[OSRS-PROJ] Unknown USSR projection

[David Orme]

Hi,

  I wondered if anybody can help me identify a projection. I need to 
digitize some range maps from a book on the birds of the USSR: all the 
maps share the same basemap but the book itself contains no projection 
details. The image is on the web: 
http://www.bio.ic.ac.uk/research/iowens/orme/FlintMap.png.

The only latitude or longitude mark on the map is the arctic circle: as 
far as I can make out this is an arc from a circle, although there is a 
hint that at the edges of the map the arc may turn down away from the 
circle. I've tried identifying 10 degree lines of latitude and 
longitude from locations around the map edge and that suggests to me 
that the map is projected on something like a equidistant conic or 
albers projection. What I've got so far:

* the central meridian is around 105 E.
* the longitude lines look like they converge on the centre of the 
circle, although if I try and draw them in from geography, they don't 
converge very well.
* a degree of longitude is about 0.4 degrees of arc on the projected 
map.
* the latitude lines don't seem to be equally spaced - in particular, 
the 80-70 N gap is wider than the other three latitudinal spacings.

I can't get it to fit - has anyone got any suggestions for projections 
or projection parameters? It doesn't help that I suspect the map is 
rather inaccurately drawn.

Thanks,
David

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