Do you want perfect tracking with no guiding?

[telecasterguru]

Want to guide perfectly with no guiding. No more PEC issues. Have a look at this. http://www.meade.de/en/products/astro-specials/product.html?tx_meadeproducts_pi1[cmd]=pdis&tx_meadeproducts_pi1[artid]=0721000&cHash=a007c0cdc4.

Sounds too good to be true and is expensive, but if it can do what it claims WOW.

Frank

[bmitchell82]

whats the product, as the link doesn't work.

[telecasterguru]

"Telescope Drive Master" which provides a revolutionary technology for demanding amateur astronomers and advanced semi-pro observers. This device does not just reduce but does completely eliminate* all of the periodic and non-periodic tracking error of your equatorial mount. You do not need to have conventional autoguider system, you do not need to spend your valuable observing time with unproductive guide-star hunting; just expose, expose and expose all the night...

Telescope Drive Master" which provides a revolutionary technology for demanding amateur astronomers and advanced semi-pro observers. This device does not just reduce but does completely eliminate* all of the periodic and non-periodic tracking error of your equatorial mount. You do not need to have conventional autoguider system, you do not need to spend your valuable observing time with unproductive guide-star hunting; just expose, expose and expose all the night...
* The rest of the tracking errors will be covered by air-mass scintillation in normal cases (except more than 2-3000 meters above the sea...).
** More and more types of mass-produced equatorial telescope mounts will be applicable with Telescope Drive Master. We support Vixen GP(-DX), Syntha EQ6, Astrophysics 1200, Takahashi NJP, Losmandy G11 and LX200 GPS 8" - 14" on an equatorial wedge.
1 arc-second tracking ability
without using conventional auto-guider or PEC software!!!



http://www.meade.de/en/products/astro-specials/product.html?tx_meadeproducts_pi1%5 Bcmd%5D=pdis&tx_meadeproducts_pi1%5Bartid%5D=072 1000&cHash=a007c0cdc4

I hope this link works, it is from Meade Europe.

Frank

[Wavytone]

Think he's referring to this:
http://www.meade.de/en/products/astro-specials/product.html?act=pdis&actid=0721000&cHash=a629017a92

The parent page is
http://www.meade.de/en/products/astro-specials.html

It has come up before on IIS and IMHO its pure snake-oil, and very expensive snake-oil at that. Take a look at the Vixen version; 300 euros for a metal cylinder...

There's no way it can correct for mount mis-alignment on the pole, non-perpendicular axes in the mount, refraction or periodic errors etc without some form of feedback, either by optical measurements during setup, encoders or a CCD.

Most likely all it really consists of is a simple dual-axis motor drive corrector for two steppers.

And lastly it does not look like a Meade product, externally.

[bmitchell82]

ahh yeah this product came up a while back before meade grabbed it! I don't think you can get rid of all of your tracking errors without live feedback from the sky. but thats just my opinion. and at close to 2500 aud... ide rather go buy a losmandy or astrophysics mount for a bit more!

[telecasterguru]

Yes this is the new improved version 2

[tlgerdes]

Ahhhhhh.

When you read the doco, it is to correct your mounts inherent tracking errors, not your alignment errors.

"The long term tracking accuracy of your mount supported by Telescope Drive Master will be determined and limited exclusively by the precision of the polar alignment of your mount and air refraction"

Secondly, it is not an unconnected phantom box.

"Our system has got two main parts: a high precision encoder unit attached directly onto the RA shaft of the mount and an electronic device (let's say a sort of "black-box"), which receives the electrical signals arriving from the encoder unit and sends control instructions to its own mount's driver via its auto-guider input connector."

[leon]

Now wouldn't that be good, ;) but i have to say It to good to be true. :shrug:

Leon :thumbsup:

[Kal]

Astro-Physics has this type of option available on their 3600GT mount as a US$6800 option. It brings the PE error down to 0.26 of an arcsecond though.

pdf link (http://www.astro-physics.com/products/mounts/3600gto/precision-encoder-complete.pdf)

[lacad01]

Sounds like the holy grail of the tracking world :question:

[rajiva]

Hi Frank,



in my opinion the TDM System is much to expensive for what it can do, you loose your Polar scope what makes south :D (north) leveling a real problem and a stand alone autoguiding system can do much more for less money. In germany, where Meade Europe is trying :lol: to sell this system many Starfriends come to the decision that the system is not worth buying it.

