Comment 1 for bug 335327

This also happens when you press "c" to show the constellation lines. The backtraces now make me suspect a bug in StelGeom, but I can't know for sure since I don't understand the code. Also, running the tests/sky_image.ssc script crashes instantly now, instead of just after loading the first image. Strange.

Here's the backtrace of pressing "c":
#0 0x00007ff702bc9015 in raise () from /lib/libc.so.6
#1 0x00007ff702bcab83 in abort () from /lib/libc.so.6
#2 0x00007ff70462fb74 in qt_message_output (msgType=QtFatalMsg,
    buf=0x2efc2a8 "ASSERT: \"fabs(n2.lengthSquared()-1.)<0.000001\" in file /home/michael/stellarium-tmp/src/core/StelSphereGeometry.cpp, line 145")
    at global/qglobal.cpp:2001
#3 0x00007ff70462fca1 in qFatal (
    msg=0x7ff7047be140 "ASSERT: \"%s\" in file %s, line %d")
    at global/qglobal.cpp:2196
#4 0x00007ff704630185 in qt_assert (
    assertion=0x6f2938 "fabs(n2.lengthSquared()-1.)<0.000001",
    file=0x6f28d0 "/home/michael/stellarium-tmp/src/core/StelSphereGeometry.cpp", line=145) at global/qglobal.cpp:1772
#5 0x0000000000584859 in StelGeom::planeIntersect2 (h1=@0x7fff0ec44cc0,
    h2=@0x7fff0ec44ca0, p1=@0x7fff0ec44d60, p2=@0x7fff0ec44d60)
    at /home/michael/stellarium-tmp/src/core/StelSphereGeometry.cpp:145
#6 0x00000000005e25e6 in Constellation::drawOptim (this=0x29fd6d0,
    sPainter=@0x7fff0ec44e80, nav=0x22ecc00)
    at /home/michael/stellarium-tmp/src/modules/Constellation.cpp:115
#7 0x00000000005e79a7 in ConstellationMgr::drawLines (this=0x26da080,
    sPainter=@0x7fff0ec44e80, nav=0x22ecc00)
    at /home/michael/stellarium-tmp/src/modules/ConstellationMgr.cpp:488
#8 0x00000000005e7ae1 in ConstellationMgr::draw