Flat Pier Plate for 1150, 1100 and all 900 Mounts - for 8" ATS and other non-Astro-Physics Piers (119FP). (For ATS piers, see Note in Description below)

10/13/25 NOTE on ATS Piers: We have been advised ATS is not accepting orders at this time.  We do not recommend ordering this item for an ATS pier until or unless you already have the pier in your possession.

This Flat Pier Plate (119FP) has been machined to the specifications of the Advanced Telescope System (ATS) 8" pier with 1/8" wall thickness.  It is sized to fit directly into the pier to provide a mounting surface for our 8" Flat Surface Adapter (119FSA) (previously 900FSA). However, we cannot guarantee that it will fit ATS piers without modification. It will add 0.35" to the height of the pier.  

Owners of the Mach2GTO and Mach1GTO will be pleased to know that additional holes have been drilled and tapped for our 6" Flat Surface Adapter (ADATRI). This will allow these mounts and all 400 and 600 mounts to be used on an 8" pier, providing greater stability for imagers when using larger scopes in windy or adverse conditions.

The bottom, pier-inserting portion of this plate has additional thickness to allow custom machining so as to fit a smaller inside diameter pier.  Please refer to the PDF schematic for dimensions.

Diagram:
Click to enlarge.

Pier options:

• Use with the 8" ATS pier with 1/8" wall thickness. The base of the 119FP has already been machined per the specifications provided by ATS to fit into their piers that have 1/8" wall thickness. However, we cannot guarantee that it will fit without modification.
• Use with the 8" ATS pier with 1/4" wall thickness (modification required). 
• Use with other piers (may require custom modification)
  Machine the bottom portion of this plate to fit the I.D. of your pier, if necessary. Please refer to the diagram to determine if your pier is suitable.

Top attachment options:

• Attach 8" 119FSA (use existing tapped holes)
• Attach 6" ADATRI (use existing tapped holes)
• Attach custom  mount adapter (machine custom tapped holes)

If you intend to attach an 1150,  1100 or older 900 mount to the ATS pier, then it is best to choose the combination Flat Surface Adapter with Flat Pier Plate (119FSA-FP).  It is a two-part adapter that combines both the 119FSA and the 119FP. 

Mach2, Mach1, 600E and 400 Mounts upgrade
For convenience we offer an assembled two-part adapter (ADATRI-8ATS). This assembly is for attaching the Mach2, Mach1, 600E and 400 Mounts to the 8” ATS piers. This upgrade in pier size provides maximum rigidity when imaging and using large scopes.

Fasteners included:
5/16-18 x 5/8" (6) and washers - attaches 119FP to ATS pier.

Note:  Since the bottom of the flat plate is designed to fit into the 8" ATS Piers, the diameter (7.700") is too small to be used in the Astro-Physics 8" Portable Piers. However, we cannot guarantee that it will fit ATS piers without modification.