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Meade LX-80 in Polar Mode

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#1 dmdouglass

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Posted 12 July 2012 - 12:22 PM

The Meade LX-80 mounts have been out for awhile now... and a few questions are developing. Thus far, the mounts have proven to be very good at Alt/AZ (Single OTA) and very good at Alt/AZ (Dual OTA). The jury is still out on Polar.

There is a seperate thread here on CN (Mounts), being "LX80 RA tracking". The issue is "drift" while in Polar mode.

Is anyone using an LX-80 in Polar mode? Some basic information would be helpful. There are a few very easy tests that can be done to produce useful figures if you are set up in Polar.

If you are not operating in Polar mode, but are familiar with the configuration, and willing to do a few basic tests, please advise here, and I will get back to you.

Thanks.

#2 jmiele

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Posted 12 July 2012 - 12:44 PM

TBH, I don't think we need another LX80 thread. Don't we have two already? This makes three...

Joe

#3 rmollise

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Posted 12 July 2012 - 12:58 PM

If he can get inputs by some other users (other than the person with the thread about polar tracking that's already here) it would be well worth it. ;)

#4 jmiele

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Posted 12 July 2012 - 01:59 PM

Fair enough Uncle Rod. :) The tracking thread has become more of a working thread so introducing additional questions could be disruptive to that process. I hadn't considered that.

.. Joe

#5 Stew57

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Posted 12 July 2012 - 02:13 PM

I am only interested in the mount's polar ability and some are only interested in the alt/az mode. Anything negative about polar mode seems to upset them. If it doesn't work well in polar mode I am uninterested.

#6 dmdouglass

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Posted 12 July 2012 - 02:56 PM

Uncle Rod has read my intentions correctly.

"LX80 RA Tracking" is a large "working" thread. To be honest, we have taken much of that "off line" (i.e. we are using emails for now...).

This thread is to seek out users to help develop some numbers.

#7 jgraham

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Posted 12 July 2012 - 03:16 PM

Same here... I'm very interested in learning how the LX80 behaves in polar mode. For starters, does it have a polar scope?

#8 rmollise

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Posted 12 July 2012 - 03:20 PM

Fair enough Uncle Rod. :) The tracking thread has become more of a working thread so introducing additional questions could be disruptive to that process. I hadn't considered that.

.. Joe


The other thread is fine, but it would be, most of all, a huge help to know if any other users are experiencing the problems he is apparently experiencing. ;)

#9 rmollise

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Posted 12 July 2012 - 03:24 PM

Same here... I'm very interested in learning how the LX80 behaves in polar mode. For starters, does it have a polar scope?


I can tell you the answer to that one: No.

Reading the manual, it seemed to suggest there was a built in polar alignment mode like AllStar, but it appears to me that is not the case either.

That is not a show stopper. Other polar scopes, like an SCT finder with a polar reticle, could be used, and if there is a demand, I would guess JMI or somebody will make one for it.

I believe Meade believes the main use of this scope will be in alt-az mode ala its inspiration, the Ioptron Cubes and Towers. ;)

#10 jgraham

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Posted 12 July 2012 - 04:45 PM

Yeah, I get that impression too. The problem is that they killed off their entry level imaging mount to introduce this one. Ugh. As you say, not a show-stopper, but one more issue to deal with. At the moment I would not consider an approach like AllStar to be a substitute for a polar scope for imaging. You really gotta get your polar alignment close and even a polar scope is only marginally acceptable. Next issues are the tracking quality and autoguiding.

#11 frolinmod

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Posted 12 July 2012 - 06:40 PM

I'm amazed anyone is even considering using this mount for astrophotography. I would never in a million years expect it to perform to that level. I wouldn't expect my Atlas to be good enough for that either. These low end loosie goosie mounts are just barely suitable for visual use and that's about it.

#12 gmartin02

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Posted 12 July 2012 - 07:15 PM

...At the moment I would not consider an approach like AllStar to be a substitute for a polar scope for imaging. You really gotta get your polar alignment close and even a polar scope is only marginally acceptable. Next issues are the tracking quality and autoguiding.

