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CG5-GT GOTO Alignment

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My first night out with my new toy but I just can't align it.

Time is correct, date correct, location correct but it just won't align.

polar alignment is pretty good, but every time I go through a 2 star align its always off.

maybe I'm using stars too close to each other? Any ideas.

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I'd recommend using at least 3 calibration stars aswell as the 2 star alignment, your alignment should get more accurate the more calibration stars you use, I had the same problem as you when I first got my CG5 GT

I'd also recommend doing an all star polar alignment to get even better accuracy if you plan on imaging,

Have a look here on how to do it http://www.celestron...olar-alignment/

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You dont need to use a star to align it.

I use the planet Juipter.Make sure the

mount is level.I have a job,telling one

star from another.It is a real pain in the

neck, trying to get it to work properly.

I have read the manual so many times.

I have drilled holes in the patio,so the

mount goes back to the same place

every time.I was spending more time

trying to get it to work, than using it.

Page 21 of the manual gives solar

system align.Try this.On page 23

you have got sync,which is what i

use.Hope this helps a bit.


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Hi Jabberwocky.

First things first. If your mount is previously loved (i.e. secondhand or open box) then I would recommend doing a factory reset - this is done from the handset. This certainly isn't essential but you might also consider checking that it has the latest firmware (see http://www.nexstarsite.com/Firmware.htm). You need a serial cable and probably an RS232 to USB connector for this (and you'll also need that if you want to control the mount using planetarium software like Stellarium).

There is no need for the mount to be level. The only purpose of leveling the mount is so that you have a reasonably similar starting point for each session for your polar alignment... Get the mount roughly level by all means, but there is no need to worry unduly about this.

If you have a polar scope in the CG-5 then use something like Jason Dale's free PolarFinder to show you where Polaris should be in the polar scope, and move the Alt and Az bolts to match where Polaris should be in the polar scope reticule.

Then fire up your mount, enter the longitude and latitude of your site, and enter the time and date (date is un US format with the month before the day, i.e. MM/DD/YY).

Doing a solar system align on the Moon or Jupiter is good advice as you can be sure of what you are looking at (and stars can look pretty much the same), but won't be as accurate as a full two star align. As part of this process, though, you can check that your finder scope is properly aligned with the main scope.

You can use this solar system alignment to take a look at what an alignment star will look like through your finder and main scope. So for example, slewing to Betelgeuse which appears very orange... There should be no need to do the solar system align step in future sessions, as I'll explain below, but it will of course give you a rough alignment if you are in a hurry.

Anyway, once you know what an alignment star looks like through your finder and eyepiece, redo the alignment using the two star align option. The FIRST time you do this it is important that you do know what the first star at least will look like as this star might be someway off, but it really should be in the finder scope at least. Then find another alignment star and add the maximum number of calibration stars.

If your handset has the All Star polar align function (accessed from the Align button) then follow that.

This is the important bit that means you should be able to dispense with the solar system align: Once you have done all of this, run the calibrate mount functions from the handset. This will help the mount to learn from the process and should mean that when you next go to align the mount, the first alignment star should - at the very least - be in the finder.

I have my favourite alignment stars depending on the season, and you quickly get to know how bright they are which helps avoid the cardinal sin of syncing the mount to the wrong star.

This all sounds really complicated, but as ever it is easier to do than to explain. I can do a full two star align with calibration stars in less than five minutes, usually.

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By the way, you should only need to run the calibrate mount function once, unless you do a factory reset...

Hope it works out; I love my CG-5 - they are much maligned IMO - and still use it regularly even though I have a CGEM DX.

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For all this to work ,the mount must go

back, in the same place all the time.

You dont have to put in Lat & Lon.

When you start up,location will be

displayed.Pick a city near you.

I use London.This will give you

a starting point.Look at page

19 in the manual.On the mount

is a bubble,which will give you

a rough idear if the mount is

level.That is all you need.It will

take a bit of time to sort out.


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That's only true from the point of view of polar alignment - which for the GoTo to work can be fairly rough and ready. I set my mount up in different locations all around my garden...

And I had suggested resetting the mount to factory settings, hence you need to re-enter latitude and longitude.


Edited by x6gas
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No you dont.You can choose a city, from

the database,which is in the handset memory.

This will give you starting point, if you dont

know your Lon & Lat.This is what i have done.

It is on page 19 of the manual.My CG-5 mount stays

in one place in the garden.It would sink in the grass.

I have got a EQ-3 mount which i can move around.

It is nice having a chat to you.




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Well, OK, yes... you can set longitude and latitude by entering a nearby city or by entering the actual coordinates of where you are... that wasn't really the point I was making - just that you will need to reenter location when you do a factory reset.

Sorry for the confusion.

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  • 2 months later...

I'd only add one item to x6gas' advice, for those (like me) who don't have a polarscope. When you are setting up the tripod, point the telescope within a degree or two of Polaris by eye, with the tripod roughly level using the bubble spirit level (make sure that the mount's triangular index markers are lined up properly when you do this). Then use the alt-dec controls on the mount to put Polaris in the centre of your finderscope. Provided that the finderscope hasn't been knocked while you were moving the telescope that should put Polaris within the field of view of your lowest power eyepiece. Centre Polaris in your eyepiece FOV, again using the mount's alt-dec adjustments, and your telescope will be roughly polar aligned before you've even switched on the handset. Then go through the AllStar procedure as described by x6gas and in the manual to fine-tune the alignment.

That works every time for me. I hope that's helpful.

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Try putting the date in dd/mm/yyy rather than the required mm/dd/yy and ther lat/long the wrong way round for three nights in a flippin row. That will confuse you. :laugh:

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