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Which mount is best?

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#1 Jay Wise

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Posted 22 August 2009 - 05:05 PM

Help! I have a 9 month old 12" LX90 that I am really enjoying, however there are issues. It is a joy visually but the mount leaves a few things to desire. The goto works fairly well but the tracking is less than great. I'm 73 and my eyesight is really over the hill. I was encouraged to get a videocam to help with my visual problems and purchased a StellarCam3. The problem seems to be that the alt-az tracking of the LX90 is such that trying to capture the number of frames necessary for a good image is causing a blurring on the moniter. The few times we have gotten the the tracking right the picture was great. Now enter temptation! A friend has offered me a 5 yr old Losmandy G11 with the goto computer at a really great price. Do I scrub the LX90 mount for the G11? The hassel will be moderate and the cost not too bad but I don't want to make the switch if it will not help things. Setup is not an issue as I have a small SkyShed Pod. I really want the StellarCam to work well and it seems that the GE mount would be more accurate. I did not realize that the Meade mount would be so sloppy. Am I just not using the alt-az mount correctly? Any help will be really appreciated.
Thanks, Jay Wise

#2 mclewis1

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Posted 22 August 2009 - 05:54 PM

Jay,

I'm not sure about your tracking issues with the LX but I know that the G11 will give you very accurate tracking if you take the time to set it up. A 5 year old model G11 might have a few issues that would be a concern if you were a serious DSO imager but for video camera work it will likely be more than sufficient.

Get a Losmandy D plate sized for your scope (along with the radius blocks to mount it), de fork it from the LX arms and you should be off to the races. I'm assuming that you're already using a good focal reducer for your scope when you're using the StellarCam? The video camera really really likes faster f ratios.

You may also want to consider a good finder scope for the setup, sometimes if the G11 doesn't put the object in the fov of the StellarCam you'll need to go looking for it. A good larger aperture finder will really help you here.

#3 Alph

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Posted 22 August 2009 - 06:00 PM

The problem seems to be that the alt-az tracking of the LX90



Get a wedge to use the scope in the polar mode.

#4 Patrick

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Posted 22 August 2009 - 06:53 PM

Hi Jay,

I agree with Alph that what you really need is a wedge. Most likely the tracking errors you're seeing are not really 'errors', but rather field rotation because you're not operating your scope with it polar aligned. Here's a Wedge that will work with your LX90. There are pros and cons to using wedges, but it may be the cheapest solution to your problem, and you won't have to defork the OTA. While the G11 is a very capable mount, it seems like overkill when a wedge will get you where you want to go.

Patrick

#5 Jay Wise

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Posted 22 August 2009 - 07:38 PM

Thank you guys very much! I really like the wedge idea and have already found a used one. Mark, I am using the recomended focal reducer. Pat, the more I think about it I think you are right and it is rotation. The goto works so well that is must not be an alignment issue. If the wedge dosen't cure the problem I'll fall back on the Losmandy. Thanks again. Ain't Cloudy Nights great!

#6 gnowellsct

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Posted 22 August 2009 - 08:16 PM

Are you crazy????

Someone offers you a G11 at a good price and you're going to stick a wedge on your Meade?????????

Well I hope it works out for you.

Greg N

#7 Patrick

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Posted 22 August 2009 - 09:31 PM

Are you crazy????

Someone offers you a G11 at a good price and you're going to stick a wedge on your Meade?????????



What's a good price? Since that wasn't mentioned we don't really know. On the other hand, I think it's fair to say that a wedge is going to cost a lot less money than a G11 at normal prices.

He's already got a pretty nice mount in the LX90. It would be crazy to defork the OTA and toss the rest of the mount. Since the setup is in a permanent spot, it will only have to be setup once, so I don't understand the problem.

One of the guys in our club uses a 12" Meade LX200 on a fork mount with a wedge and he does some really nice work with it. Forks and wedges have been, and are still, used extensively for astroimaging.

I'm certainly not knocking a G11, but given the fact that the integration times with a Stellacam are probably less than a minute I think he can accomplish his goals by simply adding a wedge to what he already has.

Patrick

#8 Charlie Hein

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Posted 22 August 2009 - 10:07 PM

Easy does it everyone... :4

No question, the G-11 is a better option.

That said, the OP has to consider the financial implications.

Let's stick to providing the facts and let the OP make his choice.

#9 Phil Cowell

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Posted 23 August 2009 - 05:13 AM

Are you crazy????

Someone offers you a G11 at a good price and you're going to stick a wedge on your Meade?????????



What's a good price? Since that wasn't mentioned we don't really know. On the other hand, I think it's fair to say that a wedge is going to cost a lot less money than a G11 at normal prices.

He's already got a pretty nice mount in the LX90. It would be crazy to defork the OTA and toss the rest of the mount. Since the setup is in a permanent spot, it will only have to be setup once, so I don't understand the problem.

One of the guys in our club uses a 12" Meade LX200 on a fork mount with a wedge and he does some really nice work with it. Forks and wedges have been, and are still, used extensively for astroimaging.

