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Christmas Wish for My Tak Mount

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#1 Dwight J

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Posted 14 December 2012 - 05:31 PM

I wish that someone would develope a PEC plugin for the ASCOM Tak EM200 driver or similar. It doesn't seem like Takahashi is too concerned about developing one in the near future. Don't get me wrong - the mount tracks and guides exceptionally. I would like to go longer exposures with longer focal lengths without the hassle of autoguiding. As of now I can expose for about 3 or 4 minutes, occassionally longer without trailing and no autoguiding. PEC training could extend this greatly. Takahashi needs to take a page out of the Astrophysics book and develop PEC and/or something like Smart Guide and have it retrofit existing models. I am sure I am not the only one wishing this. Maybe a driver for the mount in EqMod?

#2 iriise

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Posted 15 December 2012 - 01:10 AM


Dwight, I totally agree with you! I suggested this to Ray Gralak (PemPro), he seems interested but I know he is very busy with other projects, maybe you could request it also, so he knows others are interested! Very nice mounts but lacking the very basic features that most mounts have.

#3 orlyandico

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Posted 15 December 2012 - 02:11 AM

I don't understand how you can support PEC if the mount controller doesn't have the NVRAM for it.

This is not something that PEMPro can handle.

Unless the PEC curve was stored on a PC, and played back from the PC every time. Which means you would need to control the mount exclusively from the PC (if you move the RA axis using the hand control, the PC would lose track of the PEC index).

#4 iriise

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Posted 15 December 2012 - 02:40 AM

Yes, you would have to store the PEC curve on a computer, I believe that's how EQMod works also! That's not an Issue for most imagers since they use a computer for camera control, guiding and goto anyway!

#5 Dwight J

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Posted 15 December 2012 - 03:58 AM

Yes, I think a call may be in order although the Eqmod would be more likely. I am not that computer-savvy so that is why this is a wish. It would pay someone to do it as almost every Tak mount owner would want it. Using a computer is usual with these mounts anyway unless you are just visual. Another possibility is SkySafari as they have a driver for Tak mounts. Anyway, it will probably be on next years wish list too.

#6 orlyandico

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Posted 15 December 2012 - 04:43 AM

I disagree about "PEC from the PC" - the OP said he wanted to avoid the hassles of autoguiding. I submit that if you already have the darn PC, might as well autoguide. "Hassle free" in my book means no PC.

Or you can get the German Littlefoot controller and completely replace the Temma 2. $800 US. Actually costs less than the Temma hand controller (and yes you can do GoTo from the hand controller). It also has 1024-cell PEC.

#7 Ray Gralak

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Posted 15 December 2012 - 09:31 AM

I don't understand how you can support PEC if the mount controller doesn't have the NVRAM for it.

This is not something that PEMPro can handle.

Unless the PEC curve was stored on a PC, and played back from the PC every time. Which means you would need to control the mount exclusively from the PC (if you move the RA axis using the hand control, the PC would lose track of the PEC index).


Yes, a PC would need to be connected but actually I think there is a way that such an application could maintain synchronization even when slewing and moving. I plan to try this soon to prove the theory.

-Ray

#8 Ray Gralak

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Posted 15 December 2012 - 09:44 AM

Yes, you would have to store the PEC curve on a computer, I believe that's how EQMod works also! That's not an Issue for most imagers since they use a computer for camera control, guiding and goto anyway!

The difference with EQMOD is that for the mounts it controls there is a command that reads RA/Dec motor index values, which is something that is not available in the Tak mounts. This is one of the biggest roadblocks using EQMOD with any other mount (despite the EQMOD developers claims this can be done.) If the Tak mount had such a command then a PEC table could be mapped to the index values. However, since it doesn't exist another way has to be used.

-Ray

#9 tomcody

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Posted 15 December 2012 - 11:12 AM

As a former owner of an EM200 temma2, I think that the Tak is very good in the field and has a great polar scope, but an advanced astro mount it is not. If you want the advanced features? I would look to Astro Physics or Bisque Brothers. with costs and availability today, either of these is a cost effective replacement that makes the EM200 look a little crude by comparison.
Rex

#10 orlyandico

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Posted 15 December 2012 - 01:01 PM

well new-to-new I think the Mach1 is a better choice than the EM200, and the 900 is a better choice than the EM400.

These are the mounts in the same price range.

But if you already own a Tak... changing over to an AP mount would mean eating a large loss, since the resale value of Tak mounts is not that great.

#11 Dwight J

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Posted 15 December 2012 - 03:51 PM

I would buy a Mach 1 as well given the choice today. When I bought my EM200 the Mach 1 was not yet available. The Mach 1 is also now cheaper (but no counterweights). The saving grace for the Tak is the polar scope which has saved me hours in drift aligning but Astrophysics has some polar alignment routines that are probably just as good now. Our local club has an AP1200 and it is a dream to use.

#12 Denimsky

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Posted 15 December 2012 - 03:58 PM

I think the new right angle polar scope from AP is on par with Tak polar scope. It is very expensive though.

#13 orlyandico

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Posted 15 December 2012 - 08:43 PM

dwight - well like i said, the EM200 has stepper motors and is amenable to using the Littlefoot controller. If you had a USD3 it would have been a no-brainer to get the Littlefoot (converting a USD3 to Goto with the Littlefoot is cheaper than retrofitting a Temma2).

in fact i was looking at buying a non-Goto NJP or JPZ and converting it to Goto with a Littlefoot...

#14 Dwight J

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Posted 15 December 2012 - 10:01 PM

The Littlefoot looks like it would likely do the job but too rich for my blood right now in my retired state and beer budget. I do use SkySafari and my iPod as a handcontroller of sorts. Using a computer with the mount is very common for me so some way to record guiding corrections for the duration of the worm and then "playing" those back to continue the corrections would suffice. The problem seems to be if I slewed to a different object the playback wouldn't match the new position of the worm - the fly in the ointment it seems.

#15 orlyandico

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Posted 16 December 2012 - 02:36 AM

actually I understand that the Temma2 has an encoder on the RA and DEC worms. So in this case it is actually superior to other mounts which only have a PEC indexer.

The big problem is reading out the PEC index value.. if that were possible, then PEC could be implemented.

Ray - there might be a way to do this?

I understand the Temma driver can query the Alt and Az of the mount. Since we know the number of teeth in the worm wheel, it should be possible to derive the position of the worm to (some) level of accuracy.

If say the worm wheel is 180 teeth, that's 7200 arc-seconds per worm rotation. Since the Temma can return an Alt value to within (I think) 6 or is it 20 arc-seconds, you can derive at worst 360 positions of the worm (7200 / 20).






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