We present HST/STIS long-slit spectroscopy of NGC 1976 .
Our goal is to measure the intrinsic line ratio [ O iii ] 4364/5008 and thereby evaluate the electron temperature ( T _ { e } ) and the fractional mean-square T _ { e } variation ( t _ { A } ^ { 2 } ) across the nebula .
We also measure the intrinsic line ratio [ N ii ] 5756/6585 in order to estimate T _ { e } and t _ { A } ^ { 2 } in the N ^ { + } region .
The interpretation of the [ N ii ] data is not as clear cut as the [ O iii ] data because of a higher sensitivity to knowledge of the electron density as well as a possible contribution to the [ N ii ] 5756 emission by recombination ( and cascading ) .
We present results from binning the data along the various slits into tiles that are 0.5 ^ { \prime \prime } square ( matching the slit width ) .
The average [ O iii ] temperature for our four HST/STIS slits varies from 7678 K to 8358 K ; t _ { A } ^ { 2 } varies from 0.00682 to at most 0.0176 .
For our preferred solution , the average [ N ii ] temperature for each of the four slits varies from 9133 K to 10232 K ; t _ { A } ^ { 2 } varies from 0.00584 to 0.0175 .
The measurements of T _ { e } reported here are an average along each line of sight .
Therefore , despite finding remarkably low t _ { A } ^ { 2 } , we can not rule out significantly larger temperature fluctuations along the line of sight .
The result that the average [ N ii ] T _ { e } exceeds the average [ O iii ] T _ { e } confirms what has been previously found for Orion and what is expected on theoretical grounds .
Observations of the proplyd P159-350 indicate : large local extinction associated ; ionization stratification consistent with external ionization by \theta ^ { 1 } Ori C ; and indirectly , evidence of high electron density .