SED Data Model version 0.92

[Randall Thompson]

Hi,
   I just  discovered the IVOA SED Data Model document version 0.92
and wanted to ask some questions about it. Since we have been anxiously
awaiting an SSAP for distributing spectral data from MAST, we were happy
to see progress being made.
    First of all, I am confused why the document has changed from the 
Simple
Spectral Data Model to the SED Data Model when it will be used to 
"represent
SED, spectra and time series data".  Do you plan to write separate 
documents for
each data type?
    Also, I am confused about the FITS serialization in section 8.1. Are 
you requiring
variable-length arrays and not allowing array fields within the binary 
table itself?
I would think not all data sets require variable-length arrays and the 
FITS standard even
recommends a simpler format when this feature is not necessary.
    Finally, I think there are errors in the sample FITS header shown. 
It look like
there are actually 15 fields, not 14 (there are 2 sets of TTYPE2 & 
TFORM2 keywords), and
there is no THEAP keyword describing the offset to the data heap. Unless 
the convention has
changed, this should have the value of NAXIS1 * NAXIS2 if there is no 
gap between the binary
table and the data heap.
    Sorry if these issues were already addressed.

Randy Thompson