New product - 1 arc-second tracking ability without using conventional auto-guider

[DGK (David)]

Hello,

Thought it was about time I joined iceinspace. I'm an Australian and have lived in Salt Lake City, UT USA for just over 11 years now. I'm the "dodgy guy" that posted my early experience with the TDM. Its all ridgy didge, to my mind the TDM is a little rip snorter!

Cheers

David

[h0ughy (David)]

Originally Posted by DGK

Hello,

Thought it was about time I joined iceinspace. I'm an Australian and have lived in Salt Lake City, UT USA for just over 11 years now. I'm the "dodgy guy" that posted my early experience with the TDM. Its all ridgy didge, to my mind the TDM is a little rip snorter!

Cheers

David

Welcome to IIS David, can you throw some more light onto this discussion other than the one that was linked to you initailly

[DGK (David)]

Sure, but I've not been able to test the unit outside since my IM809 became available. Winter weather here is rubbish (and very cold....).

A winter project for me at the moment involves putting together a circuit to generate 2000tic/rev TTL quadrature from the encoder to send to my Argo Navis. Some critical components arrive tommorrow after a bit of a lead time, these are significantly higher quality than those I could pick up at Radio Shack! I've also managed to find an ERN120 on ebay for $99 (and a spare for $20!) to fit on the DEC and am visiting a friend this weekend to get adapter components turned up. All with a view of having the TDM encoder serve double duty and the Argo Navis gets to see 20,000tic/rev on both axis.

The developer asked me not to reveal the TDM encoder model to anyone so please don't ask What I will say is inspection of the TDM interior board component layout was enough for me to confirm in my mind roughly how things are being executed to achieve 0.125arcsec resolution. There's a few tricks that are very clever.

Cheers

David

[Kal (Andrew)]

Just to clarify the technology that is being offered, is this in principle the same technology that Astro-Physics has developed for its 3600GTO mount? (which gets PE down to less than 1/2 arc second for long exposures)

http://www.astro-physics.com/product...r-complete.pdf

[Dennis]

Originally Posted by DGK

Hello,
Thought it was about time I joined iceinspace. I'm an Australian and have lived in Salt Lake City, UT USA for just over 11 years now. I'm the "dodgy guy" that posted my early experience with the TDM. Its all ridgy didge, to my mind the TDM is a little rip snorter!
Cheers
David

Hi David

Welcome to Ice In Space!

Ah, so you are the guy on CN who has actually tried one of these units! Thanks for dropping by; it is good to hear about your positive experiences.

Not too sure why some of the natives here took a rather uncharitable view of this product; nor why they would want to be so rude to a complete stranger who had been kind enough to present such a good report, with accompanying graphs, etc., but clearly you’ve seen through the BS, have a good sense of humour and a thick skin too boot!

Hope the weather clears up so we can hear more about your tweaks to the system.

Cheers

Dennis

[DGK (David)]

Hi Andrew,

The AP concept is the same but the encoder design is naive (and no doubt very expensive), as is the signal processing. The TDM encoder is an off the shelf item and relatively inexpensive.

Naive is not a word that I should have used used when referring to AP, an excellant high end kit company - "overdesigned" would have been more appropriate. Their rationale for using a 9" disk is to make sure that over a full revolution there is no timing drift. However, by using an appropriate industrial grade encoder and signal processing, the TDM is capable of achieving pretty much the same performance. The TDM encoder housing diameter is 2 1/4". The AP 9" disk is probably wrapped in very expensive CNC'd aircraft grade alumin(i)um making it even bigger and more expensive.

Cheers

David

[bojan]

Originally Posted by DGK

Hi Andrew,

The AP concept is the same but the encoder design is naive (and no doubt very expensive), as is the signal processing. The TDM encoder is an off the shelf item and relatively inexpensive.

Cheers

David

Autoguiding is still way cheaper, and I strongly believe much more accurate (because of all the reasons mentioned earlier in this thread).

[Kal (Andrew)]

The technologies don't have to be exclusive of each other bojan. There are also some applications where on long focal length imaging you will not find a guide star that is bright enough and where autoguiding is not a viable option.

Long term I can see autoguiding will still be the cheaper, adequate for 99% of people, and more common solution used, but I can also see the demand for this technology from some specialist applications.

[bojan]

Kal, in principle I can agree with you about your estimate of potential users numbers, perhaps it will be a bit lower, and that will depend (among other reasons) on quality of the final product and of course, price.
The problem with future production may be the high price, as there will be no volume where those guys can find the room to keep the margin low.
Other alternative will be to compromise the quality to stay in the market (using cheap of-the shelf products, as David mentioned in his post earlier)
We shall see...

My problem here is that this is not the new technology and there still exist the need for auto-guiding in most cases, so I see something like this not really necessary. You can always find a suitable guiding star.. this is part of the challenge and fun in this game, right? And, easiest way is to go to the shop, spend couple of k$ and have that warm feeling inside..
Also, there are other ways to improve PE, for those skilled with mechanical tinkering (for EQ6 specifically, the replacement of gearbox with belt drive or even using better quality worm gear improves the PE drastically, for much less money).

