QHY offers a very comprehensive and flexible adapter system that allows our cameras to achieve focus with a variety of accessories, including camera lens adapters, off-axis guiders, filter wheels and numerous optical systems. Based on users’ feedback, we provide fixed combination of adapter kits to meet mainstream needs of most users (e.g., Multi-Purpose Coma Corrector, Canon lens adapter, Nikon lens adapter, etc.). Users can choose the corresponding adapter set according to their needs to ensure focus. There is no need to measure and calculate the back focal length, choose adapters, and customize screws.
Back Focal Length Defined
Back Focal Length (BFL), in the commercial camera field, refers to the design distance from the center of the rear lens element to the surface of the sensor. Generally, the lens will only focus correctly at infinity if the camera’s back focal length meets the standard requirements provided by the lens manufacturer. This is also true for many Multi-Purpose Coma Correctors designed to be used on telescopes before the camera.
| Optical system | Back focal length required |
| Typical Multi-Purpose Coma Corrector | 55mm – 57.5mm |
| Canon 35mm lens | 44.1mm |
| Nikon 35mm lens | 46.5mm |
Note: Not all astrophotography gears have specific BFL requests, for example, some refractor scopes with internal flat correctors. In such cases, you needn’t use the following adapter kits. Instead, you can use a T ring or any adapter that can help connect your camera and scope.
"Back Focus Consumed" Defined
When an optical system requires the sensor of the camera to be located at a specific distance from the last optical element, mechanical spacer adapters are used to position the camera at the right location. If the camera system also includes a filter wheel and an OAG, for example, between the camera and the telescope, the space required for these items must be taken into account. As a simplified explanation, for example, if a telescope’s field flattener requires the camera focal plane to be 55mm behind the last optical element, and the filter wheel is 20mm thick, and the OAG is 10mm thick and the sensor is set 10mm inside the camera then these items all take up 20+10+10=40mm of the back focal distance. Still, the camera needs to be 55mm away so we need to add spacers that take up this remaining 15mm. This also means that if you have an optical system that requires 55mm of backfocus distance and your filter wheel is 25mm thick and the OAG is 20mm thick and the sensor in the camera is 17mm from the front plate, then these items take up 25+20+17=62mm of backfocus. Too much! In this case something has to go to reduce the total back focus distance of the camera to 55mm or a different optical configuration must be found.
For the convenience of calculation, all the data displayed are the increase in the back focal length taken up by using the adapter, which is not necessarily equal to the thickness of the component itself. All the adapter data provided by QHYCCD are based on the focal length increment.
Recommend Combinations
At present, our adapter combinations for monochrome cameras are based on the focal length of the following combinations, which are also our recommended combinations. If you use combinations other than those recommended, the adapter set may not achieve its purpose.
Please refer to: https://www.qhyccd.com/product/astrophotography-combos/
Adapter Kits Introduction
Note: in 55mm solutions, if you do not want to use an OAG in the above combinations, we provide an additional 10mm spacer adapter in some kits to replace it.
A1-A3 (for 163M, 294M)
A1
A1: Connecting MPCC that requires 55mm BFL and M48 interface to Camera with Filter Wheel and OAG.
Note:
- If you only own CFW3M-SR whose BFL is 20.5mm rather than 17.5mm, this adapter combination can still be used, just remove the 3mm and 0.5mm adapters.
- If your MPCC requires a BFL different from 55mm, this adjustment can be made by selecting the appropriate spacer between the MPCC and the OAG. For example, an MPCC that requires 57.5mm can be used instead by adding a spacer ring or rings that add 2.5mm of BFL. to the diagram above.
- If you don’t use an OAG, you can use a 10mm spacer adapter in the adapter kits to replace the original position of OAG.
- Put OAG at the position next to the M48 Output to make both main cam and guiding cam focused.
A2
A2: Connect Canon lens with filter Wheel. You need to remove the filter wheel and the original connection interface of the camera and replace it with a new adapter.
A3
A3: Connect Nikon F Lens to Camera with Filter Wheel
B1-B3 (for 268M, 600SBFL)
B1
B1: Connecting MPCC that requires 55mm BFL and M48 interface to Camera with CFWL and OAG. B1 is standard accessories of QHY600M SBFL and QHY268M, so you needn’t purchase it if you’ve had the cams. If you own a CFW3M-US (which is 17.5mm) rather than CFW3L (21.5mm), you need to add another 4mm adapter and longer screws, which are also included in B1. Below shows two examples:
Note:
- If your MPCC requires a BFL different from 55mm, this adjustment can be made by selecting the appropriate spacer between the MPCC and the OAG. For example, an MPCC that requires 57.5mm can be used instead by adding a spacer ring or rings that add 2.5mm of BFL. to the diagram above.
