Saturday, November 6, 2021

Russian Catadioptric ZIKAR-1A f1.2/100mm anastigmat lens for space use

Today about a lens I have forgotten to write about it here: the Russian catadioptric ZIKAR-1A f1.2/100mm anastigmat lens I found in 2018, which had been developed for the Russian space defence program, to detect fired rockets aiming at the (then) USSR from about 45.000 km away, mounted at some special (unknown) camera system from a satellite in orbit around earth. It is a catadioptric system with two Beryllium mirrors, very fast f1.2/100mm and some fluorite auxiliary lenses. Several such systems were successfully launched into space and were in operation several years long.

(source: net)

I found a russian document about it HERE (Google translated) :
On September 19, 1972, the first space-520 experimental SPACECRAFT was launched from the Plesetsk cosmodrome. On Board in addition to the control equipment and reset information were installed two types of BAO: television (MBT-A) and heat direction finding (105-A). The TV-type equipment was a two-chamber receiver with IR-vidicons Radian with a lens”Zikar-1A". One camera had a relatively wide angle of view (SPK) and the other narrow band (UPK). The field of vision of the CPC was inside the field of vision of the SPC. The TP-type equipment had one line of fifty sensitive elements scanning the field with the help of a swinging mirror. The total field of view was no more than 10 square degrees. (end)

From that and more data I found that it was designed for SWIR, 1.5 - 2.5 microns, I assumed that this lens would only useful for IR and possible visible light, but having it on my spectrometric UV-VIS-IR system surprisingly revealed that it could be used in UV down to 320nm!

(own spectrometric measurement)

Further research showed that his lens was a part of TB (телевизионная аппаратура) unit, possibly used as an auxiliary lens to help aiming a much larger main lens unit. That main TП (теплопеленгатор) unit was a massive lens with a main mirror having a diameter of one meter (100 centimeters or 1.000 millimeters) [early versions УС-К had a diameter of 50cm; later versions УС-КМО had 100cm (1.000 millimeters)].

That impressive main unit УС-К/УС-КМО looked like this:

(source: net)

1 - a mirror made of vitrified beryllium with a diameter of 60 cm, the surface shape being a convex hyperbola of the second order.
2 - a mirror made of vitrified beryllium with a diameter of 100 cm, a surface shape being an aspheric of the 12th order.
3 - correcting lenses made of fluorides of calcium and lithium.

That ZIKAR-1A lens will be given a suitable adaption to fit my digital multispectral cameras and I will certainly take multispectral photos with it as soon as possible and report about here later on. That will not be easy, as it has a very short back focal length.

Data of this lens, as well as its normal (= non catadioptric) quartz fluorite sister lenses with shorter focal length may be found on my macrolenses database site HERE

Stay tuned, more will follow on that fascinating subject...