2.7" and Traveler Focusers and Feather Touch Upgrade and Dedicated Accessories
3.5" Focuser with Feather Touch and Dedicated Accessories
4" Giant Focusers, Feather Touch Upgrade and Dedicated Accessories
Electronic Focusing Control for Astro-Physics Focusers
Adapters, Extensions and Covers for all Focusers and Related Parts
|
Achieve very fine critical focus by upgrading your 2.7" or Traveler Focuser with the Feather Touch Micro Upgrade. This dual-speed pinion assembly features a 9:1 speed reduction knob designed and produced for Astro-Physics by Starlight Instruments. The coarse-focus knobs allow you to rack the drawtube out quickly, and the fine knob is used to find and hold the final focus point. Ideal for very high powers with short focus oculars and Barlow amplifiers. It will also allow quick, precise manual focusing with CCD cameras. You'll love the smoooooooth feel and the very cool reflection of the gold anodized knob on the polished aluminum knob. We highly recommend the dual-speed focuser for both visual and imaging use. When manually focusing your CCD or DSLR camera, you will see improved accuracy and ease. Adding the Starlight Instruments’ "Focuser Boss Digital Kit" allows automated focusing using FocusMax or any of the many automated focusing software. |
This upgrade is available for most focusers and refractors shipped since July 2001. This includes scopes purchased from RC Optical, Optical Guidance Systems, Parallax Instruments, D&G Optical and Telescope Engineering Company that have Astro-Physics focusers. In order to determine whether your focuser can be upgraded, please compare the hole pattern of your focuser's pinion block to these focuser block photos. If your Traveler was shipped between March - September 2001 and your pinion block looks like this focuser block photo (part # A1034), please give us a call for special instructions. Regretablly, all other scopes shipped prior to July 2001 cannot be retrofit with this Feather Touch Micro assembly due to the configuration of the pinion block. However, in most cases, complete new focusers can be easily installed onto your Astro-Physics refractor. Please refer to the information regarding the new 2.7" Focuser (27FOC3E-FT) and new Traveler Focuser (TFOC3E-FT), both featuring greaseless drawtubes and the Instructions: Installing Feather Touch Focuser Upgrade - 2.7" Traveler and 4" Focusers A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. |
Back to top
Astro-Physics
2.7" Focuser with Feather Touch Micro (27FOC3E-FT)
The silky smoothness of the 2.7" Astro-Physics focuser and the dual-speed mechanism of the Feather Touch Micro are both realized in this superb focuser. The dual-speed feature is particularly advantageous for critical focusing of scopes with fast focal ratios.
|
||
These are the additional enhancements available for this Feather Touch model:
|
![]() |
|
|
||
Who should use this focuser?
|
||
Focuser Dimensions The focuser includes the 2" (ADA2003A) and 1.25" (ADA125) adapters. You may prefer a sturdier cover than the included plastic plug. Astro-Physics also offers an optional aluminum cover that will accommodate this part, depending on your storage needs. Please review the information regarding the Threaded Cover for AP 2.7" Drawtubes and Accessories with 2.7" Female Threads (A1005). More information can be found on our Accessory Reference Chart for 2.7" Threaded Covers. A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. |
Back to top
Astro-Physics
Traveler-Style Focuser with Feather Touch Micro (I27FOC3E-FT)
This Traveler-style focuser is virtually identical to the 2.7" Focuser described above, except that the focuser body (that houses the drawtube) has an internal thread that attaches to the Traveler tube. All other construction features and specifications are the same. The new I27FOC3E-FT focuser offers critical focusing and a greaseless drawtube with a "mm" focusing scale. All of these are attributes that Traveler owners will find appealing. This Traveler-style focuser is identical to the Traveler focuser, except that it does not have the word "Traveler" engraved on the housing. To replace the focuser, simply unscrew the focuser from the OTA (counter clockwise) and replace with the new one. It's that easy! Be sure that you don't use the focuser knobs for leverage, or you may bend the pinion gear. We suggest that your Traveler be attached to your mounting or have someone else hold the tube as you remove the focuser. The focuser includes the 2" (ADA2003A) and 1.25" (ADA125) adapters. |
|
