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Equipment Discussions >> Mounts

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akulapanam
super member


Reged: 08/27/12

Re: What's the deal with Meade and GEMs? new [Re: orlyandico]
      #5939014 - 06/25/13 12:40 AM

The Meade LX850 and LX600 look really nice. In fact it looks like the "iphonesk" solution for astrophotography. However, until the whole Meade financial issue gets straightened out I'm leery of buying. PHD and All Star Polar Align are also pretty easy to use and if my guiding breaks I don't have to go to the trouble of sending it back to Meade to get it fixed.

I have recently been thinking about exactly what mid range is in astronomy. I figure if you want at least a basic astrophotography option:

Low end - Under $2K for mount and telescope (basic refractor ED-80, Basic Mount CG-5)

Low-Mid end - $2K to $5K (CGEM/Atlas/CPC and Edge/Nicer Refractor)

Mid-End - $5K to $10K (Specialty 10"/C14/Nice Refractor on CGE Pro or AP mount). The limit in this range is probably a C14 or Meade 14 LX850 although you might be able to do a 150mm refractor or AT12RC on CGE Pro.

Upper End - $20K-$35K Now there is a huge jump($10K) at this point for some reason, probably lack of competition. This is where you find a $10K-$15K mount (like a Paramount or ASA DirectDrive) and a $10K - $15K scope (Planewave 12"/17", Meade 16", ASA INs, RCOS, Hyperion ect...) . Oh by the way you also probably need a $10K 35mm or better ccd camera to have any field too. I personally wonder about the value of some of the smaller scopes and the mounts in this field... How much better is an ASA IN or a Planewave 12.5 compared to the equivalent GSO product? I have to imagine that the Paramount and the ASA DirectDrive is a lot better then a CGE pro but I'm not sure if it is worth double the price especially without onboard computers.

Elite End - Again a real big jump here to the $35K+ level but you start to see 20" scopes. I personally wonder how many Planewave .7 meter scopes they are selling.


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freestar8n
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Reged: 10/12/07

Re: What's the deal with Meade and GEMs? new [Re: Spacetravelerx]
      #5939123 - 06/25/13 03:39 AM

Quote:

Is sub-arcsecond typical for you? Isn't this beyond the resolution of a pixel for a CCD camera used on, lets say, a C11?




You are talking about imaging, but I don't know that you have much experience with it on your current mount or other mounts. The only images I have seen from you are video captures.

Guiding with a small guidescope can certainly be sub arc-second, but it is limited by flexure - and that flexure will occur with any mount when guidescope guiding because a lot of it is within the OTA itself - except for refractors.

There are many ways to align a mount, and I thought the lx850 relied on a semi-automated drift alignment procedure that you in fact touted. Any time you do a drift alignment you need to wait to measure the drift and then adjust, and iterate. Since the lx850 does rely on a form of drift alignment - it is already slower than something like all star polar alignment.

One thing that rarely comes up in these discussions is that the "integrated" aspect of the lx850 is only between the guiding system and the mount - but it leaves out one of the most important elements: the imager. This means, for one thing, that you cannot dither.

Unless there is some mechanism for the imaging system to talk to the mount and tell it to dither between exposures, the inability to dither is a major downside that most *any* mount/guiding/imaging system can do as long as the imaging software is in control.

The benefit offered by starlock is that when you tell the mount to move, it can turn off guiding and then make the move all by itself. When guiding software is in control, you press one button to turn off guiding, and then do the goto. Thus it saves a single button press - but you lose the ability to dither.

Frank


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cn register 5
scholastic sledgehammer


Reged: 12/26/12

Re: What's the deal with Meade and GEMs? new [Re: freestar8n]
      #5939130 - 06/25/13 03:56 AM

Quote:

The benefit offered by starlock is that when you tell the mount to move, it can turn off guiding and then make the move all by itself. When guiding software is in control, you press one button to turn off guiding, and then do the goto. Thus it saves a single button press - but you lose the ability to dither.

Frank




This should be pretty easy to do with an ASCOM guiding/scope driver. It acts as an ASCOM telescope hub and also connects to PHD.
When a slew is commanded guiding is turned off and when the slew completes a new star is found and guiding started. Only then is the slew reported as finished.
It could also hook into a camera so dithering could be done.

Come to think of it Sequence Generator Pro does most of this - for $99.

Chris


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freestar8n
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Reged: 10/12/07

Re: What's the deal with Meade and GEMs? new [Re: cn register 5]
      #5939144 - 06/25/13 04:15 AM

MetaGuide was the first guide software I know of to allow dither control from imaging apps such as ImagesPlus - by allowing the imaging software to communicate to the guide software and tell it to adjust the guidestar location in a random manner. I believe other software has since offered similar functionality. The key is that it must happen between exposures - so the imaging software must make the dither command.

