The Baader Fluorite Flatfield Converter was designed by a top German optical inventor to cover up to a 6x7 cm format at magnifications up to 8x. The 4-element fluorite design provides a diffraction-limited, apochromatic flat field over a 90 mm image circle. It produces a sharp, color-free image for any projection photography need. It can be coupled to 35 mm cameras, 6x7 cameras (adapters are available for various camera models), as well as any CCD camera using 1.25" or 2" nosepieces or threaded custom adapters. The BPFFC also can be used visually for critical high-power lunar/planetary/double star viewing.

The fluorite lenses do not add any chromatic aberrations or other optical defects to the image. The lenses are corrected from deep violet to the IR regions, and present an excellent match to the new extended-wavelength CCD cameras.

The BPFFC is fully multi-coated with a hard 7-layer design, each layer exactly matched to the material index. The result is very high transmission while suppressing stray light. Looking into the front of the lenses shows a black tube with the elements barely visible as shown in the photo. All optical surfaces are polished to the highest optical standards of 1/10 wave accuracy, in order not to disturb the incoming wavefront from your telescope's optics.

For projection photography, the BPFFC is unmatched for image fidelity. Unlike eyepiece projection systems, the BPFFC is free of the common defects such as chromatic aberration, pincushion/barrel distortion, astigmatism, coma, and vignetting of the light cone.

Assembled unit: ADAT2, BPFFC, AP16T. Shown with the following three extension tubes threaded together on the right:

BP25A - T-2 Extension Tube, 15 mm long
BP25B - T-2 Extension Tube, 40 mm long
BP25C - T-2 Extension Tube, 7.5 mm long

The FFC System - PDF document from Baader Planetarium
This is an exploded diagram of the various parts in the FFC System and their relationship to one another. Pertinent notes:

• The numbers beneath the extension tubes indicate their length in mm.
  
• Our part numbers are derived from the numbers in the circles. Simply add the letters BP to the circled number, i.e. the circled part 1 is our part number BP1.
  
• Part number 3 is now included with part number 1, so it should not be ordered separately when used with the prism star diagonal (order as BP1 to receive both components).

• Basic Configuration for 4x Focal Extension
• Visual use with 2" Diagonal and 2" or 1.25" Eyepieces
• Visual use with 1.25" Eyepieces and T-2 (Zeiss) Star Diagonal

The power of the BPFFC will vary depending on the distance to the focal plane behind the Barlow. As the spacing increases, so does the magnification. However, remember that as you increase the spacing (magnification) you also will need to shift the BPFFC forward in the focuser. The amount of in-travel available becomes a consideration as you reach towards the higher magnifications. The following is a list of the magnifications and the distances required: 2x = 42 mm, 3x = 96.2 mm, 4x = 150 mm, 5x = 206.4 mm, 6x = 259 mm, 7x = 314 mm, 8x = 368 mm.

Visual
When using the Astro-Physics Maxbright Diagonal, we suggest one of the following configurations:

• Basic Set: ADAT2 (Astro-Physics 2"/T2 adapter) + BPFFC (FFC) + AP16T (2"/T-2 nosepiece)
  or
• FFC system components: BP17 (2" adapter) + BP28 (expanding ring) + BP6/7 (T-2 changer system) + BPFFC (FFC) + BP16 (T-2 nosepiece)

  BP17

  $64.00

  in stock

  BP28

  $45.00

  in stock

  BP6/7

  $88.00

  in stock

  
  
  

Using either the "Basic Set" or the "FFC System Components" in front of the AP Maxbright Diagonal, the eyepiece focal plane will be effectively 152 mm (+/-10% depending on the style of the eyepiece) behind the BPFFC for an approximate 4x magnification. To get an exact measure of power requires the exact position of the eyepiece field stop with respect to the rear flange of the BPFFC. Using various extension tubes, the power can be increased to 8x, assuming that your telescope focuser has sufficient in-travel to allow this configuration to come to focus.

Lower powers can be achieved by placing either the “Basic Set” or the “FFC System Components” into the AP Maxbright Diagonal and then adding the eyepiece. This setup will place the focal plane approximately 50 mm behind the BPFFC, yielding about 2x magnification. The magnification will vary somewhat with eyepiece design.

35 mm Camera
35 mm SLR and DSLR cameras have a 55 mm spacing distance to the film/sensor plane when using a T-ring system. The lowest magnification of 2x is achieved by threading a standard T-ring directly to the back of the BPFFC body (without a 2" adapter).

3x to 8x magnifications are achieved by adding 50 mm - 320 mm of extension tube(s).

If you use the 2" Astro-Physics Adapter (ADAT2) and a 2" Astro-Physics Prime Focus Camera Adapter (part # starting with PFC or PFCT), the distance to the film plane will be 140 mm for 3.7x magnification.

ADAT2

$40.00

in stock

BPFFC

$793.00

in stock

PFCT

$50.00

in stock

PFCTCAN

$70.00

in stock

PFCTKON

$70.00

in stock

PFCTMAF

$70.00

in stock

PFCTMIN

$70.00

in stock

PFCTNIK

$70.00

in stock

PFCTOLY

$70.00

in stock

PFCTPTS

$70.00

in stock

6x7 Camera
To use a medium format camera requires the Baader M68 Quick Change System and the appropriate adapters and extension tubes. The lowest power without extension tubes will be between 3x and 3.3x depending on camera type: Hasselblad: 74.9 mm and Pentax 67: 84.95 mm.

CCD Camera
The FFC system allows you to achieve various powers with your CCD Cameras (such as the
ST-7/8/9/10 or the STL-11000). If you thread the BPFFC directly into your camera (without the 2" nosepiece or with a custom low profile adapter) the lowest possible magnification will be approximately 2x. By inserting the 2" nosepiece of your CCD Camera (with color filter wheel closely coupled) directly into the Astro-Physics 2"/T2 Adapter (ADAT2), which you have attached to the back of the BPFFC, the power will be approximately 3x. This will increase with the addition of extensions or other intermediate accessories.