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Mount Dilemma...

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#201 sg6

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Posted 18 October 2019 - 06:49 AM

Really no problem - look at the assorted small mount there are like the iOptron SkyGuider and SW Star Adventurer. They are in reality not guidable and people get good images - IF they put in the effort to set them up well.

 

Next come this urge to obtain a longer exposure then anyone else has managed. Really do get the idea that astrophotography is less about images and more about "I managed a single exposure of 28 hours 38 minutes, anyone beat that? Shame the sun wiped everything out but just look at the duration."

 

So if you do not want a guided system you have to accept that shorter exposure are the ONLY option. Trying for 10 seconds more because you think you might manage it results in failure. When you step over the limit the whole session is lost.

 

So not difficult, identify a mount that should track for your equipment and well set up for 60 seconds. Then take 60 second exposures. Not 80 sec or 90 sec  but 60 sec!!!!!



#202 mmalik

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Posted 18 October 2019 - 08:25 AM

Also, judging from what could be find here ( https://www.astrobin...=i&t=all&page=2 ), your statement about...

Apples and oranges. Those pics are analog, guided. I've been talking about dual absolute (M2/10μ), un-guided. Regards

 

 

Note: On the side, I also want to try un-guided tracker for precision imaging. Will be reviewing/testing soon.


Edited by mmalik, 18 October 2019 - 10:50 AM.


#203 spokeshave

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Posted 18 October 2019 - 11:14 AM

When it comes to precision engineering like mounts, it is all or none law; this argument of 'this copy is good that copy bad' is lame. Imagine absolute vendors saying 'oh, it is just a few bad ones, rest are all good'. Regards

It's interesting how you conflate your opinion with "law". Not everyone has the same lofty regard for your opinion as you do. There is no such "all or none" law. Every manufacturer of every product has "a few bad ones, rest are all good". No manufacturing process is perfect. There are always some flawed products in every product line. That is a law. It is pure fantasy to expect a manufacturer to produce a perfect product every time. You don't do your credibility any favors when you make such statements.

 

Tim


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#204 Hesiod

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Posted 18 October 2019 - 01:46 PM

Apples and oranges. Those pics are analog, guided. I've been talking about dual absolute (M2/10μ), un-guided. Regards


Note: On the side, I also want to try un-guided tracker for precision imaging. Will be reviewing/testing soon.

Apples to oranges only if the delusional statement that encoders and guiding are mutually esclusive is taken for good...and some of those pictures indeed have been taken without guiding.
However you have not answered to my question: from which sampling value/range begin "precision imaging"?

Edited by Hesiod, 18 October 2019 - 01:47 PM.


#205 mmalik

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Posted 18 October 2019 - 07:39 PM

...from which sampling value/range begin "precision imaging"?

Equation:

 

Precision Tracking = Precision Imaging (...not withstanding external variables)

 

 

Note: Sampling value/range has 'no' direct bearing on the above as long as those values/ranges are 'within reason' of the intended system; we are not talking extremes here. Regards


Edited by mmalik, 18 October 2019 - 11:24 PM.


#206 mmalik

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Posted 18 October 2019 - 08:45 PM

Given all pieces of the intended precision system, price aside, are not even available at this time and may not be until next year for reviewing/testing, I am taking an interim shortcut to another 'subsystem' variation on the same theme... precision imaging with a tracker. Stay tuned on the makings and results of such an 'affordable' system for most. Regards

 

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#207 mmalik

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Posted 19 October 2019 - 03:57 AM

Whether I go for dual encoded or a tracker system, a core piece of the puzzle is the camera. Just like there aren't that many choices when it comes to dual encoded, same goes for the camera. We are talking best in its class here.

 

 

Click the image below to follow along what's transpiring on the camera side. Know that there will be NO compromises when it comes to precision imaging. Goal in the end is a perfect setup for imaging, be it >20K or <3K; in short there is something for everyone in terms of affordability and accessibility. Let's get started without further ado. Regards

 

 

Note: Click the image for details

 
post-205769-0-75160400-1571473563_thumb.


Edited by mmalik, 19 October 2019 - 07:37 PM.


#208 Hesiod

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Posted 19 October 2019 - 04:43 AM

Equation:

 

Precision Tracking = Precision Imaging (...not withstanding external variables)

 

 

Note: Sampling value/range has 'no' direct bearing on the above as long as those values/ranges are 'within reason' of the intended system; we are not talking extremes here. Regards

Circular logic...clocks used as kitchen timers, alarms, sport or for navigation are all "precision devices", but what it changes is the actual level of precision required. Precision is not a value in itself, is only a consequence of the task: would I notice difference between the precision of my kitchen timers and a sport chronograph when cooking a cake? Of course not; but have the feeling that the judges of 100m at Olympic games would not be very pleased by my timer's precision

 

The same is for mounts: until you do not fix a minimum level of performance which must be attained, all are "precision devices" and all have "precision tracking".

