Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Mounts

Pages: 1 | 2 | 3 | 4 | 5 | 6 | (show all)
johnpd
sage


Reged: 04/13/08

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5955088 - 07/04/13 06:11 PM

Moromete,

It is very unlikely that you would get perfectly round stars imaging in Az with any mount for that length of time. I use a Mallincam Xtreme video camera on a C-8 @ f/3.3 and I would not go much beyond a minute. I had no GoTo issues with that configuration except with the problems I had indicated. When Synta resolves the current intermittent GoTo problems with v3.35, the mount should be very good.

JohnD


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike X.
scholastic sledgehammer


Reged: 06/28/10

Loc: Greece-Athens and Rome-Italy
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5955200 - 07/04/13 07:42 PM

Hello Moromete, thank you, you are too kind

Well a C11 as i said before i think it's a borderline OTA for this class of mounts both because of the weight and the focal Lenght.That's regarding DSO photography.But..with patience it can be done.
Regarding the GOTOs i think it wouldn't be hard to have the mount put a DSO in an APS-C sensor format (Most non full frame DSLRs).
Regarding the AZ mode i'm afraid i have no clue to help you with as i never tried it.
I am only guessing that if it tracks ok for visual observing it should be ok also for video astronomy but..still..maybe a friend that has used the mount in AZ mode can help you more than me.


Post Extras: Print Post   Remind Me!   Notify Moderator  
johnpd
sage


Reged: 04/13/08

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: johnpd]
      #5955223 - 07/04/13 08:08 PM

I just read a post in a Yahoo group from another AZ-EQ6 owner that Synta is aware of the GoTo issue and a fix will be released in the next firmware update. No release date was mentioned.

JohnD


Post Extras: Print Post   Remind Me!   Notify Moderator  
Patrick
Postmaster
*****

Reged: 05/16/03

Loc: Franklin, Ohio
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5955490 - 07/05/13 01:32 AM

I owned and tested both the CGEM and Atlas mount side by side. I still have the CGEM. I found that the accuracy of the CGEM with a 2+2 alignment was dead on accurate, while the 3 star alignment with the Atlas was within the field of view of a wide field eyepiece, meaning it was not quite as accurate. One of the big issues for me though was that the CGEM offered more alignment star choices than the Atlas. This can be a issue if you have a lot of trees or obstructions in your observing area like I do. There were a few times when I could not find three alignment stars with the Atlas.

Patrick


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5955682 - 07/05/13 08:11 AM

You might get some shots at this f/l with a C11 in alt-az mode, but only in a couple of areas. Usually field rotation will mean you will have non-round stars with exposures this long.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Patrick]
      #5956091 - 07/05/13 01:17 PM

Quote:

I owned and tested both the CGEM and Atlas mount side by side. I still have the CGEM. I found that the accuracy of the CGEM with a 2+2 alignment was dead on accurate, while the 3 star alignment with the Atlas was within the field of view of a wide field eyepiece, meaning it was not quite as accurate. One of the big issues for me though was that the CGEM offered more alignment star choices than the Atlas. This can be a issue if you have a lot of trees or obstructions in your observing area like I do. There were a few times when I could not find three alignment stars with the Atlas.

Patrick




@Patrick thx for your valuable feedback. Seems logical what you said and I know Celestron software is better.

What keeps me away from CGEM unfortunately is its weight, cogging issue and DEC issue which is hardware related. Otherwise Celestron software attracts me more than Skywatcher.

Without beeing able to compare Celestron and Skywatcher mounts I feel that software difference in respect of GOTO resides in polar alignment. I feel that Skywatcher needs much better polar alignment for precise GOTO and Celestron is much more forgiving because its software computes better human error in this process due to different math formulas and more callibration stars. When coming down to photography I suppose both mounts need almost as accurate polar alignment for longer exposure and maybe in this case the software difference fades away.
Still this difference in computing precision could be important when ASPA because Skywatcher I think can not compute as well Celestron the polar alignment error and maybe it needs more itterations to reach Celestron's precision. Am I thinking correctly?

Patrick, how scrupulous were you with polar alignment with Skywatcher when you said the object was to the border of the FOV and scope and eyepiece have you been using?

I generally put Polaris in the middle of the polar scope with CG5-GT and I do 2+2 star alignment.

@Uncle Rod maybe I have too much expectations from AZ mode but I was thinking at 1-2 minutes exposures with C11 at F/3 for video astronomy. For photograhpy I would be using EQ mode only with C11 at F/6 on AZ-EQ6 for exposures of up to 5 minutes guided. Am I still crazy?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: rmollise]
      #5957202 - 07/06/13 08:48 AM

The following 2 questions refer only to Skywatcher Synscan hand controller with the latest firmware 3.35 and not EQMOD software.