1. The system has no correction possibilitys in DEC, so you need some kind of real good alignment. With a lost polar scope ... :screwy:
2. As no DEC corrections are available by the TDM you need some extra Guiding system. If you have such extra guiding system there is no need for a TDM at all as this system will guide RA as well.
3. For just 30% of the TDM price you can get a stand alone guiding (http://www.teleskop-austria.at/prod.php?lng=slo&tid=30#ccd-standalone-hu) system that will do the job in RA and DEC and you keep your polar scope. ;)


A such revolutionary technology that it was implemented as a improved and FREE :eyepop:
Feature in the LFE Photo, called PEC Tracker or EPEC, before the TDM V2 was available. :rofl:


Just my two cents to this excessively overpriced piece of electronic.
Rajiva

[Peter Ward]

Wow. Fantastic. Next time I perferctly align my zero flexure scope outside the earth's atmosphere...well... I'll just have to get me one of those.... :doh:

By the way,

P.T. Barnum is credited for saying "there's a sucker born every minute"

[allan gould]

It would be interesting to see how this holds up with Australian advertising laws and consumer protection and where Meade's let-out-clause is i.e. you didn't read the fine print.

[telecasterguru]

But this is version 2 so it must be better than version 1.

Frank

[Bassnut]

Hang on............ in reality, its an end shaft encoder, what pro observatories use, nothing magic about it at all. It elimates PE because its after the gearbox/worm gear etc..

Put aside the advertising and take it for what it is, an end shaft encoder, and its a very good price indeed for the reported res. Almost too good in fact, ive seen shaft encoders at this res for over $7K, just for the encoder.

It would suit mounts with poor PE, much cheaper than upgrading the mount.

I can see why Meade jumped on this given the spec for the price (assuming the spec is true), but its a shame the way its being promoted (no need for guiding etc), it just feeds the kind of of comments presented here.

This product, with an understanding of exactly what it does, is actually a good deal, a very good deal..

[rajiva]

Hi Frank,


yes it is a V2 version but what did they change and why was a V2 needed at all?

The main point for the V2 was the build in ST-4 Port as they realized that a autoguiding port IS NEEDED :question: and the system is useless without such a port because you need a way to correct the DEC axis, the Refraction, and align errors that the system is not aware of.

But what happens if you connect a autoguiding system to this port?

In my opinion the system is simply deactivated :eyepop: when useing this autoguider connector. The manufactor (http://www.mda-telescoop.com/index.php?option=com_content&task=view&id=54&Itemid=84), no not meade, makes this clear!



So if your autoguider sends impulses within a time period of 2 Seconds!, what is a very long time for a autoguiding system, the system is in dead-time waiting the autoguider stops working. I think this just happens after the exposure. :lol:

Other disadvantages, beside the price:


Without a polar scope :help:


A autoguider do not have such limitation.


No problem if useing an off axis autoguider.


No problem with a autoguider at all.


Any autoguider will do this job.

CS
Rajiva

[rajiva]

Hi Fred,


you should have a look at the ASA Website (http://www.astrosysteme.at/eng/monts.html)
For the price of a TDM + Mount + Guider + Telescopecontroller +++ you can get a Mount (http://www.astrosysteme.at/eng/mount_ddm60.html) that REALLY DO NOT NEED autoguiding any more. ;)

CS
Rajiva

P.S.: A discussion at CN (http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2746764/page/0/view/collapsed/sb/5/o/all/fpart/1)

[Bassnut]

What?, why?. Its a bit of a fudge, the use of the autoguide port, internal integration with the drive would have been ideal, but its a retrofit, so its the easiest way to provide correction. If you use an ASCOM hub, I cant see any reason why guide corrections cant be applied with both this system and a guide cam at the same time?.

