This polyhedron was found in 2025 by a discord member calling themself kapzduke.

Because having axial heptagonal symmetry, the numeric values are much harder to derive algebraically. However the above given circumradius (and some further values too) get generally derived for [p,q,q]-acrohedra here by formula.

As abstract polyhedron 28T-15sH-7gH is isomorphic to 28T-15H-7sH, thereby replacing small heptagrams {7/2} by heptagons {7} and great heptagrams {7/3} by small heptagrams {7/2}.

Incidence matrix

7 * *  *  * * * |  2  2  0 0 0  0  0  0 0  0 |  2  2 0 0 0 0  [3,7/2,3/2,7/5]
* 7 *  *  * * * |  0  0  2 1 0  0  0  0 0  0 |  0  2 1 0 0 0  [3,7/2,7/2]
* * 7  *  * * * |  0  0  2 0 2  2  0  0 0  0 |  0  2 2 1 1 0  [3,7/5,3,7/2,7/3,7/2]
* * * 14  * * * |  1  0  0 0 0  0  1  1 0  0 |  1  1 0 0 1 0  [3,7/3,7/5]
* * *  * 14 * * |  0  1  0 0 0  0  1  0 1  1 |  1  1 0 0 1 1  [3,7/2,3,7/3]
* * *  *  * 7 * |  0  0  0 1 0  0  0  0 0  2 |  0  2 0 0 0 1  [3,7/2,7/2]
* * *  *  * * 7 |  0  0  0 0 0  2  0  2 0  0 |  0  2 0 0 2 0  [7/2,7/3,7/5,7/4]
----------------+----------------------------+--------------
1 0 0  1  0 0 0 | 14  *  * * *  *  *  * *  * |  1  1 0 0 0 0
1 0 0  0  1 0 0 |  * 14  * * *  *  *  * *  * |  1  1 0 0 0 0
0 1 1  0  0 0 0 |  *  * 14 * *  *  *  * *  * |  0  1 1 0 0 0
0 1 0  0  0 1 0 |  *  *  * 7 *  *  *  * *  * |  0  2 0 0 0 0  acting like a meridian
0 0 2  0  0 0 0 |  *  *  * * 7  *  *  * *  * |  0  0 1 1 0 0  acting like a parallel circle
0 0 1  0  0 0 1 |  *  *  * * * 14  *  * *  * |  0  1 0 0 1 0
0 0 0  1  1 0 0 |  *  *  * * *  * 14  * *  * |  1  0 0 0 1 0
0 0 0  1  0 0 1 |  *  *  * * *  *  * 14 *  * |  0  1 0 0 1 0
0 0 0  0  2 0 0 |  *  *  * * *  *  *  * 7  * |  0  0 0 0 1 1  acting like a parallel circle
0 0 0  0  1 1 0 |  *  *  * * *  *  *  * * 14 |  0  1 0 0 0 1
----------------+----------------------------+--------------
1 0 0  1  1 0 0 |  1  1  0 0 0  0  1  0 0  0 | 14  * * * * *  {3}
1 1 1  1  1 1 1 |  1  1  1 1 0  1  0  1 0  1 |  * 14 * * * *  {7/2}
0 1 2  0  0 0 0 |  0  0  2 0 1  0  0  0 0  0 |  *  * 7 * * *  {3}
0 0 7  0  0 0 0 |  0  0  0 0 7  0  0  0 0  0 |  *  * * 1 * *  {7/2} axis-orthogonal
0 0 1  2  2 0 2 |  0  0  0 0 0  2  2  2 1  0 |  *  * * * 7 *  {7/3}
0 0 0  0  2 1 0 |  0  0  0 0 0  0  0  0 1  2 |  *  * * * * 7  {3}