- If you don’t use an OAG, you can use a 10mm spacer adapter in the adapter kits to replace the original position of OAG.
- Put OAG at the position next to the M48 Output to make both main cam and guiding cam focused.
B2
B2: Connect Canon EF lens to Camera with filter wheel
B3
B3: Connect Nikon F Lens to Camera with Filter Wheel.
Note: The current Nikon adapter used here is different from the 10mm adapter we used to provide. Now it has a back focal length increment of 12mm.
B4 for New 268C
From 2023, the top part of QHY268C will change to the shorter one just like that of 268M. In fact, you can get the “SBFL(shorter back focal length” version of 268C right now.
The previous 268c has a back focal length of 17.5mm, and since it cannot connect to the scope without CAA, so it’s actual BFL is 17.5mm+6mm=23.5mm. Now after the change, 268C’s BFL will be shorten to 14.5mm, which provides more spaces for a filter wheel drawer, or an electric CAA, or DSLR Lens, etc.
The new 268C adapts a new kit B4 which can best make use of the standard accessories. B4-2 and B4-3 share common parts from the necessary B4-1(for MPCC) .When you need to connect Canon or Nikon lens, you only need to get one Canon/Nikon adapter, not a “kit” like D2 or D3 anymore.
C1 (for 600M-PH, 600L)
Kit C1 is for connecting MPCC that requires 55mm BFL and M48 interface to Camera with CFW3L Only. C1 is standard accessories of QHY600M PH and QHY600L, so you needn’t purchase it.
Note: The combo QHY600M-PH+CFW3L+OAG combo are not compatible for MPCC because of limited BFL. If you need an MPCC while using the CFWL and OAG at the same time, or use DSLR Lens, we recommend you choose QHY600 SBFL version.
D1-D3 (For OSC cams with APS-C and Full Frame Sensor)
Combos and Adapter Kits
Generally speaking, there’s no need for an OSC (one shot colored) camera to match filter wheel. If there’s any special needs, please refer to mono cam combos and choose the corresponding filter wheel. All OSC cams use OAG M if needed.
| Model | BFL Consumed |
| QHY600C/410C/367C/128C/247C/168C | 17.5mm+6mm (CAA) |
| QHY268C (Version before 2022) | 17.5mm+6mm (CAA) |
| OAGM | 10mm |
*About IR-Cut filter：
The sealing glass of QHY OSC cameras whose format are above APS-C is AR glass instead of IR/Cut filter. That’s because when the sensor size is bigger, if IR/Cut is closed to sensor, it’s easy to cause haloing effect on image. We use IR/Cut filter as sealing glass on 4/3 format cameras or below, like 163C, 183C; as for big sensor OSC cams, such as 268C, 367C, we provide a special adapter for fixing 2-inch IR/Cut filter at a farther position from the sensor, or users can fix the filter inside the default T mount.
D1
D1: Connecting MPCC with 55mm BFL and M48 interface
If you don’t use an OAG, please use 10mm adapter in the adapter kits to fill the original position of OAG.
D2
D2: Connecting Canon EF Lens
D3
Connecting Nikon F Lens
E1 (for 533C, 294C, 174C)
E1 is designed for QHY533C, 294C, 163C, 183C, 174C. Of course, if you use 163M/294M/183M/174M while a filter wheel or OAG is not needed, you can use E1 as well.
F1 （for 533M）
M54 All-in-one Adapter Kit
If all the existing package solutions cannot meet the demand, such as the situation where the BFL requirement is very special, we also offer this all-in-one accessory package which includes almost all kinds of M54 adapters we have.
The many potential combinations of these items produce an equal variety of back-focus distances that must be considered to make it all work together. This variety and flexibility can let you get any BFL you want through this kit.
If all the existing package solutions cannot meet the demand, such as the situation where the BFL requirement is very special, we also offer this all-in-one accessory package which includes almost all kinds of M54 adapters we have.
The many potential combinations of these items produce an equal variety of back-focus distances that must be considered to make it all work together. This variety and flexibility can let you get any BFL you want through this kit.
