In every telescope, the focuser is attached close to the focal point of the light-gathering optic. Eyepieces can be connected to the focuser. For astrophotography, a camera is attached to the focuser, and the focuser serves to focus the camera.
Omegon
adapter for attaching a 2'' Crayford focuser to a Skywatcher OTA
$ 89.00
Omegon
Bundle comprising 80mm to 78mm adapter + adapter plate
RRP:
$ 138.90
Our price:
$ 89.00
Astroprints
ZWO EAF motor mounting kit for Starlight Instruments Feather Touch FT
$ 83.00
Astroprints
EAF motor mounting kit for William Optics SpaceCat and RedCat
$ 142.00
Astroprints
EAF motor mounting kit for Skywatcher Evolux
$ 95.00
Astroprints
EAF motor mounting kit for TS Optics 2" focuser
$ 106.00
Omegon
Bundle comprising adapter 80mm + adapter plate
RRP:
$ 133.90
Our price:
$ 89.00
Astroprints
EAF motor mounting kit with clamp for ASKAR FMA 180Pro
$ 118.00
Astroprints
EAF motor mounting kit for Askar ACL 200
$ 142.00
ZWO
CAA-M42 Adapter
$ 54.00
Astroprints
EAF motor mounting kit for William Optics RedCat 71
$ 142.00
Astroprints
EAF motor mounting kit for R&P 2" OTA
$ 71.00
Astroprints
EAF motor mounting kit for Askar FMA230
$ 142.00
Starlight Instruments
2'' focuser riser, extends by 1.4''
RRP:
$ 235.00
Our price:
$ 165.00
Astroprints
EAF motor mounting kit for TS Optics 2.5" focuser
$ 83.00
TS Optics
V-Power adaptors Crayford / Newton 340-360 mm
$ 254.00
TS Optics
V-Power adaptors Crayford / Newton 285-305 mm
$ 254.00
TS Optics
V-Power adaptors Crayford / Newton 225-245 mm
$ 254.00
Astroprints
ToupTek AAF motor attachment kit for Monorail 3" focuser
$ 106.00
Astroprints
ToupTek AAF motor attachment kit for TS Optics 3.7" Deluxe rack and pinion OAZ
$ 95.00
Astroprints
ToupTek AAF motor attachment kit for Baader Diamond Steeltrack BDS
$ 95.00
Astroprints
ToupTek AAF motor attachment kit for Crayford N2 focusers
$ 106.00
Astroprints
ToupTek AAF motor attachment kit for UNCN2-G2 and TSRPN2 focusers
$ 95.00
Astroprints
ToupTek AAF motor attachment kit for Starlight Instruments Feather Touch
$ 83.00
Astroprints
ToupTek AAF motor attachment kit for Monorail 2" focuser
$ 106.00
Astroprints
ToupTek AAF motor attachment kit for FOCR25 and FOCR25S focusers
$ 95.00
Astroprints
ToupTek AAF motor attachment kit for R&P 30 and R&P 30S OAZ
$ 95.00
Astroprints
ToupTek AAF motor attachment kit for Skywatcher Evolux
$ 95.00
Astroprints
EAF motor mounting kit for Starlight FTF True 3.5
$ 89.00
Astroprints
EAF motor mounting kit for Starlight FTF True 3.2
$ 83.00
Astroprints
EAF motor attachment kit for TS Optics Monorail N2
$ 106.00
Astroprints
EAF motor mounting kit for TS Optics 3.7" Deluxe OAZ
$ 95.00
Astroprints
EAF motor mounting kit for Monorail 3"
$ 141.00
TS Optics
Starlight Feather Touch 3" adaptors
$ 196.00
TS Optics
Motor focus mounting kit for TS 2.5" RPA focusers for TS Autofoc
$ 211.00
Starlight Instruments
2'' focuser riser around 2.75'' extension
$ 130.00
Skywatcher Crayford focuser on a Newtonian telescopeEyepieces and cameras are usually equipped with connector sockets. Two diameters have been established for the connector socket, which are specified in inches: 1.25" = 31.8mm and 2" = 50.8mm.
The focuser consists of two interlocking and sliding tubes, so that the eyepiece can be moved into focus using a small wheel. Not only eyepieces can be attached to focusers, but cameras as well.
Precise focusing is especially important for astrophotography. Therefore, high-quality focusers with reduction adjustment should be used for this application. For astrophotography, many focusers also have a connector thread, so that the camera is screwed into place instead of being be plugged in.
Simple focusers are adjusted using a rack and pinion mechanism. In the higher quality versions, this rack and pinion is angled and made of brass. Instead of a rack and pinion, the adjustment can also be made by exerting pressure on a special surface. Such focusers are usually referred to as Crayford focusers.
Helical focusers work in a completely different way. Here, the adjustment is made by rotating the inner barrel using a longitudinal screw (helix). One advantage is that a rotary knob is not necessary, which can get in the way, for example, of a guidescope.
As a rule, focusers can also be motorised. This improves focusing accuracy and also allows the remote operation of the telescope.