Celestron NexStar EVOLUTION 9.25 EDGE HD Guide De Démarrage Rapide page 11

Your EdgeHD 9 .25" is equipped with a removable
secondary mirror that allows you to convert your f/10
telescope into an f/2 imaging system using an optional lens
accessory made by Starizona . This adds versatility to use
the telescope at different focal ratios for astrophotography .
Imaging at f/2 is favored for wide-angle deep sky imaging
with short exposures, well suited to large deep sky objects .
Optional Focal Reducer
A dedicated 0 .7x Focal Reducer for the 9 .25" EdgeHD is
available from Celestron . This focal reducer maintains the
flat-field and coma-free imaging performance specifically
designed for this telescope .
Collimation
Your telescope is factory aligned and generally should not
need collimation unless it is transported roughly . However,
you should be aware of the eventual need to collimate your
telescope to keep it operating at peak performance .
1 . Using your included 25mm eyepiece (or a higher power
eyepiece if you have one), point the telescope at a
moderately bright star center it in the eyepiece .
2 . Defocus the star about 1 turn on the focus knob .
3 . Inspect the star pattern . When collimated, the pattern
should look like a concentric doughnut . If the pattern is
concentric, no adjustment is necessary .
4 . Adjust the telescope collimation if needed by slightly
adjusting the 3 Phillips head screws in front of the
secondary mirror .
5 . If the star pattern is thin on one side, adjust the
collimation so that the star moves towards the thin side,
then adjust the position of the telescope to re-center the
star . Repeat this until you achieve correct collimation .
Secondary Mirror Collimation Adjustment Screws
A defocused star where
the secondary shadow
is not concentric to the
star pattern indicates
the telescope requires
collimation.
The telescope is
collimated if the
defocused star pattern is
concentric as shown.
ENGLISH
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