[Bassnut]

Oh Rajiva, you quote ASA as a source of anything that actually works?, as if they are perveyors of usable equipment?. I wouldnt trust them with laying a brick. With the experience of others here, and samples of products so very bad they were actually totally unusable, thats a very bad quote.

[rajiva]

Hi Fred,


because of the Dead-time of 2 Seconds.


If I use a PC and a ASCOM hub to get a guide cam doing the guiding job I can't see any reason why pay such a lot money for a system that i do not need in a autoguiding environment. Any autoguider will do the complete RA and DEC job perfectly so what is the point to spend the money for a RA correction only? :question:

Even autoguiding without the need of a PC (stand alone) is much cheaper then this system that requires additional guiding equipment. In my opinion the TDM is simply waste of money.

CS
Rajiva

[Bassnut]

If you have smooth PE and a short FL, yes , external autoguiding at 2 secs can work perfectly, it will track PE, but if for instance you use internal guide with an SBIG guiding with 10 sec guide exposures or more with long FL, PEC and low PE become very important.

The point in spending money on low PE, is the reduced reliance on fast tight guiding. This product becomes very usefull with long FL long internal guide exposure times. Rather than a waste of money, it saves money on expensive mount upgrades

[rajiva]

Hi Fred,


no, I do not have a ASA mount and i would never buy one!:eyepop:
But this mount DO NOT have a PE so it MUST be far better then the TDM :D

BTW, I did not say encoder driven PEC (EPEC) is a useless feature. In my opinion, beside the horrible price (the TDM Encoder is only 270 Euro ;)) and the fact you need additional guiding, the main disadvantage is that it is a external Box with no feedback of the controller! All the problems with guiding, GOTO and more could be solved if the TDM where able to know what the telescope controller is doing. ;)

CS
Rajiva

[tlgerdes]

Hi Rajiva,

You seem to keep going back to alignment problems, bringing up the lack of Polar Scope and Autoguiding.

The TDM is not designed to solve the lack of ability in system setup and alignment, it is designed to give PE accuracy to your EQ6 or similar that is only found in $20k+ mounts.

If the problem is alignment, then this product not the answer.

BTW Down in the south where we are, most people dont worry about a polar scope as you cant generally see the SCP through it as it is so faint (5.5Mag or fainter) and the stars are more than 1deg off. People here learn to drift align, or use mount based electronic alignment procedures.

[AndrewJ]

Gday Freddy

Re


This device is also being discussed on the LX200GPS Yahoo forum
Someone found the specs for the device as


The specs for the ERN-480 models show only up to 6000 lines
( which in quadrature mode gives about 54arcsec granularity )
As such, something else is going on, probably a precision geartrain between the RA axle and the encoder.
This may have PE in it, but that could be accounted for easily in the "black box" ( dunno if it is )
Also, unless the device takeoff is perfectly centred, you would still get slight tracking rate errors due to eccentricity
( assuming we are talking of 1/8 arcsec precision )
Soooo, it looks like a good device to remove the bulk of the geartrain errors, but guiding is probably still required.

Andrew

[rajiva]

Hi,


6K mounts do not even have a PE. It's really funny that the comparison with real expensive mounts come up every time. A 20K mount is more then just a small PE and nothing can make a 20K mount out of a EQ-6. ;)

Is the PE of your 2,5K G11 so bad that the autoguider can't manage it?
If no, why spend money for a TDM if you can get a G11, that will carry more weight, for the price of a EQ-6 + TDM?

I have a EQ-6 by my self and i know with a little bit adjustment nothing is so bad that a autoguider can't manage it. The TDM simply is not worth the money if you still need a autoguider that can do the FULL JOB without the TDM. I have a TDM like system in my stepper controller but with PEC the PE is so regular that I do not use it.

In fact all this PE size discussions are not worth talking about because if the PE is smooth it makes no difference for the autoguider if the PE is 5" or 50" ;)
If a system can eliminate the need of autoguiding, yes then ask me again to spend this much money. But for sure the TDM isn't such device.


