Unfortunately there is no comprehensive glossary on Astronomy in Te Reo Māori (at least to our knowledge).
Below are suggestions for a few websites that give translations of astronomical terms and concepts, as well as general information
on Māori Astronomy (Taatai Arorangi).

Pixieplots, a website on Māori star and constellation names.

Society of Maori Astronomy Research and Traditions, a website centered around Māori astronomical knowledge and traditions.

Living by the Stars with Dr. Rangi Matamua, Facebook Group.

Also check out our Ebook on Matariki and the New Year celebrations of the New Zealand Māori in the EBook section.

There are many glossaries on Astronomy and Space science on the internet.
Here is a list of our favourite ones:

Hubblesite glossary. This glossary defines terms and abbreviations used within HubbleSite, Amazing Space, and other Web sites produced by the Office of Public Outreach at the Space Telescope Science Institute.
(Alphabetic index; no search).

The Lexicon and Glossary of Terms in LEVEL 5 (NASA/IPAC extra galactic Astronomy and Cosmology) is a compilation and modern updating of astronomical terms designed to cover all of astronomy, including particle physics and some statistics.
(Alphabetic index; no search). glossary. Also links here to other glossaries, astronomy topics, etc.
(Alphabetic index; no search).

NASA’s Imagine the Universe dictionary.
(Alphabetic index; no search; Inline hyperlinks).

David Darling’s Encyclopedia of Science. Science, not only astronomy, extensive and detailed.
(Alphabetic index; search, category index).