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Equipment Discussions >> Mounts

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Phil Cowell
Carpal Tunnel
*****

Reged: 05/24/07

Loc: Southern Tier NY
Re: Telescope Drive Master - The Truth of the Matter new [Re: Stew57]
      #4888873 - 10/30/11 04:24 PM

Quote:

And poor support with 6 week minimum wait times!



Think yourself luck you didn't get a Gemini Goto. It was non-existent.


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gdd
Pooh-Bah


Reged: 11/23/05

Loc: N Seattle suburb, WA
Re: Telescope Drive Master - The Truth of the Matter new [Re: harry page 1]
      #4888885 - 10/30/11 04:30 PM

For those who do not already have a big investment in autoguiding setups you can subtract the cost of all that from the $2200, especially if you plan on imaging only at moderate focal lengths. If you subtract the weight of autoguiding setups you can go with a larger OTA on the same mount and simplify balancing. The TDM should be accurate enough to work with adaptive optics for extremely high focal lengths.

Gale


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Jerry Hubbell
member
*****

Reged: 02/16/09

Loc: Locust Grove, VA, USA
Re: Telescope Drive Master - The Truth of the Matter new [Re: BlueGrass]
      #4888891 - 10/30/11 04:33 PM

Quote:

Frankly, I would NOT spend another $2k on 'upgrading' my CGEM with this add-on. It is still a CGEM with all of its possible motor, PCB and HC failures. These reoccurring failures are posted here regularly.

The justification you refer to can be given in two words: Quality and Reliability.




That's why I went with the EQ6, that and EQMOD makes a tough to beat, reliable platform. Coupled with the TDM does it for me!

Jerry Hubbell
Lake of the Woods Observatory (MPC I24)
Locust Grove, Va


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Jerry Hubbell
member
*****

Reged: 02/16/09

Loc: Locust Grove, VA, USA
Re: Telescope Drive Master - The Truth of the Matter new [Re: dawziecat]
      #4888961 - 10/30/11 05:05 PM

Quote:

At $2220 (incl an adapter for a G11), this is not going to be flying out the door.
I don't think the market will bear it. Without drastic price reduction, this thing will be a failure in the marketplace.

My opinion.




Are the AP 1200's and Paramount ME's flying out the doors? Are these mounts considered failures? How many years went by for these products before they were considered a success? Are they a success?

Jerry Hubbell
Lake of the Woods Observatory (MPC I24)
Locust Grove, Va


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orlyandico
Postmaster
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Reged: 08/10/09

Loc: Singapore
Re: Telescope Drive Master - The Truth of the Matter new [Re: Jerry Hubbell]
      #4889162 - 10/30/11 07:23 PM

I in fact wonder if a single product like the AP1200 or PME actually make money..

Of coutse the difference is if you buy an AP1200 or PME (or AP3600..) you know what you're getting. It's like the difference between buying a Mercedes and a Ssangyong (unknown Korean car) with a licensed-from-Mercedes engine (and yes.. this car brand does exist.. and they do use Mercedes engine designs.. and they never sell anything).

OTOH, Ovision has all those pictures of AP mounts in Antarctica, so maybe they sell a lot of these to academic and research institutions.

w.r.t. TDM pricing, like I said I can't find the million-tick encoder for much below $900. So if the TDM is being sold at $1800.. I feel that the margin is perilously low already as it is.

One option is to sell just the control box for $500 (or, port it to a laptop and sell the software for $200) and then let the end-user look for their own Gurley or Renishaw. Then we'd all see how much less that would cost..


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David PavlichAdministrator
Transmographied
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Reged: 05/18/05

Loc: Mandeville, LA USA
Re: Telescope Drive Master - The Truth of the Matter new [Re: orlyandico]
      #4889394 - 10/30/11 09:51 PM

Following this thread, I've come up with a thought. In my case, I have an MI250 that is controlled with a SiTech system. As it is, Pempro will not read the PE unless I install some sort of sensor on the worm and that isn't going to happen. So....

Is there some sort of software that will improve an already good mount as far as tracking goes? SiTech has the ability to create a pointing model with as many stars as I like. I'm assuming that this model is nothing more than a very accurate pointing model and not one that improves tracking. So...anything for me to consider?

David


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Jerry Hubbell
member
*****

Reged: 02/16/09

Loc: Locust Grove, VA, USA
Re: Telescope Drive Master - The Truth of the Matter new [Re: orlyandico]
      #4889478 - 10/30/11 10:40 PM

Quote:

I in fact wonder if a single product like the AP1200 or PME actually make money..

Of coutse the difference is if you buy an AP1200 or PME (or AP3600..) you know what you're getting. It's like the difference between buying a Mercedes and a Ssangyong (unknown Korean car) with a licensed-from-Mercedes engine (and yes.. this car brand does exist.. and they do use Mercedes engine designs.. and they never sell anything).

OTOH, Ovision has all those pictures of AP mounts in Antarctica, so maybe they sell a lot of these to academic and research institutions.

w.r.t. TDM pricing, like I said I can't find the million-tick encoder for much below $900. So if the TDM is being sold at $1800.. I feel that the margin is perilously low already as it is.