I'm certainly not knocking a G11, but given the fact that the integration times with a Stellacam are probably less than a minute I think he can accomplish his goals by simply adding a wedge to what he already has.

Patrick


And he doesn't have to trade the ease of use of Autostar for the Gemini with a wedge either.

#10 Jay Wise

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Posted 23 August 2009 - 09:58 AM

Thanks for all the imput. I like strong opinions! The G-11 in question is $1000 bucks. It took me a while but I am really comfortable with the Autostar. I was dreading having to get used to a new system in the Gemini. I am in the age group that does not find computers intuitive. I must admit however that one look at the Losmandy and you can't help but be impressed with its quality. NO PLASTIC ALLOWED!

#11 Patrick

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Posted 23 August 2009 - 10:53 AM

The G-11 in question is $1000 bucks.



Wow, that would be tempting... :grin:

Patrick

#12 HunterofPhotons

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Posted 23 August 2009 - 11:02 AM

Thanks for all the imput. I like strong opinions! The G-11 in question is $1000 bucks.


That falls into the 'too good to be true' category. <g> You might want to upgrade to the ovision worms if it's an older G-11.

It took me a while but I am really comfortable with the Autostar. I was dreading having to get used to a new system in the Gemini. I am in the age group that does not find computers intuitive.

Not to worry, I've used both systems (and others). The Gemini is more professional. The learning curve on the Gemini is short, too. Lots of nervous first-timers are good drivers by the second outing.

I must admit however that one look at the Losmandy and you can't help but be impressed with its quality. NO PLASTIC ALLOWED!

Putting your Meade on a wedge is like making a diving board.
(I'm not Meade bashing, I own an LX90. It's just the physics of the situation.)
In addition, the bearings are not really up to the task of imaging off of a wedge.

dan

#13 Phil Cowell

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Posted 23 August 2009 - 11:15 AM

It took me a while but I am really comfortable with the Autostar. I was dreading having to get used to a new system in the Gemini. I am in the age group that does not find computers intuitive.

Not to worry, I've used both systems (and others). The Gemini is more professional. The learning curve on the Gemini is short, too. Lots of nervous first-timers are good drivers by the second outing.


Not all of us, I hated the Gemini. It's the reason I didn't buy an MI-250 or Titan and bought a CGE Pro. Yes I have used the latest Gemini had one as an upgrade for my CI-700 and thought it was archaic compared to most modern hand controllers.
My advice is try the Gemini controller before you buy the mount. You might love it and then again you might not. I wouldn't call it more professional as most modern controllers have the same features with easier care and feeding of the system.
Mind you for $1K the mount might be good to buy and then sell on for something that works for you if you don't like it.
Phil

#14 gnowellsct

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Posted 23 August 2009 - 03:16 PM

At $1k he should just buy the Gemini/G11, use it for six months or a year, and resell it for $2k. Most Gemini users say they "train into" the controller very quickly. Since I don't do go-to, I have to believe them. I did find it usable when I had Gemini but I didn't keep Gemini. I prefer push to.

I have been looking through a Meade 10" on an LX90 mount and it has what it calls tracking but it does this weird crunching little dance every few seconds to correct for dec drift (I guess) because it is in alt-az. Anyhow I find it problematic for visual use, let alone imaging. I guess an LX90 with a wedge is just an LX90 with a wedge. A G11 is a whole different ball game. With Ovision it can be tuned to perform to specifications more typical of Tak and Astro-Physics than anything else on the market. And some G11s perform nearly that well out of the box. (Age and type of worm gear matter in this discussion, but it doesn't matter, the Losmandy precision worms are only $50; that gets you tot one level, the Ovision costs $500 and gives you a re-engineered mount).

I have never seen anything like that in the alt-az tracking of the servoCAT scopes I have looked through. And they are rather clumsy to control in comparison to the G11 and AP900QMD.

In fact, this is something not often mentioned, highly precise control of the field of view in the eyepiece is one of the things at which the higher end GEMs really excel. The cheaper GEMs have backlash and all sorts of "up and left arrow" rules but the G11 and AP900 are just 100% pure control.

A gemini G11 for $1k is a steal assuming it is in working order; this is true even if it is an older G11. I would but it and put the Ovision on it. If it was an older one (only one screw for altitude lock) I would send it to Losmandy for the upgrade, costs about $50.

GN

#15 Phil Cowell

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Posted 23 August 2009 - 04:49 PM

At $1k he should just buy the Gemini/G11, use it for six months or a year, and resell it for $2k. Most Gemini users say they "train into" the controller very quickly. Since I don't do go-to, I have to believe them. I did find it usable when I had Gemini but I didn't keep Gemini.

I can only speak from experience but "training into" wasn't for me. The G11 is a very capable mount and there are other options to the Gemini like the SiTech. If it was me I'd buy the mount, dump the Gemini to cover the cost of the mount and later add a SiTech or something similar and a bit more modern.
Phil

#16 DeanS

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Posted 23 August 2009 - 05:09 PM

I had the MI-250 with Gemini for a couple years, had no issues learning it and it worked fine for me. Just make sure it has the latest version, of not it is easy to replace the eprom to update it.

