At the beginning of the 21 Century the new scientific branch appeared at the RI NAO - the Historical-astronomic researches. The work is carried out since 2003, within the framework of the research topic “History”. It is directed to the study of NAO contribution to astrometric researches, the description of some scientists in various fields of astronomy, the study of the history of expeditions. G.M. Petrov PhD was a Research Head till 2006. Now it is headed by Professor Gennadiy Pinigin.

Nikolaev Observatory has a rich history of development. A good tool for research is the Observatory Archive, which stores the documents from its foundation to the present time. The important tasks are to study the archival material and to write the biographical collections on outstanding personalities in the history of the observatory, to write articles describing the various stages in the development of our observatory. For present time the Marine period had been studied in detail (1821-early 20 th century). Collections of bibliography for the first two directors Karl Knorre and Ivan Kortatstsi was published. In addition, due to creative collaboration with descendants of K. Knorre the French translation of the book about K. Knorre and new book about the Dynasty of Knorre astronomers (Russian and English) appeared. Nowadays co-workers have begun a detailed study of the period relating to the Nikolaev part of Pulkovo Observatory.

Another direction of work was started in 2005 – the participation in the UNESCO project "Astronomy and World Heritage" to promote the Nikolaev Observatory as object of a World Heritage. Due to collaboration with the National Commission for UNESCO in Ukraine and the State Committee for Cultural Heritage in 2007 the Nikolaev Observatory was included to the tentative list of UNESCO. In addition, under the leadership of RI NAO the expert astronomical group was created in Ukraine.

Another area of activity of historical-astronomical research group is work with museum, archive and library. In course of time, the fund of old and rare books had been formed; also the Observatory saved old instruments and equipment. All this requires systematization and descriptions, design of the museum exhibits, repair and restoration of the pavilions.

In addition, in the framework of IYA in 2009, memorial signs were created: the symbolic center of Nikolaev Observatory and the memorial plaque in honor of K. Knorre.