Salam aleykoum,
This passage expresses the fact that Muhammad was convinced of his heavenly mission by the vision of the archangel of revelation. According to this passage, this visit by the Archangel Gabriel was made twice. On the first visit, no one doubts that the visit of the Archangel Gabriel took place here on earth, when he was positioned on the horizon. However, for the second visit, the vast majority of commentators place it in a celestial place, as shown by Muhammad Asad's translation :
53:13 And, indeed, he saw him a second time
53:14 by the lote-tree of the farthest limit,
53:15 near unto the garden of promise.
53:16 with the lote-tree veiled in a veil of nameless splendour
53:17 [And withal,] the eye did not waver, nor yet did it stray
53:18 truly did he see some of the most profound of his Sustainer's symbols.
It seems to me more appropriate here to think that this is simply the second manifestation of the Archangel Gabriel to Muhammad at the 'the place-name called al-Muntahā' on the outskirts of Mecca, in a place known and indicated by the jujube tree in question.
The key expression is: raāhu nazlatan ukh'rā / he saw it on another descent. The term raāhu/he saw him evokes physical sight and not dreaming (this form leads to the perception of sight and visualizing by eyes or discerning intellectually.). The term ukh'rā/another clearly refers to the fact that, as on the first occasion, the Archangel Gabriel manifested himself during a descent of it and not during a hypothetical physical ascent of Muhammad.
Thus, my proposal of translation:
53:13 And indeed, he saw him in another descent,
53:14 by the jujube tree of l-muntahā,
53:15 near unto the garden of l-mawā/the refuge.
53:16 whilst the Lote Tree was covered with that which covered it (i.e. the Archangel Gabriel)
53:17 [And withal,] the eye did not waver, nor yet did it stray.
53:18 Truly He has seen from the great signs of his Lord.
