[fitsbits] FITS vs. TIFF (or other image formats)

[Rick Armstrong]

Hello,

I'm writing an C++ application that gathers images acquired from a
microsocope with a motorized x-y stage. The app stitches the acquired images
into extended-field-of-view mosaics. To create mosaics of objects of
significant size, I need to create enormous image files (at 40X
magnification, with a 1300x1030 image size, a 1.5 x 1.5mm area gets a file
that's on the order of tens of GB). In the process of thinking about how to
read/write/browse files of this size, I realized that astronomers and
geo-mapper type people must run into this all the time!

While surfing about, I stumbled on FITS and I have two question for the
group:

1) Why do astronomers use FITS, instead of just writing huge TIFFs or files
of some other format?

2) Can I use CFITSIO to write a "compressed stream", i.e., can I write and
compress in the same operation using CFITSIO? Is it necessary to create a
complete, uncompressed file, _then_ compress it? Is this a naive question?
;)

Sorry if this is just RTFM stuff, I just want some opinions/perspective
before I delve too much.

TIA,

Rick Armstrong