Dario Anderle wrote:

"...Do you think that in future we can add the constellation
figure (as *.bmp file of Bayer atlas) over the stars?"

Sounds like a good idea to me, and I've actually given it a try.
I rigged up Guide so that one could select a .BMP file to be
"stretched" to fit the CCD frame. You could then adjust the frame in
position, tilt, and size until it lined up properly with the
background stars. That would let you add images of all sorts: star
atlas pages from Bayer and others, AAVSO charts (most are available
on-line), and color images such as JPEGs from Hubble and other
sources. Most of Bayer's _Uranometria_ is available as scanned
images.

However, actually getting the images to line up turned out to be
far more awkward than I'd envisioned. As a matter of fact, it was
next to impossible. I'll probably switch to a scheme wherein one
can select at least two stars in the image, plus two stars on-screen.
(This will basically resemble the way astrometry software worked
before automated pattern-matching became common.)

With extremely wide-field images such as Bayer atlas pages,
another problem arises: the images get a bit distorted. Guide shows
images (RealSky/DSS, its "built-in" DSO images, images added
through Charon, etc.) by finding the RA/dec of the four corners of
the image, then projecting those onto the screen. Then the image
is stretched and rotated to fit between those four points. That works
just fine for fields up to a few degrees, but at _really_ wide fields,
it breaks down a bit and the stars as plotted by Guide no longer
match up with those plotted by Bayer.

-- Bill