Focusers, Adapters and Extensions
2.7" and Traveler Focusers and Feather Touch Upgrade 4" Giant Focusers, Feather Touch Upgrade and Dedicated Accessories Adapters and Extensions for all Focusers and Related Parts 2.7" and Traveler Focusers and Feather Touch Upgrade

Feather Touch Micro Upgrade for Astro-Physics 2.7" and Traveler Focusers (27FTMU)


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 recommend the dual-speed focuser for those who do mostly visual astronomy and manual focusing with imaging equipment. If you plan to use electric focusing motors and accessories, we recommend that you use model 27FOC3E, featuring the standard pinion block/knob assembly.

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 on the bottom of the pinion block of your focuser to these photos. Focusers that can be upgraded must have the current hole pattern (pinion block A1034-A).

If your Traveler was shipped between March - September 2001 and your pinion block looks like this (part # A1034), please give us a call for special instructions.

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. These early pinion blocks are shown as part # A1004 and look like this. 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 Feather Touch Micro Dual-Speed Knobs .

27FTMU$415.00 Call Contact Astro-Physics about 27FTMU
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Astro-Physics 2.7" Focuser (27FOC3E)

Our 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.

Features:

  • 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 48mm 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 lbs (2.4 kg)

If you prefer the Feather Touch Micro 9:1 dual-speed option, you may wish to consider the 27FOC3E-FT model.

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.

Instructions for installation: To substitute focusers, simply loosen the set screw on the underside of the original focuser and thread the focuser from the tube. Do not use the knobs for leverage, or you may bend the pinion gear. Attach the new focuser, position with respect to the finder bracket holes, tighten the set screw and you are ready to go.

27FOC3E$645.00 Call Contact Astro-Physics about 27FOC3E
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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. 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.

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 information.

    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.

  • 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).

Instructions for installation: To substitute focusers, simply loosen the set screw on the underside of the original focuser and thread the focuser from the tube. Do not use the knobs for leverage, or you may bend the pinion gear. Attach the new focuser, position with respect to the finder bracket holes, tighten the set screw and you are ready to go.

27FOC3E-FT$860.00 Call Contact Astro-Physics about 27FOC3E-FT
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Astro-Physics Traveler Focuser with Feather Touch Micro (TFOC3E-FT)

The Traveler 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 tube. All other construction features and specifications are the same. The new TFOC3E-FT focuser offers critical focusing and a greaseless drawtube. Both of these are attributes that Traveler owners will find appealing.

To replace the focuser, simply thread the original one off (counter clockwise) and the new one on. 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.

If your scope was shipped after July 1, 2001, please consider the Feather Touch Micro Upgrade (27FTMU). If you are not sure, please review this information.

We are unable to offer this focuser to ATMs since it is specifically engraved "Traveler".



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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 recommend the dual-speed focuser for those who are primarily visual astronomers and for manual focusing with imaging equipment. If you plan to use electric focusing motors and accessories, we recommend that you do not upgrade at this time.

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 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 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) .

4FTMU$540.00 in stockAdd 4FTMU To My Cart
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Astro-Physics 4" Giant Focuser (4FOC3E)

The Astro-Physics 4 Giant Focuser is truly versatile. The 4.3 ID of the drawtube will allow maximum coverage of your negative for medium format photography, in addition to the usual pursuits of 35mm photography, CCD imaging or visual astronomy. Although the drawtube has always been 4.3", we have refered to this as a 4" Focuser. That designation probably came about because it was provided with scopes that had a 4" Field Flattener.

The Giant 4 Focuser has evolved over the years to be a very finely-crafted unit with several unique features. The components are machined to very 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 4.3", which allows the avid astrophotographer to use a medium-format camera to capture images without vignetting (assuming that the camera opening and all other adapters allow full coverage). 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 integral 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, enormous CCD imaging cameras, 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, all adapters and accessories are held securely in place. As an added advantage, the brass will not mar the surface of your accessories.

Who should use this focuser?

  • Upgrade scopes that already have prior version of 4 Focuser. These scopes include the Astro-Physics 155 f7 StarFire EDF, 180 f7 StarFire EDF and 206 f8 StarFire EDF. It may also include instruments that were manufactured by other telescope makers using our 4 Focuser or instruments crafted by amateur telescope makers (assuming that the original 4 focuser was not modified in any way). To upgrade, simply remove the screws that hold the original one in place. Slip the focuser out and insert the new one. Replace the screws and you are ready to go. It couldn't be easier.

