Orion 120ST EQ manual

IN 155 Rev . B 02/09 Providing Exceptional Consumer Optical Products Since 1975 Customer Support (800 ) 676-1343 E-mail: support@telescope.com Corporate Offices (831) 763-7000 89 Hangar Way , Watsonville, CA 95076 INSTRUCTION MANUAL Orion ® Astr oV iew ™ 1 20ST EQ #9005 Equatorial Refracting T elescope[...]

2 T ube rings Objectiv e lens cell Dew cap/lens shade Declination loc k le ver Large counterweight Small counterweight Counterweight lock knobs Counterweight shaft “T oe sa ver” T ripod leg Accessor y tray attachment point Accessor y tray brac ket Accessor y tray Leg loc k knob Finder scope Finder brac ket F ocus knob Eyepiece Star diagonal Rig[...]

3 1. Par ts List Qty . Description 1 Optical tube assembly 1 German-type equatorial mount 1 Large counterw eight 1 Small counterw eight 1 Counterweight shaft 3 T r ipod Legs with mounting hardware 1 Accessor y tra y with mounting hardware 1 Accessor y tra y brac ket 2 Slow-motion control cab les 1 P olar axis finder scope 1 Plastic co ver for polar[...]

4 2. Assembly Car efully open all of the bo x es in th e shipp ing con taine r . Mak e sur e all the par ts listed in Secti on 1 are pr esent . Sa ve the bo x es and pack aging material . In th e unlik ely ev ent tha t you need to return the telescope , y ou m ust use the or iginal packag - ing. Assembling the telescope for the first time should ta[...]

on the worm gear shaft. Then tighten the scre w . 12. T o place the finder scope in the finder scope br acket (Figure 3), first unthread the two blac k nylon thumbscrews until the screw ends are flush with the inside diameter of the bracket. Place the O-ring that comes on the base of the brack et ov er the body of the finder scope until it seats in[...]

6 3. Balancing the T elescope T o ensure smooth mov ement of the telescope on both axes of the equator ial mount, it is imperative that the optical tube is properly balanced. We will first balance the telescope with respect to the R.A. axis, then the Dec. axis. 1. K eeping one hand on the telescope optical tube, loosen the R.A. loc k lev er. Mak e [...]

The telescope is now balanced on both axes . Now when you loosen the loc k lev er on one or both ax es and manually point the telescope, it should move without resistance and should not drift from where you point it. 4. Al ig ni ng t he F in de r Sc op e A finder scope has a wide field of view to facilitate the location of objects f or subsequent v[...]

T o find P olar is in the sky , look nor th and locate the pattern of the Big Dipper (Figure 7). The two stars at the end of the “bowl” of the Big Dipper point r ight to P olaris. Obser v ers in the Southern Hemisphere aren’t so f or tunate to hav e a bright star so near the south celestial pole (SCP). The star Sigma Octantis lies about 1° f[...]

9 that is cast into the mount (located directly below the large thumbscrew; see Figure 3). Retighten the thumbscrew . 2. Rotate the date circle until the “0” line on the meridian offset scale lines up with the time meridian indicator mark. The mer idian offset scale is printed on the inner circumfer- ence of the date circle, and is labeled “E[...]

10 loosen the big tripod attachment knob directly under neath the base of the equatorial mount. The fine adjustment knobs work b y loosening one and then tightening the other . When done, retighten the tr ipod attachment knob to fir mly secure the mount and tripod. Once P olar is is centered in the small circle, you are done. The telescope is now a[...]

11 c. d. Figure 9. This illustration shows the telescope pointed in the f our cardinal directions: (a) nor th, (b) south, (c) east, (d) west. Note that the tripod and mount ha ve not been moved; only the telescope tube has been moved on the R.A. and Dec. ax es. a. b. weight shaft is horizontal (par allel to the ground). Then loosen the Dec. lock le[...]

Cooling the T elescope All optical instr uments need time to reach “ther mal equilibr i- um. ” The bigger the instr ument and the larger the temperature change, the more time is needed. Allo w at least a half-hour f or your telescope to cool to the temper ature outdoors. In very cold climates (below freezing), it is essential to store the tele-[...]

13 lence causes objects viewed through the telescope to “boil. ” If the stars are twin kling noticeab ly when you look up at the sky with just y our e yes , the seeing is bad and y ou w ill be limited to vie wing with low powers (bad seei ng aff ects images at high pow ers more sev erely). Planeta r y observing may also be poor . In conditions [...]

C. The Planets The planets don’t sta y put like the stars (the y don’t hav e fixed R.A. and Dec. coordinates), so you’ll hav e to ref er to char ts published monthly at our website, www .telescope.com, or in monthly magazines like Astronomy , Sky & T elescope , to locate them. V enus , Mars, J upiter , and Saturn are the bright- est objec[...]

15 used or the image will be blurred beyond recognition. T r y expo - su re tim es bet w ee n 1 an d 10 sec on ds , d epe nd in g up on the brightness of the planet to be photographed and the ISO of the film being used. “Piggybacking Photography” T he Mo on an d pl an e ts ar e i nt er es ti n g ta rg et s f or th e b ud di ng astrophotographer[...]

Orion T elescopes & Binoculars 89 Hangar Way , Watsonville, CA 95076 Customer Support Help Line (800) 676-1343 • Day or Evening One-Y ear Limited W arranty This Orion AstroView 120ST Equatorial refractor is warr anted against def ects in materials or workman- ship for a period of one y ear from the date of purchase. This w arranty is f or the[...]