DISCOVER NEW HORIZONS
C/2025 A6 (Lemmon)
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Imaging Camera QHY600
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Total Integration 12min
L: 450sec
R: 90sec
G: 90sec
B: 90sec
Astrophotographer
Michael Jäger,
Gerald Rhemann G00
Adapter & BFL Solution
| Kit A1 | USD40 | |
| Kit A2 | USD42 | |
| Kit A3 | USD35 | |
| Kit D1 | USD40 | |
| Kit D2 | USD58 | |
| Kit D3 | USD58 | |
| Kit E1 | USD35 |
QHY offers a very comprehensive and flexible adapter system that allows our cameras to achieve focus 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.
Related Products
Adapter System Introduction
QHYCCD has adhered to the adapter system of 6-screw + spacers for years. Compared to the typical threaded connection, this method is more robust, ensuring a stable relative position between various components (threads often have errors, leading to the final position after fixation being inaccurate). At the same time, it facilitates fine-tuning of the back focus length.
QHYCCD has consistently aimed to enhance the stability and user-friendliness of its hardware products. In terms of adapter systems, we have been continuously optimizing to adapt to the evolving needs of users, striving to improve the user experience.
Adapter System V1.0:
For the Adapter System V1.0 (before 2020), we provided various thicknesses of spacers for users to choose and purchase freely. However, for users, especially beginners, calculating the back focus and selecting the appropriate spacer can be challenging, and the tuning process is complex. Therefore, we introduced the 2.0 version.
Adapter Syatem V2.0:
In the Adapter System V2.0 (from 2021 onwards), we adopted standardized adapter kits. Various adapter kits can meet the needs of most mainstream requirements (such as correctors for 55mm/56mm back focus M48/M54 interfaces, Canon/Nikon DSLR lenses, etc.), with the adapter kit of 55mm M48 output serving as the standard accessory for most cooled cameras. Users can choose the corresponding adapter kits according to their needs, and install them following the adapter kit instruction, without the need for self-measurement and matching.
Adapter System V2.5:
Building upon the V2.0, the current V2.5 (since 2023) further enhances the compatibility and expandability of the adapters.
a. The standard adapter kits B1/C1/G1 for mainstream products have been expanded. While the V2.0 only supported adaptation to the 55mm/M48 specifications, the V2.5 offers cross-compatibility for both 55mm/56mm back focus length and M48/M54 threads. This allows coverage for back focus length and interface diameter requirements of most optical components such as correctors and telescopes.
b. By widening compatibility between different specifications, the current standard items can now facilitate connections and back focus length adaptations for some unofficially recommended combinations, such as achieving a connection between OAGL-Pro and CFW3M using the adapters.
c. Besides, 0.5mm/1mm spacers have been added as independent products to meet the needs of a few users with extremely high requirements for back focus length.
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 | Specifications |
| Typical Multi-Purpose Coma Corrector | 55mm, M48 Threads |
| Takahashi Epsilon Reflector Series | 56mm, M54 Threads |
| Canon 35mm lens | 44.1mm |
| Nikon 35mm lens | 46.5mm |
| … | … |
In addition, there are also some other special specifications, such as the refractor/reflector telescopes from Takahashi, which have different back focus standards based on their respective models.
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.
Recommended Combinations
At present, our adapter combinations 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.
Recommended Combinations for Mono Cameras
The full-frame mono camera is available in two models: QHY600M-PH (Standard Version) and QHY600M-PH SBFL (Shorter Back Focal Length Version). It is recommended to use them with CFW3L+OAGM. If you have specific requirements for the back focal length of your optical system, such as 55mm/56mm or when using a DSLR lens, it is advised to choose the QHY600M-PH SBFL (Shorter Back Focal Length Version). Additionally, some users have reported possible vignetting when using QHY600 with M48 MPCC. For better optical performance, it is suggested to connect full-frame cameras like QHY600 to telescopes using M54 or larger openings.
The APS-C mono camera QHY268M supports two types of filters: a 2-inch mounted filter using CFW3L, or a 36mm unmounted filter using CFW3M-SR 7*36mm version. According to our estimation, the 36mm filter can be used when the focal ratio of the main scope is greater than f/4. If you are using a telescope with a small focal ratio, such as f/2.8, it is recommended to use the 2-inch mounted filter. Additionally, if you choose to use unmounted filters with filter masks, it is recommended to use the thicker SR version to provide more space inside the filter wheel.
