planetary nebula luminosity function
...that the planetary nebula luminosity function is an accurate standard candle (luminosity measurement) outside Earth's home galaxy, the Milky Way, despite an average error factor of two for distance estimates to planetary nebulae within this galaxy?
...that the <b id="mwB0s"><a href="./Planetary_nebula_luminosity_function" id="mwB0w" rel="mw:WikiLink" title="Planetary nebula luminosity function">planetary nebula luminosity function</a></b> is an accurate <a class="mw-redirect" href="./Standard_candle" id="mwB00" rel="mw:WikiLink" title="Standard candle">standard candle</a> (<a href="./Luminosity" id="mwB04" rel="mw:WikiLink" title="Luminosity">luminosity</a> <a href="./Measurement" id="mwB08" rel="mw:WikiLink" title="Measurement">measurement</a>) outside <a href="./Earth" id="mwB1A" rel="mw:WikiLink" title="Earth">Earth</a>'s home <a href="./Galaxy" id="mwB1E" rel="mw:WikiLink" title="Galaxy">galaxy</a>, the <a href="./Milky_Way" id="mwB1I" rel="mw:WikiLink" title="Milky Way">Milky Way</a>, despite an average <a href="./Error" id="mwB1M" rel="mw:WikiLink" title="Error">error</a> factor of two for <a href="./Distance" id="mwB1Q" rel="mw:WikiLink" title="Distance">distance</a> estimates to <a class="mw-redirect" href="./Planetary_nebulae" id="mwB1U" rel="mw:WikiLink" title="Planetary nebulae">planetary nebulae</a> <i id="mwB1Y">within</i> this <a href="./Galaxy" id="mwB1c" rel="mw:WikiLink" title="Galaxy">galaxy</a>?