And to fix such level you have to define a sampling (whithin the "limits of reason", of course: it is totally useless to have a device with 3kg payload which can handle 0.5"/pixel because the required load will be too big for the mount anyway...).

 

 

Since you have imposted the discussion as "philosophical" so far, it sounds strange that now do not provide us with a real, unambiguous, quantitative definition of the object of the discussion itself


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#209 BarrySimon615

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Posted 19 October 2019 - 06:04 AM

Post 207 jumps to a different forum category and thus swings the discussion away from mounts.  Either stick with a mount discussion or start a new thread in one of the imaging/astrophotography forums.

 

Barry Simon



#210 mmalik

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Posted 19 October 2019 - 07:41 AM

The same is for mounts: until you do not fix a minimum level of performance which must be attained, all are "precision devices" and all have "precision tracking".

I misunderstood you; I was talking 'within reason' in terms of acquisition parameters and the final output of precision imaging. If you are talking mount, then of course it would have to be sub arc second of error in dual encoded ones of which there are not that many to get confused about. Half the battle in this thread has been getting the point across. Regards


Edited by mmalik, 19 October 2019 - 07:45 AM.


#211 mmalik

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Posted 19 October 2019 - 07:49 AM

Post 207 jumps to a different forum category and thus swings the discussion away from mounts.  Either stick with a mount discussion or start a new thread in one of the imaging/astrophotography forums.

Come on Barry, that's exactly what I did. There will be many segues in this thread as it was discussed earlier on; precision imaging encompasses lot of things, mount being one of the pieces of the puzzle. Regards



#212 Hesiod

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Posted 19 October 2019 - 08:26 AM

I misunderstood you; I was talking 'within reason' in terms of acquisition parameters and the final output of precision imaging. If you are talking mount, then of course it would have to be sub arc second of error in dual encoded ones of which there are not that many to get confused about. Half the battle in this thread has been getting the point across. Regards


Probably we are still misunderstanding each other.
To define precision imaging I think the first step should be to define a sampling from which it begins.
Only once this had been done it makes sense to argue about tracking requirements and accuracy.
In truth, even the mere sampling is not enough because it risks to be unnecessarily conservative if opt for fast astrographs (<f/4 becomes rather hard to push the exposures without resorting to narrowband).

#213 AndyK997

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Posted 20 October 2019 - 02:06 PM

Pardon the interruption, but what type of auto guider would you recommend in this case?

 

Scope: Sky-Watcher Evostar 80 - https://www.skywatch...c5d2d175&_ss=r  +

 

Camera: https://www.meade.co...i-iv-color.html {includes an auto guider port)

 

Mounts available to us:

 

(1)  Sky-Watcher EQM-25 Mount: https://www.skywatch...9abf265f7&_ss=r

 

(2)  Celestron CGEM II EQ Mount - https://www.celestro...gem-ii-eq-mount

 

Thanks. 


Edited by AndyK997, 20 October 2019 - 04:55 PM.


#214 Raginar

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Posted 20 October 2019 - 11:18 PM

Hey Andy,

I haven’t played with a CGEM 2 but I’m leery of Celestron mounts. Maybe a CEM40 or a GM8 is up your alley in that price range?

Don’t forget a guiding setup.

#215 mmalik

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Posted Yesterday, 03:29 AM

Andy, some background info will help; are you planning to buy or have you already bought the stuff you list? If you haven't bought and if you are starting out, then hold off. I'll be delving into some tracker level imaging soon and will be able to give you some pointers in that regard... the mount, the scope, the camera, etc. Guiding... is something I have been trying to get away from. You will NOT need to guide with a tracker if done correctly. Plus tracker setup may not be as expensive. Correct me if I may have misunderstood your needs and/or where you might be in that process? Regards



#216 Hesiod

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Posted Yesterday, 05:00 AM

If have understood you rightly and already own all the equipment, I suggest to get a guiding package from QHY or ZWO.
The short focal of your esprit allows you to use very short focals to guide, as the modified finderscopes in those bundles.
I do not know how works that meade camera, but given the specs of the esprit 80 should be doable unguided imaging (even if the somewhat small pixels of the camera does not help, unless you resort to binning, going from 1.6"/pixel to a rather generous 3.2"/pixel)


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