In this mode there need not be any ascom involved at all and you can just have the guide software wired to the st4 port - and it all works.

If you did have ascom involved, then you would have a number of elements: ascom, guide software, imaging software, mount control software - and they could indeed all communicate and cooperate happily - including turning off guiding when a slew happens.

But I guess my main point is - there are some advantages to having things more loosely coupled - and pressing an extra button is no big deal in the first place - especially if you sacrifice the ability to dither just for that button press.

Another point is - if you are imaging, then you need some kind of imaging software to take exposures in the first place. There are many options there, from free to expensive. If you are going to have it anyway, you can use it as the main form of integration - and then you have a fully integrated system without special hardware.

Frank


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orlyandico
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Reged: 08/10/09

Loc: Singapore
Re: What's the deal with Meade and GEMs? new [Re: freestar8n]
      #5939171 - 06/25/13 05:36 AM

sub-arcsecond is common. My C9.25 at native FL with my (cheap) large pixel OSC is under 1" per pixel. And if you think that sort of resolution is not needed by us non-advanced imagers.. the Eskimo and Cleopatra's Eye both need even more focal length than I can muster.

Hardly a "high end" setup or "advanced" imaging requirements..


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freestar8n
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Reged: 10/12/07

Re: What's the deal with Meade and GEMs? new [Re: orlyandico]
      #5939184 - 06/25/13 06:02 AM

Quote:

And if you think that sort of resolution is not needed by us non-advanced imagers..




I assume by "you" you mean Spacetraveleretx/Andrew - and not "me" - since my guiding work with MetaGuide is focused on optimal imaging with mid-range equipment - and I achieve sub 2" fwhm in long exposures regardless of large PE - etc.

Since people were talking about the CGE, I have one of the early ones, nearly 10 years old now and with the original cables. It has 25-30" pk-pk PE with gearbox noise - and using OAG and MetaGuide with 1s guide updates I am getting sub 2" fwhm in 15m exposures from a non-special sea level suburban location.

Frank


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orlyandico
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Loc: Singapore
Re: What's the deal with Meade and GEMs? new [Re: freestar8n]
      #5939185 - 06/25/13 06:04 AM

Yes Frank, of course.

I have the greatest of respect for the work and results you've achieved with MG.

What sort of camera are you using to get 1s updates with an OAG, though? that must be a pretty sensitive - and spendy - camera..


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freestar8n
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Reged: 10/12/07

Re: What's the deal with Meade and GEMs? new [Re: orlyandico]
      #5939191 - 06/25/13 06:24 AM

My early work with MG was mainly with Lumenera, which is fairly expensive. But as long as the guidestar is bright enough, video rates at 5 fps are not difficult and allow 1s updates with low latency. You can do it with an inexpensive toucam pro or neximage if the star is bright enough.

With the lumenera and oag on c11 I could guide on 9+ mag. stars at 7 fps.

Nowadays I am focused on the QHY5L-II, which is much cheaper and looks much more sensitive and lower read noise - despite tiny 3.75um pixels. It also has an st4 hardware port built in, which MG now supports for direct pulseguiding. The small pixels are also well suited to guidescope guiding.

So you don't need an expensive video camera to guide at 1s periods - since most will allow rates of 5-10 fps that work for guiding. But new ones like the qhy are very well suited for video guiding.

This stuff should work well with any mount but in terms of cost and added components, a celestron mount includes nexremote and pectool - so if you add a small guidescope and the qhy camera, plus MG (free) and imaging/control software for your imaging camera - you have a complete system with a hardware connection to the mount. For best results use OAG and then you don't need the guidescope.

Thanks,
Frank


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LLEEGE
True Blue
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Reged: 03/03/05

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Re: What's the deal with Meade and GEMs? new [Re: freestar8n]
      #5939306 - 06/25/13 08:42 AM

Until used LX850's start showing up on the used market, it's speculation, but I'm willing to bet what you spend "up front" will be gained back in resale value. Using the CGE-Pro as an example, its fit, finish and performance falls far short of what a Mach 1 gives. I wouldn't give two nickles for a used Pro.

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OzAndrewJ
scholastic sledgehammer
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Reged: 11/30/10

Re: What's the deal with Meade and GEMs? new [Re: freestar8n]
      #5939307 - 06/25/13 08:42 AM

Gday Frank

Different Andrew here

Re
Quote:

One thing that rarely comes up in these discussions is that the "integrated" aspect of the lx850 is only between the guiding system and the mount - but it leaves out one of the most important elements: the imager. This means, for one thing, that you cannot dither.




