NAOJ OPEN DAY 2024
Captain’s log: Stardate 60602.5.
Today marks the annual event: the opening day (三鷹星・宇宙の日) of the National Astronomical Observatory of Japan (NAOJ). This occasion holds special significance as it is the first fully public open day since the COVID-19 pandemic, where, in previous years, attendance was limited to selected individuals.
Our group’s exhibition remains largely unchanged from last year. However, this year we welcome a unique addition—the Marimo (moss ball). These fascinating green algae, which form into spherical shapes and thrive in cold waters, have caught the attention of both scientists and visitors alike. Their ability to survive in extreme environments offers valuable insights into astrobiology and how life might exist beyond Earth.

As I ventured into the other exhibitions, one particularly interesting display was the model of the future JASMINE telescope. This model serves a critical role in the testing phase for the telescope’s mirrors. It is used to measure the deformation of the mirrors when exposed to temperature changes, ensuring that any potential warping is within acceptable limits. Additionally, the model undergoes oscillation tests to confirm that the mirrors remain stable and undistorted under various vibrations and mechanical stresses. It’s a reminder that even the smallest imperfections in space instruments can lead to significant errors in astronomical data—a fascinating blend of engineering and astronomy.
Another exhibition that caught my attention was a hand-made radio telescope, ingeniously assembled using parts readily available on Amazon, for a cost of around 20,000 yen. Impressively, this DIY telescope is capable of detecting the 21 cm hydrogen emission line, a critical wavelength in radio astronomy that allows us to map the distribution of neutral hydrogen in the galaxy. This exhibition brilliantly showcased the accessibility of science, demonstrating how even with minimal resources, one can engage in meaningful astronomical observation. The ingenuity behind this creation reflects the enduring spirit of curiosity and innovation that defines our field.
As we look toward the future, I can only hope that next year’s exhibitions will bring even greater marvels for the public to enjoy.
Captain out.
Captains log, Supplemental:
During the wrap-up party, a sense of nostalgia settled over us as we discussed the absence of the beloved card game, Andromeda Fantasy. This game, once a staple of camaraderie and fun before the pandemic, seems to have faded away with time. Perhaps, with a little effort, we can breathe new life into it for the next generation.

