Finally, after many months fiddling with various ideas and availability of parts here its is.
The design is based on and using some scrapped components and parts I managed to collect over the years in my drawers and boxes.
Basically, it is a variant of WPO design (
http://www.astroman.fsnet.co.uk/newspec.htm)
It uses a small flat 45° mirror (1x3mm) coming from what seems to be the moving coil of the sensitive microamp meter (the type that uses reflected light beam as pointer-indicator). I have couple of those devices, the mirrors appear to be of very high quality.
I am focusing the light of the single star to that mirror (the plan is to place it in the focus of my MTO-1000A telephoto lens, but currently I am experimenting with 50mm lens, as visible on photos), from where the light bounces 90° into 50mm lens (Industar 50 from my old Zenit camera). collimated spectrum beam is to be reflected back by blazed grating (Edmund Optics most likely, still not purchased, currently I am using a piece of DVD) back into the lens, passing closely near the small mirror (but not striking it).
The secondary focus is some 15 mm further than small mirror, where I intend to place the camera, Phillips PCVC690K or something else with BW CCD chip.
What you see on the photos is a terrestrial (erecting) eyepiece (10x microscope actually), currently used for viewing the spectra.
Now the real work may begin