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Equipment Discussions >> Mounts

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SunBlack
professor emeritus


Reged: 05/05/11

Loc: Rome (IT)
Celestron VX mount: experiences and problems
      #6053771 - 08/30/13 03:28 AM

See at http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5613234/page... for my first doubts and problems.

So:
1) the RA clutch lever doesnt secure properly the RA axis: even if i tighten the bolt, the RA axis turns (if i put a bit of pressure by hand). How to fix?

First night negative.
I just went with AP setup (canon 5d+300mm), unguided for 2 minutes at celestial equator. No ASPA, nor calibrating stars, tried to use the polar scope only, setting it on (roughly since no hour rings on mount) to what Polar Finder software indicates about Polaris position. Probably this inaccurancy led to trailed stars. (Used 1 star alignment. Goto was pretty accurate. )

Tomorrow, if no clouds, i would try again with polar scope, at about 11pm LT, when i saw on Polar Finder, Polaris will be a 9 hour Clock.

2) Skymap has the Ha Polaris data, how to calculate the Polaris Clock data? (i installed Cartes du Ciel but it gives me only Ha Polaris data too)


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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Celestron VX mount: experiences and problems new [Re: SunBlack]
      #6053833 - 08/30/13 05:06 AM

1) Balance the scope.

2) Use ASPA

Chris


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SunBlack
professor emeritus


Reged: 05/05/11

Loc: Rome (IT)
Re: Celestron VX mount: experiences and problems new [Re: cn register 5]
      #6053848 - 08/30/13 05:21 AM

If i'd use the ASPA: consider that on my home backyard i have limited portion of sky.
I see north, (little) north east and north west, no west, no est, South and south west (limited to 30° alt).
So in these conditions, could i try and succeed with ASPA?
In these conditions, how to choose right 2+4 stars?


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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Celestron VX mount: experiences and problems new [Re: SunBlack]
      #6053896 - 08/30/13 07:14 AM

South is fine for ASPA.

If you look at the sky you can see which bright stars are visible to you. A planisphere can help with identifying them, or there are smart phone apps.

Choose those for the align stars and the first calib star, it will be easier to be sure that you have the right one. After the first calib star the pointing should be good enough that later stars are in the EP. If the scope isn't looking at the sky then try a different star.

I think you may be over analysing this, it's worth practicing with the mount and HC indoors to become familiar with how it works but really just get outside and have a go.

Or get StarSense. I've been beta testing it in a more obstructed location than you describe and it was fine.

Chris


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SunBlack
professor emeritus


Reged: 05/05/11

Loc: Rome (IT)
Re: Celestron VX mount: experiences and problems new [Re: cn register 5]
      #6054706 - 08/30/13 04:15 PM

Real-time: how to change long and lat coordinates instead of preset cities? I goto to view time-site menu, go to cordinates but cant change anything.....

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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: Celestron VX mount: experiences and problems new [Re: SunBlack]
      #6054794 - 08/30/13 05:16 PM

press undo when you get to the time prompt, this gets to the setting latitude and longitude pages.

Chris


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SunBlack
professor emeritus


Reged: 05/05/11

Loc: Rome (IT)
Re: Celestron VX mount: experiences and problems new [Re: cn register 5]
      #6055537 - 08/31/13 05:11 AM

Second night: success (partial, according my standards).
No way to have a good tracking with polar scope.
So i went for a 2+4 than ASPA. A long procedure i'd say.....since even with Skymap software is difficult/long to understand where is located the named star indicated in the HC. Then, i tried one PEC session via HC.....better tracking but no so much. Finally i tried a sequence of 5 PECs by PC, and results are in line with what i obtained with my ex Vixen GPDX.
I think that if my accurancy in guiding during PEC sessions will be improved (i remember i dont use autoguide and so my guide is manual), taking more care about what keys i'd press if the guiding star move i.e. left or right in respect of eyepiece reticle, i could obtain even better results.

