Agena StarGuider II 50mm Finder / Mini Guide Scope with Helical Focuser for CCD Autoguiding

Agena's compact 50mm StarGuider II Mini Guide Scope with Helical Focuser package will be just the ticket for your long exposure astrophotography autoguiding needs. It is an excellent accessory for telescopes with a focal length of up to 1500mm, and is perfectly suited for use with small-chip CCD autoguiders. Its light weight adds very little to your autoguiding setup thus putting less strain on your mount's tracking mechanism, allowing for smoother guiding. A guidescope is a must for accurate astrophotography exposures even with high precision mounts. And the price of this accessory will add little strain to your astrophotography budget.

The StarGuider II features a 50mm fully-multicoated achromatic doublet objective. Its 162mm (f/3.2) short focal length design provides a bright, wide field which aids in the location of suitable guide stars. All internal surfaces of the tube are painted a flat black to improve contrast.

The helical focuser on the StarGuider II retains a fixed orientation so that your CCD autoguider will not rotate during focus adjustments. The focuser moves the autoguider in or out while maintaining its orientation relative to the light path. This ensures that the guide star field stays fixed while focus adjustments are made.

The helical focuser has a 12.5mm travel range and is designed to produce zero backlash. This eliminates flexure while focusing. The helical focuser ring is ribbed to improve grip and a thumbscrew locks the focuser in place once best focus is achieved.

In addition to an optical tube with a helical focuser, this package includes an adjustable finder bracket, a universal dovetail mounting base, as well as an adapter plate to allow you to easily mount this guide scope on a variety of telescopes in various configurations. The bracket should also fit directly into the Synta/Vixen style finder bases already found on many telescopes, without the need for the included mounting plate/base (although these are also provided should the need arise). However, please note that although this base has a standard Vixen/Synta style design, there is no standard defined size for this design. As a result, it is possible that this bracket may not fit into other bases and some filing/adaptation may be required.

The 1.25" autoguider receptacle features three locking thumbscrews for a secure fit. Simply insert the 1.25" nosepiece of your CCD camera and tighten. Couple this package with a main scope and a 1.25" autoguider CCD, and you will be ready to experience a new level of accuracy that autoguiding brings to long exposure astrophotography - without the bulk and expense of a larger dedicated guide scopes that were formerly required. The camera-end of the 1.25" eyepiece holder also features a short male T / T2 thread (M42x0.75) on the outside.

Focusing is achieved by turning the helical focuser ring at the rear of the scope. The CCD will not rotate during focus adjustments. Using the included parfocal ring on the autoguider or CCD camera nosepiece provides some more focusing flexibility, and it also allows you to repeat the autoguiding setup between different imaging sessions.

Specifications:
- Objective Diameter = 50mm
- Focal Length = 162mm
- Focal Ratio = f/3.2
- Fully multicoated, air-spaced achromatic doublet objective lens with smooth helical focus
- OTA Material = Aluminum
- OTA weight (with finder bracket and end caps) = 1 lb - 8.3 oz
- OTA length = 180mm (7.09")
- Main OTA diameter = 53.4mm (2.10")
- Dewshield outside diameter = 57.45mm (2.26")
- CCD locking screws = 2x, M4 threaded aluminum
- Helical Focuser locking screw = 1x, M4 threaded aluminum
- Finder adjustment screws = 2x, M6 threaded plastic (may be white or black)
- Flat mounting plate hole specifications = Center hole, 1x, M6 thread (not 1/4"-20 thread); Holes on sides, 2x, M4 thread
- 1.25" parfocal ring weight = 0.2oz; Vixen-style dovetail base weight = 1.5oz; Flat mounting weight plate = 1.8oz

What’s Included and What's Not:
A 50mm achromatic doublet guidescope with helical focuser, finder bracket, dovetail base, flat mounting plate, 1.25" aluminum parfocal ring, Allen wrench (hex key), objective end cap, and 1.25" dust plug are included. Please note that no instruction sheet is included, but you can find this easily online for similar guidescopes. Also note that no CCD is included but compatible CCD cameras are readily available. The only requirement is that the CCD has a 1.25" nosepiece installed.