Personally, I intend to stick to amateur philosophy in my astronomy projects: that means, I am avoiding commercial products wherever there exists a slightest chance of making something myself or using freeware from other amateurs. Even if it is slightly more expensive (I am prepared to pay for the fun I have here, you see :-)) In the same spirit, that also means that I will always offer my amateur advice and know-how (when I come up with something good enough) free of any charge, as it should be widely practiced in amateur community.

[renormalised (Carl)]

And, easiest way is to go to the shop, spend couple of k$ and have that warm feeling inside..

That's the slow acting poison that SWMBO just slipped into your cuppa, that only she has the antidote for...and that she slipped into your cuppa for just spending that $1000 on a guidescope and camera

[bojan]

Originally Posted by renormalised

That's the slow acting poison that SWMBO just slipped into your cuppa, that only she has the antidote for...and that she slipped into your cuppa for just spending that $1000 on a guidescope and camera

You may be right here
But man, we are living in real world. And, this morning, when I had a careful peek into the status of my super (what was left of it) believe you me it was a horrible experience.. much worse that PE of my mount.
I still prefer the challenge, though

[renormalised (Carl)]

Maybe your super needs one of those TDM's to keep it on track

[bojan]

Originally Posted by renormalised

Maybe your super needs one of those TDM's to keep it on track

Now THAT would have been useful.
Unfortunately, TDM systems for superfunds are still on the drawing boards.. if they ever become reality

BTW, some DIY here would also be much better solution that relying on others... maybe.

[renormalised (Carl)]

Problem with DIY is not everyone is competent enough to tackle those sort of projects. Some are more competent at one thing than another...for example, they can build obs' but can't solder a PCB...and some are just plain lazy. Why make it yourself when you can buy it already made

[bojan]

I agree with you.... So they need help in developing DIY skills.
Also, what bothers me is most prospective "businessmen" tend to offer only partly accurate information, usually only the part that is in their interest. The good example of this behavior is the situation with Darren's firmware mod for standard EQ6 (freeware, which I am using and it works very well. However, commercial counterpart is even offering the replacement of processor used in hand-pad, only to have red LED on instead of green. And the only thing that needs to be done here is to replace/rewire couple of resistors.
Similar thing is happening with forgetting to mention the (free) Mel Bartels software and its capabilities when promoting commercial products with subset of Scope.exe functionality).
That blurs the picture to people who do not know that they are potentially good with DIY approach, and it promotes laziness, by all means. It can not possibly be an amateur philosophy, IMHO.

[DGK (David)]

Originally Posted by Kal

Long term I can see autoguiding will still be the cheaper, adequate for 99% of people, and more common solution used, but I can also see the demand for this technology from some specialist applications.

Andrew et al,

I am in the 1% tail you posit because of the following:

1/ I want portability and quick setup/pulldown time.

2/ I am a "serious" visual observer, not a "serious" imager. A matter of personal preference. Thank goodness many others are different otherwise I wouldn't get to see their wonderful images.

3/ I like to push/go-to my Stellacam3 to objects and then have the image come up straight away on the monitor without fussing about. The portable mount combo gives me bang on pointing and polar alignment good enough for 1-2min exposures, with the TDM in the background I should be able to approach 10min, which I think is pretty cool.

4/ I like to set my truss dob up at the same time as the SC3 on either the M809 or ED80 (usually the big one tho...) and have both pointing at the same object. Fun at star parties but a bit of a work load, autoguiding is just out of the question unless there's help....

When I finally decided that the MTS-3SDI PE correction was not going to work well enough for me I contemplated upgrading my mount to a G11 or even a Mach1. Fortunately sanity kicked in and I went looking at what I could do to implement autoguiding. After much thought I decided the xtra weight was going to kill my GPD (the M809 is about the limit visually and is okay with the SC3, probably not for a STL-11000CM ...) and the extra setup, operating and pulldown time was going to kill me. Then I came upon the TDM around fall and haven't looked back since. Fits my needs perfectly .

Cheers

David

[DGK (David)]

I just noticed that Meade Europe has the TDM up on their site now:

http://www.meade.de/news/news/archiv...ash=4def1d0efb

No pricing, I'm not sure how this company is affilliated with Meade however. They may just be a dealer.

Cheers

David

[renormalised (Carl)]

Meade Europe have been sold by the parent company in order to get Meade out of its troubles.

[Dennis]

Originally Posted by DGK

I just noticed that Meade Europe has the TDM up on their site now:

http://www.meade.de/news/news/archiv...ash=4def1d0efb

No pricing, I'm not sure how this company is affilliated with Meade however. They may just be a dealer.

Cheers

David

Thanks David – I notice that they have added the Tak NJP to the list of mounts supported. And there is a Mk II on the original TDM website.

Cheers

Dennis

[DGK (David)]

Hi Dennis,

I'm struggling a bit to see what advantage there is in having TDM correcting with an autoguider. Maybe it makes a difference with high resolution imaging?

The first version I have is not supposed to work below a 1.25x guide rate but I have found it works fine down to 1.15x. Maybe v1.6 had this software fix included?

Poor weekend weather has prevented further tests and am still putting together the kit to generate position info off the TDM encoder.

Cheers

David