New observations of the unidentified 30 μm spectral feature found in two planetary nebulae and four carbon stars are reported. The carbon star IRC + 10216 was observed from the Kuiper Airborne Observatory over the range 30 to 37 μm. These new data confirm the existence of the feature and determine its shape beyond 30 μm. The determination of the long wavelength end of the spectral excess depends critically on the assumed underlying continuum. A combined spectrum of the excess is presented and shows the feature to extend at least to 37 μm.