If you perform a Pointing Accuracy Enhancement (PAE) on 3 stars AFTER doing a 3 star alignment with EQ6 hand controller, is this similar to Celestron 2+4 star alignment and give the same GOTO accuracy with EQ6 mount or not?

Keeping the same idea and the same procedure described above, will ASPA with EQ6 give the same polar alignment precission as with ASPA on Celestron CG5GT/CGEM or not?


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5957274 - 07/06/13 09:54 AM

Quote:


Without beeing able to compare Celestron and Skywatcher mounts I feel that software difference in respect of GOTO resides in polar alignment. I feel that Skywatcher needs much better polar alignment...




The SynScan software now has exactly the same polar alignment routine as the NexStar branded scopes. "AllStar," IOW. The go-to alignment process is also considerably more automated with respect to good alignment stars, now. Frankly, I find the SynScan go-to accuracy and the NexStar pretty much the same, now.

Synta/Celestron has also released beta firmware that appears to eliminate the cogging problem (which never affected all users).


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5957275 - 07/06/13 09:56 AM

The PAE can work, but I never use it. It's like Sync, will throw your go-tos off in different parts of the sky, and, frankly, is not needed if you do a good go-to alignment.

The polar alignment routine in the SynScan version doesn't seem any different from in the NexStar branded HCs.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike X.
scholastic sledgehammer


Reged: 06/28/10

Loc: Greece-Athens and Rome-Italy
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: rmollise]
      #5957325 - 07/06/13 10:41 AM

It has a small difference in the steps to follow only.I guess in the performance must be pretty much the same.
The main difference is that in the Synscan version the HC asks to center the star in 2 different steps.One only in Altitude and one only in Azimuth.But that's about it.

Edited by Mike X. (07/06/13 10:41 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Mike X.]
      #5957454 - 07/06/13 12:26 PM

I suppose Skywatcher makes calculations GOTO the same as Celestron software because ASPA is done the same and you have to use Up and Right arrows when doing final alignment on a star. Even AZ-EQ6 hand controller is presented now to have a database of 42000 like Celestron.
There should be some legal difficulties probably or management decision which prevent using a 100% Nexstar software on a Skywatcher mount but the GOTO calculations done in software seem to be the same.

I'm waitting to see 2+4 star alignment and CPC Auto 2 Star alignment on AZ-EQ6. I think it's a matter of time.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Mike X.
scholastic sledgehammer


Reged: 06/28/10

Loc: Greece-Athens and Rome-Italy
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5958081 - 07/06/13 07:28 PM

I'm guessing that it has to do with the fact that they use 2 entire different ways to make the gotos that make the 2 protocols incompatible.
Synscan counts steps to reach a position, while the nexstar uses the encoders on the motors to reach the desired position.
For implementing nexstar on a SW mount I'm only guessing that the motors should at least have encoders...but again never say never.

For sure both protocols are keep evolving in parallel so..who knows...maybe in the future Synta could come up with a different alignment method for SW mounts...but still..this one is pretty good..I doubt they would do it anytime soon.
I was in love with my celestron mount and I had similar doubts regarding accuracy but I confess to you that the synscan is equivalent to the nexstar regarding this matter.
It is less user friendly than nexstar that's true but it is accurate virtually as the nexstar.


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5958618 - 07/07/13 09:10 AM

Quote:

I suppose Skywatcher makes calculations GOTO the same as Celestron software because ASPA is done the same and you have to use Up and Right arrows when doing final alignment on a star. Even AZ-EQ6 hand controller is presented now to have a database of 42000 like Celestron.
There should be some legal difficulties probably




There are no legal difficulties. Synta owns both systems. It is the parent company of Celestron AND SkyWatcher. The problem is that the mounts are so different:

Celestron = servo motors and encoders.

SynScan = stepper motors and no encoders.


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Mike X.]
      #5958620 - 07/07/13 09:12 AM

Quote:


I was in love with my celestron mount and I had similar doubts regarding accuracy but I confess to you that the synscan is equivalent to the nexstar regarding this matter.
It is less user friendly than nexstar that's true but it is accurate virtually as the nexstar.




Exactly. I do note that later releases of the SynScan software seem to be less user unfriendly than the old ones, though.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: rmollise]
      #5960046 - 07/08/13 06:11 AM

Quote:

The PAE can work, but I never use it. It's like Sync, will throw your go-tos off in different parts of the sky, and, frankly, is not needed if you do a good go-to alignment.

The polar alignment routine in the SynScan version doesn't seem any different from in the NexStar branded HCs.




