Astro-Physics 2.7" Focuser (27FOC3E)
The superb Astro-Physics focuser is a very finely crafted unit with several unique features. If you currently own an Astro-Physics refractor with a 2.7" focuser, you may wish to upgrade to this new greaseless version. This focuser is also a first-class choice for the do-it-yourselfer who takes pride in constructing his/her own tube assembly (we no longer offer a separate unengraved focuser for ATMs; you are welcome to use the engraved version). The components are machined to extremely high tolerances, assuring that there is no wiggle between the drawtube and housing. 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. The inside diameter (I.D.) of the drawtube is 2.7" which allows the avid astrophotographer to use a medium-format camera to capture images in a 2.25" x 2.25" format with minimal vignetting. The helical rack and pinion provides smooth motion, free of backlash or wobble, for precision focusing. Our machined aluminum knobs were designed with comfortable, firm handling in mind. The adapter thumbscrews are substantial and easy to grasp.
Brass locking rings are an important feature of our focuser. We realize that many of our customers use a variety of heavy and expensive accessories including 2 lb. eyepieces, 35mm and medium-format cameras, binocular viewers, etc. So, we designed our focuser with recessed brass locking rings at each thumbscrew location. As you tighten the thumbscrews), the brass locking ring clamps onto the part that has been inserted. Consequently, your focuser drawtube, and 2" and 1.25" accessories are held securely in place. As an added advantage, the brass will not mar the surface of your accessories.
- Greaseless drawtube.
- All components are machined of high quality aluminum. Housing is black-anodized .
- Brass locking rings to secure focuser drawtube, 2" and 1.25" accessories
- 2" adapter is aluminum, black-anodized, screws into focuser drawtube, brass locking ring and 3 thumbscrews. The extra two thumbscrews provide an extra measure of security for your heaviest and most valuable accessories. If you prefer a single thumbscrew, simply remove the extra ones and store them for later use. Also sold separately as ADA2003. Note: the photo above shows the adapter with a single thumbscrew.
- 1.25" adapter is aluminum, black-anodized, slips into 2" adapter or 2" diagonal, brass locking ring, thumbscrew, threaded for 48 mm filters. Also sold separately as ADA125.
- Inside diameter of focuser draw tube is 2.7". The thread pitch is 24 threads per inch.
- Focus travel with the 2" adapter is 4.4"
- Focus travel with telecompressor is 5.0"
- Overall length of the focuser when fully racked in with 2" adapter is 5"
- Overall length of the focuser when fully racked in with 1.25" adapter is 5.3"
- Weight of the focuser with the 2" and 1.25" adapters is 5.25 lb. (2.4 kg)
If you prefer the Feather Touch Micro 9:1 dual-speed option, you may wish to consider the 27FOC3E-FT model.
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.
- FeatherTouch Micro assembly with 9:1 dual-speed focusing knobs to allow fine adjustments for critical focusing.
- Focusing scale with "mm" graduations that will enable you to return to a particular position easily. (Photo above)
Who should use this focuser?
- Upgrade scopes that already have prior version of 2.7" focuser. This focuser is offered to owners of Astro-Physics refractors shipped prior to July 1, 2001 as a replacement for their original focuser. If your scope was shipped later than July 1, 2001, please consider the Feather Touch Micro Upgrade (27FTMU) rather than replacing the entire focuser. Not sure? Please review this focuser block information.
- Amateur Telescope Makers. This focuser is a great choice for do-it-yourselfers who are constructing their prize scope (we no longer offer a separate unengraved focuser for ATMs; you are welcome to use the engraved version).
The focuser includes the 2" (ADA2003A) and 1.25" (ADA125) adapters.
Weight is 5.6 lb. (2.5 kg).
External thread of the focuser housing is 4.875" x 24.
Astro-Physics Traveler-Style Focuser with Feather Touch Micro (I27FOC3E-FT)
This Traveler-style focuser is virtually identical to the 2.7" Focuser (27FOC3E-FT) 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 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.
Weight is 5.6 lb. (2.5 kg)
Internal thread of the focuser housing is 4.320" x 24
Note: Traveler end tube male thread is 4.300" x 24
Instructions for installation:
If you have a very early scope with an Astro-Physics cast aluminum focuser (painted black), Jaeger's 2" focuser with red knobs or a 2" Japanese style focuser, please read this.
To substitute focusers, simply unscrew the focuser from the OTA (counter clockwise) focuser and replace with the new one. Do not use the 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.
Accessories to consider:
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 Kits or the Posi Drive Motor System for more details.
Order additional motors for multiple scopes:
Select an additional HSM motor for your other telescopes:
FB2HSM20 for 2" Starlight focuser
FB2HSM30 for Stowaway 2.5" focuser
FB2HSM30 for AP 2.7" focuser
FB2HSM35 for AP 3.5" or 4" focuser
Select an additional PDM motor for your other telescopes:
FB2PDM30 for Stowaway 2.5" focuser
FB2PDM30 for AP 2.7" focuser
FB2PDM35 for AP 3.5" or 4" focuser