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PEC for AVX --- total failure


saiph

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That is good news, with the PHD.

The rest is kind of killing the mood :)

Well, yes, I tried to get some images, but not longer than the very basic 30s earlier mentioned (on a longer FL, I have to admit); there's that wider field Dumbbell nebula with the C80 reduced - only there I used 60s subs, but in either case, no PEC involved, since none of my trials produced the desired effect.

I think I may have a basic idea of what you're talking about, and I must agree, I saw some decent shots with insufficient or too aggressive post-proc involved in the final pic. Personally, I try to take it easy, although not letting the image suck too much from under-processing. I use DSS for basic frame stacking and also saving an "augmented luminance" layer which I use in post (PS CS5) to bring those fuzzy patches of color out into the light. I use HDR masks, darks flats and biases, but still have to become friends with RAW, as so far I couldn't make too much use of it.

 

 

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48 minutes ago, saiph said:

People, people. come on.. really?  :)

 

 

Hmmm....You seem to have gone from complaining about not getting responses to now complaining because you don't like the content of the answers that people have taken the time to give you. No one is under any onus to offer help to you and the way you respond might be part of the issue.

48 minutes ago, saiph said:

But, on the other hand, I don't see myself spending big K of money, on super high-end mounts, just to enjoy taking some 2-3min pictures, come on.. you realize too this is plain ridiculous, right? That is why I was after a quick solution for a simple (in my mind) problem.
 

if you want to do unguided long exposures then a Celestron Advanced VX mount is not really the tool for the job. You can do 2-3 minute unguided exposures with a cheap entry-level mount, but in my experience (with an EQ6 and some others) you will end up dumping a lot of the sub-exposures. Unguided long exposures is far from a simple problem which is why only relatively high-end mounts can do them. Again, I use a £5k+ Mesu 200 mount and I don't do unguided as i know that i will end up dumping some data. My imaging time is severly restricted so I cannot afford to dump data to star trailing. Hence, I guide.
The problem clearly isn't simple- the Dunning Kruger effect might apply in this case. :icon_biggrin:

 

48 minutes ago, saiph said:

The portable solution proposed by Stephen (?) [Zakalwe] seems pretty interesting, provided PHD can work well under Win10 and it will manage to communicate with my cam (which I think I already mentioned it pretty much failed to, so I may have to upgrade that too). So far I'm waiting for the reply of another fellow stargazer who has a Synguider for sale - I just hope he won't "miss" my PM too, as another fellow stargazer did, with another ad, earlier this year... I'm willing to give it a try this way - if it works, it works; if it doesn't, i'll explore more options, but for sure, it won't be a very pleasant endeavor. I am this close to giving up on this wonderful hobby (the photo part, mainly) due to excessive expenses, for my pocket at least.

PHD works fine with Win 10.
I cannot comment on your camera, but I've had no problems using an Atik, a couple of different QHY and a number of ZWO camera with Win 10. As long as the camera has a driver then it will work. if the camera has an ASCOM driver then it should also work under PHD.

I've no experience of Synguiders, but I did investigate them as i considered them once. From what I have gleaned, they are temperamental but can deliver results. The issue as I saw it, was that you need to be fairly experienced to get the best from them (or even to get them working!) which is a bit of a contradiction as most experienced imagers wouldnt use a Synguider. Camera technology has moved on a LOT since the Synguider launched. I hear that the MGEN standalone guider is supposed to be very good?

48 minutes ago, saiph said:

Anyway, if PEC is such a hostile thing to deal with, y.t.h. did Celestron even implement it in the first place, and how on Earth could those people, bragging about their success, make it through?.. It's puzzling me big time, to say the least

Best direct that question at Celestron

 

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9 minutes ago, newbie alert said:

Maybe you need to speak to the guys that brag about their pec training success .. I'd guess that there's a good few thousand people out there that are using a guiding system such as phd..and maybe have a handful of people that have pec trained their mounts and even less that have successfully trained them..whats the sort of sub length that's attainable from a fully pec trained avx? Maybe a pretty average guided sub length..

To get 2-3 min subs from a AVX you only need decent PA with a 80ed if you didn't want to use a guiding system...

Interesting post that Droogie said about the OAG... thanks for that..

If I was you I'd forget about the pec training..return it to factory settings and enjoy some imaging..after all that's what it's all about..enjoying this frustrating hobbie...best of luck..

