As time goes on, this page will outline a variety of options and spare parts for the 1100GTO German Equatorial Mount.

The 1100GTO has a new extension adapter to allow its Control Box (single or double adapter) to be used when upscaling to a 10” ATS pier. If you have a custom pier that requires even more spacing, then the new extension can be stacked with as many extensions as needed to do the job. 

The adapter adds 1" (25.4 mm) of spacing.

Includes two 8-32 x ½” BHCS.

Note: The Q6281KIT in the photo at left is shown as silver for easy identification in its mounted position. It is anodized black as a finished product (see above left).

1100GTO
The base of the 1100GTO slips directly into the 119FSA. There is no need for an extra pier adapter, as the 1100 incorporates the functionality of the Precision-Rotating Pier Adapter into its base. The extended latitude range of the 1100 also eliminates the need of a polar wedge.

900 (all versions)
Use this adapter for these applications:

• Interface between the Precision-Adjust Rotating Pier Adapter (900RPA) and the flat plate on your custom-made pier or tripod.
• Attach to the top of your 900 Hi-Lo Latitude Wedge (900WDG) if you wish to use the 900RPA.
• Although the Standard Pier Adapter (900SPA) can bolt directly onto the flat plate of your pier or tripod, you can use this adapter to give a more finished appearance.

The Flat Surface Adapter is black-anodized, precision-machined aluminum.

Attach to flat surface
The Flat Surface Adapter bolts onto the flat surface on the top of your pier or tripod. Your pier's top plate should be a minimum of 7.75" in diameter. The 119FSA itself is 8.375" in diameter. It adds 1.265" to the height of your mount.

The bolt circle for attaching the 900 Flat Surface Adapter to your pier is 7.230" in diameter. Please refer to the PDF link provided on the diagram to the right for detailed information on attachment preparation.

The holes for mounting the 119FSA to your flat surface are counter-bored to accept the head of standard ¼" socket head cap screws (13/32" or 0.406" diameter). This allows the 1100 base or 900 Pier Adapter to sit in the Flat Surface Adapter without interference. Because installations will vary, we do not provide the screws for mounting the Flat Surface Adapter to your pier or tripod.

Attach to 900 Hi-Lo Latitude Wedge
Match four holes and bolt the 119FSA in place. Then, your Pier Adapter simply slips in (just as it fits into our pier) and you fasten from the side with the six screws and washers provided with the Pier Adapter for your 900 mount.

Fasteners are not supplied.

Pier options:

• Use with the 8" ATS pier with 1/8" wall thickness (no modification required)
  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 without further modification.

• Use with the 8" ATS pier with 1/4" wall thickness (modification required)
  If you choose to order the 8" ATS Pier with the 1/4" wall thickness, ATS will modify the base diameter for a small up-charge.

• 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 1100GTO 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. 

Fasteners included:
1/4-20 x 3/4" (8) - attaches 119FSA to Flat Pier Plate (119FP)
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.

Use with 8" ATS Piers and 1100GTO

• The base of the 119FSA-FP has already been machined per the specifications provided by ATS to fit into their piers that have 1/8" wall thickness (I.D. 7.700") without further modification. The 1100GTO will fit directly into the top portion of the 119FSA-FP. If you choose to order the 8" ATS Pier with the 1/4" wall thickness, ATS will modify the base diameter for a small up-charge. This adapter adds 1.616" to the height of the ATS pier.

Use for Other Piers and 1100GTO

• 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. The base of the 1100GTO will fit directly into the top portion of the 119FSA-FP.

Use for Other Piers and 900 Mounts

• 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.
• These adapters for the 900GTO will fit into the top portion: Precision-Adjust Rotating Pier Adapter (900RPA), Standard Pier Adapter (900SPA), or 900 Hi-Lo Latitude Wedge (900WDG or 900WDGA).

Fasteners are supplied for attaching the 119FSA-FP to ATS or other similar pier.

If you own an 1100GTO-AE or 1100GTO-AEL, your mount has a double control box bracket to accommodate both of your GTOCP3 and GTOAE Control Boxes. You can continue to use the double bracket by mounting the GTOCP4 off-center and then securing it to the side.

Alternatively, you can purchase this single control box adapter, which attaches to your mount in the same manner. The GTOCP4 will look more aesthetically pleasing in this adapter.

Includes two 8-32 x 3/8" Thumbscrews.

Mounts used with this adapter: 1100GTO or any other mount that is bolted to a flat square plate.