Meade ETX-90EC instruction manual Optional Accessories

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OPTIONAL ACCESSORIES

The Meade #126 2x Barlow lens is an achromatic, high- performance, short-focus Barlow Lens, perfectly suited to the low-profile design of both ETX models. Lens surfaces are multi- coated for maximum image contrast and light transmission.

#825 8 x 25mm Right-Angle Viewfinder: Included as standard- equipment on ETX-125EC models, the 8 x 25mm Right-Angle Viewfinder (Fig. 27)

permits a comfortable 90° viewing position with 90mm ETX models as well. The #825 fits into the same bracket as the 8x21mm viewfinder sup- plied with ETX-90EC telescopes. The finder’s

wide-angle 7.5° actual Fig. 27: #825 Right-Angle field facilitates object Viewfinder.

location and a helicoid mechanism allows precise focusing.

#64 T-Adapter:The basic means of photography through any ETX telescope, the #64 T-Adapter (1,Fig. 28) threads to the rear cell of the telescope, followed by a T-Mount appropriate to the user’s brand of 35mm camera. In this way, the camera body is rigidly coupled to the telescope's optical system, which in effect becomes the camera's lens (seePHOTOGRAPHYWITHBOTH ETX MODELS, page 15).

#880 and #881 Table Tripods: ETX-90EC and ETX-125EC models permit pushbutton tracking of astronomical objects from their standard-equipment Electronic Controllers. For fully automatic tracking a table tripod (Fig. 28), or the #883 Deluxe Field Tripod may be added allowing for polar alignment of the telescope.

#1422 Low-Latitude Balance Weight (for ETX-90EC): If the ETX-90EC is to be used with the #880 Table Tripod and polar- aligned at latitudes below 30°, the telescope can become unbalanced, particularly if heavier accessories (e.g., a camera body) are attached to the eyepiece-end of the telescope. The low-latitude balance weight (4, Fig. 28) slides onto the standard tripod leg and enables rock-solid stability of the telescope even at lower latitudes.

NOTE:The low-latitude balance weight for the ETX-125EC is supplied with the #881 Table Tripod and is recommended for use at all latitudes covered by the standard tripod leg.

#883 Deluxe Field Tripod: Manufactured of strong, lightweight extruded aluminum, the #883 Deluxe Field Tripod (Fig. 29) allows standing or seated observations through both ETX models. Tripod height is continuously adjustable from 34” to 54”. Micrometric controls in both azimuth and elevation-angle permit precise polar alignment of the telescope’s fork mount for astronomical applications (inset, Fig. 29).

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Fig.28: Example of astronomical photography using the #880 Table Tripod with an ETX-90EC. (1) #64 T-Adapter;

(2)Standard tripod leg; (3) Fixed tripod legs;

(4)Balance weight; (5) High-latitude tripod leg.

Each table tripod includes two fixed legs and two variable-length legs inscribed with a range of latitude settings for quick polar alignment. The #880 Table Tripod (for the ETX–90EC) and #881 Table Tripod (for the ETX-125EC) attach quickly to the telescope drive base.

Two identical fixed tripod legs (3, Fig. 28) mount to holes on the side of the drive base. The adjustable standard tripod leg (2, Fig. 28), with its two latitude scales, is mounted to one of two holes on the bottom of the drive base. It permits the telescope to be polar aligned for latitudes between 22° and 48.5° (ETX-90EC) or between 23.25° and 49.5° (ETX-125EC). The shorter high- latitude tripod leg (5, Fig. 28) is substituted for the standard tripod leg at latitudes between 44° and 66° (ETX-90EC) or 44.5° and 67° (ETX-125EC).

Fig. 29: The #883 Deluxe Field Tripod shown with an ETX- 90EC Astro Telescope, set up in the Alt/Az configuration (tripod head locked at 90°), for terrestrial applications. (Inset) Tripod head tilted for polar alignment.

Designed exclusively for both ETX model telescopes, the #883 Deluxe Field Tripod includes all the rigidity and stability required for high-power observing through the telescope. For terrestrial observing, where altazimuth orientation of the telescope is desirable, the tripod head tilts and locks at 90°.

#932 45° Erecting Prism: All ETXmodels include an internal optically-flat mirror to reflect light to the telescope’s 90° astronomical observing position. In this position the telescope’s image is upright, but reversed. For terrestrial observing with either ETX model, the #932 45° Erecting Prism (1, Fig. 30) gives a fully correctly oriented image and a convenient 45° observing angle. The #932 prism threads onto the telescope’s photo port (17, Fig. 1). An eyepiece of any focal length (magnifying power) may be inserted into the #932 prism. Note that the flip-mirror control (4, Fig. 30) must be in the “down” position for use with the #932 prism.