 

Thanks :)

Yes, so I did. But no one replied. That is part of the reason I am so confused and slightly upset. Where is everybody..?

That is what I thought too, about the max exp time, but after seeing the PE graph, math shows us that 2-3 min will definitely exceed the acceptable deviation at my imaging scale, with a ~ +/-25" of error. No way in heaven that will produce anywhere near round stars.

Just for the record, two nights ago my PA was dead-on: all the stars I slewed to stopped straight into the tiny square of the reticle in my eyepiece. I guess that means it was pretty damn good. And then PEC happened.... :)  ooohh..  it would be funny, if it didn't wreck my nerves.

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5 minutes ago, saiph said:

Just for the record, two nights ago my PA was dead-on: all the stars I slewed to stopped straight into the tiny square of the reticle in my eyepiece. I guess that means it was pretty damn good. And then PEC happened.... :)  ooohh..  it would be funny, if it didn't wreck my nerves.

That's your star alignment spot on..not the PA..totally different..if you was using a guide cam I'd suggest using sharpcap polar alignment feature..

Run throu your PA routine 

I'd suggest that your star alignment is pretty much spot on..think you're getting drift because of your PA 

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8 minutes ago, saiph said:

That is good news, with the PHD.

The rest is kind of killing the mood :)

Well, yes, I tried to get some images, but not longer than the very basic 30s earlier mentioned (on a longer FL, I have to admit); there's that wider field Dumbbell nebula with the C80 reduced - only there I used 60s subs, but in either case, no PEC involved, since none of my trials produced the desired effect.

I think I may have a basic idea of what you're talking about, and I must agree, I saw some decent shots with insufficient or too aggressive post-proc involved in the final pic. Personally, I try to take it easy, although not letting the image suck too much from under-processing. I use DSS for basic frame stacking and also saving an "augmented luminance" layer which I use in post (PS CS5) to bring those fuzzy patches of color out into the light. I use HDR masks, darks flats and biases, but still have to become friends with RAW, as so far I couldn't make too much use of it.

 

 

Thos images are pretty good! The Dumbell Nebula widefield is a cracker.

You absolutely MUST shoot in RAW. You are wasting your time shooting in JPEG. All of the data that you want to develop is in the dark parts of the image. JPEG compression discards the dark parts, so you are throwing away the very information that you are trying to capture!

Comparison of processing JPEGs and FITS V2.pdf

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4 minutes ago, Zakalwe said:

 

Hmmm....You seem to have gone from complaining about not getting responses to now complaining because you don't like the content of the answers that people have taken the time to give you. No one is under any onus to offer help to you and the way you respond might be part of the issue.

---

Best direct that question at Celestron

 

Hehe :) well, not exactly complaining, but I appreciate your input. All of you, guys. Don't get me wrong on that. I really do.

I asked Celestron about it, and their reply couldn't be more late or incomplete.  Still waiting for the enlightening answer to arrive.

About that MGEN guider, though... oh boy.. :)  " a bit" over budget, let's say...

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6 minutes ago, newbie alert said:

That's your star alignment spot on..not the PA..totally different..if you was using a guide cam I'd suggest using sharpcap polar alignment feature..

Run throu your PA routine 

There was extremely little if any Dec drift noticeable after more than two worm turns, and after doing PA check, after the ASPA routine, it showed something like 3' deviation.

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2 minutes ago, newbie alert said:

ASPA I found isn't that accurate either..the handset might tell you one thing and the drift in the image another..

Are you saying 3 arc seconds or degrees..

I'm looking for under an arc sec pa

No, no, sorry - my mistake: I meant 3 arcmin :)  sticky Shift key..   Edited the text a minute later.

I don't get it down to arcseconds even if I cast a spell over it :) I'm using only a polar finder and my own eyes to estimate deviation.

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Like I say I'm looking for under an arc min as a minimum..3 arc mins you will get drift..

I bet that's what you are seeing as pec error...id suggest get phd ,use sharpcap for your pa (also free,or very little for the new version) phd will give you all the PA and pec errors you want..but I'm sure it's your PA..

You can even use it's drift alignment feature.. (Not tried it yet)

Try it and see

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6 minutes ago, newbie alert said:

I bet that's what you are seeing as pec error

RA drift larger than with no PEC, and larger than an unPECed/unguided EQ5, due to 3 arcmin PA deviation? Are you sure?