  • Upgrade Astro-Physics 155 f7 StarFire EDF refractors originally sold with the 2.7 focuser. Choose this option if you plan to purchase the 4 Field Flattener for the 155 (S155EDFFF) or if you like the feel of a an excellent large focuser. To upgrade, remove the screws that hold the 2.7 focuser and the adapter piece ahead of it. You will notice that the new 4 Focuser is the same length as these two components together. Bolt the new 4 Focuser into place and you are ready to go. There are no collimation issues to consider.

  • Amateur telescope makers. 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). If you are showcasing a fine large lens, this focuser is particularly suitable given its proportions and weight. You will need to offset the weight of the lens with comparable weight in the rear of the tube assembly in order to achieve a balance point near the center of the tube.

The 4FOC3E version includes large, standard knobs. If you prefer the Feather Touch Micro 9:1 dual-speed option, you may wish to consider the 4FOC3E-FT model. If you are upgrading an existing 4 focuser and do not wish to purchase the adapters (you already own them), select S4FOC3E-FT or S4FOC3E . In this case, you may wish to purchase ADA2003 as a separate item, if you prefer the security of the new design with three thumbscrews.

Features:

  • Greaseless drawtube.
  • Inside diameter of drawtube is 4.3".
  • All components are machined of high quality aluminum. Housing is black-anodized .
  • Brass locking rings to secure focuser drawtube, 2.7" adapter and 2" and 1.25" accessories
  • 2" adapter is aluminum, black-anodized and threads into the 2.7" adapter. It has a brass locking ring and 3 thumbscrews. The extra two thumbscrews provide an extra measure of security for yur heaviest and mosst valuable accessories. If you prefer a single thumbscrew, simply remove the extra ones and store them for later use. This component is also sold separately as ADA2003.
  • 1.25" adapter is aluminum, black-anodized and is threaded for 48mm filters. It has a brass locking ring with thumbscrew and slips into the 2" adapter or 2" diagonal. It is also sold separately as ADA125.
  • 4.3" to 2.7" adapter (A1024) allows you to simulate a 2.7" drawtube, which is needed in order to use the .75x Telecompressor (27TVPH) and to attach the 2" adapter for use with visual and photographic accessories. It also allows you to use any other extensions that thread into the 2.7" opening (A1008, A3502, A3503, A3504). This adapter can be rotated, which allows you to more easily frame your photographic objects. It is machined of aluminum and black-anodized.
  • Focus travel with the 2" adapter is 4.2"
  • Focus travel with 2.7" Telecompressor (27TVPH) is 4.2"
  • Overall length of the focuser when fully racked in without any adapters is 6.5".
  • Overall length of the focuser when fully racked in with 2" adapter is 8.25".
  • Overall length of the focuser when fully racked in with 1.25" adapter is 8.5".
  • Weight of the focuser with the 2.7", 2" and 1.25" adapters is 10 lbs (4.5 kg).
  • Weight of the focuser without any adapters is 8 lbs. (3.6 kg).
4FOC3E$695.00 NO LONGER AVAILABLEAdd 4FOC3E To My Cart
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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 prefer the 4 Giant Focuser with the standard knobs, you may wish to consider the 4FOC3E model. If you are upgrading an existing 4 focuser and do not wish to purchase the adapters (you already own them), select S4FOC3E-FT or S4FOC3E . In this case, you may wish to purchase ADA2003 as a separate item, if you prefer the security of the new design with three thumbscrews.

Who should choose this focuser?

  • Upgrade scopes that already have prior version of 4 Focuser. These scopes include the Astro-Physics 155 f7 StarFire EDF, 180 f7 StarFire EDF and 206 f8 StarFire EDF. It may also include instruments that were manufactured by other telescope makers using our 4 Focuser or instruments crafted by amateur telescope makers (assuming that the original 4 focuser was not modified in any way). To upgrade, simply remove the screws that hold the original one in place. Slip the focuser out and insert the new one. Replace the screws and you are ready to go. It couldn't be easier.


  • Upgrade Astro-Physics 155 f7 StarFire EDF refractors originally sold with the 2.7 focuser. Choose this option if you plan to purchase the 4 Field Flattener for the 155 (S155EDFFF) or if you like the feel of an excellent large focuser. To upgrade, remove the screws that hold the 2.7 focuser and the adapter piece ahead of it. You will notice that the new 4 Focuser is the same length as these two components together. Bolt the new 4 Focuser into place and you are ready to go. There are no collimation issues to consider.


