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ap900 or tak em400?

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#1 nik hodges

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Posted 15 March 2009 - 01:42 PM

Ive had my heart set on an AP900 mount for well over a year now and have been on the waiting list for an AP900 for almost 12 months.I now have a chance of getting a tak em400 + metal tripod + pda handset for a good price and with the price of the UK pound against the dollar been so bad the AP is getting steadily more expensive for me.

So this is my dilemma do i spring for the TAK or wait (hopefully not to much) longer for the AP900?

pros and cons as i see it

AP - better documentation, more sophisticated electronics (e.g. PEC) i kind of like the software part of the hobby too.. to me the AP900 looks better (i know this shouldnt matter -: )

TAK - the polar scope is meant to be as good as it gets. this is potentially important to me as it will be a portable set up to start with. On the other hand ive pretty much mastered drift aligning with PEMPro.

several people have commented that the TAK is more "robust" not sure how true this is

TAK has no PEC but both mounts track so well its not really needed for guided imaging?

Id love to hear comments from owners of either mount to help me decide. :confused:

#2 David Pavlich

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Posted 15 March 2009 - 02:33 PM

I would say that the Tak mounts are on the same level as the AP mounts for tracking ability based on several of our CNers. The EM 400 has a big advantage in capacity over the 900.

If I'm not mistaken, you need to use a Palm or laptop for the gotos with the Tak mount using something like Sky 6.

You also have to remember that when you buy an AP mount, the price is "as is". You have other stuff to buy before a scope can be mounted on it. The AP guys can tell you what else is needed.

Here's something else to consider: The 1200 is not that much more than the 900. The 1200 has more capacity than the EM400, but is not what I'd consider a real portable mount, although it does break down.

I nearly bought the EM400 before I decided on the MI250, but because of Larry Myers excellent service, I went with the 250.

Either way you go, you're going to have a top shelf mount.

David

#3 skyler

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Posted 15 March 2009 - 02:53 PM

David has some very good comments on the AP side of this and I don't think anyone can go wrong with these choices. My next move up will be the EM400 for more capacity and you will need a laptop, pc, or pda to use the Temma II for gotos. There is a Tak GOTO HC unit that may work on the EM400. I just sold mine since I am sticking with my PDA and The Sky6 Pocket Edition to run both EM10/11 and EM200 mounts.

The Polar Alignment System is so accurate that I am sold on it. I have not had to make any additional adjustments when autoguiding my small refractors or larger SCTs when using that system on both the EM200 and EM10/11 mount. Just superb. In fact, this is probably the main reason why I will stick with Tak mounts over any of the other similarly priced alternatives.

BTW, I have had nothing but exemplary service from Art and the team at Texas Nautical so I can vouch for the PAS. He has been very flexible and accommodating so that has been a big bonus.

Good Luck!
S

#4 Jaxdialation

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Posted 15 March 2009 - 05:38 PM

I have an AP1200 and an EM 400 on HD tripod.

I use PemPro for Polar Alignment with the 1200.

For portable or roll-out imaging I'd go with the Tak. Hands down it is MUCH faster to set up.

In terms of quality, they are peers.

#5 Rusty

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Posted 15 March 2009 - 08:48 PM

I've had my NJP for over 3 years, and it's been a delight. Polar alignment with the included polar scope is superb (I think the EM-400 uses the same polar scope; the EM-200 doesn't). Using a Dell Axim X51v and TheSky6 Pocket Edition, GOTO alignment is a 2-minute drill. GOTO remains dead-on. One drawback of the Tak is that no PEC app I'm aware of will do those corrections, but auto-guiding neutralizes that issue.

#6 Dean

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Posted 16 March 2009 - 09:34 AM

I've had my NJP for over 3 years, and it's been a delight. Polar alignment with the included polar scope is superb (I think the EM-400 uses the same polar scope; the EM-200 doesn't).


The EM-400 uses the same PA setup as the EM200.

#7 Emanuele

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Posted 16 March 2009 - 09:39 AM

The EM400 has the new Polar Scope which has a magnification of 11X. Polar alignment now is within 2 arcmin of the pole! :)
Same design as the EM200 though.

#8 Dean

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Posted 16 March 2009 - 09:44 AM

I tend to recommend Tak mounts if you need to setup often. The PAS makes polar alignment a non-issue taking only a minute. Tak mounts are also power misers which is a plus if you are out in the boonies running off a battery.

On the downside, Tak mounts slew very slowly - the EM400 max slew rate is 250x sidereal on 12 volts and 500x on 24 volts where the AP900 has a max slew rate of 1200x.

AP mounts also have many more features. For example, they have a meridian delay that lets you synch/goto the "wrong" side of the meridian. Tak mounts won't synch (correctly) on the wrong side of the meridian and trying a goto to the "wrong" side will induce a meridian flip.

#9 nik hodges

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Posted 16 March 2009 - 11:57 AM

thanks everybody for comments, i now have a chance to buy a mint used (2006) AP900, so its a choice between the convenience of the TAK polar scope vs the electronic sophistication of the AP900

tough call me thinks

#10 Alph

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Posted 16 March 2009 - 12:14 PM

so its a choice between the convenience of the TAK polar scope vs the electronic sophistication of the AP900



Just to be sure. There is nothing sophisticated about the electronics of the AP900. The AP-GTO system is light years behind the Nexstar and the Gemini controllers.