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If you PA correctly and use phd I'm sure all your frustrations will disappear...any thing with gears is going to deviate...no 2 mounts are the same,even if they are the same model.. unless you spend mega money on a mount you will get errors on these budget mounts..stands to reason..

A good friend of mine says keep doing the same things over and over will bring you the same results...

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On 8/31/2017 at 15:57, saiph said:

I'm using only a polar finder and my own eyes to estimate deviation.

 

15 hours ago, saiph said:

I'm not using a camera and software to estimate PA

I do hope that after 2 pages of help to increase your useable exposure time you're not saying that the only Polar Alignment you are doing is with the polarscope......... ?

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ok, i know it may sound dumb to you, and you may laugh all you want, but i didn't really start doing this yesterday. i may have "some" idea about the difference between drift caused by improper PA and crappy PEC, alright?  not everyone who's not using the latest fancy high-tech methods is a looser, you know? in fact, some of the senior imagers will confirm you that people were doing drift alignment long before the dawn of "pole master", and guess what - no one complained. 

so, how about you choose a less condescending tone, and let me judge if all two pages so far have been helpful or not (some people really had some good advice - unlike others - and i am truly grateful for their feedback, from the bottom of my heart).

fyi, just because i don't afford super modern gear, or have two hundred thousand posts around, doesn't automatically make me your Piñata. so, unless you have some really valuable on-topic things to say, i will choose to ignore your further input. thank you very much.

 

ok, let's get back to our topic, shall we? let's not loose focus here. :)  sorry for that little intermezzo, folks. 

i just received reply from Celestron, after asking what is the actual format of the PEC data that needs to be uploaded to the controller, and what kind of operation does it do with it (if it's transformed in any way, added, subtracted, multiplied.. there must be some relation to the motor speed) and all i get is more or less a quote from the manual...  as if.....

great job, Celestron! ;)  you know how to keep your clients satisfied

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4 hours ago, saiph said:

ok, i know it may sound dumb to you, and you may laugh all you want, but i didn't really start doing this yesterday. i may have "some" idea about the difference between drift caused by improper PA and crappy PEC, alright?  not everyone who's not using the latest fancy high-tech methods is a looser, you know? in fact, some of the senior imagers will confirm you that people were doing drift alignment long before the dawn of "pole master", and guess what - no one complained. 

so, how about you choose a less condescending tone, and let me judge if all two pages so far have been helpful or not (some people really had some good advice - unlike others - and i am truly grateful for their feedback, from the bottom of my heart).

fyi, just because i don't afford super modern gear, or have two hundred thousand posts around, doesn't automatically make me your Piñata. so, unless you have some really valuable on-topic things to say, i will choose to ignore your further input. thank you very much.

Wow.:confused2:

 

I'm out.

 

 

<EDIT>

Final thoughts on this subjetct
The manual states

"Does the PEC function make unguided astroimaging possible? Yes and no. For solar (filtered), lunar and piggyback (up to 200 mm), the answer is yes. However, even with PEC, autoguiding is still mandatory for long exposure,deep sky astroimaging."

You're using an ED 80 (focal length ~600mm) Even with a 0.85 reducer you are working at >500mm of focal length. This is more than double what the manual says PEC is applicable to. There's nothing wrong with the mount or it's PEC routine- the fault lies with your expectations of being able to do something that is far outside the design specifications of the equipment.

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I personally think you are looking at the wrong avenue regarding the pec..i think you are seeing drift because of bad PA..you can't see through a finder or even a polar scope as near to perfect PA as you can...im very happy with the method I use..im not asking you to do the same..as you explained..drift alignment has been around for years..why not use that..perfectly fine to do..PA is PA whatever method you use..but eyeballing through a finder isn't.. 

Most have tried to help but you put the barriers up..if you don't like using methods that use software,what method are you using to measure the pec? 

Can't see what you're going to achieve, or what the main goal is..if it's 3 min unguided subs, you can do that with  the equipment you have now without even looking at pec..

