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Hi I was wondering if someone can give me a little help/advice please on my CG5-GT mount.

After a very frustrating night last night when we finally had a lovely clear night but nothing was going right with my equipment; my question is: I was trying to do a better set-up of my mount before having another go at imaging M31. I did the normal two star alignment and then tried to do the 'Polar Align' option that is supposed to be under 'Utilities' in the handset 'Menu'. Trouble is that my handset skips from 'Home Position' straight to 'Light Control', totally missing out the 'Polar Align' option! :huh:

Am I doing something wrong - I didn't do any calibration stars before trying to access the 'Polar Align' option? So I was wondering; is this option only available after you have done a two star alignment AND included 3 calibration stars, or should it be there all the time? There is nothing in the manual (yes I did actually read it! :wink: ) that say this option is only available after completing xyz.

I flashed both the mount and the handset about 3-4 months ago with the latest firmware and everything else seems to be operating correctly. The handset says 'Advanced GT' on it at start-up so I have no reason to believe that it isn't an advanced set (I bought it second hand).

Any help would be most gratefully welcome. :smiley:

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Hi do your polar alinement first (find polaris) without the use of the hand set, then do your two/three star alinement.

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Hi starnut,

In the manual it says:

1. With the telescope set up and roughly positioned towards Polaris, align the mount using the Two-Star Alignment method.

2. Select Polar Align from the Utilities menu and press Enter.

Based on your current alignment, the telescope will slew to whre it thinks Polaris should be. Use the equatorial head latitude and azimuth adjustments to place Polaris in the center of the eyepiece. Do not use the direction buttons to position Polaris. Once Polaris is centered in the eyepiece press ENTER; the polar axis should then be pointed towards the North Celestial Pole.

...Once polar aligned you must re-align your telescope using the Two-Star alignment method and adding calibration star as an option.

Finally, use the Utility/Calibrate Mount/R.A. Index feature to properly calibrate the R.A. axis of the mount.

Which is what I need as the last time I tried to image M31 I was limited to 30" exposures because anything longer was starting to cause star trails. But I don't have the 'Polar Align' feature in my handset menu.

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I've never used the 'Polar Align' routine, but its not accessible on my handset until after you have done the first 2 star align routine.

You can then access the 'Polar Align' routine by a simple press of the 'Align' button.

I cannot find it under 'Utilities'.

You don't have to wait until dark to try it. I have just run through the process in my dining room to find out where to find it in the handset.

Edited by allcart
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its not under utilities its under align do 2 star 3 alignment stars go to a star in the south hit align then hit polar align follow instruction this is with nexstar plus handset took me a while to find it

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Thanks guys.

It looks like it's going to be a clear night tonight but I have a blood donating session at 19:00, so I probably won't get out until nearly 20:00. Then home, have something to eat, etc so it doesn't look like I will get out tonight. I will try and have a 'dry' run in the dining room as you suggest Allan.

Thanks again for your help - have some green! :smiley:

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Something that may help alignment. If it's the same as the Vixen mount it has a sort of alt az type correction built into the drive. Maybe you should try not using it initially for alignment. I have used several scopes with normal equatorial heads and no goto or other aids. Setting the polar axis to suite the latitude usually isn't too difficult. I use a magnifying glass. The head base has to be level of course. If you then point the axis roughly north as well as you can using a compass, enable the drive and watch a star drift can be corrected by swinging the entire stand or at least the head around to compensate. It takes a while to be able to judge the amount of swing needed and some stands make that easier than others. You can then augment the alignment with the alignment stars. I aligned a plain C8 this way years ago and it can be surprisingly quick to do. No imaging though but I will suspect some will be surprised how accurate this method can be.

John

-

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I have a C8 on the CAM mount ( Celestron Advanced Mount) I was not doing the align as well as I thought I was, now I take scope out position rough North, 15mm Ep in scope, level the mount ( built in bubble probably not brilliant but seems to work ok), do a Two Star Align then press Align again & it does the Polar Align Rotine next, mine slewed to Deneb( which it also picked for me on 2 star align) then told me to centre in finder using directional keypad ONLY then hit enter, then align in eyepiece using the Alz & Alt adjuster Only then press Align, now I have done 5 min piggy back shots with no trails.

