Monday, February 5, 2018

ZUFAR 4/350mm quartz fluorite catadioptric lens

Today about a Quartz Fluorite catadioptric ZUFAR-2CA f4/350mm anastigmat lens which took me over 10 years to locate. It had been developed for the Soviet MARS 2 to 5 missions to planet Mars.

It was made of synthetic Quartz and Calcium Fluorite (CaF2) crystals to be able to work in UV and also visible light, 300-700nm without focus shift, so actually is an apochromatic (APO) f4/350mm catadioptric lens. The whole useful wavelength range is 230-700nm. Lens transmission is 60-65% and the lens resolution is 57 lpm in its center, 47 lpm in corners. Viewing angle is approx. 6 degrees. There has also been made a ZUFAR-1 lens with f4 / 500mm and 4 degrees viewing angle.

ZUFAR lenses have been designed in the 70s under the lead of Institute head and chief designer Prof. Volosov together with N. Khmelnikova, I. Driatskaya, K. Mikhailova at GOI, the russian state lens design institute in St. Petersburg / Leningrad. Details were published by Prof Volosov in 1974.

(Made for my use by my dear friend Marco Cavina)

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

This lens was made to be used on a very elaborate camera system which could take multispectral images on film, develop that and scan it and send the scanned data back to Earth in selectable resolutions (up to 2000x2000 pix, which took over one hour to transmit).

NASA also wrote about this lens (quote):

Zufar objectives were used on the television cameras carried by the Mars-2, 3, 4, and 5 spacecraft. The compact catadioptric quartz-fluorite anastigmat was developed as a result of research on the possible optical arrangements of lens and mirror-lens systems meeting the rigid criteria for spaceborne operation. The system is characterized by precise correction of all aberrations over a broad spectral range, about 300-700 nm. The spectral transmission is about 60% over this range. The Zufar-2CA version of the objective has a geometric aperture ratio of 1:4 and a focal length of 350 mm. The image format is 24 x 24 mm. The housing is 164 mm long and 130 mm in diameter, and the mass of the objective is 1500 g.

Here one of the published images from Mars taken on Mars-5 mission:

The 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.

There is more about this lens HERE including some first images taken with it.

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