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CG-5 w/C8 will not go to the alignment stars

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#1 maxisp1000

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Posted 14 July 2013 - 07:08 PM

CG-5, C8 with Telerad, spotting scope.

I have followed the manual and talked to other astronomers but cannot figure this out.
I set it up mechanically with Polaris through the polar sight in the middle of the mount. It is leveled and set on the alignment marks after aligning north.
Then I start the alignment process (date, time and location) and pick Arcturus. I was around Tonopah, NV (~37) It slews west, and stops 2 hands to the north and about 5 oclock, to Arcturus, not even close. I tried 10 combos of time, zone, date and anything to get it the scope close. All attempts are way off. It doesn't matter what star I try to use.

This about 10 sessions with this scope in, it doesn't goto anything.

Once using the SkyQ and app with a single star align I was able to navigate (goto) last year. Never again.
It's not switching left/right or up/down, it goes grossly to the correct place but never in a usable way, the controller drops out of alignment if the correcting slew is too far.

I no longer have an iPad for using the SkyQ.

Using an android sky app verifies that I am trying to get to the correct stars. Last weekend, I did not have Vega on the menu for anything. I got this used from a friend who never opened it so it's out of warranty.

Try to re-flash the controller or send it in for repairs?

If it worked once it should work again.

Anyone have one that didn't track?

#2 orlyandico

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Posted 14 July 2013 - 08:07 PM

1) possibly a loose power connection or insufficient power

2) try to reflash, can't hurt (but fix the power issues first)

3) in my case, after doing the two above, the mount still would not behave. turned out the motor encoders were not properly spaced. If it's in warranty I'd send it back. If not... you could try re-spacing the encoder wheels yourself.

#3 JazzSky

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Posted 14 July 2013 - 08:13 PM

I had some issues earlier and I reset the mount to factory settings. I had do do that a couple of times, but is seems to have done the trick.

#4 spectre

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Posted 15 July 2013 - 04:43 AM

My CG-5 is also pretty far off the first alignment star but I just use the controller buttons to move the scope to the star and proceed with the alignment routine. The first star is usually off quite a bit, the second is closer, the first calibration star is closer yet, and the 2nd, 3rd, and 4th cal stars are almost dead on the cross hairs in my eyepiece. My goto's are very accurate after that and if I'm going to be imaging I'll do the ASPA also.
I am starting with a fresh setup every observing session and this is normal for me. I would suggest just going through the entire alignment routine before you do anything more drastic.

#5 orlyandico

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Posted 15 July 2013 - 07:20 AM

if the stars don't get closer and closer to the center, something is wrong.

i did all the usual stuff - power supply plug, better power supply, reflash controller and motor firmware, reset to factory - none of them worked. i was convinced Nexstar sucked.

after re-spacing my motor encoder disks, the change in behavior was eye-opening. By the 1st alignment star, the mount should be putting it right on the reticle.

also make sure to use only UP and RIGHT buttons when doing the final align on each star.

#6 rmollise

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Posted 15 July 2013 - 08:32 AM

It is very unlikely he is suffering from bad encoder disks. More likely? An error in time/date/time-zone or DST status. It's easy to look at the values and see what you want to see:

OP...your "two hands" sounds suspiciously like "15-degrees," which would indicate an error like having DST off when it should be on, etc.

However, as others have said, checking your power cord, connection, and source, and resetting your HC are all advised.

#7 rdandrea

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Posted 15 July 2013 - 09:45 AM

I don't think my CG-5 has ever gone anywhere close to the first alignment star. It's usually way off. The second is usually closer. After about two calibration stars, it's dead on. Just slew it to the alignment stars with the slew buttons.

If it doesn't work after that, check your power as has already been suggested, and if that doesn't work, try a hard reset of the controller. That usually fixes most ills. I don't think a reflash will buy you much except it does a hard reset in the process.

#8 jrcrilly

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Posted 15 July 2013 - 09:59 AM

The controller stores a "fudge factor" that tries to improve the first alignment star slew based on how much correction was required on the first few alignments after a reset. If incorrect time/date info was used then, requiring a substantial correction to center the first alignment star, the fudge factor will be large. That fudge factor will be applied even with correct data and that slew will be off every time. A reset will clear that data.