Results:

No pec, 10 exposures

2 extra trailed
3 medium trailed
1 low trailed
4 good
-------------
1 pec, 10 exposures

3 extra trailed
2 medium trailed
2 low trailed
3 good
--------------
5 pec, 6 exposures
(2min at 300mm FL + Canon 5D)
6 good
--------------
5 pec, 4 exposures
(2min 15s at 300mm FL + Canon 5D)
2 low trailed
2 good



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SunBlack
professor emeritus


Reged: 05/05/11

Loc: Rome (IT)
Re: Celestron VX mount: experiences and problems new [Re: SunBlack]
      #6058647 - 09/02/13 02:50 AM

Last night new sequence of PEC (this time 4 iterations) with (previous) best-aligned polar witnessed (used eyepiece illuminated reticle)
4 pec, 4 exposures (2min 15s + Canon 5D at 300mm FL)
4 good


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SunBlack
professor emeritus


Reged: 05/05/11

Loc: Rome (IT)
Re: Celestron VX mount: experiences and problems new [Re: SunBlack]
      #6058715 - 09/02/13 05:33 AM

Some questions now:
1) What could be reason i had to correct frequently on DEC? ASPA inaccurate?
2) My Firmware versions are: HC: 5.22.3141 MC: 7.08.3071, should i upgrade something?
3) On Aligning and GOTOing, there's a feature that after pointing a star west to meridian, on going to a second star at east of meridian, i can avoid that the mount twists on itself, and goes to second star passing in front the meridian, doing "less road"? (my english is bad, i know)


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Dr.Don
member


Reged: 05/31/13

Loc: Northern California
Re: Celestron VX mount: experiences and problems new [Re: SunBlack]
      #6064395 - 09/05/13 12:54 PM

I bought my AVX 3 weeks ago and have had nothing but problems with it.

I set the index marks and have manually polar aligned using the bore hole or polar scope over several nights.
I balance the scope although both axes seem stiff. The mount almost always finds the first star (Arcturus) and sometimes the second star (Vega). Even if it finds Arcturus and Vega, it sometimes cant find its way back to Arcturus. It has never found a calibration star (Altair), missing by 5-15 degrees.
It won't consistently find Arcturus and sometimes misses the second alignment star by 5-10 degrees.

The RA motor sounds fine.
During a large slew the dec motor is OK at first but then starts a slow decrease in RPM's over a few seconds. It sounds like what you expect if a battery was running down but I power it from a 15 Amp supply.
The right arrow button sometimes moves the scope smoothly but other times it doesnt move at all. I can hold the arrow key down or give it several pushes. After several seconds the mount will make a quick jump like it was in high speed slew mode and sometimes put the object out of the EP.
The other 3 buttons always work.
Factory reset did not solve the problems.
At least the RTC keeps the correct info.

If it were not for the problem with the right arrow I could be convinced I'm not doing the alignment correctly.

The Orion store is 10 minutes from my office. The mount goes there today.

Don


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron VX mount: experiences and problems new [Re: Dr.Don]
      #6064461 - 09/05/13 01:32 PM

1. Always use a fully charged 12-vdc battery or Celestron's 5-amp AC supply.

2. Don't worry about it "finding" stars, don't worry about how far away they are from where the scope stops. Just center them up after it stops.

3. Make sure you center the correct stars. "Almost" ain't good enough.

4. Don't obsess over the axes being "too stiff." That won't affect go-tos at all.



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Dr.Don
member


Reged: 05/31/13

Loc: Northern California
Re: Celestron VX mount: experiences and problems new [Re: rmollise]
      #6064552 - 09/05/13 02:20 PM

I am using a high quality MFJ 15 Amp supply. There is no reason to change.
If it can go from Arcturus to Vega and then cant get back to Arcturus there is something wrong.

The dec motor issue is enough reason to return the mount for replacement. And I have another 8 days left in my 30 day money back guarantee so the whole C9.25 could find its way back.