M42 All-in-one Adapter Pack for QHY183M
Currently We only provide M42 All-in-one pack for QHY183M. Different from kits above, all adapters/spacers in this pack share M42 screws rather than M54. This kit ONLY suits the combo of QHY183M+CFW3S-US/CFW3S-SR+OAGS. Below lists some examples of using the kit (M42 Nikon/Canon adapter not included in this pack)
Note: this kit also suits other cameras with sensors one inch or smaller (e.g., QHY183/178/174/290).
Currently We only provide M42 All-in-one pack for QHY183M. Different from kits above, all adapters/spacers in this pack share M42 screws rather than M54. This kit ONLY suits the combo of QHY183M+CFW3S-US/CFW3S-SR+OAGS. Below lists some examples of using the kit (M42 Nikon/Canon adapter not included in this pack)
Note: this kit also suits other cameras with sensors one inch or smaller (e.g., QHY183/178/174/290).
If you need an adapter not listed on this page we closely work with our partner PreciseParts: All types of custom adapter can be designed online to assemble custom image trains using QHY cameras.
Click the logo or the link: https://www.preciseparts.com for more information!
Specifications
| Model | Inc. | Note | Retail Price/USD |
| Combo A1 | 5mm M54 to M48 Adapter*1
3mm Spacer*1 0.5mm Spacer*1 10mm Spacer*1
22mm M3 Screws*8 |
Standard accessory of QHY294M | 40 |
| Combo A2 | 10mm M54 Canon EF Adapter*1
4mm M54 Screwed Adapter*1 3mm Spacer*1 1mm Spacer*1 Cam Top Adapter (original name 020063)*1
10mm M3 Screws*8 |
_ | 52 |
| Combo A3
(Nik Adapter1) |
10mm M54 Nikon F Adapter*1 | _ | 35 |
| Combo B1 | 5mm M54 to M48 Adapter*1
3mm Spacer*3 1mm Spacer*1 10mm Spacer*1
24mm M3 Screws*8 28mm M3 Screws*8 |
Standard accessory of QHY268M\QHY600 Short BFL Ver. | 52 |
| Combo B2
(Can Adapter) |
10mm M54 Canon EF Adapter*1 | _ | 35 |
| Combo B3
(Nik Adapter2) |
12mm M54 Nikon F Adapter*1
0.5mm Spacer*1 |
_ | 40 |
| Combo C1 | 5mm M54 to M48 Adapter*1
7mm Spacer*1
14mm M3 Screws*8 |
Standard accessory of QHY600M-PH | 25 |
| Combo D1 | 5mm M54 to M48 Adapter*1
2.5mm 2inch Filter Fixer (Original Name 020055) 10mm Spacer*1 14mm Spacer*1
36mm M3 Screws*8
|
Standard accessory of QHY600C
QHY268C |
40 |
| Combo D2 | 10mm M54 Canon EF Adapter*1
4mm M54 Screwed Adapter*1 2.5mm 2inch Filter Fixer (Original Name 020055) 3mm Spacer*1 1mm Spacer*1
14mm M3 Screws*8 |
_ | 58 |
| Combo D3 | 10mm M54 Nikon F Adapter*1
4mm M54 Screwed Adapter*1 2.5mm 2inch Filter Fixer (Original Name 020055) 3mm Spacer*2 0.5mm Spacer*1
16mm M3 Screws*8 |
_ | 58 |
| Combo E1 | Under Developing | TBD | TBD |
| M42 All-in-one Kit
(Available Soon) |
8mm M42 to M48 Adapter*1
3mm M42 Screwed Adapter*1 Cam Top Adapter (original name 020063)*1
0.5mm/1mm/2mm/3mm/7mm/10mm Spacer*1
21mm M3 Screws*8 10mm M3 Screws*8 12mm M3 Screws*8 |
60 | |
| M54 All-in-one Kit
|
5mm M54 to M48 Adapter*1
3mm M54 to M42 Adapter*1 2.5mm 2inch Filter Fixer (Original Name 020055) *1 4mm M54 Screwed Adapter (Original name 020070)*1 Cam Top Adapter (original name 020063)*1 0.5mm/1mm/2mm/3mm/7mm/10mm/14mm Spacer*1
8mm M3 Screws*8 10mm M3 Screws*8 12mm M3 Screws*8 14mm M3 Screws*8 16mm M3 Screws*8 21mm M3 Screws*8 24mm M3 Screws*8 28mm M3 Screws*8 36mm M3 Screws*8 50mm M3 Screws*8 |
135 |