NavList:

I’m afraid this is driving me mad and taking up far too much time.  Therefore, I’d be obliged if someone will post their full working, always assuming the starry bit matches the position of the Observatory and it’s not a trick shot.   This is what I’ve got so far.  Shaula is above Antares in the photograph, but dec Shaula is south of dec Antares, so the sky’s upside down, i.e. we’re in the Southern Hemisphere.
Scaling the photograph
Galactic Coordinates Lat       Long
Shaula                                  -2.21   351.74
Antares                                15.06   351.95
Difference                            17.27   000.19
Therefore, Shaula and Antares are on the same Galactic Meridian.   They’re also within 5 degrees of being one above the other in the photograph, so the Galactic equator must be within 5 degrees of being horizontal, so perhaps we can work with a 2D diagram as with a meridian passage calculation.
On my print of the photograph the distance between Shaula and Antares is 45mm, so the photo scale is 45/17.27 mm/degree. 
The distance from Shaula to the horizon is 81mm, so Shaula is 81x17.27/45=31.1 degrees above my horizon, and ZD=58.1.  Dec Shauna is 37.1S.  Codec Shaula=52.9
From now on it should be easy, but I’m having great difficulty standing on my head and thinking at the same time.  If anyone will finish this off for me, or tell me they wouldn’t have started from here, I’d be most grateful.  It’ll save me from falling behind with my 4miles/day 1460miles/year challenge.  DaveP