You may prefer a sturdier cover than the included plastic plug. Astro-Physics also offers an optional aluminum cover that will accommodate this part, depending on your storage needs. Please review the information regarding the Threaded Cover for AP 2.7" Drawtubes and Accessories with 2.7" Female Threads (A1005). More information can be found on our Accessory Reference Chart for 2.7" Threaded Covers. Please notice the drawtube position scale that has been incorporated into all our focusers to help with set up and focusing precision. Internal thread of the focuser housing is 4.320" x 24. |
|
Focuser Dimensions A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. |
Back to top
Adapter to use Astro-Physics 2.7" Focuser - 2.7" overall length (A1025-B)
![]() |
This adapter was designed for owners of our 155EDFS StarFire refractor who are looking for more focuser in-travel. Most of the 155EDFS were originally shipped with a longer adapter. This adapter has a net spacing distanceof 2.0". Additionally, this adapter can be used to replace a 4" focuser in a 155EDF or similar Astro-Physics EDF refractor, for those who wish to step down to an A-P 2.7" focuser with an external thread. The collar end bolts into the tube via the six 8-32 tapped holes. Our 2.7" standard and FeatherTouch focusers simply thread into the internal female threads on the eyepiece end of the adapter. Please note this adapter cannot be used for the 130EDF Gran Turismo or 105mm Traveler focusers. For the amateur telescope builder, this adapter also facilitates adding an Astro-Physics 2.7" focuser to a homemade instrument. Outer diameter of the attachment ring is 5.395". Internal female thread is 4.889" x 24. |
3.5" Focuser with Feather Touch and Dedicated Accessories
Astro-Physics 3.5" Rotating Focuser with Feather Touch Micro 9:1 Dual-Speed (35FOCER-FT)
Our 130 Starfire GTX refractor ushers in a new era focuser…the 3.5” Astro-Physics focuser with a greaseless drawtube and the dual-speed mechanism of the Feather Touch 9:1 Micro. The focuser has been designed to meet and exceed the high-precision requirements of modern imaging. Today’s smaller pixel cameras can magnify any focuser flexure problems, so we have engineered this focuser from the ground up, reviewing every part so that even the heaviest cameras will be free from flexure and have focusing repeatability. More than a dozen knife-edge baffles are machined into the wall of the drawtube and painted flat black in order to maximize contrast by essentially eliminating any internal reflections. |
|
![]() |
Visual and imaging astronomers often want a different “feel” to their focusers, as their requirements differ. Adjusting the “feel” of the focuser is easy. There are two adjuster screws located on the underside of the housing. By slightly tightening or loosening the screws one changes the resistance that is felt when turning the focuser knobs. They should be adjusted equally. A locking brake is also provided in the form of a thumbscrew located on the underside of the focuser block. It allows you to quickly change the tension when using heavier eyepieces or to completely lock the focuser, depending on the pressure exerted The rotatable-focuser style is incorporated in its design. The “captain’s wheel” locking collar is loosened to rotate the focuser and then tightened to lock the focuser at any chosen angle. To remove the focuser, one simply unscrews the collar completely. Upgrade possibilities:
|
Features:
|
![]() |
An endcap screws onto the focuser drawtube and can be locked into place using three set screws that are found in the endcap’s surface (this is an optional action that imagers may want to use). The endcap terminates in a 3.5” circular dovetail which ensures absolute orthogonality for your imaging needs and allows you to quickly swap accessories or cameras. The male threads on the drawtube onto which the endcap screws are 4.100" x 24. Three adapters are provided: a 3.5” circular dovetail to 2.7” AP thread, a 2.7” AP thread to 2” compression and a 2” to 1.25” compression. A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. The focuser has 4.5" (115 mm) of travel and with adapters weighs 6.9 lbs. (3.14 kg.). |
Astro-Physics 3.5" Rotating Focuser with Feather Touch Micro 9:1 Dual-Speed, without Adapters (S35FOCER-FT)
There may be circumstances when you do not need all the adapters with the focuser. For example, you may be using custom adapters for imaging pruposes only. For this reason we offer the same focuser as described above, but without the 3.5” circular
dovetail to 2.7” AP thread, the 2.7” AP thread to 2” compression