One option is to sell just the control box for $500 (or, port it to a laptop and sell the software for $200) and then let the end-user look for their own Gurley or Renishaw. Then we'd all see how much less that would cost..




Just to let you in on some details, the encoder used for the TDM is a heidenhain rate encoder (not an absoute encoder) which is a 5000 cycle encoder. What this means is that the encoder does not only put out a digital signal, it also puts out sine/cosine signals which are analog. The way you boost an analog sine cosine signal from 5000 cycles per rev to 10,000,000 counts per rev is through a 14 bit a/d converter on each signal. This is why you can't just hook the encoder up to a laptop. You need a micro controller to read the sine/cosine signals convert it to digital and then do some calculatIons on the signals to calculate the rate of change of the signal. Then you scale that and figure out your rate error compared to a standard rate provided by a high accuracy digital clock (hardware). This is straight forward, but very hardware dependent, so you would never be able to put it on a laptop by itself.

Jerry Hubbell
Lake of the Woods Observatory (MPC I24)
Locust Grove, Va

Edited by Jerry Hubbell (10/30/11 10:43 PM)


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orlyandico
Postmaster
*****

Reged: 08/10/09

Loc: Singapore
Re: Telescope Drive Master - The Truth of the Matter new [Re: Jerry Hubbell]
      #4889502 - 10/30/11 10:54 PM

Jerry - interesting point.

As I noted in one of my prior posts, the only companies I know of which make million-tick encoders are Gurley, Renishaw, and (Dr. Johannes) Heidenhain. And yes, these high-tick encoders require an external decoder box to get the full resolution..

I didn't think a laptop (alone) could do it. But an external box with a quartz oven crystal timebase and an ADC could surely be manufactured for $200-$300.. besides which Arduino microcontrollers are dirt-cheap ($30).


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Jerry Hubbell
member
*****

Reged: 02/16/09

Loc: Locust Grove, VA, USA
Re: Telescope Drive Master - The Truth of the Matter new [Re: orlyandico]
      #4889528 - 10/30/11 11:04 PM

Quote:

Jerry - interesting point.

As I noted in one of my prior posts, the only companies I know of which make million-tick encoders are Gurley, Renishaw, and (Dr. Johannes) Heidenhain. And yes, these high-tick encoders require an external decoder box to get the full resolution..

I didn't think a laptop (alone) could do it. But an external box with a quartz oven crystal timebase and an ADC could surely be manufactured for $200-$300.. besides which Arduino microcontrollers are dirt-cheap ($30).




I have done some work with PIC microcontrollers, and the Propeller chip from Parallax. They have some really cool tools and tons of documentation. I have thought about building my own encoder microcontroller system (similar to TDM) that would interface directly into EQMOD directly and provide a substitute signal for the stepper motor ring counter on the RA axis. That way it could be used with the pulse guide mode of correction which is more accurate than the ST4 interface. Maybe someday when I have the courage to start interfacing directly with my expensive encoder. I may have to buy an encoder to test on.

Jerry Hubbell
Lake of the Woods Observatory (MPC I24)
Locust Grove, Va


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orlyandico
Postmaster
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Reged: 08/10/09

Loc: Singapore
Re: Telescope Drive Master - The Truth of the Matter new [Re: Jerry Hubbell]
      #4889548 - 10/30/11 11:21 PM

Jerry.. the 48000 tick Gurleys can be had for $20

http://www.ebay.com/itm/New-Gurley-Precision-8125S-04096P-5P01-A18TQ-Encoder-/370341076692?pt=LH_DefaultDomain_0&hash=item563a0c5ed4#ht_2839wt_952


http://www.gurley.com/Encoders/PDF/825pdf/825pdf.pdf


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CounterWeight
Postmaster
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Reged: 10/05/08

Loc: Palo alto, CA.
Re: Telescope Drive Master - The Truth of the Matter new [Re: orlyandico]
      #4889808 - 10/31/11 06:36 AM

I've been looking at this as a possibility in my next GEM purchase (and have been stewing alternatives for a goof while now...) that's why I'm thankful for the review and positive posts from those who have actually used it.

I am glad it is 'as is'(yes, with the electronics box and encoders - about as 'kit level' as I care for) and not after being diluted by some marketing dept. person who decides - "ok now make 1/5 as good at 1/10 the cost"... I like that it is a pretty much self contained hardware solution.

This arrangement may be beneficial to the average user (the two that have actually used did not complain), simpler to support and warranty. More important though is it might make metrology errors less likely by being simple.

But sticking to what the unit is and does do-

Some intelligent discussion about tradeoffs in other existing products and performance.

As far as I understand the vendor TOS is that they can discuss their own products-

-direct quote from the CN TOS-
"In addition, vendors/manufacturers are to refrain from commenting on their competitor’s equipment (directly or indirectly). Please restrain your comments to products you manufacture or resell."


