I went to this site:
http://www.breslov.com/ref/Isaiah40.htm
which has the bible in Hebrew and English. The English translation of Isaiah 40:22 is this:
It is He that sitteth above the circle of the earth, and the inhabitants thereof are as grasshoppers; that stretcheth out the heavens as a curtain, and spreadeth them out as a tent to dwell in;The site has a Hebrew-Engish dictionary. "Circle" in English gives this in Hebrew: gwx. Transliterated (whatever that means) it's Chuwg, which is what you gave. The definition (for both, presumably) is given as: 1. circle, circuit, compass; 2. (BDB) vault (of the heavens)
The same word is in Proverbs 8:27. When he prepared the heavens, I was there: when he set a compass upon the face of the depth.
And in Job 22:14. Thick clouds are a covering to him, that he seeth not; and he walketh in the circuit of heaven.
I am no bible scholar (obviously) but I see no hint of "sphericity" in any of these uses of the term.
For the most part it means letter for letter translation. If you don't know what a word means you can translate each letter then look up the transliterated word in a Hebrew dictionary.
I'll take a look at this thread later.
I brought up the star of Bethlehem because I thought it might interest you in strict scientific terms. I say this because even if someone thinks the three wise men are a myth, something occurred in the heavens coinciding with the birth of Christ and His death.
Anyway, I hope you due a search on this as well.