He was an expert on gamma ray astronomy, the physics of neutron stars, and solar energy and worked on several key topics in modern astrophysics.

His main interests in the field of astrophysics were the study of gamma ray astronomy and compact objects such as neutron stars and pulsars.

[4] He then worked at Goddard Space Flight Center from September 1967 to January 1970 as National Academy of Sciences Research Associate.

Additionally, he worked with the METU's Carbon-14 Dating Group, led by Yeter Güksü, a physics department colleague who would later become his second wife.

[3] During Ögelman's time at METU, his astrophysics group's major projects used data of NASA's SAS-II (Second Small Astronomy Satellite) gamma ray telescope.

With this group and his former NASA colleagues, Ögelman co-authored several critical papers on gamma ray astronomy published using the SAS II data.

Under Ögelman's leadership, his group carried out actual data analysis at METU with graduate and undergraduate students, and contributed significantly to the SAS II project's success.

In 1974 he took a sabbatical leave of absence to serve as a National Academy of Sciences Senior Research Associate at the Goddard Space Flight Center in Greenbelt, Maryland, working with his colleagues at NASA's Gamma Ray Astronomy Group led by Dr. Carl E. Fichtel.

In 1977, at the invitation of the president of Çukurova University (CÜ) in Adana, Turkey, Ögelman took another leave of absence and with three of his METU colleagues (and, later, some of his graduate and post graduate students from METU, who formed the core of the new Physics Department) moved to Çukurova to start and establish its Faculty of Arts and Sciences.

Eventually, Ögelman arranged for funding from the Ford Foundation and the USAID to start a modern research laboratory in the campus.

Ögelman gave priority to solar energy research in the Physics Department because in the Çukurova region there is plenty of sunshine throughout the year.

After the launch of the hugely successful ROSAT (Röntgensatellit - German X-Ray Satellite) Observatory (June 1, 1990 – February 12, 1999) led by Principal Investigator (PI) Joachim Trümper at MPE and developed through a cooperative program between Germany, the United States, and the United Kingdom, Ögelman became one of the main investigators with this satellite.

[10] At Max Planck, Ögelman had met the University of Wisconsin astrophysicist Prof. William F. "Jack" Fry, who would become a good friend and mentor.

During Ögelman's tenure at Wisconsin, he continued to pursue his interest in compact objects, and published roughly sixty papers on the subject between 1991 and 1998.

Ümit Kızıloğlu Mehmet Emin Özel, Akif Esendemir, Solen Balman and with İlhami Yeğingil at Çukurova—all of whom had become professors by this time—and also with Prof. Altan Baykal.

Ögelman in his later years also turned his robust intellect and attention to exploring sustainable solutions to the changing climate and the world's evolving energy needs.