#9 rmollise

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Posted 15 July 2013 - 10:22 AM

I don't think my CG-5 has ever gone anywhere close to the first alignment star. It's usually way off. buy you much except it does a hard reset in the process.


Yep, it's not unusual for the first star to be far off...but the second star should be closer, and by the time you do three calibration stars, #3 should be near the center of the finder crosshairs if not in the eyepiece field. The OP doesn't say how the rest of his alignment goes...

#10 TennDon

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Posted 15 July 2013 - 03:14 PM

It is very unlikely he is suffering from bad encoder disks. More likely? An error in time/date/time-zone or DST status. It's easy to look at the values and see what you want to see:

OP...your "two hands" sounds suspiciously like "15-degrees," which would indicate an error like having DST off when it should be on, etc.

However, as others have said, checking your power cord, connection, and source, and resetting your HC are all advised.


I had a similar problem when I first started using my CG5. Uncle Rod and several others pointed out I was using the wrong ST/DST option. I changed that and since then the first alignment star is almost always in the finder and subsequent stars are closer as others have said. It was one of those DUH how stupid can I be moments. :foreheadslap:

Clear skies!

#11 spencerj

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Posted 15 July 2013 - 03:41 PM

I don't think my CG-5 has ever gone anywhere close to the first alignment star. It's usually way off. buy you much except it does a hard reset in the process.


Yep, it's not unusual for the first star to be far off...but the second star should be closer, and by the time you do three calibration stars, #3 should be near the center of the finder crosshairs if not in the eyepiece field. The OP doesn't say how the rest of his alignment goes...


I don't think it goes at all. I think he gives up when the first star is not in the FOV. Doesn't sound like he has ever really gotten it completely aligned.

As others have said, the first star will be off. Use the controller to slew to the star and move to the next one. If a star you are looking for is not on the list, hit the "Menu" button. that flips the start list from "East" to "West".

#12 WOBentley

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Posted 15 July 2013 - 06:16 PM

I had a similar problem with my scope but sometimes it wuld just stop and want to start again from the beginning of the alignment process...that WAS a power cord problem. A replacement solved the issue nicely...while it is worthwhile to check it always...your problem seems different from what I experienced.
Dave

#13 maxisp1000

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Posted 15 July 2013 - 08:58 PM

Thanks for all the replies.

I have about 10 hrs in trying to align this scope, then I give up and go manual. The first star is so far off the hand controller goes out of alignment mode,either blank or to the first screen.

I have tried every combination of DST/STD/PST/MST/CST.

The hand controller used to lose power in the middle of an alignment. It used to turn around in circles when I first powered it on. I taped the connectors to the pins and don't lose power or spin around anymore. Did not remove the connectors, did not touch the mechanism.

I have gotten close to a second star, but it goes to the first screen before I can get it aligned.

I got this to work one time with a iPad and a SkyQ with a one star alignment.

How did it work one time?

#14 orlyandico

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Posted 15 July 2013 - 10:55 PM

I vote encoder disk... My CGEM worked well enough a few times to screw me up. The behaviour got worse and worse as time went by until it was unusable.

Until I fixed the motor encoders.

The first star will always be off. But not that far off. Each additional star will be closer and closer - the first calibration star should be almost dead Center in your reticle eyepiece.

Like I said if each additional star is far off in some random direction in both RA and DEC its gotta be encoder.

If its only off in RA its probably a timezone or DST issue.

#15 jrbarnett

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Posted 15 July 2013 - 11:40 PM

What you describe indicates that the mount is working perfectly. The first alignment star is NEVER in the FOV. You ALWAYS must use the hand controller buttons to finish slewing the mount to the alignment star and centering it in the eyepiece. This is why the routine has you first center it in the finder (a 5-to-7-degree field) and then the eyepiece. Same for the other stars, alignment and calibration. The mount will get closer and closer to being on target with each iteration.