Actually, I would not consider a polar scope as a substitute for All-Star for imaging (I guess we are talking about Celestron mounts, becaue the All-Star is currently only available on Celestron mounts, except for the current 3.28 beta release for SynScan). I can get a much more accurate alignment using the All-Star polar alignment compared to the Celestron polar scope on my CGEM or AS-GT (within about 1 arc minute on both axes with All-Star - you will never get that close with a Celestron polar scope). Celestron even states on their web site that using the polar scope to polar align is not sufficient for long exposure astrophotography.

#13 OzAndrewJ

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Posted 12 July 2012 - 08:41 PM

Gday Rod


Same here... I'm very interested in learning how the LX80 behaves in polar mode. For starters, does it have a polar scope?


I can tell you the answer to that one: No.

Reading the manual, it seemed to suggest there was a built in polar alignment mode like AllStar, but it appears to me that is not the case either.



Just on this topic, i havent seen anything much new in any of the aligning code etc
hence i assume that the LX80-Polar is treated the same way as LXD75s for general operation and aligning.
Ie it would appear it just has the std one two and three star modes that have always been there.

Andrew

#14 Lee Jay

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Posted 12 July 2012 - 09:27 PM

I'm amazed anyone is even considering using this mount for astrophotography. I would never in a million years expect it to perform to that level. I wouldn't expect my Atlas to be good enough for that either. These low end loosie goosie mounts are just barely suitable for visual use and that's about it.


I'm considering it for planetary astrophotography, and for wide-field astrophotography. It should be plenty suitable for those purposes.

#15 Mkofski

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Posted 12 July 2012 - 09:40 PM

I'm amazed anyone is even considering using this mount for astrophotography. I would never in a million years expect it to perform to that level. I wouldn't expect my Atlas to be good enough for that either. These low end loosie goosie mounts are just barely suitable for visual use and that's about it.


So, AP is limited to those that can afford $2500 for a higher end mount and $5000 for a nice SBIG CCD? I can't provide a link quickly but have seen many pictures that I'd be more than happy with, taken with less expensive camers and scopes and mounts that are "not suitable" for AP. Not everyone in the hobby has $5 or 10K or more to give it a try. If my LX80 ever arrives, I'll be trying AP with that, my used SCT and used DSLR.

Your original comment and my reply are very off topic. Why don't we leave this for the LX80 polar mode discussion?

#16 rmollise

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Posted 13 July 2012 - 06:37 AM

I'm amazed anyone is even considering using this mount for astrophotography. I would never in a million years expect it to perform to that level. I wouldn't expect my Atlas to be good enough for that either. These low end loosie goosie mounts are just barely suitable for visual use and that's about it.


You haven't used an Atlas, have you? ;)

#17 MeadeSquared

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Posted 13 July 2012 - 07:37 AM

I'm amazed anyone is even considering using this mount for astrophotography. I would never in a million years expect it to perform to that level. I wouldn't expect my Atlas to be good enough for that either. These low end loosie goosie mounts are just barely suitable for visual use and that's about it.


You haven't used an Atlas, have you? ;)


:funny:

There are at least two users on Cloudynights who take pretty great shots with a CG-5. Can they do 10 minute subs? I know Mary Blue (if I'm remembering her name right) has gotten there but I don't know that 10 minutes is at all necessary when you're learning the ropes. This hobby has grown a bit and a newbie like me can now break into AP for less than $2000, all in. And if you buy your gear used? Fuhgetaboutit.

Craig

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#18 jgraham

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Posted 13 July 2012 - 08:25 AM

I've been imaging with two LXD75s for many years and they've given me excellent service. My oldest LXD75 is showing signs of wear and I was kinda looking for its eventual replacement, hence the interest in the LX80. Treated with care the LXD75 and CG5 class mounts do a fine job.

Back to the polar scope thingy... a properly aligned polar scope (one aligned with the rotational axis of the mount) works fine. Aligning to the pole with the main scope requires that the optical axis of the telescope also be parallel with the rotational axis of the polar axis of the mount. To align the rotational axis of the mount with the rotational axis of the Earth using an optical refence point other that the pole requires that the angular offsets in R.A. and Dec. be accurately known. I'm not suggesting that they are not, but it does place an additional burden on the system if you are going to use it to the accuracy needed for imaging. I've built enough mount over the years to know where most of the ghosts are hiding. AllStar sounds really slick, but I'll take it with a grain of salt for now.

