We present and discuss the pulsational characteristics of the Delta Scuti star 38 Eri from photometric data obtained at two widely spaced epochs , partly from the ground ( 1998 ) and partly from space ( MOST , 2011 ) .
We found 18 frequencies resolving the discrepancy among the previously published frequencies .
Some of the frequencies appeared with different relative amplitudes at two epochs , however , we carried out investigation for amplitude variability for only the MOST data .
Amplitude variability was found for one of three frequencies that satisfy the necessary frequency criteria for linear-combination or resonant-mode coupling .
Checking the criteria of beating and resonant-mode coupling we excluded them as possible reason for amplitude variability .
The two recently developed methods of rotational-splitting and sequence-search were applied to find regular spacings based only on frequencies .
Doublets or incomplete multiplets with l = 1 , 2 and 3 were found in the rotational splitting search .
In the sequence search method we identified four sequences .
The averaged spacing , probably a combination of the large separation and the rotational frequency , is 1.724 \pm 0.092 d ^ { -1 } .
Using the spacing and the scaling relation \bar { \rho } = [ 0.0394 , 0.0554 ] gcm ^ { -3 } was derived .
The shift of the sequences proved to be the integer multiple of the rotational splitting spacing .
Using the precise MOST frequencies and multi-colour photometry in a hybrid way , we identified four modes with l = 1 , two modes with l = 2 , two modes with l = 3 , and two modes as l = 0 radial modes .