and the 2” to 1.25” compression adapters. It does include the Drawtube Endcap with the three thumbscrews (S35RFAA). |
|
![]() |
The focuser has been designed to meet and exceed the high-precision requirements of modern imaging. Today’s smaller pixel cameras can magnify any focuser flexure problems, so we have engineered this focuser from the ground up, reviewing every part so that even the heaviest cameras will be free from flexure and have focusing repeatability. More than a dozen knife-edge baffles are machined into the wall of the drawtube and painted flat black in order to maximize contrast by essentially eliminating any internal reflections. Visual and imaging astronomers often want a different “feel” to their focusers, as their requirements differ. Adjusting the “feel” of the focuser is easy. There are two adjuster screws located on the underside of the housing. By slightly tightening or loosening the screws one changes the resistance that is felt when turning the focuser knobs. They should be adjusted equally. A locking brake is also provided in the form of a thumbscrew located on the underside of the focuser block. It allows you to quickly change the tension when using heavier eyepieces or to completely lock the focuser, depending on the pressure exerted The rotatable-focuser style is incorporated in its design. The “captain’s wheel” locking collar is loosened to rotate the focuser and then tightened to lock the focuser at any chosen angle. To remove the focuser, one simply unscrews the collar completely. |
Upgrade possibilities:
Features:
|
|
An endcap screws onto the focuser drawtube and can be locked into place using three set screws that are found in the endcap’s surface (this is an optional action that imagers may want to use). The endcap terminates in a 3.5” circular dovetail which ensures absolute orthogonality for your imaging needs and allows you to quickly swap accessories or cameras. The male threads on the drawtube onto which the endcap screws are 4.100" x 24. A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. The focuser has 4.5" (115 mm) of travel and weighs 5.8 lbs. (2.62 kg.). |
3.5" Focuser Drawtube Endcap (S35RFAA)
|
|
![]() |
This Drawtube Endcap (S35RFAA) is integral with the Astro-Physics 3.5” Rotating Focuser. It screws onto the focuser drawtube’s 4.100” x 24 tpi male threads. It then uses a proprietary three thumbscrew locking dovetail system to secure accessories. The dovetail system has been designed to provide absolute orthogonality when attaching matched accessories, pulling them flush when tightened. It allows easy rotation of your accessory, yet safely prevents it from becoming dislodged while rotating. |
This endcap can also be attached to Starlight Instruments 3.5” focusers, such as those used on TEC scopes and other popular brands. |
3.5” Circular Dovetail to 2.7” AP Thread Adapter (A5012)
|
|
![]() |
The A5012 is a 3.5” circular dovetail to 2.7” AP thread adapter used with the 3.5” Rotating Focuser (supplied with the 130 mm Starfire GTX) as a step-down adapter allowing the use of our many 2.7” accessories. This adapter is similar to the A1085 (supplied with the 3.5” Honders focuser), but with a smaller net spacing distance. It can be used with the Honders 3.5” focuser if more in-travel is needed (and even more in-travel can be obtained by using the 2” Thin Adapter with Three Thumbscrews – ADA20132). |
The unique dovetail design of the A5012 provides an extremely robust and orthogonal attachment to the focuser endcap. It allows easy rotation of your accessory, yet safely prevents it from becoming dislodged while rotating. It has a net spacing distance of 0.281” (7.14 mm). |
130GTX Tube and Focuser Covers (T13012 and T13014F-B)
The new 130 Starfire GTX refractor continues the Gran Turismo tradition of being airline transportable. These optional covers are offered for those who enjoy travelling with their scope. |
|
![]() |
If you are travelling by air, you do not want to trust your irreplaceable scope optic to baggage handlers, nor do you want it to be carried in a sub-pressurized hold. However, there is a carry on size restriction of 22” length. Enter the 130 Starfire GTX Gran Turismo. |
The new Gran Turismo is designed to separate into two sections, the optical tube (21") and the focuser (11"). These covers provide both dust and damage protection while the scope is disassembled into its components. The female threaded cover (T13012) screws onto the optical tube and the male threaded cover (T13014F-B) goes on the focuser. With the scope now meeting the carry on restrictions you’ll be able to confidently travel with your lens safe-and-sound overhead. The focuser can be packed with your luggage (it is replaceable in worst case) or carried by your travel partner. |
