Mount advice - Takahashi EM-200/Temma2 or Losmandy GM11/Gemini?

[Omaroo]

Hi all

I'm trying to research, the best I'm able, any salient points that will let me decide between purchasing a new Takahashi EM-200 Temma2 or Losmandy GM-11 with Gemini. Arrgghh!


I can import an EM-200T2 from Asia for AU$5,073 landed in Sydney via 3-day courier. From America it'd be $5,975 + shipping!

I can buy a (if they're ever in stock!) GM-11 Gemini locally in Australia for $5,495 including the tripod.

The major difference is that the EM-200 does not come with a tripod for that price - that's quite a bit extra. I'd like to say that I'll be building a pier in my back yard soon, so a tripod won't matter. All except for the fact that it will - if I decide to go tripping around with it in the car.

The scopes will be either a Tak FSQ106 or TSA102 alongside a Tak FS60-C which I already have - side-mounted on a plate, along with my DSLR and a webcam for guiding. The imaging and guiding duties will be swapped between the two scopes depending on the duty at hand. Total weight will be in the vicinity of 12kg - easily within the weight limits of both mounts.

How hard? Very! Is there any advice I can purloin from the gallery? I'd rather stay with gear all from a single manufacturer - for the sake of compatibility and consistency - but maybe the G-11 (which I've used before and quite enjoyed - thanks Zane) will do the job just as well?

[Omaroo]

Just thinking - maybe a standard G-11 and an ArgoNavis?

[glasseyes]

Hi Chris,
Takahashi mounts are very nice and I very much like the EM200 Temma 2. Moving up to a Tak mount seems the logical step up when you are looking for better tracking, low PE etc.
One thing that bothers me however is the apparent lack of information on the GOTO functionality, which never seems to be explained in any of their advertising material. :shrug:
The EM200 comes with a Pegasus-21 software disc and an RS-232 cable, but nowhere can I find any information about what this software looks like or what it offers in functionality.
Even with the basic GOTO mounts like Celestron, SkyWatcher and Losmandy, there is a multi-button handset that facilitates alignment, tracking, and a list of thousands of easily accessible sky objects in NGC, Messier and IC lists and user programmable memories to store favourite objects. On my SkyWatcher HEQ5 Pro SynScan handset there is a "sky tour" showing popular objects and an "identify" function which can be used to point to and identify objects that you are not sure of. These types of GOTO handsets are very useful if you have your mount set up out in the bush at a dark sky location, where setting up a laptop can sometimes be a problem.
It seems that there is no such handset available for Tak mounts, so I assume that it all needs to be done on a laptop?
Takahashi have hand controllers (available for extra $$) that only offer the most basic functionality for slewing the mount, etc. but nowhere have I seen any details of the Pegasus-21 software or what features are offered.
It bothers me that after the relatively major expense of buying any Tak product, there are many "add-on" accessories that also must be purchased at considerable extra cost before you can actually do anything with the gear. OK, granted they supply you with an RS-232 cable...20 bucks worth maybe?
Am I missing something here ?? :rolleyes:
John

[Dennis]

I have a Tak EM200 Temma 2 mount and leaving aside the mechanical capabilities of the Tak mounts in general, here are some issues you should consider:

The EM200 does not have any PEC capability.
The EM200 hand controller is a basic motor control unit; Up, Down, Left, Right.
To implement GoTo you either need a notebook computer, a PDA running e.g. TheSky Pocket Edition or the expensive and limited functionality Tak hand controller.

There are some annoying quirks about the EM200 as follows:

You have to press and hold Button S1 at power up to switch to S Hemisphere mode; if you forget, it tracks as if in the N Hemisphere.
When auto guiding, you need to flip the motor speed switch from H to N so that auto guiding occurs at tracking speed. When you forget and have it set to H, the auto guider calibration makes the mount take off at high speeds (x700 slew speed).

General comments:

Takahashi manuals and instructions are appalling given the cost of their equipment. Very little information and poorly translated.
Pegasus 21 seems quite competent and looks like it will do a good job, although I use The Sky as my telescope control application.
The EM200 seems very dated in terms of the electronic/computer interface and capabilities when I compare it to my (10 year old) Vixen Skysensor 2000.
Changing the guide rate via the hand controller requires you to press and hold one switch whilst pressing another switch repeatedly for each x0.1 change; that is, it is a physical implementation, not via software unless you attach a computer.

The above points have generally covered specific limitations I have encountered with the EM200 and when listed in sequence like this, can look quite damming. I’m sure the G11 and other mounts would generate a similar list so please bear that in mind.

Overall, if Vixen had kept their Atlux and Skysensor 2000 combo product line alive or if the Astro Physics Mach 1 mount had been available at the time of making my decision, I would have purchased one of those simply due to their more advanced electronics, documentation and support.

The EM200 has a superb Polar Alignment ‘Scope.

Cheers

Dennis

[gbeal]

Dennis has summarized what I found to be the mis-givings of the EM200 as well. Especially annoying was the indecision of what speed I was slewing or guiding at, and also the south/north requirement on startup.
A great mount, but for goto operation you are tied to some form of computer or PDA.
I am happy with what replaced mine.

[Dennis]

The Takahashi tripods (SE-M & SE-L) that I have are just superb. Their legs are wood and although non-adjustable, in terms of set up and stability, they are very quick to deploy and are rock solid. I think that they are considered to be amongst the best in the market.