Not sure i understand this bit ( or if its totally correct ).
As far as i can tell from the coding, there is nothing to stop an imager from dithering between frames.
The guiding code in the firmware is smart enough to know if an incoming giuide/move command is from StarLock, ( based on comms channel used ).
If a pulseguide command comes in on the free rs232 channel, or an ST4 request comes in, it looks like Starlock auto disengages until the move finishes, then immediately reacquires a guide star and keeps on trucking at the new location.
As such, the dithered move should be respected/preserved.
I cant test it in real life, but the mechanism sure appears there to allow it.

Andrew Johansen Melbourne Australia


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freestar8n
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Reged: 10/12/07

Re: What's the deal with Meade and GEMs? new [Re: OzAndrewJ]
      #5939338 - 06/25/13 09:07 AM

The key point is that the command "dither" is a special command to the component that is doing the autoguiding and, for example, is holding the star centroid to a particular x,y location. Does the lx850 command set include a dither command? If so, can a generic imaging application such as maxim or imagesplus make that command between exposures?

The way MetaGuide implemented it long ago, and I think others do also, is to allow a special windows message as a crude IPC that just says "dither". It needs no special coordinates or other parameters - it just triggers the guide software to change the target xy location a small amount, and randomly, and - most importantly - between exposures so it doesn't mess up the image. The guide software needs to make the decision of how much to move - and to keep track of the original "home" guide location.

Imagers learn pretty quickly that dithering is important - especially with relatively noise dslr's - and especially when flexure causes unpleasant streaking in the stacked images.

Unless the lx850 has such a command set, and it is supported by whatever imaging software people choose to use, I don't know how it could currently dither. I imagine it could be added in later - but it would still require a coordinated effort between the guide software and the imaging software - as has already occured for MG and imagesplus - for example.

In MG I provide both the windows message and a simple executable that causes a "dither" to happen. You can't send a windows broadcast from apps like maxim - so one way maxim can make mg dither is by calling that exe between images - with a few second delay to recover from the shift.

Frank


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orlyandico
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Reged: 08/10/09

Loc: Singapore
Re: What's the deal with Meade and GEMs? new [Re: LLEEGE]
      #5939476 - 06/25/13 10:37 AM

I disagree I think $2500 for a used Pro is acceptable.. your point about resale is well-taken however..

Thank heavens I don't ever expect to re-sell my Mach1. If ever I go bigger I will almost certainly keep it for backup. But bigger will mean I will have a nice yard in a nice dark-sky spot. Likely not to happen for years, decades maybe. Goes back to the Mach1's weight. It's the best reasonably-light mount you can buy.


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dawziecat
Carpal Tunnel
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Reged: 10/20/10

Loc: Rural Nova Scotia
Re: What's the deal with Meade and GEMs? new [Re: WadeH237]
      #5939487 - 06/25/13 10:47 AM

Quote:

I just hate to see the AP get a bad rap for goto performance, when it's just not a problem.




I eagerly await the arrival of an AP1100 as soon as A-P gets it ready to ship. In the interim, I have read the manuals and, fresh from a G11 Gemini 2, it seems clear to me that A-P software is lagging way behind. The A-P keypad seems reminiscent of the clunky original Gemini HC that almost nobody liked. It bears no resemblance to the glitzy Gemini 2 HC! There are so many features that the A-P HC doesn't have compared to Gemini 2, I would surely miss several if I attempted to list them. And more new ones are being added regularly . . . see Hilmi's post of just today.

A-P mounts may well be mechanically superb. I sure hope so as I will be buying one very soon. But their software and their HC seems aeons old.

The GOTO accuracy is of small concern to me but, considering A-P's price point and reputation, we really shouldn't even be discussing this.

I look forward to my AP1100. But I already miss my Gemini 2. All the teeth gnashing from its growing pains aside, Gemini 2 seems the GOTO software of the future. A-P's is of a rapidly fading past.

If I could graft a Gemini 2 onto an AP1100 . . . I'd love to do so!

Edited by dawziecat (06/25/13 11:01 AM)


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EFT
Vendor - Deep Space Products
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Reged: 05/07/07

Loc: Phoenix, AZ
Re: What's the deal with Meade and GEMs? new [Re: akulapanam]
      #5939493 - 06/25/13 10:49 AM

Quote:

The Meade LX850 and LX600 look really nice. In fact it looks like the "iphonesk" solution for astrophotography. However, until the whole Meade financial issue gets straightened out I'm leery of buying. PHD and All Star Polar Align are also pretty easy to use and if my guiding breaks I don't have to go to the trouble of sending it back to Meade to get it fixed.