#11 EricCCD

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Posted 16 March 2009 - 12:25 PM

thanks everybody for comments, i now have a chance to buy a mint used (2006) AP900, so its a choice between the convenience of the TAK polar scope vs the electronic sophistication of the AP900


I'll echo what Dean said: if you set up and tear down every session, the Takahashi gets the nod from me. Now, if you have issues with the weight of the individual pieces, the AP900 gets my vote. The EM400 does break down into pieces like the AP900, but its heaviest piece is around 40+ pounds. The AP900 breaks down into 25-pound components.

HTH,
Eric

#12 PGW Steve

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Posted 16 March 2009 - 01:05 PM

so its a choice between the convenience of the TAK polar scope vs the electronic sophistication of the AP900



Just to be sure. There is nothing sophisticated about the electronics of the AP900. The AP-GTO system is light years behind the Nexstar and the Gemini controllers.


I'll agree with that statement. With the AP you must have a spot on polar alignment, and no cone error in your mounting system. Since there is no provision for a 3 or more star alignment, only a 1 star 'sync' you will be pretty lost on a meridian flip. There is no "PAE" or "High Precision Pointing", you have to fudge it as you go along.

#13 Jaxdialation

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Posted 16 March 2009 - 01:20 PM

Tak doesn't have high precision pointing either, if I understand what you mean. But both of them can have pointing models utilized via TPoint, etc in concert with TheSky 6. But who needs that for AP when plate solving gets you where you need to be anyway?

Not sure what cone error is, but I have found neither scope to be more or less fussy about needing polar alignment when doing AP. It pays to get it as good as you can within your own level of patience.

I use my Tak 400 for 30 minute narrow band exposures, so the PAS is barely passable at that length. When I have time I usually run PAM to iron out any error possible.


I'll agree with that statement. With the AP you must have a spot on polar alignment, and no cone error in your mounting system. Since there is no provision for a 3 or more star alignment, only a 1 star 'sync' you will be pretty lost on a meridian flip. There is no "PAE" or "High Precision Pointing", you have to fudge it as you go along.



#14 Alph

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Posted 16 March 2009 - 01:49 PM

But who needs that for AP when plate solving gets you where you need to be anyway?



Plate solving takes additional time and some people prefer to point quickly to a target in blind. The AP-GTO system is a show stopper to me. Mounts that cost few hundred dollars come with better control systems. The AP-GTO system in a $10,000 mount is a shame. The AP promissed a better mount modeling by the end of 2007. Where is it?

#15 lineman_16735

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Posted 16 March 2009 - 02:29 PM

AP has everything other mount controllers have other than a modeling feature. AP also has Meridian delay and, Smart guide not to mention Pulseguide support. The AP command center is due to be unveiled at NEAF. Like John said if your not well polar aligned, then you need to be. Cone error correction does nothing for polar alignment. I get about 7-10 arcminutes of error after a meridian flip with no model. BTW a plate solve can take less than a minute or only a few seconds depending on the size of your chip. FWIW I sold an NJP when I bought the 900. Having a permanent observatory the AP 900 was a better fit for remote imaging than the NJP, a much better fit.

#16 Alph

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Posted 16 March 2009 - 03:23 PM

AP has everything other mount controllers have other than a modeling feature.



There is more to it than just mount modeling. BTW, does anyone use pulse guiding? A search on the AP Yahoo groups brings up only few posts.

#17 nik hodges

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Posted 16 March 2009 - 03:37 PM

never had the need to use pointing models, as said just polar align to best of ability, sync, slew, plate solve, reslew (all using the sky6/maximDL) and job done your ready to image .....

when i get an obs would probably make a tpoint model but not until permanently mounted -)

what im after is a high end rig for AP, what im hearing is that there is no clear winner and its a matter of taste with both systems having pros and cons

#18 lineman_16735

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Posted 16 March 2009 - 04:47 PM

I have used PulseGuide once. It is useful for comet/satellite tracking.

#19 lineman_16735

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Posted 16 March 2009 - 04:47 PM

What else is there to it other than mount modeling??

#20 LLEEGE

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Posted 16 March 2009 - 05:08 PM

I know when my mount is polar aligned I can put objects on my DSI chip slewing from any point in the sky. The AP doesn't need to build a model. If you do the meridian delay align procedure, it is very accurate. It doesn't compensate for polar misalignment, it gets you aligned. :grin:

#21 Jaxdialation

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Posted 16 March 2009 - 05:14 PM

Good for you! I assume the AP will have the latest controller?

Either way, you have a no-loose decision. It isn't like you are comparing an Gemini with either of these mounts :)

thanks everybody for comments, i now have a chance to buy a mint used (2006) AP900, so its a choice between the convenience of the TAK polar scope vs the electronic sophistication of the AP900

tough call me thinks



#22 Timber

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Posted 16 March 2009 - 06:02 PM

The Tak uses a "micro-stepper" motor drive and the AP uses a "Servo Drive", does this make any difference for either of them?

Richard

#23 Jaxdialation

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Posted 16 March 2009 - 06:31 PM

http://astro.umsyste...1/msg00524.html

Could be the reason the Taks don't have PEC programming.

#24 Timber

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Posted 16 March 2009 - 06:57 PM

Good link John, thanks

Richard

#25 nik hodges

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Posted 17 March 2009 - 02:58 PM

Hi
went for the AP900, so excited, will post pictures when it arrives :jump: :jump:






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