The Topic says: Do you want perfect tracking with no guiding? (http://www.iceinspace.com.au/forum/showthread.php?p=520744#post520744)
And I say: This product is not the answer. Everybody has to deside by it's own if it is worth to spend 1,5K to have a "add on" for the still required autoguider and everybody has to deside if the autoguider really needs such expensive toy. :question:

Enough for today? :)

CS
Rajiva

[rajiva]

Hi Andrew,


yes a Heidenhain Encoder is used. The price for TDM encoder is 270 Euro ;)

CS
Rajiva

[Bassnut]

Andrew. OK, if its not a true output encoder, then that changes every thing, Id be very wary.

Rajiva. Your right, PE, no matter how bad, as long as its smooth, can be guided out with 2sec or so guiding. Not so with 30 secs or longer guide exposures though, thats what Im talking about. Anyway, given that this product is not what I thought it was, it may be indeed a waste of money, and the TDM may well do the same thing for less money.

[AndrewJ]

Gday Fred



Not necessarily wary, it does what it says, to a point.
If we assume it has a precision gearbox between the RA axle and the encoder, any PE in this is simply tested for and accounted for,
This could be done as a factory setup.
Thus, when in place and running, this gizmo would give a good "smooth and steady" tracking rate, thus removing a lot of the std problems seen with high freq PE and tooth spacing errors.
However, unless there is a true sky feedback mechanism, it cannot ever give a "perfect" tracking, "for taking piccies"
Also, look at how it gets fitted to a Meade Fork unit
No more swinging the OTA between the forks :question:

Andrew

[rajiva]

Hi Fred,


yes i totally agree to that point and for sure there are very rare situations where the TDM makes sense. But this is not what the company is telling.

The truth is simple: You still need a guider, the PE size is not the main argument, the TDM do not make a 20K mount out of a EQ6 and in most situations the TDM is simply wasting money for nothing.

CS
Rajiva

[AndyTheDoc]

Hello!

I just read datasheets for Heidenhain encoders and I think they use model ERN 480 with sinewave incremental signal output.

Here is citation from datasheet:
HEIDENHAIN encoders with sinewave output interface provide voltage signals that can be highly interpolated.

At photo http://www.slas.us/gallery2/main.php?g2_itemId=1386 there are 2 IC's at the left side of the box, I think it's a OP amplifiers, but what IC is on SOIC adapter? Probably 2 channels ADC... ;)
Simple use of hi-res encoder on RA shaft - it's too expensive! That is why company asks their customers to not publish labels on the encoder, but it is very simply to discover by form... and nevertheless on one photo is visible number 5000 :)

Yep, price is too hi for this device!

Cheers!

[ASTROMONK]

I think you are missing an esential point here guys....yes a Heidenheim ERN 480 5000 is expensive for us amateur astonomers, but its a delicate piece of equipment, a professional would not think twice at spending £800 for an encoder. If you use an autoguider with it, you can guide on MUCH fainter stars, because the update frequency can be MUCH less.
For it to work properly the polar shaft does need to be accurately aligned, and it is best used on fixed observatory mounts rather than field trips. Yes, I use one on an Alter D6 (made the adaptor myself) and the PEC was reduced from +/- 4 arc secs to +/-0.5 arc secs.

[DavidTrap]

What's wrong with guiding?

I heard David Malin say in a lecture that the Siding Springs scope had an autoguider with a 10fps correction rate - faster than most of us use and I'd hope that mount is well polar aligned!

DT

[Barrykgerdes]

I don't think it is polar aligned.

Barry

[g__day]

I must say I agree with Fred's comments - it sounds like a high precision RA encoder, and I'd guess a black box to apply King rates of elevation (and possibly altitude) calculated refraction adjustment to a bodies apparent motion. I smiled at Peter's comments - becuase that was exactly what I was thinking at the time. So basically a very expensive RA gearbox, marketed as the whole enclidea!

[AndrewJ]

Gday Matthew



Nup ( or at least "i" no longer think so )
In the original thread, i think "AndyTheDoc" got it right
with this bit

I read up on that a bit.
By not using quadrature encoding, they can effectively get much better resolution from the encoder, hence no gearbox etc reqd.
I still wonder how they control temp compensation and eccentricity in mounting to the accuracy specified, but im sure its going to be pretty close to what they specify.
Where it all gets interesting now is how the feedback loop into the scope
itself works.

