User manual MEADE MA 12MM

[. . . ] Astrometric Reticle Scales: There are 4 reticle scales etched into the glass reticle (Fig. 2) of the eyepiece that correspond to the table below: Scale 1 Type Linear Diameter Scale Semicircular Position Angle Scale Description 0 to 50 Units; Segmented in Single Units with Circular Center Position 0 to 90 Degrees with Circular Center Position ® 3 1 MEADE MA ASTROMET ILLUMINATED 2 Fig. (1) Eyelens Focuser; (2) Red LED Illuminator with Continuously Variable Brightness Control; (3) Brightness Control Knob. Take three timings (in seconds) of a star as it crosses the Linear Diameter Scale. [. . . ] Tighten the set-screw of the eyepiece holder to lock the position. Find the object that the position angle is measured for (e. g. , discernable edge or center line of a comet's jet or tail that extends across the eyepiece field of view). Read the position angle. 3. For example, if the nucleus of a comet is placed in the center of the Linear Diameter Scale, and the center of the tail (the object the PA measures for) is in-line with the first segment after 300 on the Position Angle Scale, then the PA of the center of the comet's tail is 305°. 3. 6. Important Note: The Position Angle Scale reads clockwise from 0° to 360° as used through mirror-lens Cassegrain telescopes (e. g. , Schmidt-Cassegrain, Maksutov-Cassegrain), or refractors where a diagonal mirror/prism is being used. If the Astrometric Eyepiece is being used without a diagonal prism or through a Newtonian reflecting telescope, the position angle reading should be reversed (e. g. , 90° translates to 270°). If the PA of a double-star, or other closely spaced objects is to be measured, use the Semicircular Position Angle Scale (2, Fig. To make a measurement on this scale follow the same steps outlined above, but with these important differences: · The Semicircular Position Angle Scale reads from 0° to 90° clockwise and counterclockwise. The clockwise direction is for measurements being made through mirrorlens Cassegrain telescopes (e. g. , Schmidt-Cassegrain, Maksutov-Cassegrain), or refractors where a diagonal mirror/prism is being used. Translate the 90° mark on the opposite side of the scale as 270°. The counterclockwise direction is for a Newtonian reflecting telescope or a telescope without a diagonal mirror/prism. In this case the 90° mark should be on the "left" side of the scale. Translate the 90° mark on the opposite side of the scale to 270°. 7. Once the scale is successfully calibrated along the east-west line of the sky, follow these steps to measure the position angle of a celestial object: 1. Place the reference object (e. g. , primary component of a comet nucleus) in the circular mark at the center of the Linear Diameter Scale (1, Fig 2. ). · 0 2 33 0 30 0 30 30 3 0 60 60 60 30 90 90 270 90 4 0 10 20 30 40 50 0 12 24 0 Fig. 2: MA 12mm Astrometric Eyepiece Reticle. (1) Linear Diameter Scale, (2) Semicircular Position Angle Scale; (3) 360° Position Angle Scale; (4) Double Crossline/Concentric Circle Guiding Scale. 180 1 15 0 21 0 -3If the object to be measured is "below" the east-west line, then the entire reticle must be rotated 180° to position the object within the Semicircular Position Angle Scale. Place a star on the 90° mark on the Position Angle Scale Release the thumbscrew of the eyepiece holder and rotate the eyepiece until the same star is lined up on the 270° mark. Tighten the thumbscrew to lock the eyepiece in position. zWith the Semicircular Position Angle Scale turned "upside-down" the scale markings should be translated as shown: The Semicircular Position Angle Scale reads from 0° to 90° clockwise and counterclockwise. The clockwise direction is for measurements being made through mirrorlens Cassegrain telescopes (e. g. , Schmidt-Cassegrain, Maksutov-Cassegrain), or refractors where a diagonal mirror/prism is being used. The 90° mark on the "right" side is correct, and the opposite side of the scale translates to 270°. The counterclockwise direction is for a Newtonian reflecting telescope or a telescope without a diagonal mirror/prism. The 90° mark on the "left" side is correct, and the opposite side of the scale translates to 270°. [. . . ] MIC specifically disclaims special, indirect, or consequential damages or lost profits, which may result from a breach of this warranty. Any implied warranties which cannot be disclaimed are hereby limited to a term of one year from the date of purchase by the original retail purchaser. This warranty gives you specific rights. You may have other rights which vary from state to state. [. . . ]