For cameras with a 3/4-inch sensor, like QHY294, it is recommended to use CFW3M-SR+OAGM. For cameras with a 1-inch or smaller sensor, like QHY533, it is recommended to use CFW3S-SR+OAGS.
| Camera | CFW | OAG | Adapter Kits | Filter Size |
| QHY461M-PH | QHYCFW3-XL | QHYOAGL-Pro | – | 50mm Square |
| QHY600M-PH-SBFL | QHYCFW3-L | QHYOAGM-Pro | B1 | 2” Mounted or 50mm Round |
| QHYCFW3-XL | QHYOAGL-Pro | B1 | 2” Mounted or 50mm Round | |
| QHY600M-PH | QHYCFW3-L | QHYOAGM-Pro | C1 | 2” Mounted or 50mm Round |
| QHYCFW3-XL | QHYOAGL-Pro | C1 | 2” Mounted or 50mm Round | |
| QHY268M | QHYCFW3L QHYCFW3M-SR QHYCFW3M-US |
QHYOAGM-Pro | B1 | 2” Mounted or 36mm Round |
| QHY294M | QHYCFW3M-SR QHYCFW3M-US |
QHYOAGM | A1 | 36mm Round |
| QHY533M | QHYCFW3S-SR | QHYOAGS | F1 | 1.25” Mounted |
Recommended Combinations for Color Cameras
Color cameras usually do not need to be paired with a filter wheel. There is no need to switch filters, or only a few filter changes are necessary using a filter drawer. If a filter wheel is required for special reasons, refer to the combination recommendations for the corresponding mono model of the camera.
| Camera | CFW | OAG | Adapter Kits | Filter Size |
| QHY600C-PH QHY600C-PH-SBFL |
– | QHYOAGM-Pro | G1 | 2” Mounted (IR-Cut or Duo Band) |
| QHY268C | – | QHYOAGM-Pro | G1 | 2” Mounted (IR-Cut or Duo Band) |
| QHY533C | – | – | E1 | 2” Mounted (IR-Cut or Duo Band) |
Adapter Kits Introduction
Note: 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.
B1 (QHY268M, QHY600M-PH SBFL)
The New Combo B1 is designed to be more flexible to achieve multiple output specifications. Since June 2023, we are adding a 5mm spacer with M54 threads into Adapter kit B1. This addition gives the user a choice of terminating the output in either M48 or M54 threads. You can get 55/56mm BFL with M48/M54 threads according to your needs. Since are standard accessories included with the camera, this addition has no affect on the price. 55mm M48/M54 are suitable for standard flatteners and multiple purpose coma correctors (MPCC), while 56mm M54 threads are common for Takahashi reflectors.
Note: Please position the OAG as far forward as possible (for example, placing it under the M48 thread), and extend the OAG prism slightly outward to ensure simultaneous focus for both the main camera and the guiding camera.
In 2023, we launched the new version of the QHYOAGM-Pro with a larger prism. Its thickness is 12mm, so it is necessary to reduce the spacer thickness by 2mm in the COMBO above while keeping the rest part unchanged.
The QHY600M-PH SBFL and QHY268M with CFW3L filter wheel can fit an optional Canon EF or Nikon F Lens Adapter without additional spacers. Smaller filter wheels may require additional spacers.
C1 (QHY600M-PH/L)
Since June 2023, we are adding a 5mm spacer with M54 threads into Adapter kit C1. This addition gives the user a choice of terminating the output in either M48 or M54 threads. Since C1 are standard accessories included with the camera, this addition has no affect on the price list.
Note:
Combo C1 is the solution without OAG. The QHY600M-PH or QHY600M-L with CFW3L and OAG result in a backfocus greater than 55mm. Therefore, if you must limit this BF distance to 55mm due to a corrector lens or DSLR lens, we recommend the QHY600M-PH SBFL.
If you need more than 7 x 50mm filter positions for the QHY600, you can use the CFW3XL filter wheel with 9 x 50mm filter carousel.
E1 (QHY533C, QHY294C, etc.)
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 （QHY533M）
A1-A3 (QHY163M, QHY294M)
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
D1-D3 (QHY600C-PH,QHY247C,367C,168C,128C,410C, etc.)
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: Connecting MPCC with 55mm BFL and M48 interface
D2: Connecting Canon EF Lens
D3: Connecting Nikon F Lens
0.5mm/1mm M54 Spacer
0.5mm/1mm Spacer is designed for those who have vary strict requirments of back focal length of the optical system, or the default 55/56mm solutions are not suitable (for example, some correctors require 57.5mm BFL). Combined with our Adapter Kits, the spacer can be used for precise adjustment.
M54/M42 All-in-one Accessory Packages
First please confirm whether there are specific requirements of BFL on your equipment. If not, just use a standard T-ring to connect the telescope.
If you do have strict requirements of BFL, since 7/23 we have provided 0.5mm and 1mm spacers as purchasable items for a precise adjustment.
If all the existing combo kits cannot meet your demand, such as special back focus requirements, we also offer M42 and M54 all-in-one adapter packages that contains nearly all of the adapters we provide in the kits: 0.5, 1, 2, 3, 7 and 14mm spacers can be combined to make any back focus needed from 0.5mm to 27.5mm.