According to the Skywatcher Synscan manual: "The pointing accuracy enhancement (PAE) function enables the telescope mount to obtain enhanced pointing accuracy in specific small areas.
After a 1-star, 2-Star or 3-star alignment, the telescope mount might still have a small pointing error due to many factors, such as the flexure of the telescope, atmospheric refraction or other mechanical issues. The amount of pointing error might vary in different portions of the sky.
The SynScan hand control divides the sky into 85 small zones, and users can calibrate the pointing error for each of these zones. The next time that the SynScan controller tries to locate an object in the calibrated zone (or a zone nearby), it will automatically apply the recorded calibration data to compensate the pointing error.
This function is useful for locating faint deep sky objects, and it is also helpful to obtain consistent pointing accuracy for a permanent observatory."


I don't know if I'm reading correctly but the Skywatcher PAE hand controller function doesn't seem to have the same effect like Celestron's Sync after which you have Unsync because, as you said Rod, the GGOTOs will be worse in other parts of the sky than the synced one.

Theoretically PAE should not degrade GOTOs in some parts of the sky because it needs no Unsync, is applied automatically during GOTOs and models the sky better after every added star to it. Seems similar to N-Point function from EQMOD.

Has anyone experience with Skywatcher GOTOs and ASPA after doing PAE on a few stars?


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: Moromete]
      #5960272 - 07/08/13 10:19 AM

I've used this function a time or two. I can tell you rat-cheer that PAE in one are of the sky will throw off accuracy in another.

Post Extras: Print Post   Remind Me!   Notify Moderator  
HowardK
Pooh-Bah
*****

Reged: 10/20/10

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: rmollise]
      #5960952 - 07/08/13 05:29 PM

Quote:

I've used this function a time or two. I can tell you rat-cheer that PAE in one are of the sky will throw off accuracy in another.




So Rod
U reckon its worthwhile using PAE?
Or does it mean that once u have used it in one part of the sky u have to keep using it in all others?


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: HowardK]
      #5960993 - 07/08/13 06:03 PM

I don't think it's worthwhile in most circumstances. It's better just to do a good alignment. A decent polar alignment with the polar scope and a 3-star using the guidance found in the manual, and the mount will put anything I request from horizon to horizon on the chip of My Mallincam Xtreme; that is good enough for me.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy new [Re: rmollise]
      #5961899 - 07/09/13 09:49 AM

Quote:

I've used this function a time or two. I can tell you rat-cheer that PAE in one are of the sky will throw off accuracy in another.




If that's the case in practice than you have been right saying Skywatcher PAE is like Celestron Sync function. Thx for sharing your opinion and test results.


In respect of Celestron ASPA, after reading CG5-GT website support page and CGEM DX manual (newer) I discovered something very interesting regadring the number of callibration stars needed before doing ASPA.
According to point 18 of CG5-GT support page before doing ASPA you need to align on 2+1(or more) callibration stars. http://www.celestron.com/c3/support3/index.php?group=c3&_m=knowledgebase&...
According to point 39 of CG5-GT support page before doing ASPA you need to align on 2+2 callibration stars. http://www.celestron.com/c3/support3/index.php?group=c3&_m=knowledgebase&...
According to page 29 of AVX mount manual before doing ASPA you need to align on 2+1 (or more) callibration stars: "Before using the Polar Align feature, the scope must first be roughly pointed towards north and should be aligned with three stars in the sky. See the “Latitude Scale” section for help with finding north and adjusting the mounts latitude. Once your telescope is aligned on two stars and at least one additional calibration star, slew the telescope to any bright star in its Named Star database list."

According to CGEM manual before doing ASPA you need to align on 2+1 (or more) callibration stars.

In conclusion, for doing an useful ASPA Celestron needs a 2+1 star alignment, more callibration stars giving higher precision.

Considering many people say that 2 star aling is much better than 3 stars alignment with Skywatcher mounts for accurate GOTOs, I wonder how efficient is ASPA with Skywatcher mounts after doing only a 2 star alignment without any callibration star like Celestron.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: Celestron Nexstar vs Skywatcher Synscan GOTO pointing accuracy [Re: rmollise]
      #5961921 - 07/09/13 10:02 AM

Quote:

I don't think it's worthwhile in most circumstances. It's better just to do a good alignment. A decent polar alignment with the polar scope and a 3-star using the guidance found in the manual, and the mount will put anything I request from horizon to horizon on the chip of My Mallincam Xtreme; that is good enough for me.




If your EQ6 puts DSO on Mallincam's chip when using a C11 at F/3.3, than EQ6 GOTO's are OK with me too.

It seems you have no problems with 3 star alignment with EQ6 like other users do and you prefer this method to 2 star alignment. This sounds reassuring to me.

But what do you mean by "decent polar alignment"?

Rod, how long are your exposures in general with Mallincam + C11 + Meade 0.33x reducer?

In wonder if instead of buying a AZ-EQ6, my CG5-GT with C11 reduced at F/3 and a Mallincam like camera will be good enough for up to 60s exposures without star trailing.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | 6 | (show all)


Extra information
16 registered and 26 anonymous users are browsing this forum.

Moderator:  Dave M, richard7, bilgebay 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 5923

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics