this case.</div><div><br></div><div>I think it might be a good idea to add another backend for this, we could be utilizing JPL Development Ephemeris (e.g. 406+) for solar system calculations. Another option is to switch to MPC for data source, but I'm not sure what difference will this make.</div><div><br></div><div>Regards,</div><div>Jasem</div><div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Sep 2, 2017 at 3:45 PM, robert <span dir="ltr"><<a href="mailto:robert@navsoft.plus.com" target="_blank">robert@navsoft.plus.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Great - I'm starting with <a href="https://bugs.kde.org/show_bug.cgi?id=384276" style="color:rgb(102,51,102);font-family:Helvetica,Arial,Geneva;font-size:16.6667px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:bold;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" target="_blank"><b>Bug 384276</b></a><span style="color:rgb(0,0,0);font-family:Helvetica,Arial,Geneva;font-size:16.6667px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:bold;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(208,208,208);text-decoration-style:initial;text-decoration-color:initial;display:inline!important;float:none"><span> </span></span><span id="m_1828286541412418006summary_container" style="color:rgb(0,0,0);font-family:Helvetica,Arial,Geneva;font-size:16.6667px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:bold;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">-<span> </span><span id="m_1828286541412418006short_desc_nonedit_display">[kstars 2.8.2] Wrong placement
of asteroid Florence</span></span></p><span class="HOEnZb"><font color="#888888">
<p><span id="m_1828286541412418006summary_container" style="color:rgb(0,0,0);font-family:Helvetica,Arial,Geneva;font-size:16.6667px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:bold;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"><span id="m_1828286541412418006short_desc_nonedit_display">R<br>
</span></span></p></font></span><div><div class="h5">
<br>
<div class="m_1828286541412418006moz-cite-prefix">On 02/09/17 13:05, Jasem Mutlaq wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi Robert,
<div><br>
</div>
<div>You can start by submitting patches to me, and then later
on we'll create you an account on the system to handle it
directly. So yeah clone KStars, then when you have a fix, run
git diff and send me a patch.</div>
<div><br>
</div>
<div>Thanks for the help!!</div>
<div><br>
</div>
<div>Regards,</div>
<div>Jasem</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, Sep 2, 2017 at 2:38 PM, robert
<span dir="ltr"><<a href="mailto:robert@navsoft.plus.com" target="_blank">robert@navsoft.plus.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Hi Jasem,<br>
</p>
<p>I've had a look. Reminds me of when I worked for a
living; but very happy to help.<br>
</p>
<p>1. I guess I need, at least, permission to assign
myself the bugs that I am working on.</p>
<p>2. Is the source at <span style="color:rgb(68,68,68);font-family:monospace;font-size:13.3333px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:justify;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;display:inline!important;float:none">"git
clone git://<a href="http://anongit.kde.org/kstars" target="_blank">anongit.kde.org/kstars</a>"</span>?</p>
<p>3. How should I submit proposed mods? Published KDE
procedures?<span class="m_1828286541412418006HOEnZb"><font color="#888888"><br>
</font></span></p>
<span class="m_1828286541412418006HOEnZb"><font color="#888888">
<p>Robert<br>
</p>
</font></span>
</div></blockquote></div></div></blockquote></div></div></div></blockquote></div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><br></div></div></div>
</div></div>