The Korean Astronomical Society (KAS) Education & Public Outreach Committee has provided education services for children and school teachers in Cambodia over the past three years from 2016 to 2018. In the first year, 2016, one KAS member visited Pusat to teach astronomy to about 50 children, and in the following two years of 2017 and 2018, three and six KAS members, respectively, executed education workshops for ∼ 20 (per each year) local school teachers in Sisophon. It turned out that it is desirable to include both teaching of astronomical knowledge and making experiments and observations in the education in order for the program to be more effective. Language barrier was the main obstacle in conveying concepts and knowledge, and having a good interpreter was very important. It happens that some languages, such as the Khmer of Cambodia, do not have astronomical terminologies, so that lecturers and even the education participants together are needed to communicate and create appropriate words. Handout hardcopies of the education materials (presentation files, lecture/experiment summaries, terminologies, etc.) are extremely helpful for the participants. Actual performing of assembling and using astronomical telescopes for night sky observations has been lifetime experience for some of the participants, which might promote zeal for knowledge and education. It is hoped that these education services for developing countries like Cambodia can be regularly continued in the future, and further extended to other countries such as Laos and Myanmar.

We have analysed near-infrared JHKL observations of the members of the ≈9 Myr-old η Chamaeleontis cluster. Using (J - H)/(K - L) and (H - K)/(K - L) IR colour-colour diagrams for the brightest 15 members of the cluster, we find the fraction of stellar systems with near-IR excess emission was 0.60 ± 0.13 (2σ). For the CTT and WTT star population, we also find a strong correlation between the IR excess and Ha emission which is also known as an accretion indicator. The (K - L) excess of these stars appears to indicate a wide range of star-disk activity; from a CTT star with high levels of accretion, to CTT - WTT transitional objects with evidence for some on-going accretion, and WTT stars with weak or absent IR excesses. Among the brightest 15 members, four stars (RECX 5, 9, 11 and ECHA J0843.3-7905) with IR excesses Δ(K - L) > 0.4 mag and strong or variable optical emission were identified as likely experiencing on-going mass accretion from their circumstellar disks which we confirmed their accretion disks from the optical high-resolution echelle spectroscopic study. The result-ing accretion fraction of 0.27 ± 0.13 (2σ) suggests that the accretion phase, in addition to the disks themselves, can endure for at least ~ 10 Myr.