4" Giant Focusers, Feather Touch Upgrade and Dedicated Accessories
Feather Touch Micro Upgrade for Astro-Physics 4" Focusers (4FTMU)
Watch your images snap into focus with this Feather Touch Micro Upgrade. Astro-Physics teamed up with Starlight Instruments to produce this dual-speed assembly, which features a 9:1 reduction knob. The coarse-focus knobs allow you to rack the drawtube out quickly, and the fine knob is used to find and hold the final focus point. Ideal for very high powers with short focus oculars and Barlow amplifiers. It will also allow quick, precise manual focusing with CCD cameras. You'll love the smoooooooth feel. It can be mounted so that the fine focus knob is either on the right or the left side for your convenience. We highly recommend the dual-speed focuser for both visual and imaging use. When manually focusing your CCD or DSLR camera, you will see improved accuracy and ease. Adding the Starlight Instruments’ "Focuser Boss Digital Kit" allows automated focusing using FocusMax or any of the many automated focusing software. This upgrade is available for 4" Focusers and refractors shipped since October 2001. In order to determine whether your focuser can be upgraded, please compare the hole pattern on the bottom of the pinion block of your focuser to these focuser block photos. Focusers that can be upgraded must have pinion block A1022-A. If you prefer a total upgrade to the new greaseless version, please refer to the options below. All other scopes shipped prior to October 2001 cannot be retrofit with this Feather Touch Micro assembly due to the configuration of the pinion block. These early pinion blocks are shown as part # A1022 at this focuser block link. If your scope was produced prior to October 2001 and already has a 4" focuser, you can easily substitute the new version that features the greaseless drawtube and Feather Touch Micro Dual-Speed Knobs. Please refer to this upgrade information regarding the new 4" Focuser (part# S4FOC3E-FT) . Instructions: Installing Feather Touch Focuser Upgrade - 2.7" Traveler and 4" Focusers A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. |
Back to top
Astro-Physics
4" Giant Focuser with Feather Touch Micro (4FOC3E-FT)
![]() |
The silky smoothness of the robust 4" Giant Focuser and the dual-speed mechanism of the Feather Touch Micro are both realized in this superb focuser. The dual-speed feature is particularly advantageous for critical focusing of scopes with fast focal ratios. This focuser also features our new greaseless drawtube. Refer to the description and feature list above for dimensions and specifications that are in common with the standard focuser. The only difference between the standard focuser and Feather Touch models is the pinion/block/knob assembly. If you are upgrading an existing 4" focuser and do not wish to purchase the adapters (you already own them), select S4FOC3E-FT. In this case, you may wish to purchase ADA2003A as a separate item, if you prefer the security of the new design with three thumbscrews. Please notice the drawtube position scale that has been incorporated into all our focusers to help with set up and focusing precision. (2.7" focuser shown) |
Who should choose this focuser?
|
A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. The focuser has 4.125" (105 mm) of travel and weighs 10.15 lbs. (4.60 kg.). | |
NO LONGER AVAILABLE
Back to top
Astro-Physics
4" Giant Focuser with Feather Touch Micro, without Adapters (S4FOC3E-FT)
![]() |
What if you already own one of our 4" focusers, but want the new greaseless drawtube and Feather Touch Micro features? This option is for you. We offer S4FOC3E-FT, which is the new assembly without the adapters (2.7", 2" and 1.25") or focuser extension. After all, you already own these parts from your previous focuser. Please refer to the description of 4FOC3E-FT for a description of this focuser and ignore the information regarding the adapters. Keep in mind that all of the adapters can be purchased as a separate item, if you need a replacement. You may want to consider the newer version of the 2" adapter that has 3 locking screws (ADA2003A). Please notice the drawtube position scale that has been incorporated into all our focusers to help with set up and focusing precision. (2.7" focuser shown) |
Who should choose this focuser?
