I think it's arguably a slide rule; I would pick a modern astrolabe I made a few years back based on this model http://www.pyxplot.org.uk/astrolabe/astrolabe.pdf
https://imgur.com/a/b7OB3 https://imgur.com/a/gHMJP
It doesn't do multiplications like other slide rules but you can use it to calculate what time it is and where you are amongst other things, which I think compensates.
I think it's arguably a slide rule; I would pick a modern astrolabe I made a few years back based on this model http://www.pyxplot.org.uk/astrolabe/astrolabe.pdf
https://imgur.com/a/b7OB3
https://imgur.com/a/gHMJP
It doesn't do multiplications like other slide rules but you can use it to calculate what time it is and where you are amongst other things, which I think compensates.