Cheers

Dennis

[Omaroo]

Thanks for your really considered replies John & Dennis :)

The foibles that Takahashi have failed to address are pretty minor - but nontheless a bit of a PITA. I'm always criticising the documentation, which quite frankly is atrocious. They should have sorted out translation issues decades ago. They produce arguably some of the best hardware in the world, but their literature has always been terrible. I have my little FS60-C, which I love, but have never been able to find reference to the flat on top of the clamshell that has a 1/4x20 thread popping up out of it. What the heck is it for? No amount of searching has told me. Documentation should be a priority to them.

Anyway - that aside, I'm also looking seriously at a G-11 without Gemini. I've used Zane Hammonds EM200 and G-11 side by side at Magellan - and I do like using both. I find the G-11 more natural to use, as I repeatedly went for the latitude lock instead of R/A lock a number of times in the dark on the EM200. Silly design. His G-11 has Gary Knopf's wonderful Argo NAvis on it - and all I want is push-to. The Gemini and Temma2 are superfluous to my needs.

Considering that the G-11 without Gemini also comes with a tripod, the price is incredible in comparison - not that this issue is driving the decision. Also considering that I'll be stuck with DSLR photography for the forseeable future, I'll only need 5-minute (tops) tracking periods - and guiding will help, so the extra tracking accuracy for me isn't ultra-critical.

Hmm.. many decisions still.... thanks for your input!

[Dennis]

Hi John

The Tak auto guider cable is an extra at US $150, and that is discounted from US $180!

Having said that, the supplied Tak RS232 telescope interface cable is very well made, longer than most, handles and drapes very well, rather than being too stiff like most cables I have seen.

I made up my own SBIG ST7E to Tak auto guiding cable using standard parts from Dick Smith for less than AU $20.00.

Cheers

Dennis

[acropolite]

That combination works very well, talk to Paul [1ponders] I was most impressed with the ease of operation of his setup @ astrofest.

[Dennis]

Hi Chris

One very big plus with the EM200 for grab and go imaging at multiple dark sky sites, is the superb Polar Alignment Scope. It uses a couple of circular, illuminated reticules to achieve very accurate PA. There is a Month/Day circle (outer) and a 24 Hour circle (inner) which you set to the current Date/Time to position Sigma Octans correctly in the FOV.

Although it is designed for the N hemisphere, I have written an Excel spreadsheet to convert to S hemisphere values and I run this on both my notebook and PDA.

The conversions are simple. Make Months run Anti-Clockwise and make the Hours run Clockwise. See attached diagram for N hemisphere reticules.

Cheers

Dennis

[JohnG]

Whilst I cannot comment on any of the Takahashi mounts mentioned other than to say they are superb mounts, I can comment on both the G-11 and the GM-8, having used both for quite a number of years.

The G-11, I have is fitted with a Gemini controller and is used in my Observatory with a Takahashi FS-128 mounted on it. I have found that the mount itself is quite rugged and easily carries what weight I put on it BUT, with the servo motors of the Gemini, it needs to be balanced properly, you just can't plonk a scope on it and expect it to track properly, balance is critical. The Gemini system is, once you get used to it, very accurate once you have built up a pointing model and can easily interface using ASCOM to just about all computer programs.

My GM-8 is my field unit, it is fitted with encoders and the superb Argo Navis DTC. With the stepper motors on the GM-8, out of balance situations are handled with ease because of the significantly increased torque of the drive motors. As a field unit, the Digital Drive Unit only draws some 500 milliamps and I have no trouble running the Drive system, Argo Navis and Dewstraps using a standard jump start battery pack.

As you are looking at the G-11, the standard stepper motor setup would be identical to the GM-8. The new Losmandy mounts have a new bronze worm (High Preccission) and are a lot better produced than the older versions.

Both my mounts have worked well straight out of the box with the GM-8 only requiring a worm adjustment after I regreased it, the G-11 has had no problems at all.

Something I would bear in mind is that at some stage you will have to learn to make adjustment to the worm re backlash etc although the stepper model takes this in it's stride.

Photographically, both mounts are good in my opinion with the G-11 being the pick, only because it has a 360 tooth worm gear, I would imagine the Tak mounts would be a step better again.

Cheers

[[1ponders]]

Like John I have both the G11 and GM8 but I use the Argo on the G11 only atm. I can't add much more to what John has said except to say if I was going for a permanent mount (as I am) I would consider the Gemini over the AN, but the AN over the Gemini for a mobile mount.

[Omaroo]

Thanks John and Paul - great advice :)

I'm pretty sure I've decided on the standard GM-11 with Argo Navis now. Until I build an obs somewhere, it will be relegated to field-related work for the greater portion of its work cycle.

When I do get around to building that observatory in Cooma, I'll probably go with a Tak NJP/Temma at that stage.

Thanks once again fellas.

[montewilson]

Hi Dennis,

"The Tak auto guider cable is an extra at US $150, and that is discounted from US $180!"

I got a guide cable and RS232 included with mine. They shouldn't be extra.

Apart from that I made a second guide cable with $10 of parts from Jaycar.

BTW - I am still using your TAK polar scope converter. It is a godsend! Thanx.

BTW2 - For those who might worry that the EM200 has no PEC, don't, it doesn't need it!

BTW3 - The EM200 works really well with TheSky (& TPoint if you want to be pedantic) and autoguiding cameras.