A digital focusing system is available for imaging automation. Visual observers may also enjoy using the available hand paddle with the digital system. See the Focuser Boss II Electronic Focusing Control Kit for more details. The focuser has 4.125" (105 mm) of travel and weighs 8.70 lbs. (3.95 kg.). |
NO LONGER AVAILABLE
Back to top
Extension with Brass Locking Ring for 4" Focuser (4FOCEXT)
![]() |
This accessory provides 2.2" of extension with an overall length of 3". It is typically used in lieu of a diagonal when straight-through viewing is desired. The extension features our brass locking ring and two large thumbscrews. Slip it into the drawtube of the Giant 4" Focuser, then insert one of our 4" to 2.7" adapters or any other accessory that you produce. The ID of the extension is 4.3", the same as our 4" focuser drawtube. Note the tapered barrel of the focuser end. This tapered profile assures a secure connection as the brass ring of the drawtube grabs the taper at the narrow diameter. This extension is provided when the 4" Focuser is shipped on our refractors, however we offer it as a separate item when the 4" focuser is purchased separately. This part was previously sold as S40FOCUET. We simplified the part number, but the design itself is unchanged. This extension has a net spacing distance of 2.2" (55.9 mm). |
3.5" Adapter for 4" Focuser (ADA435)
![]() |
Use the 0.72x QuadTCC with the 4” Focuser! This extension has a net spacing distance of 0.90" (22.9 mm). |
Focuser Boss II Electronic Focusing Control Kit
We are pleased to be able to offer the Starlight Instruments Focuser Boss II Electronic Focusing Control Kit for digital focusing of our telescopes. This wonderful system allows computer controlled focusing to be added to our 2.7" (27FOC3E-FT and TFOC3E-FT ) and 4" (4FOC3E-FT) focusers that are fitted with the Feather Touch Micro. It is also compatible with the Riccardi-Honders 3.5" Focuser (PDM version only). This superbly CNC-machined, all aluminum kit is a worthy addition to your Astro-Physics scope. The ergonomic Hand Controller is convenient, whether you’re at the eyepiece, or choose to manually focus your imaging. Intuitive software works invisibly with your autofocus programs, such as FocusMax™, when you want to sit back and let the computer do the work. The kit is available with a choice of two different motors. Both consist of a Control Hub, a Hand Controller, a motor (either the high-torque HSM Motor or the heavy-duty Posi Drive Motor) and the required cables. Your choice of AC transformer or 12 volt DC power connector is also included. |
|
![]() |
The HSM (Handy Stepper Motor) motor takes motorized focusing to a new level. Its radical design allows you to switch from motorized to hand focusing by a simple twist of the motor housing. By utilizing the reduction assembly for attachment, it provides high precision focusing. The high-torque motor provides all the power needed to lift your camera / filter wheel combo. Each unit incorporates a built-in temperature sensor. The PDM (Posi Drive Motor) motor is designed for the heaviest imaging packages. This new motor connects directly to the pinion shaft of the focuser and not the reduction assembly, which eliminates any slip and offers precise repeatability with heavier payloads. It has been tested with loads up to 56 lbs.! |
The PDM has 24,000 steps of the motor per turn of the focuser pinion for extremely fine resolution. A drive disconnect system is built in should you need to switch to manual focus without dismantling the system. Each unit incorporates a built-in temperature sensor. Note: The Riccardi-Honders requires the use of the PDM motor, rather than the HSM motor, due to the dimensional restrictions of the scope's handles. This only applies to the Honders. |
|
![]() |
![]() |
Included with kit:
|
|
Order additional motors for multiple scopes:
|
|
Optional Control Hub upgrades (above right):
|
|
Links to software: |
Adapters and Extensions for all Focusers and Related Parts
1.25"
Adapter (ADA125)
![]() |
The 1.25" adapter is included with our focusers (and refractors); however, we also offer it as an accessory to use with any telescope. It slips into a 2" opening and is used for 1.25" accessories. It features a brass locking ring and is threaded for 48 mm filters. Please note that if you use long-barreled eyepieces, such as TeleVue Radians, you may strike the filter. In this case, we suggest that you add our 2" Barrel Extension w/ 48 mm Threads (A3703) to the bottom of the adapter before installing the filter. Alternatively, install the 48 mm filter on our 2" MaxBright Diagonal (PMDMAX). |
2" Adapter With 3 Large Machined Thumbscrews (ADA2003A)
![]() ![]() |
Custom CNC machined thumbscrews provide an elegant update to our 2" compression adapter. Use this adapter for critical applications and heavy loads, i.e. to center your CCD camera securely for an imaging run. Threads into our 2.7", 3.5" and 4" focusers. If you prefer to use just one thumbscrew on occasion (perhaps if you are interchanging accessories frequently), simply remove the extra 2 thumbscrews for that session. This adapter is also perfect with our ADASCTLM27 Adapter for large Meade SCT's and our ADASCTLC27 Adapter for large Celestron SCT's. This adapter attaches via 2.7" male threads. This adapter has a net spacing distance of 0.77" (19.6 mm). |
Back to top
2" Thin Adapter with 3 Thumbscrews
(ADA20132)
![]() |
Use this adapter for critical applications and heavy loads where more in-travel is required. This adapter is 11/32" thinner than our regular 2" Adapter. It threads into our 2.7", 3.5" and 4" focusers. If you prefer to use just one thumbscrew on occasion (perhaps if you are interchanging accessories frequently), simply remove the extra 2 thumbscrews for that session. This adapter attaches via 2.7" male threads. This adapter has a net spacing distance of 0.43" (10.9 mm). |
Back to top
2.7" Thread-On Extensions for Astro-Physics Focusers and
Accessories (A3502-A, A3503-A, A3504-A, A3505, A3506, A1008-A)
This series of extensions is designed to utilize the robust 2.7" Astro-Physics thread size, while providing a variety of lengths for use with barlows, telecompressors and camera systems. These extensions can be used in various combinations to achieve the perfect spacing distance for your system. These extensions thread directly into the drawtube of the 2.7" focuser and into the 4" to 2.7" Adapter (A1024), or its shorter version (A1024-A), which fit the 4" focuser. They feature knife-edge baffles and an interior that is painted flat black to eliminate internal reflections. Accessories with 2" nosepieces can easily be attached by using the ADA2003A, ADA20132, ADA200 (discontinued), or ADA2013 (discontinued) 2" Adapters with Thumbscrews. Thread-on Extension with the following applications:
The re-design of these extensions include a lip on the outer diameter to prevent the extension from being racked inside the focuser housing. |
![]() |
A3505 This extension has a net spacing distance of 0.60" (15.2 mm).
