[General] Phonemic symbol ɜʊ

[englishhobby]

Have you ever come across this phonemic symbol?
[ɜʊ]
I was taught at university (long ago) that it's the same as [əʊ] (for example in note), used when writing by hand. But I am beginning to doubt. Can you clear it up for me a bit?

 

[probus]

The upside-down omega [ʊ] is the vowel in "foot" and I believe the [3] is a hard g.

 

[Raymott]

ɜ is another version of ə

Phonetic Symbol Guide, Pullum and Ladusaw, 1996