ASTRO-PHYSICS GTO KEYPAD Addendum - Page 9

Parcourez en ligne ou téléchargez le pdf Addendum pour {nom_de_la_catégorie} ASTRO-PHYSICS GTO KEYPAD. ASTRO-PHYSICS GTO KEYPAD 10 pages. Plus supplemental information for customers outside of north america and the revised gto quick star drift method of polar alignment

Imprimer la page

8.● SOME HINTS & COMMENTS:

a)● You●may●not●have●a●good●conveniently●placed●star●just●hanging●around●at●the●zenith●waiting●for●you●to●polar●align.●●●

That's●OK.●●●Pick●the●best●available●star.●●●●●Remember●to●set●the●meridian●delay●accordingly●if●you●are●more●than●

one●hour●in●RA●from●the●meridian,●and●take●special●care●to●be●sure●that●your●scope●will●not●hit●the●pier●when●you●

flip●to●the●other●side●of●the●meridian!●●(see●2-a●above).●●●Also,●if●your●first●star,●your●"Altitude●Star"●is●a●ways●away●

from●the●zenith,●the●azimuth●adjustment●process●may●also●need●a●bit●of●modification.●●●●●In●that●case,●first●pick●your●

second●star●so●that●it●is●in●line●with●an●imaginary●line●going●through●both●the●altitude●star●and●the●zenith.●●●Then,●ask●

yourself:●What●is●the●relationship●between●the●altitude●star,●the●zenith●and●the●second●star?●●●●If●the●Altitude●star●is●

further●from●the●second●star●than●the●zenith●point●(in●other●words,●you●cross●the●zenith●slewing●from●star●to●star),●

your●azimuth●correction●can●be●a●slight●bit●under●and●then●finish●the●last●little●bit●with●the●direction●buttons.●●●If●the●

altitude●star●is●closer●to●the●second●star●than●the●true●zenith,●then●you●can●very●slightly●over-correct●with●the●azimuth●

adjuster,●and●then●come●back●to●the●perfect●center●with●the●direction●buttons.●●●If●you●do●this●and●use●the●direction●

buttons,●remember●to●re-calibrate.

b)● The●illustrations●above●are●simply●representative●illustrations●and●will●almost●certainly●differ●somewhat●from●what●

you●see●in●your●own●eyepiece.●●●●●You●may●be●starting●out●on●the●other●side●in●either●azimuth●or●altitude●depending●

on●whether●you●are●east●or●west●of●the●pole●in●azimuth●and●above●or●below●it●in●altitude.●●●●The●concept●is●the●same.

c)● It●is●not●necessary●to●do●this●at●high●power,●nor●is●it●necessary●to●get●the●star●to●fall●exactly●on●the●crosshair.●●●●A●

standard●8x50●finderscope●was●used●in●our●tests●with●this●procedure●to●achieve●enough●accuracy●to●take●30●second●

unguided●frames●at●a●3810●mm●focal●length!●

d)● YES!!●●●Performing●this●procedure●does●take●the●finder●scope●out●of●alignment●with●the●main●optical●tube.●●●That●is,●

in●part,●why●the●method●works●so●well!●●●However,●it●is●very●quick●and●easy●to●realign●the●finder●back●to●the●main●tel-

escope●optical●axis,●and●it●takes●only●a●few●moments.●●●Many●of●those●who●use●this●method●have●found●that●they●no●

longer●really●need●their●finders●for●anything●other●than●performing●the●alignment●anyway.●●●The●subsequent●GoTos●

are●simply●that●good!●●●●As●a●result,●they●simply●leave●the●little●scope●adjusted●to●be●orthogonal●to●the●mount,●and●let●

the●mount●find●their●targets.●