|
![]() |
A3503-A This extension has a net spacing distance of 0.75" (19.1 mm).
|
![]() |
A3506 This extension has a net spacing distance of 0.90" (22.9 mm).
|
![]() |
A3504-A This extension has a net spacing distance of 1.25" (31.8 mm).
|
![]() |
A3502-A This extension has a net spacing distance of 1.75" (44.5 mm).
|
![]() |
A1008-A This extension has a net spacing distance of 2.55" (64.8 mm).
|
You may prefer a sturdier cover than the included plastic plug. Astro-Physics also offers an optional aluminum cover that will accommodate this part, depending on your storage needs. Please review the information regarding the Threaded Cover for AP 2.7" Drawtubes and Accessories with 2.7" Female Threads (A1005). This part can also accommodate the Threaded Cover for AP 2.7" Field Flatteners and Accessories with 2.7" Male Threads (A1225). More information can be found on our Accessory Reference Chart for 2.7" Threaded Covers. |
Back to top
2" Extension - Length 1.8" (ADA202)
![]() |
This extension slips into a 2" opening and can be used with 2" accessories or the 1.25" adapter. It features our brass locking ring to hold your accessories firmly. The overall length is 3" and it is threaded for 48 mm filters. This extension has a net spacing distance of 1.8" (45.7 mm). |
![]() |
Back to top
2" Extension - Length 3.6" (EXTTLR)
![]() |
Use this extension when you require additional length. It slips into a 2" opening and can be used with 2" accessories or the 1.25" adapter. It features our brass locking ring The overall length is 4.8" and it is threaded for 48 mm filters. This extension has a net spacing distance of 3.6" (91.4 mm). |
Back to top
2" Adapter for 2.7" Focuser to use SCT Accessories (ADA204)
![]() |
If you have thread-on accessories for an SCT and own one of our refractors, a Ritchey-Chretien with an Astro-Physics focuser or built your scope with our 2.7" focuser, you will appreciate this item. This adapter threads into our drawtube and has SCT threads on the accessory side. For owners of larger Meade SCT's with the 3.25" rear cell, simply thread this adapter into our ADASCTLM27 or ADASCTLC27 and you no longer need your Meade or Celestron 2" visual back. The ADA204 is also popular with owners of Finger Lakes Instrumentation CCD cameras. It can be used with several configurations of Astro-Physics CCD Adapters and 2.7" Extensions to reach proper backfocus distances for the particular combination of components you are using. This adapter has a net spacing distance of 0.3" (7.6 mm). |
Back to top
2" Adapter for 9.25" SCTs and under, with Brass Locking Ring (ADASCT)
![]() |
This visual back fits rear cells that have a 2" opening with a 24 TPI (threads per inch) male thread. It can be used with the 8", 9.25" (except the 9.25" Celestron EdgeHD) or other SCT with the standard SCT rear cell. It can also be used with the Maksutov-Cassegrain scopes from Telescope Engineering Company (TEC) that have this specification. Note: Celestron EdgeHD scopes recommend a 146 mm back spacing distance (reference Celestron Tech information). Contact Celestron for further information. This adapter has a net spacing distance of 2.1" (53.3 mm). |
Back to
2" Adapter with Brass Locking Ring and 3 Large Thumbscrews - for larger SCTs with 3.25" Rear Cell, (ADASCTLC and ADASCTLM)
![]() |