I have recently been thinking about exactly what mid range is in astronomy. I figure if you want at least a basic astrophotography option:

Low end - Under $2K for mount and telescope (basic refractor ED-80, Basic Mount CG-5)

Low-Mid end - $2K to $5K (CGEM/Atlas/CPC and Edge/Nicer Refractor)

Mid-End - $5K to $10K (Specialty 10"/C14/Nice Refractor on CGE Pro or AP mount). The limit in this range is probably a C14 or Meade 14 LX850 although you might be able to do a 150mm refractor or AT12RC on CGE Pro.

Upper End - $20K-$35K Now there is a huge jump($10K) at this point for some reason, probably lack of competition. This is where you find a $10K-$15K mount (like a Paramount or ASA DirectDrive) and a $10K - $15K scope (Planewave 12"/17", Meade 16", ASA INs, RCOS, Hyperion ect...) . Oh by the way you also probably need a $10K 35mm or better ccd camera to have any field too. I personally wonder about the value of some of the smaller scopes and the mounts in this field... How much better is an ASA IN or a Planewave 12.5 compared to the equivalent GSO product? I have to imagine that the Paramount and the ASA DirectDrive is a lot better then a CGE pro but I'm not sure if it is worth double the price especially without onboard computers.

Elite End - Again a real big jump here to the $35K+ level but you start to see 20" scopes. I personally wonder how many Planewave .7 meter scopes they are selling.




You left out the $10K to $20K range in which there are a significant number of mounts. What would you consider those?


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orlyandico
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Reged: 08/10/09

Loc: Singapore
Re: What's the deal with Meade and GEMs? new [Re: EFT]
      #5939507 - 06/25/13 10:58 AM

Terry, I know that AP electronics seems absolutely stone age compared even to Celestron - let alone the Gemini 2.

But you'll get used to it. Trust me.

I believe AP doesn't actually build their electronics, it is sub-contracted to some other company. And supposedly these electronics are mil spec. You never hear about bugs in the GTO controllers (unlike the numerous ones over the years in Gemini 2).

The GTO electronics does what it does very, very well. Not a lot of bells and whistles, but reliable.

If you read the manual as well, AP notes that in case of RA motor failure, you can swap the motors and keep on imaging (albeit you lose GoTo since no more DEC motor). Can any other mount controller claim that?

That said, I am not blind to the relative lack of features of the AP controller. Coming from a Nexstar that is. But you can remedy this with an iPad and Skyfi or Skywire (to some extent).

and heck, if we want to cast blame for stone age electronics, there's a certain Takahashi Seisakusho which is a far worse offender..

I personally think that a Nexstar hand controller on an AP mount would be tremendous! and this is in the realm of the possible: use the existing AP servos, get a custom Nexstar controller board (the NexSXD folks have done it for Vixen, I am sure they can do it for AP) and use a Nexstar hand controller.

But I fail to see any AP owner ever going down that route...


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Dwight J
scholastic sledgehammer
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Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: What's the deal with Meade and GEMs? [Re: dawziecat]
      #5939586 - 06/25/13 11:46 AM

Our club has an AP 1200 with a C14. I am wondering what features you are missing that you feel you need with an AP mount. Polar alignment is easy using the polar scope and a quick tweak in drift alignment (although ours is permanently mounted). It has a synthetic autoguide feature ( pulse guide I think it is called) PEC, park, etc. although I don't image much with it I can routinely get 4 to 5 min unguided images with it using a Mallincam or DSLR on the piggyback refractor. The hand controller is very robust an upgradeable. I think simple but overbuilt is the way to go and the extra "features" are unnecessary and, if they quit working make the mount inoperable. My personal mount is a Tak EM 200 and it is even simplistic. I really like how these mounts just work out of the box and continue to do so for years. My previous mounts were an EQ6 Synscan which I could never get to autoguide despite 2 years of trying and a LXD 55 which I don't need to elaborate on my adventures with it.
If I was in the market for a lower price mount I would consider an Ioptron model. From what I have seen on NightSkiesNetwork they work extremely well, particularity the IEq75.
A litmus test for mounts ( and lots of other equipment) is how many posts they generate and, to a lesser extent, the content of those posts.
BTW, congrats on the new mount and you won't regret your decision to buy it.