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Thanks for that Ewan, If I ever get outside again with my scope I will give that a go. :clouds2:

5 mins with no star trails sound excellent! :headbang:

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No probnlem i actually thought the mount would have slewed to Polaris & then do the centering / Alt adjustment there but it didn't. I may not have been very clear in my last post, just a recap so you get it he same as i did :-

Do a 2 Star Align first then press ALIGN again, the Polaris Align rotine will kick in, it will probably go to the last star you did the 2 star align on, you have to centre that star in the finder then press Enter, then centre it again in the EP then press ALIGN, next the mount will go back to the same star again (for the third time), it will tell you to ALIGN the star in the finder then press ENTER then ALIGN the same star using the eyepiece BUT do not touch the handset, only use your Altitude adjuster & Azimuth adjuster & get the star as near as centre as possible (i guess a crosshair eyepiece would be best for this tbh any thoughts anyone ? ) then press ALIGN & you should be good to go.

Bryan i was doing really long runs piggy back last night, best align ever i feel a bit of a wally now thinking i had it good before but live & learn, through the scope the most i tried was 3 mins & my stars still looked very round.

Good luck Bryan but if in doubt drop me a PM if you like & let me know how you get on ?

Really good night last night i managed an all nighter again but shattered now.

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Thanks again Ewan, I have had a bit of a play with the mount in the living room as there is no prospect of me getting outside in the near future. I wrote off Saturday night as there had been a complete white out for most of the afternoon and early evening - last looked about 6pm. Then on locking up for the night I had a quick check outside and it was the clearest sky I have seen in quite a while! :BangHead: Oh well, that's life I suppose. :grin:

I have now finished my mains power box so I shouldn't have a problem with my battery dying half way through a run now.

Thanks for all your help. Much appreciated. :icon_salut: I will let you know how I get on - and hopefully post some pictures when I finally get outside.

Clear skies!

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Hi can I add another question to this old thread, after doing the polar alignment how do does one reselect two star alignment on the handset as some people suggest you I cannot find it as an option in the menu any help would be much appreciated

thanks Gordon

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Hi thanks for that info but I still can't seen two star align in the menu except at start up, it gives option to replace single stars I must be looking in the wrong part of the menu?

cheers Gordon

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Hi thanks for that info but I still can't seen two star align in the menu except at start up, it gives option to replace single stars I must be looking in the wrong part of the menu?

cheers Gordon

Hi Gordon,

You are pressing the align button to bring up the align menu? I might be wrong (not near mount at the mo) sure that's where I found it though. If its not, you could park the mount after doing the polar align & switch it off. When you switch it back on the alignment menu should come up again with options to do 2 or 3 star alignment.

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You will have to re enter the time & date & then go into the 2 star alignment routine. It keeps its location details. The polar alignment routine is a physical position, so as long as you don't move the alt & az screws on the head then all will be ok.

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Hi thanks for that I have the GPS system linked into it so I guess as long as I don't physically alter those screws I just go through the normal start up proceedure ?

thanks Gordon

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as you say I'm sure there must be a better option in the menu to go to two star alignment but I can't see it perhaps if you find it you could let me know

cheers Gordon

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as you say I'm sure there must be a better option in the menu to go to two star alignment but I can't see it perhaps if you find it you could let me know

cheers Gordon

Next time I fire it up I will check & let you know.

Rob

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Hi thanks for that I have the GPS system linked into it so I guess as long as I don't physically alter those screws I just go through the normal start up proceedure ?

thanks Gordon

Yep, that's all there is to it.

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Gordon i am getting great results with this mount now when guiding, this mount CAN do it but you have to setup correctly, ignore what you have read in the manual regarding doing 3 calibration stars, i don't think Polar Align routine is even available unless you do ALL 4 calib stars (4 is max in the routine) & another thing is when you select Polar Align the mount DOES NOT go to where it thinks Polaris is as per Celestron manual it will go back to the last star you aligned on.

I do 2 star, 4 calib stars, then press Align & select Align Mount, then select Utilities, Calibrate Then Select RA Index first then press BACK & select GOTO (in the same Calibrate Menu) once done turn the mount off, re park to the Home position, turn back on the mount & RE DO 2 star + 4 star calibration to complete, you should easily be able to get the mount into single figures.

Use an illuminated Recticle to centre the stars while doing PA as even though you think the star is middle diddle it probably is not, well worth the money.

I have now been to hell & back with this mount, especially as in regards to guiding with it so if you need any more advice feel free to drop me a line.

All the best.

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