This 2" visual back threads onto the rear cell of 10" to 14" SCTs with 3.25" male threads on the telescope's rear cell. It provides a full 2" unobstructed opening (unlike most visual backs). Use with 2" accessories that slip in, i.e. 2" diagonal, Barlow, 2" eyepiece or binocular viewer. It features our unique brass locking ring design and 3 large thumbscrews to hold your accessories securely and squarely; ideal for critical applications. If you prefer to use just one thumbscrew on occasion (perhaps if you are interchanging accessories frequently), simply remove the extra 2 thumbscrews for that session. We offer two models with slightly different thread specifications. Please verify that your instrument has a 3.25" male thread on the rear cell before ordering. This adapter does NOT fit the 16" or 20" Meade telescopes with 4" rear cells. Note: Celestron Edge HD scopes have a restricted rear cell that may not allow accessories with a long nosepiece to fully seat in this adapter (the AP Maxbright diagonal will not seat). It is recommended to choose the ADASCTLC27 and ADA2003A (or ADA20132) as an alternative when using the Edge HD scopes. Note: Celestron EdgeHD scopes recommend a 146 mm back spacing distance (reference Celestron Tech information). Contact Celestron for further information. ADASCTLC - for 11 and 14" Celestron SCTs This adapter has a net spacing distance of 1.5" (38.1 mm). |
Back to top
2.7" Adapter Threads onto larger Meade SCT’s with 3.25" Rear Cell - Allows the Use of AP 2.7" Accessories (ADASCTLM27)
Please verify that your instrument has a 3.25" male thread on the rear cell before ordering. This adapter does NOT fit the 16" or 20" Meade telescopes with 4" rear cells. The adapter is one-piece, machined aluminum and is anodized black. See SCT System Chart for examples of usage. Note: Meade uses a 3.25" x 16 thread. This adapter has a length of 2.5" (63.5 mm). Meade SCTs mesures the spacing distance from the end of their male threads which bottom against the inside flange of this adapter. That makes the net spacing distance of this adapter 2.1" (53.3 mm). |
Back to top
2.7" Adapter Threads onto larger Celestron SCT’s with 3.25" Rear Cell - Allows the Use of AP 2.7" Accessories (ADASCTLC27)
![]() |
This 2.7" threaded back allows the use of Astro-Physics 2.7" accessories with 11" & 14" Celestron SCT’s and EdgeHD's and the Celestron 9.25 EdgeHD. Note: Celestron EdgeHD scopes recommend a 146 mm back spacing distance (reference Celestron Tech information). Contact Celestron for further information. The accessory back was designed primarily to accept the popular 0.75x, 2.7" Photo-Visual Telecompressor (27TVPH), but it will also work well with other accessories. Combine it with our 2" adapter (ADA2003A) or our thin 2" adapter (ADA20132) and you have an unobstructed 2" visual back. Screw in our ADA204 2.7" to 2" SCT Adapter and you are right back to the standard Celestron 2" visual back. Attach our 2.7" to 6x7 Outer Bayonet Adapter (ADA2767) along with either of the STL Adapters for the 6x7 Outer Bayonet (ADA671 & ADA672), and you have the maximum available light path to your STL Series camera, and easy image framing to boot! Virtually any accessory from 2.7" diameter on down in size can be used with this adapter, greatly increasing the versatility of your large Celestron SCT. |
![]() |
See SCT System Chart for examples of usage. Note: Celestron uses a 3.29" x 16 thread. This adapter has a length of 2.5" (63.5 mm). Celestron SCTs mesures the spacing distance from the end of their male threads which bottom against the inside flange of this adapter. That makes the net spacing distance of this adapter 2.1" (53.3 mm). |
Back to top
Threaded Cover for Astro-Physics 2.7" Drawtubes and Accessories with 2.7" Female Threads (A1005)
This versatile cover was designed to protect your focuser from gathering dust when not in use. It has 2.7" male threads and can be threaded into any Astro-Physics 2.7" focuser, as well as the Traveler focuser. The front side of the A1005 bears the Astro-Physics name engraved on the center flat surface. |
Copyright © 2012, Astro-Physics, Inc. - All Rights Reserved
This page was last modified:
October 23, 2018
Astro-Physics, Inc.
11250 Forest Hills Road, Rockford, IL 61115, U.S.A.
Phone: 815-282-1513 Fax: 815-282-9847