  • Amateur telescope makers. 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). If you are showcasing a fine large lens, this focuser is particularly suitable given its proportions and weight. You will need to offset the weight of the lens with comparable weight in the rear of the tube assembly in order to achieve a balance point near the center of the tube.


If your Astro-Physics refractor with the 4 Focuser was shipped later than October 1, 2001, you may wish to consider the Feather Touch Micro Upgrade (4FTMU) rather than replacing the entire focuser. Not sure? Please review this information.

4FOC3E-FT$1,453.00 Call Contact Astro-Physics about 4FOC3E-FT
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Astro-Physics 4" Giant Focuser with Feather Touch Micro, without the 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 (ADA2003).

Who should choose this focuser?

  • Upgrade scopes that already have prior version of 4 Focuser. These scopes include the Astro-Physics 155 f7 StarFire EDF, 180 f7 StarFire EDF and 206 f8 StarFire EDF. It may also include instruments that were manufactured by other telescope makers using our 4 Focuser or instruments crafted by amateur telescope makers (assuming that the original 4 focuser was not modified in any way).

    To upgrade, simply remove the screws that hold the original one in place. Slip the focuser out and insert the new one. Replace the screws and you are ready to go using the adapters that you already have. It couldn't be easier.


If you prefer the 4 Giant Focuser with the standard knobs without adapters, you may wish to consider the S4FOC3E model.

S4FOC3E-FT$1,327.00 Call Contact Astro-Physics about S4FOC3E-FT
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Astro-Physics 4" Giant Focuser with Standard Knobs, without the adapters (S4FOC3E)

If the standard knob configuration suits your needs, but you would like the advantage of the greaseless drawtube, you should consider this model. The S4FOC3E includes the drawtube, focuser body, and standard knob assembly. You add the 2.7", 2" and 1.25" adapters and focuser extension that you already own. Please refer to the description of 4FOC3E 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 separate items, if you need a replacement. You may want to consider the newer version of the 2" adapter that has 3 locking screws (ADA2003).

Who should choose this focuser?

  • Upgrade scopes that already have prior version of 4 Focuser. These scopes include the Astro-Physics 155 f7 StarFire EDF, 180 f7 StarFire EDF and 206 f8 StarFire EDF. It may also include instruments that were manufactured by other telescope makers using our 4 Focuser or instruments crafted by amateur telescope makers (assuming that the original 4 focuser was not modified in any way).

    To upgrade, simply remove the screws that hold the original one in place. Slip the focuser out and insert the new one. Replace the screws and you are ready to go using the adapters that you already have. It couldn't be easier.


If you prefer the 4 Giant Focuser with the Feather Touch Micro Dual-Speed knobs without adapters, you may wish to consider the S4FOC3E-FT model.

S4FOC3E-FT$1,327.00 Call Contact Astro-Physics about S4FOC3E-FT
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2.7" Adapter for 4" Focuser (A1024)

This adapter is provided with the complete Giant 4"; Focusers described above - 4FOC3E-FT and 4FOC3E. The tapered end slips into the 4.3"; drawtube and the brass locking ring of the drawtube holds it securely in place. When you loosen the thumbscrews of the drawtube slightly, this part can rotate allowing you to position your film, CCD or video camera to frame your objects.

The threads of the opposite side are the same as our 2.7"; drawtube (24 threads per inch), which allows you to use our .75x Telecompressor (27TVPH) alone for film or with our various threaded extensions (A3503, A3504,A3502) for CCD imaging. The 2" Adapter (ADA2003) threads in here, as well.

The length that extends from the 4.3"; drawtube connection is 1";, the overall length of this part is 1.6";. It is machined from aluminum and black-anodized. If you have this adapter, but find you need just a little more in-focus travel, consider either the shorter version of this part (A1024-A) or our Thin 2" Adapter (ADA2013).

A1024TBD TBD
Contact Astro-Physics about A1024
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Short 2.7" Adapter for 4" Focuser (A1024-A)

If you need just a little more in-travel to reach focus, consider this shorter version of A1024, described above. It is constructed in the same manner with the tapered portion on one end and threads to accept 2.7" accessories on the other, however it is shorter. The length that extends from the 4.3" drawtube is 3/8" long, so you will gain 5/8" more in-travel with this adapter compared with the one above.