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harry page 1
sage


Reged: 07/25/09

Re: Telescope Drive Master - The Truth of the Matter new [Re: CounterWeight]
      #4890522 - 10/31/11 03:19 PM Attachment (43 downloads)

Hi

One of the great boons to me also for the TDM is simplicity of use , no hrs training or retraing your scope just switch it on and it just works .
I have just finished my first image with unguided 10 min subs Iris high res--- the seeing was a bit soft but I am enjoying the help TDM is giving me in aquiring my images
KInd Regards Harry

Edited by harry page 1 (10/31/11 03:20 PM)


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TDM
Vendor, MDA-Telescoop


Reged: 08/24/10

Loc: Hungary, Europe
Re: Telescope Drive Master - The Truth of the Matter new [Re: harry page 1]
      #4890717 - 10/31/11 05:48 PM

Yepp! Congratulation, Harry!

One picture tells much more then one thousand words...

Attila


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TDM
Vendor, MDA-Telescoop


Reged: 08/24/10

Loc: Hungary, Europe
Re: Telescope Drive Master - The Truth of the Matter *DELETED* new [Re: Alph]
      #4890764 - 10/31/11 06:30 PM

Post deleted by David Pavlich

Edited by TDM (10/31/11 06:59 PM)


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alpal
Post Laureate


Reged: 06/15/09

Loc: Melbourne Australia.
Re: Telescope Drive Master - The Truth of the Matter new [Re: TDM]
      #4890798 - 10/31/11 06:53 PM

Hi Jerry,
Please excuse my ignorance.
I can't quite follow this thread.

Are you using PHD guiding with a guide camera at
the same time as you're using Telescope Drive Master? -

or is Telescope Drive Master a stand alone system of
software & encoder hardware using a guide camera
or not using a guide camera?


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Jerry Hubbell
member
*****

Reged: 02/16/09

Loc: Locust Grove, VA, USA
Re: Telescope Drive Master - The Truth of the Matter new [Re: alpal]
      #4890845 - 10/31/11 07:35 PM

Quote:

Hi Jerry,
Please excuse my ignorance.
I can't quite follow this thread.

Are you using PHD guiding with a guide camera at
the same time as you're using Telescope Drive Master? -

or is Telescope Drive Master a stand alone system of
software & encoder hardware using a guide camera
or not using a guide camera?




Hello Alpal, no need to apologize. Our conversation does take place with some unstated assumptions and knowledge, it can be hard to follow sometimes. The TDM is more correctly a drive (Right Ascension axis) rate corrector.

It uses the ST4 Guide port to effect change in the nominal RA tracking rate of the mount to counter any PE in the mount, plus most, if not all, of the non-PE components of the mount's drive system. It uses a very high resolution encoder to measure the actual rate of the RA axis, and compares this to a very accurate hardware clock to control the drive rate to as close to Sidereal rate (or average King rate) as possible.

This system is integrated into the operation of the normal mount controller and does not use any camera system to provide feedback from the sky (star images). The fact that it uses the ST4 guide input may confuse some because the TDM makes an innovative use of this standard input that most mounts provide. The ST4 standard is an open interface to any rate correction system be it camera (sky feedback) based or internal standard based as the TDM is. To make it clear, I do not use any camera based autoguiding system (SSAG + PHD for example) to obtain the performance I am demonstrating here.

I hope this explains it for you.

Jerry Hubbell
Lake of the Woods Observatory (MPC I24)
Locust Grove, Va


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frolinmod
Carpal Tunnel


Reged: 08/06/10

Loc: Southern California
Re: Telescope Drive Master - The Truth of the Matter *DELETED* new [Re: Ray Gralak]
      #4890989 - 10/31/11 09:05 PM

Post deleted by David Pavlich

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frolinmod
Carpal Tunnel


Reged: 08/06/10

Loc: Southern California
Re: Telescope Drive Master - The Truth of the Matter new [Re: Alph]
      #4891012 - 10/31/11 09:22 PM

Quote:

....you can achieve same results with modest equipment.



Of course you can, particularly if you're highly experienced and highly skilled or very persistent and not easily frustrated.


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dawziecat
Carpal Tunnel
*****

Reged: 10/20/10

Loc: Rural Nova Scotia
Re: Telescope Drive Master - The Truth of the Matter new [Re: Jerry Hubbell]
      #4891044 - 10/31/11 09:48 PM

Quote:

The TDM is more correctly a drive (Right Ascension axis) rate corrector.




But guiding is necessary in dec anyway, no? Others may have perfect alignment and need no correction in dec but I never expect to achieve that myself.

So, TDM or no TDM, there has to be a guider in the system too.

So, I don't really see the advantage of this thing. It tracks perfectly in RA but you still need a guider for dec. What has been gained?


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gdd
Pooh-Bah


Reged: 11/23/05

Loc: N Seattle suburb, WA
Re: Telescope Drive Master - The Truth of the Matter new [Re: dawziecat]
      #4891053 - 10/31/11 09:54 PM

Quote:

So, I don't really see the advantage of this thing. It tracks perfectly in RA but you still need a guider for dec. What has been gained?





Doesn't it depend on the FL and length of exposure? If you stay within the capabilities of the TDM you gain simplicity and less equipment weight.

Gale

Edited by gdd (10/31/11 09:57 PM)


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