In most cases, we recommend the M54 All-in-one Kit. The M42 All-in-one Kit is only suitable for use with the QHY183M and QHYCFW3S.
Specifications
| Model | Product No. | Compatible with | To Connect | Kit Includes | Note |
| Combo A1 | 020100 | QHY294M/163M + CFW3M-US + (OAGM)* |
55mm BFL M48 Threads | 5mm M54-M48 Threads Adapter*13mm Spacer*1
0.5mm Spacer*1 10mm Spacer*1 22mm M3 Screws*8 |
This Combo A1 is included as a standard accessory with the QHY294M |
| Combo A2 | 020101 | QHY294M/163M +CFW3M-US |
Canon EF Lens | 10mm M54 Canon EF Adapter*14mm M54 Screwed Adapter*1
3mm Spacer*1 1mm Spacer*1 Cam Top Adapter (originally 020063) 10mm M3 Screws*8 |
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| Combo A3
(Nik Adapter1) |
020102 | QHY294M/163M +CFW3M-US |
Nikon F Lens | 10mm M54 Nikon F Adapter*1 | _ |
| Combo B1 | 020103 | QHY268M+CFW3L/CFW3M-US + (OAGM)orQHY600M-PH SBFL +CFW3L + (OAGM) |
55mm/56mm BFL M48 Threads
55mm/56mm BFL M54 Threads |
5mm M54-M48 Threads Adapter*15mm M54-M54 Threads Adapter*1
3mm Spacer*3 1mm Spacer*1 10mm Spacer*1 24mm M3 Screws*8 28mm M3 Screws*8 |
This Combo B1 is included as a standard accessory with (a) QHY268M and (b) QHY600M-PH SBFL version |
| Model | Product No. | Compatible with | To Connect | Kit Includes | Note |
| Combo C1 | 020106 | QHY600M-PH+CFW3L |
55mm/56mm BFL M48 Threads
55mm/56mm BFL M54 Threads
|
5mm M54-M48 Threads Adapter*1
5mm M54-M54 Threads Adapter*1 1mm Spacer*1 7mm Spacer*1 14mm M3 Screws*8 |
C1 is supplied as a standard accessory with QHY600M-PH |
| Combo D1 | 020107 | QHY268C (Version before 2023)/ QHY600C-PH/QHY168C/ QHY247C/QHY128C/QHY410C/ QHY367C | 55mm M48 Threads | 5mm M54 to M48 Adapter*12.5mm 2inch Filter Fixer
(Original Name 020055) 10mm Spacer*1 14mm Spacer*1 36mm M3 Screws*8 |
D1 is supplied as a standard accessory with QHY600CQHY268C (Version Before 2023) |
| Combo D2 | 020108 | QHY268C (Version before 2023)/ QHY600C-PH/QHY168C/ QHY247C/QHY128C/QHY410C/ QHY367C | Canon EF Lens | 10mm M54 Canon EF Adapter*14mm M54 Screwed Adapter*1
2.5mm 2inch Filter Fixer (Original Name 020055) 3mm Spacer*1 1mm Spacer*1 14mm M3 Screws*8 |
_ |
| Combo D3 | 020109 | QHY268C (Version before 2023)/ QHY600C-PH/QHY168C/ QHY247C/QHY128C/QHY410C/ QHY367C | Nikon F Lens | 12mm M54 Nikon F Adapter*14mm M54 Screwed Adapter*1
2.5mm 2inch Filter Fixer (Original Name 020055) 3mm Spacer*1 1mm Spacer*1 0.5mm Spacer*1 14mm M3 Screws*8 |
_ |
| Combo E1 | 020110 | QHY294C / QHY163C QHY183C/ QHY533C |
55mm M48 Threads | Three Customized adapters and a 0.5mm spacer | This Combo E1 is included as a standard accessory with the QHY533C |
| Combo F1 | 020120 | QHY533M | 55mm M48 Threads | 8mm M42-M48 Threads Adapter*1
3mm Spacer*3 10mm Spacer*1 23mm M3 Screws*8 |
This Combo F1 is included as a standard accessory with the QHY533M |
| M54 All-in-one Kit | 020111 | All Cooling CMOS Cameras
CFW3M-SR CFW3M-US CFWL OAGM |
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 |
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| M42 All-in-one Kit | 020112 | QHY183MCMOS
CFW3S-SR CFW3S-US OAGS |
8mm M42 to M48 Adapter*1
3mm M42 to Screwed Adapter*1 Cam Top Adapter (Original Name 020063)*1 0.5mm/1mm/2mm/3mm/7mm/10mm/ Spacer*1 10mm M3 Screws*8 12mm M3 Screws*8 21mm M3 Screws*8
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