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron VX mount: experiences and problems new [Re: Dr.Don]
      #6064711 - 09/05/13 03:45 PM

Not "going back to Arcturus" would be expected if there is a problem with your alignment/procedure to begin with.

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Dr.Don
member


Reged: 05/31/13

Loc: Northern California
Re: Celestron VX mount: experiences and problems new [Re: rmollise]
      #6064806 - 09/05/13 04:38 PM

Alignment procedure:
1. Balance
2. Reasonably good polar alignment using the polar scope from my C8.
3. Set index marks.
4. Turn on, hit Align.
5. It usually get pretty close to Arcturus.
6. Use arrow keys to center in finder, hit Enter.
7. Use arrow keys to center in EP, hit Align.
8. Repeat with second star as selected by the HC.
9. See if it properly tracks the second star.
If it tracks the second star, select another object. One night it actually made it to M13 and another night to M57. But most times it couldn't find Altair, Alcor, or Arcturus.

If tracking or slewing fails, turn off power, go back to step 1 or 2 and repeat until frustrated. Then go into the house and let my son try it himself several times. Guess what? He gets the same results.

Since I am still within the 30 day window the very nice folks at Orion have ordered a new scope for me. I just have to pack up the whole telescope and bring it back to Orion.

Don


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron VX mount: experiences and problems new [Re: Dr.Don]
      #6065027 - 09/05/13 07:03 PM

If you are not doing the calibration stars, your go-to accuracy will be limited.

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Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Celestron VX mount: experiences and problems new [Re: rmollise]
      #6065158 - 09/05/13 08:32 PM

I don't know if you are doing this but always finish with up and right when aligning. Add at least 1 calibration star. GOTOs should be fine. I will say I had one CGEM that Celestron had me test over and over and finally replaced it because it just wouldn't point. The replacement is dead on!

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schluterdude
super member


Reged: 08/05/13

Loc: Centerville, OH
Re: Celestron VX mount: experiences and problems new [Re: Stew57]
      #6065215 - 09/05/13 09:15 PM

I never bother with hitting "enter" in the finder first. I get it centered in the eyepiece then hit enter the align. I also use all 4 calib star slots. Lethal accuracy.... I also use a 12mm EP during this on an 8" f6 reflector...

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Gary Minder
member


Reged: 06/23/13

Re: Celestron VX mount: experiences and problems new [Re: schluterdude]
      #6065236 - 09/05/13 09:30 PM

IMHO if someone isn't doing a careful 2+4 before deciding a mount can't accurately Go-To then getting another mount may not be any less frustrating.

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seawolfe
sage


Reged: 06/26/13

Loc: N 47.11.23 W 122.20.18
Re: Celestron VX mount: experiences and problems new [Re: Gary Minder]
      #6065608 - 09/06/13 05:36 AM

Agreed.

You HAVE to do a 2 + 4 and it's very plain on the handset that you press Enter after centering on the finder scope and then Align after centering in the EP.

Using a medium power EP or better yet, a illuminated reticle helps greatly in the EP alignment.

That said, I know from experience to have the scope well balanced, have the Rec and Dec locks ON... Have the correct latitude alignment. Have the correct time, day, time zone and type of time... i.e. DST vs. Standard time.

Next, first and second alignment stars will NOT be spot on, but you have to move the scope to it using the arrow keys. Use Up and Right to keep the backlash down.


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schluterdude
super member


Reged: 08/05/13

Loc: Centerville, OH
Re: Celestron VX mount: experiences and problems new [Re: seawolfe]
      #6065652 - 09/06/13 06:48 AM

Running the mount calibration/ra switch routine helps as well. And the "precise goto" function if you are strapping on accessories/running at the high end like I am... My OTA with rings/dovetail/camera tips the scales at 27 lbs... It's rated for 30, and I can hear the ap'ers groaning at the 50-75% rule!!!! Someday I'll get a monster ;-)

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