Australian Sky & Telescope — January 01, 2018

68 AUSTRALIAN SKY & TELESCOPE January 2018

thestarinthefieldofview.Iusedthis

method for all my astrophotography

with the CGX and found it to be very

good.ButIhavesomeadvicethatisn’t

inthemanualorgiveninthealignment

instructions that scroll across the

hand control’s display. Your alignment

star should be near the meridian and

celestialequator,andtighteningthe

locksonthemount’saltitudeand

azimuth adjustments should be done in

smallsteps,sincethemountislikelyto

moveslightlyintheprocess,requiring

tweaks to the adjustments to keep the

alignmentstarcentredasthelocksare

fully tightened.

Visual tests

InitiallyIsetuptheCGXinmy

drivewayanduseditonahandfulof

nightsforvisualobservingwiththe

101-mm refractor and 20-cm SCT.

There’snoneedtorepeatinstructions

here for initialising the mount for Go

To operation, since they are clearly

spelledoutinthemanual,aswellas

(andperhapsmoreimportantly)onthe

hand control as you work through the

procedure. Suffice it to say the process

isfastandeasy,butthelargeselection

of alignment stars available is only

shown by name on the hand control.

Evennovicesshouldbecomfortable

with Arcturus, Regulus, Vega and the

like,butotherstarssuchasAlsciaukat,

RukbahandWasatmightwellleave

veteran skygazers scratching their

heads.Ialwaysmanagedtoinitialise

the CGX with familiar stars even

undertherestrictedviewoftheskyI

have from my driveway. Nevertheless,

having decent star charts handy is a

good idea.

For visual observing the CGX proved

firstrate.Themountissolidand

certainly capable of handling a 27.5-

or 30-cm SCT. Slewing is smooth and

very quiet, and the mount responded

preciselyandwithoutbacklashwhen

Ipressedthedirectionkeysonthe

hand control. All the celestial-object

databases we’ve come to expect with

Go To telescopes are available from

thehandcontrol,andeventheSunis

included in the Solar System listing.

The hand-control’s illuminated and

clearlylabelledkeys,combinedwith

scrollinginstructionsforthemount’s

variousfunctionsandmenusthat

arerelativelystraightforward,kept

thelearningcurvefortheCGXquite

reasonable.

WhileIdidn’tcontroltheCGXfor

visualobservingwithanyexternal

planetarium software, including the

version ofStarry Nightsupplied with the

mount,Iexpectitwouldbevirtually

identical to the positive experience

RodMollisehadtestingtheCelestron

NexStarEvolutiontelescope(AS&T:July

2017,p.66).

Astrophotography

Forastrophotographytests,Icobbled

togetheranadaptertoattachtheCGX

tooneofthepiersinmybackyard

observatory. I used the software-

assisted method mentioned earlier

topolaralignthemount.Theresult

wasn’t perfect, but it was more than

adequate for 10-minute exposures

withanopticalsystemworkingat

an image scale of 1.4 arcseconds per

pixel. Furthermore, the mount was

plug-and-playcompatiblewithanSBIG

autoguider operating throughMaxIm

DLsoftware. The system worked so

flawlesslyfromtheoutsetthatInever

bothered refining the polar alignment

or training the CGX’s periodic-error

correction.

Thisbodeswellforanyone

consideringtheCGXforportable

astrophotography, since it should take

aslittleas15minutesorsoinatwilight

skytogetthemountsufficientlypolar

aligned and ready for long-exposure

photography.IespeciallyliketheCGX’s

fine-adjustment control on the polar-axis

elevation. It is precise and easy to operate

even when the mount is fully loaded

withatelescopeandcounterweights—

somethingthat’sbeenaproblemwith

othermountsI’veused.

W Clearly marked keys and a straightforward menu

system make it relatively easy to master the basic

operation of the CGX with its NexStar+ hand control.

SThe CGX saddle accepts both Losmandy- and

Vixen-style dovetail bars.

SThis articulating mechanism on the CGX’s

polar-axis adjustment provides precise control

of the mount’s elevation even when it is loaded

with a heavy telescope and counterweights.

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