Andrew

[bojan]

I second to that.
We had almost exactly the same discussion couple of years ago (V1?) and no-one managed to answer the question "what is the benefit of TDM +autoguiding (needed to sort out the rest of issues like flexures, poor alignment, refraction..) , when you have autoguiding?"

[cventer]

Another option if you believe the hype is the ASA DDM85

Direct drive. No PE. Supposed accuracy of 0.25" rms for 5 min exposures. And 0.4" for 10 to 15 min.

Sounds impressive. Massive payload and massive price.anyone know if these claims are true?

[alistairsam]

Hi,

Do these mounts automatically change the tracking rate depending on where it is pointing to in the sky as the tracking rate would vary slightly at different positions. so the high precision encoders I'm guessing are to ensure tracking rate at that position is within tolerance?
guiding is definitely far cheaper, but is dec guiding really necessary?

[Barrykgerdes]

It is with an alt/azm mount which is what many of the large observatory telescopes are these days.

Barry

[gregbradley]

I haven't followed them recently but the ASA DDM85 mounts were in fact delivering impressive results in images I have seen regularly.

There are a few mounts out now that use these precision encoders on the final shafts. The Earths speed of rotation is a constant and known amount. So the spin rate on the shaft can be monitored to maintain that exact rate. I believe that is how they work. Like an internal autoguider.

Its someone's attempt to implement that approach on an existing mount.

Not sure why it is so contentious. It may work once your polar alignment is nice and accurate. You've got drift alignment and T-Point to get your polar alignment accurate. I guess the upset about no polar scope is more for Northern Hemisphere users who orient off their Pole star (which is not totally accurate anyway).

I think its good someone is developing mounts and improving guiding performance as an alternative to autoguiding which as well all know has its own set of problems and frustrations attached to it.

So I nominate Rajiva as the guinea pig to test it out!!

Greg.

[frolinmod]

Wow this is an old thread. My Paramount ME can go 5 minutes unguided at 3911mm focal length with pinpoint stars. Not too shabby. A mount that slews faster and is quieter might be nice though. I wish SB would build a direct drive mount.

[gregbradley]

Is that using ProTrack or just by itself? With PEC turned on?

That's super impressive.

Greg.

[frolinmod]

That's with PEC programmed, good polar alignment, a 180 or so point Tpoint model and ProTrack turned on.

[gregbradley]

I've got to make a large T-point model and use Pro Track like that. Super impressive.

Greg.

[g__day]

I'm curious - is all over sky tracking that good with a well distributed Tpoint model, or do you find its optimised in some spots better than others (high versus low, East vs West) with a balanced distribution of stars in Tpoint?

[ReaPerMan]

It would appear that these type of encoders are starting to make their way into the 'cheaper' mounts.

http://www.ioptron.com/index.cfm?select=productdetails&phid=cdde52d7-5d26-4d5b-84ee-cab88ed07bd2

http://www.ioptron.com/pdf_articles/iEQ45-GT_PE_test_results.pdf

The first of these should be due here in Oz by September at about 5K.

:D

[cventer]

That's amazing performance on those graphs. Better than a 20k ddm85.

To me it looks like tracking axis on those graphs are reversed and it's showing the seeing. Mine looks like that in pempro when I get it reversed. If it has a worm and wheel then uncorrected there must be pe.

[gregbradley]

I found recently some areas tracked better than others.

Not sure if I can say it was due to T-point though. I'd have to recheck balance. Plus my Lodestar does not guide as well when using "autodark" which is a really a light subtract not a dark subtract.

Also some heavy rain last week potentially caused my pier to shift slightly?? Perhaps not.

Greg.

[ASTROMONK]

I have an Alter D6 mount with TDM drive corrector. The tracking graph improved from +/- 4.5 arc secs to +/- 0.5 arc secs. Now i can expose for 5 minutes through a narrow band filter without guiding! Worth every penny!!
I also fitted one to my home built mount with a 12" f4 Newtonian - every bit as good!