Left panel: integrated yearly observing time T in hours of a given star from a hypothetical astronomical observatory at latitude φ = 28.5°, as a functionof its equatorial coordinates α (color scale) and δ (horizontal axis). The two curves refer to two different sets of thresholds imposed on the maximum airmass X and the maximum solar elevation h_⊙, as in legend. The declination range spanned by the |β| > 38° “outer envelope” and |β| > 63° “allowed region” (see Fig. 2) for the LOPN field is highlighted with gray boxes. Choosing an observatory with the same |φ| but in the southern hemisphere would yield the same results but with the δ sign reversed. Right panel: same as above, but now the integrated time T_w is weighted by 1∕X, as a more effective follow-up metric.