A1024-ATBD TBD
Contact Astro-Physics about A1024-A
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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.

A1024-ATBD TBD
Contact Astro-Physics about A1024-A
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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 48mm filters. Please note that if you use long-barreled TeleVue Radians, you may strike the filter. In this case, we suggest that you install the 48mm filters in your 2" diagonal.
ADA125$40.00 in stockAdd ADA125 To My Cart
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2" Adapter With 3 Large Thumbscrews (ADA2003)
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" 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.

The 2" adapter version ADA200 with a single thumbscrew is no longer available.


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2" Thin Adapter With 3 Thumbscrews (ADA2013)
Use this adapter for critical applications and heavy loads where more in-travel is required. This adapter is 3/8" thinner than our regular 2" Adapter. Threads into our 2.7"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.


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Thread-On Extension for Astro-Physics Focusers - Length 0.75" (A3503)
This adapter threads directly into the 2.7" drawtube or the 4" to 2.7" adapter that is included with the 4" focuser. It features knife-edge baffles and the I.D. is painted flat black. The 2" adapter referred to below can be either ADA200 or ADA2003

Applications:
  • Use with the Telecompressor for CCD Imaging: Remove the 2" adapter from the focuser drawtube, thread on the Telecompressor, then A3503 and 2" adapter . Use this 0.75" length with your SBIG ST-7/ST-8/ST-10 or Finger Lakes Instruments CCD cameras with the Color Filter Wheel closely coupled to the CCD camera to provide the optimal 0.75x compression. You may wish to review the exploded diagram showing the A3503 with the Telecompressor. Note that this is a PDF file and requires Acrobat Reader v3.0 or above. Download the FREE Acrobat Reader.
  • As an extension: Remove the 2" adapter from the focuser drawtube, thread on A3503, then thread the 2" adapter on the other side. Note, you can thread two of these extensions together or with A3504, A3502 or A1008 to form a longer tube.


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Thread-On Extension for Astro-Physics Focusers - Length 1.25" (A3504)
It threads directly into the 2.7" drawtube or the 4" to 2.7" adapter that is included with the 4" focuser and contains the same knife-edge baffles and the I.D. is painted flat black. Note, you can thread two of these extensions together or with A3503, A3502 or A1008 to form a longer tube. Add your 2" adapter ADA200 or ADA2003 and you are ready to go.


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Thread-On Extension for Astro-Physics Focusers - Length 1.75" (A3502)
Itthreads directly into the 2.7" drawtube or the 4" to 2.7" adapter that is included with the 4" focuser and contains knife-edge baffles and the I.D. is painted flat black. The 2" adapter mentioned below can be either ADA200 or ADA2003.

Applications:
  • Use with the Telecompressor for CCD Imaging: Remove the 2" adapter from the focuser drawtube, thread on the Telecompressor, then A3502 and the 2" adapter. Use this 1.75" length with your SBIG ST-8/ST-10 or Finger Lakes Instruments CCD cameras (without a Color Filter Wheel) to provide the optimal 0.75x compression. You may wish to review the exploded diagram showing the A3502 with the Telecompressor. Note that this is a PDF file and requires Acrobat Reader v3.0 or above. Download the FREE Acrobat Reader.
  • As an extension: Remove the 2" adapter from the focuser drawtube, thread on A3502, then thread the 2" adapter on the other side. Note, you can thread two of these extensions together or with A3504, A3503 or A1008 to form a longer tube.


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Thread-On Extension for Astro-Physics Focusers - Length 2.5" (A1008)
Use this extension if you wish to observe straight-thru without a diagonal. It threads directly into the 2.7" drawtube or the 4" to 2.7" adapter that is included with the 4" focuser and contains the same knife-edge baffles and the I.D. is painted flat black. Note, you can thread two of these extensions together or with A3504, A3503 or A3502 to form a longer tube.


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2" Extension - Length 1.75" (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 48mm filters. This extension is included as part of our Convertible Barlow.

ADA202$50.00 in stockAdd ADA202 To My Cart
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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 48mm filters.
EXTTLR$75.00 in stockAdd EXTTLR To My Cart
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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. It is ideal for the new Adaptive Optics (AO) from Santa Barbara Instrument Group (SBIG).

