Quote:No one had both Celestron and Skywatcher mounts to make a GOTO accuracy comparison?
Uncle Rod Uncle Rod's Astroblog: http://uncle-rods.blogspot.com/
Clear Skies! Mike ------------- My Site
Quote: Hold your horses. You just axed.
Quote:Ok. I would like an Az-Eq6 quite badly but I've read on astro forums more opinions of people not so content with EQ6 or AZ-EQ6 GOTOs accuracy and than CGEM's GOTOs. In fact I rarely have seen people complaining about CGEM or CG5-GT GOTOs accuracy.I know that CGEM is not so good for photography at >1000mm due to cogging issue which affects DEC guidance and 8/3 issue, the last one being a hardware flaw which can't be fixed with a software update.Secondly the CGEM is just too heavy for my back.Till now I've heard good things about AZ-EQ6 but it seems that some people are not so content with GOTO accuracy of this mount in AZ mode. I heavn't read opinions regarding the GOTOs of AZ-EQ6 in EQ mode but I suppose they are quite identical with the GOTOs of EQ6 Pro.Regarding EQ6 Pro GOTOs I've read that they are very much dependant of an accurate polar alignment in contrast with Celestron mounts GOTOs which seem to be much less dependant on accurate polar alignment.On the other hand it seemed to me that, as Astrobabay said somewhere, with EQ6 it's better to align only on 2 stars and not on 3 if you want workable GOTOs, which is somehow weird.In plus some users said about EQ6 that if it's GOTOs were quite good for first part of the observing sesion than suddenly they degraded badly without understanding why.Now I have a C11 on a CG5-GT which has accurate GOTOs after 2+2 stars alignment and with very rough polar alignment (Polaris outside the polar scope FOV) and I like it but the C11 is too heavy for the mount. I have put the mount on pier and reduced Custom Rate 9 to 6 to avoid stalling and stressing the motors when slewing but now slewing became too slow.The only things which keep me back from buying AZ-EQ6 are GOTO accuracy in both EQ/Alt-Az modes and cord wrap problem in Alt-Az mode. Otherwise I would like to use the AZ-EQ6 with the C11 and Meade AR5 mounted in parallel in Alt-Az mode.I know AZ-Eq6 has lower noise too when slewing than CGEM and has much less weight.From personal experince I know that CG5-GT has very good GOTOs due to 2+2 star alignment and not being so dependant on accurate polar alignment and I suppose the CGEM is the same in this respect. Lousy polar alignment with CG5-GT means bad traking but really inaccurate GOTOs.With CG5-GT I always pick the stars I want for initial alignment and refuse the ones given by the hand controller and GOTOs are very good which means Celestron software does a good job for me.I really would like to put the C11 on a more serious mount but under 2000 USD and if I spend so much money on a new mount than the first priority for me are accurate GOTOs (e.g. placing a DSO on DSLRs frame with C11 at F6 or in the FOV at ~100x visually) and than mount must perform well when guided for exposures up to 5 minutes at 1700mm)!So can the AZ-Eq6 GOTOs put a DSO on the middle of a Canon 550D(T2i) frame with C11 at F6 or in the FOV at ~100x visually) and than mount must perform well when guided for exposures up to 5 minutes at 1700mm) or only the CGEM can do this?Do you think Synta will offer a 2+4 alignment in EQ mode or an Auto Two Star Align (like Celestron CPC scopes have) in Alt-Az mode for AZ-EQ6 in the near future (1-2 years)?
Quote:Thx Mike. Sure you helped.I'm looking forward to see a review from you for AZ-EQ6 which will be usefull for many potential buyers of this mount.With what scope and eyepiece have you tried the pointing accuracy of this mount in EQ mode? Were the viewed objects in the center of the FOV?Regarding Skywatcher ASPA precision I have some concerns because of this: before using ASPA with Celestron mounts you have to align on 2+4 stars but with Skywatcher ASPA is calculated after aligning the mount only on 2+1 stars, which I suppose means a lower precision in calculating Polaris position. Does it make any sense?Another thing that puzzled me about EQ6/Az-Eq6 pointing precision is that many users say they obtain much better GOTOs after only 2 stars alignment than 2+1 stars which seems to make things worse and computes cone error strangely. Have you experienced this situation in EQ mode?Regarding the Alt-Az pointing accuracy I see that there are problems according to the end of this review http://www.astroshop.com.au/guides/sky-watcher-azeq6gt.asp
SCOPES: CPC1100; AT66ED; EdgeHD 8";SVR90T RAPTOR
MOUNTS: CGEM; Vixen GP2; iOptron Sky Tracker; Celestron AVX
CAMERAS: Canon 60D;Lodestar
EYEPIECES:TV N31T5;Delos14;Delos8;Pan27; PL20;PL25;PL32;TMB9
The Lord sits enthroned above the circle of the earth...He stretched out the heavens like a canopy.
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
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...
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
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.
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.
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.
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.