Here is Percival Lowell’s observatory in Flagstaff, Arizona – not very good observing weather, but it was about the only rain we saw in Arizona in 2016. It was here that Clyde Tombaugh discovered Pluto in 1930, using the telescope below to take his photographs. I didn’t manage to get a snap of the blink comparator itself.
This turned into quite an American crossword. The idea originated in Flagstaff and I ended up writing the last few clues on a visit to Kansas City two years later.
The blink comparator is a bit of a gift for a right and left puzzle since it exploits the side-by-side nature of two similar images. Ideally (it seemed to me) you would have a pair of identical grids except that the movement of Pluto and the removal/addition of its letters would produce new words. I tinkered mildly with that, but I immediately started to worry about how the across entries might fare – very hard to have new words on a row using exactly the same letters. Presumably you would have to have CART + RIP transforming itself into CAR + TRIP or something similar; but then if you weren’t to have a plethora of short answers the grid would rapidly become rather large.
So I confined myself to simply moving PLUTO against a background of ‘letters’ rather than ‘sky’. Even that took a little bit of manipulation. Here’s the draft diagram I could find – I am pretty certain there were others. You can see there were certain constraints from the outset – AB____F was clearly never going to fly, so Flagstaff went on the right hand side, and determined that there would be two ten-letter down entries in each half. Other things also fixed themselves – BLINK COMPARATOR went straight into place, given I had decided Pluto was going to obey rotational symmetry! You can also see I was enumerating Tombaugh’s name to see how many entries I might need (“The X letters spell an appropriate forename” “…an appropriate surname” “…an appropriate name”).
Right-and-left puzzles are quite fun, but the clues can be a slog. The idea of something moving between otherwise fixed images encouraged me to keep the clues unlinked but to have a word move between them. And once Tombaugh’s middle name was in the mix, there were the right number of pairs to fit everything together (with a bit of grid tweaking).
The title first emerged as Snap Snap (playing Snap with two snaps) but I eventually – ah – telescoped it.