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22 minutes ago, newbie alert said:

...if you don't like using methods that use software,what method are you using to measure the pec? 

it was about using software to estimate PA, not PE :) i already mentioned i use pecprep to deal with the PE data collected by Metaguide. so, what are we talking about here....  but, anyway, i'm not putting any barrier up against a good advice.

and i'd appreciate if i didn't see my words twisted around, thank you ;)

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On 8/31/2017 at 10:29, Zakalwe said:

I always thought that it was a bit of a waste of time on mounts with clutches. As so as you open the clutch then the relation between where the scope is pointed and the geartrain is lost.

Where the scope is pointing is immaterial. PEC needs to track where the RA physical gear train is in its cycle not where the scope is pointing.  Releasing the clutch and moving the scope will not cause any problems since the gear train and encoders don't move.

Problems for PEC arise in some cases when the mount is moved with the clutch engaged (or partially engaged) as the gear train will then move and the mount controller may not know about it.  Depends on the mount and controller as to whether it is an issue or not.  (E.g. Earlier Skywatcher mounts don't have encoders, they just count stepper motor steps and re-syncing PEC is hard in such cases).

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On 01/09/2017 at 08:27, saiph said:

I'm not using a camera and software to estimate PA

I'm not twisting any words..just seems strange the barrier on estimating PA with software  but you would rather guess with your eyes through a polar scope and then use a software to give you all sorts of info which hasn't worked..

Stop worrying about pec.. drift align and see if it makes a difference 

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5 hours ago, IanL said:

Where the scope is pointing is immaterial. PEC needs to track where the RA physical gear train is in its cycle not where the scope is pointing.  Releasing the clutch and moving the scope will not cause any problems since the gear train and encoders don't move.

Problems for PEC arise in some cases when the mount is moved with the clutch engaged (or partially engaged) as the gear train will then move and the mount controller may not know about it.  Depends on the mount and controller as to whether it is an issue or not.  (E.g. Earlier Skywatcher mounts don't have encoders, they just count stepper motor steps and re-syncing PEC is hard in such cases).

 

That makes sense. Thanks for the correction :icon_salut:

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17 hours ago, saiph said:

ok, i know it may sound dumb to you, and you may laugh all you want, but i didn't really start doing this yesterday. i may have "some" idea about the difference between drift caused by improper PA and crappy PEC, alright?  not everyone who's not using the latest fancy high-tech methods is a looser, you know? in fact, some of the senior imagers will confirm you that people were doing drift alignment long before the dawn of "pole master", and guess what - no one complained. 

so, how about you choose a less condescending tone, and let me judge if all two pages so far have been helpful or not (some people really had some good advice - unlike others - and i am truly grateful for their feedback, from the bottom of my heart).

fyi, just because i don't afford super modern gear, or have two hundred thousand posts around, doesn't automatically make me your Piñata. so, unless you have some really valuable on-topic things to say, i will choose to ignore your further input. thank you very much.

HA HA, and you wonder why your PMs get ignored... hey post more aggressive text.. perhaps more exclamation marks... that'll get more responses. 

There is more than enough very useful advise posted here to cover your dilemma, but you just ignore it. Perhaps you need someone to set it up for you and all you need to do is press the shutter button?

At the end of the day, this is meant to be a hobby, something that gives you pleasure with the challenge involved... and that's what it is, a challenge... for people who get joy from overcoming the challenges, but if this frustrates, angers and drives you nuts than perhaps it is time to give up AP rather than insult the people who were trying to help you.

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aaaand, of course, people got it all wrong because someone was too lazy to read what i posted and now everyone thinks i'm the bad guy :)

nice...

believe it or not, i DID say i appreciate all the help i received; when i said i'm grateful form the bottom of my heart i really meant it, i i was referring to what Zakalwe and others had posted - and again, i thank them for their well intended advice.

but, hey - i'm the bad guy..  :)  because i stood up for myself (?) in a conversation that could have otherwise been private - it didn't bring anything new or useful to the topic.

 

i was hoping for a little different approach, really.  especially after seeing the earlier topics (few years ago) about the matter i brought to your attention, where people confirmed that they had succeeded.  and btw, i don't remember who said it earlier, but if you do the math, you don't get 2-3 min of unguided and unPEC-ed exposure at this image scale simply by perfect 0.00" PA, not even if you stand in your hands  :)  at least not without any clearly visible star trails.

 

anyway, i respect the point of view people expressed so far, even though i cannot agree 100% with them.  and thanking you for your kind words, i wish you all "clear skies", gentlemen! ;)

 

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