Regards,

Jim

#16 Falcon-

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Posted 16 July 2013 - 01:05 AM

The first star is so far off the hand controller goes out of alignment mode,either blank or to the first screen.


"blank or to the first screen"? That SOUNDS like a momentary power loss to me..... When you say Blank do you mean no light at all? when it goes "blank" can you get a response from it or do you have to toggle the power switch to get interaction back?

#17 rmollise

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Posted 16 July 2013 - 09:03 AM

Thanks for all the replies.

I have about 10 hrs in trying to align this scope, then I give up and go manual. The first star is so far off the hand controller goes out of alignment mode,either blank or to the first screen.


That's a power problem. The HC will not "go blank" because the alignment star is too far away. ;)

Use a fully charged battery every time, spread the pin-halves of the mount-side power connector gently with a knife or jeweler's screwdriver. Then just follow the alignment instructions.

#18 jrcrilly

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Posted 16 July 2013 - 09:17 AM

Thanks for all the replies.

I have about 10 hrs in trying to align this scope, then I give up and go manual. The first star is so far off the hand controller goes out of alignment mode,either blank or to the first screen.


That's a power problem. The HC will not "go blank" because the alignment star is too far away. ;)


Good catch. :waytogo:

#19 rdandrea

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Posted 16 July 2013 - 11:08 AM

"blank or to the first screen"? That SOUNDS like a momentary power loss to me.....


Me too.

#20 jloweva

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Posted 16 July 2013 - 08:20 PM

I was discouraged at first, too. Took the advice of others and bought a new power cord at RadioShack for about $18 and also purchased a very good portable power station. As others have said, first star is quit e a bit off, second a bit closer, first calibration star gets you just about perfect and second calibration star and I am good to go.

#21 frito

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Posted 17 July 2013 - 01:56 PM

it could be an encoder problem but it could also just be as simple as a bad connection to one of the motors. awhile back i took my RA electronics out so i could fix my power jack (negative leaf was not putting enough pressure on the cord connector) and when i reassembled somehow the RA motors cable got knocked half off the MC board. the first night i used it all was well and it worked fine. the next day i take it out to a dark site for a club event and right off the bat it was acting very strange. if i powered it on it would straight away start slewing one direction in RA and then stop. trying to align it was pointless and pressing the RA control in one direction resulted in a slewing at high speed and acting funny and stopping. i ripped the electronics out as it was just starting to get dark to find the connector was half way connected crooked. fixed that and all is well with my mount now.

as Uncle Rod said if your HC is turning off at random you are suffering from the all too common power jack issue. you don't have to buy anything to fix that just get a small flat head screwdriver and gently spread the center pin out a little bit and if its still doing it then you probably need to do the same to the negative leaf connection inside the jack. just wiggle the cable with the mount on and if you have fixed it it should not turn off. if it goes off and back on then you need to bend em a little bit more.

#22 maxisp1000

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Posted 04 July 2014 - 10:12 PM

I am back.
I got a SkyQ and was able to get the mount to align once using a single star align.
I joined a local club and no one could get this telescope to align during sky parties. I waited for the StarSense, I thought that would be the best thing possible.
In the meantime, my friend in another state bought a CGEM DX 1100 Computerized Telescope.
I talked him through the steps I used to work on my scope, and he was able to use it right away. We conclude my procedures should work on my mount.
My StarSense finally arrived after months of backorder. I tried it in my back yard, and it could not find any stars automatically. Thought it was our city skies.
Took it to Death Valley; it could not find any stars in sparkling clear weather. Went through every option on the device to get it to work. Took it home, for 5 nights it would occasionally find some stars.
I did a manual alignment and got it to work properly manually. It was everything I hoped for. It was awesome!
Once.
It now finds 3 sets of stars but gives me an error message saying “insufficient resolution” and hangs, or just spins.

I have a dozen emails to Celestron at least. I updated the firmware. It still doesn’t work.
So I re-contacted them after a year of waiting for a resolution.
They are now sending me the correct Aux splitter to replace the original. Apparently there was a design problem for the CG-5 mount.
Last chance, if it doesn’t work, I am parting the kit out. Four years of aggravation is enough for me.






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