Segner is a lunar impact crater located near the southwestern limb of the Moon, to the northeast of the giant walled plain Bailly. The crater Zucchius is a few kilometers to the south-southwest of the rim, and to the north east lies the unusual formation Schiller. The smaller crater Weigel is located to the east.
Segner has a low, worn rim, and is generally much less prominent than the nearby Zucchius. The floor is distinguished only by a pair of small craterlets and a slightly undulating surface. There is no indication of a central peak. A low ridge runs to the north from the edge of the northern rim.
Segner lies within the southwest portion of the Schiller-Zucchius Basin.
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Segner.
{| class="wikitable"
!width="25%" style="background:#eeeeee;" |Segner
!width="25%" style="background:#eeeeee;" |Latitude
!width="25%" style="background:#eeeeee;" |Longitude
!width="25%" style="background:#eeeeee;" |Diameter
|-
|align="center"|A
|align="center"|57.2° S
|align="center"|47.0° W
|align="center"|9 km
|-
|align="center"|B
|align="center"|57.8° S
|align="center"|56.0° W
|align="center"|35 km
|-
|align="center"|C
|align="center"|57.7° S
|align="center"|45.9° W
|align="center"|19 km
|-
|align="center"|E
|align="center"|57.6° S
|align="center"|56.9° W
|align="center"|13 km
|-
|align="center"|G
|align="center"|56.4° S
|align="center"|55.3° W
|align="center"|12 km
|-
|align="center"|H
|align="center"|58.4° S
|align="center"|48.0° W
|align="center"|7 km
|-
|align="center"|K
|align="center"|56.1° S
|align="center"|54.1° W
|align="center"|10 km
|-
|align="center"|L
|align="center"|58.7° S
|align="center"|47.0° W
|align="center"|5 km
|-
|align="center"|M
|align="center"|59.8° S
|align="center"|45.3° W
|align="center"|5 km
|-
|align="center"|N
|align="center"|59.2° S
|align="center"|44.2° W
|align="center"|5 km
|}