If you could only have one Slide Rule, which one would it be?
First, it sure is nice that we don't actually have to choose just one slide rule and stick with that, but if you had to choose just one, which one would it be?
I think a lot of folks would choose "the big slide rule", like a Pickett Model 4, a Faber-Castell Novo Duplex 2/83N, a Nestler Multimath, a K&E Deci-Lon, or any manufacturer's "flagship" slide rule. Because anything you're likely to need to do with a slide rule, you can do with one of these big rules.
However, what if your use case is that you're not an engineer? I like my N4-ES, but I just never have the need for hyperbolic trig scales.
What, besides the number of scales, makes a slide rule the one rule that you would select?
I am partial to pocket rules, but I also like a rule that is easy to read. These two interests can be mutually-exclusive.
I am not an engineer, so I usually use a slide rule for quick multiplication & division, or I'll use trig scales to figure the lengths of legs of a triangle when I'm building something. So I don't actually need Log-Log scales.
I like a rule that is durable enough that I'm not afraid to carry it around and actually use it.
Of the pocket rules I have, my Aristo 867U Darmstadt checks the "legibility" box the best, and has a nice set of scales, even including a couple of Log-Log scales should the need arise. I'm not sure about its durability as a rule to carry around every day. Its case isn't very robust, compared to Pickett "Saddle Leather" cases.
The next candidate is my Pickett 700. It is smaller, and has enough scales to be useful, even including folded scales! It falls short on legibility, cramming all of these scales on one side of a little Pickett pocket rule. On the other hand, it's kind of an unusual rule, being an "Aerial Photo Slide Rule", so it has the extra quality of "I just like it". And its durable leather case has a window with conversion factors displayed.
The rule I actually carry and use most often is my Pickett N200-T. Having fewer scales, it's easier to read than the 700. I also think its later-model cursor should be more durable than the 700's four-screw flat cursor. It has trig scales, CI and L scales, but no folded scales. Also, this rule has a leather case with a top flap, so the rule is very well protected.
If I could only have one, though, I think it would be the 700. It's hard to fight the "I just like it" quality.
Probably a Pickett N600-ES. I feel like it's the most bang for buck size-wise. I really like the Concise / Sama & Etani slide rules with the reference tables too. I have several of those stashed around in case I need to reference a formula or periodic table
I didn't really think about the Concise circular rules. I have a CTCS-552. The reference tables are a handy feature!
The Pickett 600 is a solid choice! I have an older magnesium 600. It's a great rule, but that's a lot of scales to cram onto such a small rule. I find it a little hard to read. Not really any worse than the 700, though.
Part of the appeal is the space factor too. That photo of Aldrin with his pipe and slide rule on Gemeni is one of my favorite pictures even though it's sadly underexposed
I think that one is a 1006 rather than a 600. I have attached a comparison picture, with an N600, an N1006, and Aldrin's slide rule with its contrast turned up a bit.
It looks like we are looking at the side without the logo, and it looks like the near end of the slide has "Pickett All Metal Slide Rules", which the 600 does not have. And the slide looks like it has CF, CIF, CI, and C scales, and the bottom rail has D and L.
I'm not saying Aldrin didn't take a 600 to the moon. I just don't think that's a 600 in the Gemini XII picture. What do you think?
Image Credits: NASA and International Slide Rule Museum. I used the ISRM pictures because they are clearer than my pictures of my own 600 and 1006.