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dawziecat
Carpal Tunnel
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Reged: 10/20/10

Loc: Rural Nova Scotia
Re: What's the deal with Meade and GEMs? [Re: Dwight J]
      #5940198 - 06/25/13 05:41 PM

Hi Dwight:

First off, STAY DRY out there!

I am not here to totally hijack this thread
And certainly not to "trash" A-P. That said, I would like to see some changes. Since you ask, two things spring immediately to mind that I will miss when I begin using my AP1100:

1/ Easy setting and access to multiple bookmarks. I have learned how to set up a sort of bookmark to use when shifting away from a target to check focus and then back to the target with accurate, repeatable framing. In Gemini 2 it's easier and you can have four bookmarks.

2/ No Sharpless catalogue. I will miss it.

Of course neither of these is insurmountable. I do not disagree that many of the frills in Gemini 2 are just that . . . frills. Doesn't make 'em bad.

If I thought I'd be better off sticking with a G11 Gemini 2, rather obviously I would have done so. No doubt the AP1100 will outperform the G11 . . . at least I sure hope so! It will be a staggeringly expensive lesson for me to find out it doesn't! There will be copious

Hi Orlando:
I am prepared to accept A-P software as it is. No harm wishing it were more up-to-date. Perhaps you can't have "cutting edge"(Gemini 2) and "bulletproof" (A-P) both.

Now, back to "Meade and GEMs."

Edited by dawziecat (06/25/13 05:43 PM)


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OzAndrewJ
scholastic sledgehammer
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Reged: 11/30/10

Re: What's the deal with Meade and GEMs? [Re: freestar8n]
      #5940219 - 06/25/13 05:53 PM

Gday Frank

Quote:

Does the lx850 command set include a dither command?




Not based on it having to know where it is relative to a "home" position.
( considering it is an openloop process )
A random move command could be easily scripted to do a dead reckoning
move "between" exposures without problems, but controlling the absolute delta is not possible ( that i can see ) as it would always be an open feedback loop.
How much error in position would be a problem before later stacking got affected??

Andrew Johansen Melbourne Australia

PS there are new commands to allow small multi axis moves,
but the encoder resolution and target resolution used are too large
to get accurate "nudges", as the commands are really fullblown slews,
vs the much more precise pulseguides,
( which can apply absolute deltas to the encoder positions to do a "tweak" )


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Aquatone
sage


Reged: 03/23/06

Loc: Moraga, CA (Bay Area)
Re: What's the deal with Meade and GEMs? [Re: dawziecat]
      #5940283 - 06/25/13 06:51 PM

Quote:

I eagerly await the arrival of an AP1100 as soon as A-P gets it ready to ship. In the interim, I have read the manuals and, fresh from a G11 Gemini 2, it seems clear to me that A-P software is lagging way behind. The A-P keypad seems reminiscent of the clunky original Gemini HC that almost nobody liked. It bears no resemblance to the glitzy Gemini 2 HC!




I suspect that being accused of not being "glitzy" is the highest compliment you could pay AP. Honestly the handpad is industrial strength. (It is an industrial hand controller after all) You could drop it from 50 feet or even into a swimming pool (uh, I did) and it will still work. It's clunky big buttons are easier to use with gloved fingers in the cold, oh and it will work at ridiculously low or high temperatures for years on end. The GTOCP3 control box has a small hole in it to let moisture OUT. Somethings should be non-glitzy and timeless. If you want the ultimate in software control and features plug the mount into a planetarium program!

Chris


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Starhawk
Space Ranger
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Reged: 09/16/08

Loc: Tucson, Arizona
Re: What's the deal with Meade and GEMs? [Re: Spacetravelerx]
      #5940298 - 06/25/13 07:02 PM

Andrew,

Your responses on the Mach 1 GTO show you just aren't familiar with the product. It's ready to go out of the box. You get a kit of parts for what you are doing, so there are no extra parts with no obvious purpose. You can put it on a Losmandy tripod Berlbach, AP, or a pier. Plug it in and it runs. There's no alignment; it's already aligned. It's far more similar to a large observatory's operating behavior than a consumer product.

Your posts are just reflecting you didn't know what your alternatives actually were when you got the LX850. I know you think it's great; your repetitions of the spec sheet are 32% of the total content on CN at this point. So I've got it- after looking at it and nothing else, you've concluded it's awesome.

Unfamiliarity with an alternative product is not evidence of its inferiority. The Mach 1 GTO has many things it does well; starting with doing from the moment it is asked to.

So, the point in a thread like this is the discussion about mount performance- not a small subject, and one I'm really not feeling like getting into today. Something like 120 pages of thread on various high end mounts should suffice to talk to the issue.

-Rich


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