ADA204$40.00 in stockAdd ADA204 To My Cart
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2" Adapter for 9.25" SCTs and under, with Brass Locking Ring (ADASCT)

This visual back threads onto your 8", 9.25" or other SCT with the standard SCT rear cell. It allows you to use 2" accessories that slip in, i.e. 2" diagonals, Barlows, 2" eyepieces or CCD camera. The brass locking ring and 2 thumbscrews set this adapter apart from others on the market. It will hold your expensive accessories with ease. Also fits DayStar T-Scanner cover that has male T-thread. This adapter measures 2.06" in length.

ADASCT$40.00 in stockAdd ADASCT To My Cart
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2" Adapter for 10" and larger SCTs, with Brass Locking Ring (ADASCTLC and ADASCTLM)

This 2" visual back threads onto the rear cell of 10" and larger SCTs (3.25" opening). 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:

ADASCTLC - for 11 and 14" Celestron SCTs
ADASCTLM - for 10" and larger Meade SCTs. Adapter cannot be used when the Microfocuser is attached to the LX200GPS .

ADASCTLC$60.00 in stockAdd ADASCTLC To My Cart
ADASCTLM$60.00 in stockAdd ADASCTLM To My Cart
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RoboBracket™ (JRFBRK)
The RoboBracket™ is a professionally fabricated aluminum bracket for accurately and securely attaching the Technical Innovations Robo-Focus™ remote focus driver to all modern Astro-Physics Focusers. This bracket can be used with all Astro-Physics 2.7" and 4" Focusers that have two 8-32 tapped holes available on the pinion block. Two 8-32x5/8" sockethead cap screws and two #8 washers are provided. It is unlikely that it will work with other focusers since the dimensions are specific to Astro-Physics focusers.

Photographs shown:

  • RoboBracket alone
  • RoboBracket attached to the Robo-Focus
  • RoboBracket with Robo-Focus attached
    Astro-Physics 2.7" focuser.
JRFBRK$52.00 NO LONGER AVAILABLEAdd JRFBRK To My Cart
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2" Desiccant Dust Cap from Particle Wave Technologies (PWDDC2)
Particle Wave Technologies Desiccant Dust Cap is now available in an exclusive Astro-Physics version. It was designed to close the 2" opening of your telescope and absorb the excess moisture in the air. Once inserted, the compression ring on the 2" adapter retains it in place, just like an eyepiece or a diagonal. We specified that the cover of the PWDDC2 be produced with a low, smooth, flat profile so that your telescope will fit nicely into your case. It is very easy to grip even with gloves.

The Desicant Dust Cap is comprised of two pieces, the neck and the handle, which are screwed together.

The neck is hollow and contains a chamber for storing desiccant. Once the desiccant (molecular sieve) is inserted in the chamber, the two halves are screwed together. A cleverly placed O-ring seals the chamber/threads from outside air and moisture.

The bottom of the Desicant Dust Cap (the base of the neck) has strategically placed openings to expose the desiccant to the interior of the optical tube. Once the Desicant Dust Cap is inserted into the optical tube, the same O-ring which seals the inside chamber and the threads from the outside air and moisture seals the interior of the optical tube, preventing moisture from entering the eyepiece end. The desiccant inside the Desicant Dust Cap then absorbs the moisture from the interior of the optical tube while keeping the dust out at the same time. A plastic cover is also provided so that when the cap is removed from the telescope during your observing session, you can cover the holes. This will prevent the desiccant from absorbing moisture from the outside air. Of course, Desicant Dust Cap can be used without the desiccant as a stylish and super quality dust cap. The Dust Cap is supplied with 6 refills of desiccant, including indicator packs.

The PWDDC2 can be used on any telescope with a 2" opening and with 2" accessories that have optical components. You may wish to consider one for your diagonal, for instance.

PWDDC2$60.00 NO LONGER AVAILABLEAdd PWDDC2 To My Cart
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20-Recharge Kit (PWRK20)

Kit includes 40 Desiccant Packs and 20 Indicator Packs for Desiccant Dust Cap from Particle Wave Technologies.
PWRK20$19.00 NO LONGER AVAILABLEAdd PWRK20 To My Cart
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Copyright © 2005, Astro-Physics, Inc. - All Rights Reserved
This page was last modified: September 26, 2005

Astro-Physics, Inc.
11250 Forest Hills Road, Rockford, IL  61115, U.S.A.
Phone: 815-282-1513   Fax: 815-282-9847