Lest this be Heaven indeed — Astronomy Observatory

Lest this be Heaven indeed 1
An Obstacle is given
That always gauges a Degree
Between Ourself and Heaven.
(F.1000/J.1043)
[1] Heaven:: a wonderful place; indicating an astronomy observatory here.
[3] gauges:: measures and ascertains (degrees of an astronomical telescope).
[4] Heaven:: the outer space.