I say for the money you can't go wrong.

#17 gnowellsct

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Posted 23 August 2009 - 09:56 PM

Phil, I truly understand, because I decided that not only the paddle wasn't for me: I didn't want anything to do with go-to at all.

But some people hook this system up to laptops and run it off their laptops. So the paddle is often not an issue, and others, as we can see, get used to the paddle. The software has been regularly updated but it remains menu driven. Far fewer buttons means a mechanically more robust system, and judging by the number of returns I've seen of autostar units in my club (several) there may be a tradeoff here. Losmandy usually goes for durability in its designs. Bolting on the electronics to the mount is one example, though Gemini compromises that somewhat (stepper G11 does not, the controller is a tiny switch box and the brains are bolted to the mount).

regards
Greg N

#18 Phil Cowell

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Posted 24 August 2009 - 04:21 AM

Greg,
Having to change a PROM as a method to upgrade a device is very primative and much riskier than just flash updating. Also the non-opto isolated guide interface wouldn't be for me.
The SiTech allows you to interface directly to a PC.
The user interface on the Gemini was also to me "bloody awful" to show how to do a simple one handed interface properly there is the Argo Navis which is elegant two buttons and a wheel setup.
But to each their own. Just showing there are other options for the G11 than Gemini.
Phil

#19 DeanS

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Posted 24 August 2009 - 07:46 AM

An interesting note here, the creator of CCD Commander, Matt Thomas, uses a MI-250 with Gemini. And I know of a couple others do do automated imaging with MI-250's.

The interface is certainly not the most intuitive, but it only took me a couple evenings to get used to.

#20 Phil Cowell

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Posted 24 August 2009 - 07:52 PM

An interesting note here, the creator of CCD Commander, Matt Thomas, uses a MI-250 with Gemini. And I know of a couple others do do automated imaging with MI-250's.

The interface is certainly not the most intuitive, but it only took me a couple evenings to get used to.


The MI-250 is a wonderful mount and I almost bought one but there was no other option but the Gemini and that killed it for me. The larger MI's offer other options so there might be an MI in my future.

#21 CounterWeight

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Posted 24 August 2009 - 08:25 PM

Wedges arent all created equal... in fact they are very unequal.

Really good wedge - I mean robust = $$

Certainly wedge mounting your SCT can be done and it will remove the field rotation. Some folks use something called a field de-rotator on them with good results - don't know if they are still sold as I quit fork mounts forever about 7 years ago.

But lets say you get a really robust wedge (so that vibration isn't an issue [outside the inadequate forks that is) )and all... to make your alt az mount act like a GEM...

I say why not get the GEM and forget about alt/az on a wedge or a field de rotator and all the probs that go with them. Trade UP to the real thing - get the equitorial mount and it's problems...

You'll be confused on a higher level about more important things.

#22 David Pavlich

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Posted 24 August 2009 - 08:48 PM

Wedges arent all created equal... in fact they are very unequal.

Really good wedge - I mean robust = $$

Certainly wedge mounting your SCT can be done and it will remove the field rotation. Some folks use something called a field de-rotator on them with good results - don't know if they are still sold as I quit fork mounts forever about 7 years ago.

But lets say you get a really robust wedge (so that vibration isn't an issue [outside the inadequate forks that is) )and all... to make your alt az mount act like a GEM...

I say why not get the GEM and forget about alt/az on a wedge or a field de rotator and all the probs that go with them. Trade UP to the real thing - get the equitorial mount and it's problems...

You'll be confused on a higher level about more important things.


Agreed. The only way I'd use a wedge is if I were to grab one of the Meade RCX vintage. For it to do what it does, it needs to be on its forks. Other than that, it's a GEM all the way.

David

#23 mclewis1

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Posted 25 August 2009 - 09:27 AM

The 12" LX90 is not exactly the preferred scope to be put on a wedge. Those arms are not very robust (not like the LX200) and those gears, well lets just say that you'll become very familiar with the term "backlash".

Yeah you could make the wedge work for a setup with the Stellarcam since you don't need to be accurately polar aligned and such but you're going to get a lot of vibration problems with it. The Meade wedge is the cheapest but also the most problem prone. Get a good 3rd party wedge for more money and you'll still have to deal with the limitations of the LX90 fork arms and gears.

The G11 will definitely be a more stable setup and IMHO a better investment overall. I'm not sure I agree with Greg about the ability to sell the mount for $2000 but certainly at $1000 initially plus some for mounting the 12" ota (Losmandy D plate) and a few other upgrades (cables, etc) and maybe a little time and elbow grease you won't lose money if you sold the mount later on.

Yeah Autostar to Gemini is a learning curve but so what ... you'll become proficient in two of today's most popular control systems. Different isn't always bad.

I've recently seen posts by folks who are resurrecting the use of a field de rotator with video imaging setups. Most folks found that the field de rotators didn't work well for longer exposure work but seem to fit with the video imaging requirements of only up to a minute or so. If you already had a de rotator setup I'd say you might want to try it out ... otherwise go for the G11 and put all of this behind you.






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