Sorry for being a stickler, I'm originally from Missouri and it took me a long time to figure out why they call it the Show-me State. :)

#19 DaveJ

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Posted 13 July 2012 - 09:22 AM

[quote...AllStar sounds really slick, but I'll take it with a grain of salt for now...[/quote]

Another vote here for Celestron's ASPA routine over a polar scope. I get far better polar alignment with my CGE and CGEM DX using ASPA than I ever got with a perfectly aligned polar scope in my Losmandy G-11. The mount errors you mention are fully accounted for by the 2+4 alignment routine which corrects for the "cone error" inherent to all GEMs. Proper use of the ASPA requires a 2+4 goto alignment FIRST, THEN you do the ASPA where the mount is adjusted physically with the ALT and AZ adjustments. Sorry, but the ASPA completely eliminates the need for a polar scope. I must admit that I was skeptical, too; but after routinely getting near-perfect polar alignment using ASPA I no longer consider using a polar scope.

#20 rmollise

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Posted 13 July 2012 - 09:40 AM

AllStar sounds really slick, but I'll take it with a grain of salt for now.

Sorry for being a stickler, I'm originally from Missouri and it took me a long time to figure out why they call it the Show-me State. :)


Plenty of people here with a lot of experience with mounts in general and Celestron mounts have used ASPA successfully for imaging. If you don't want to believe us, that's fine. Enjoy the salt. Ain't no law against that. :lol:

#21 Stew57

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Posted 13 July 2012 - 09:45 AM

Celestron engineers will tell you to expect around 5 arc minutes depending on how well you do your 2+4 alignment and the pointing accuracy of your particular mount. They will tell you if you need to be more accurate you will need to drift align. I would assume other software solutions will result in similar results.

It will be interesting to see Meade's solution for the LX80 if it is to be a replacement for the LXD75. So far it looks like bring back the LXD.

#22 rmollise

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Posted 13 July 2012 - 09:48 AM

The LXD75? It don't believe it will be back. There is not enough of a customer base to justify producing both it AND the 80. Assuming Meade remains afloat, I believe they will, as they usually do, work to improve the 80, and that it will wind up being considerably better--including in polar mode--than the pore old 75.

#23 mclewis1

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Posted 13 July 2012 - 10:39 AM

Celestron engineers will tell you to expect around 5 arc minutes depending on how well you do your 2+4 alignment and the pointing accuracy of your particular mount.

Mark, Wasn't this one Celestron employee who told you that he routinely got 5 arc min accuracy from ASPA with his mount?

Sorry to be a bit picky but I just wanted to be sure that I understood the origin of the number.

Since the s/w function is based on the accuracy of the initial alignment the overall accuracy of the ASPA function will be dependent on a particular mount's characteristics. Therefore any stated accuracy should really be a range (numbers from a CG-5 to CGEPro) or be identified with a particular mount.

#24 Stew57

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Posted 13 July 2012 - 11:05 AM

I will start another thread as this has nothing to do with the LX80, I hope you understand.

#25 jgraham

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Posted 13 July 2012 - 11:42 AM

Actually, it has a lot to do with the LX80. If you can't get a good polar alignment then it won't work well as an imaging mount. Polar alignment is just the first step. Right behind that is how well it tracks, periodic error, and gear lash. The lack of a polar scope is an obvious limitation to using the LX80 in polar mode, and potentially a big one. Celestron has apparently addressed this through ASPA and it would be helpful to know of Meade included a similar feature with the LX80.

Rod; it would ne nice to hear from imagers that can report that when using ASPA their dec drift was nothing unusual. Visually I can believe it, GoTos I can believe it, but for imaging polar alignment can drive you crazy even when using PHD. Of course my believing is not a huge issue (or even a little issue), just a source of entertainment. I make my living asking people to show me the data; 'cause I say so just doesn't cut it. It's fun to get to the facts, that takes all of the opining out of the discussion.






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