Re: [MaxImDL] Re: reading vs. downloading in maximDL


Feb 22 8:06 AM

 


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#48557 Feb 22 8:06 AM

can someone explain what is going on in maxim when it is 'reading' a light frame vs. 'downloading' it. i notice it takes twice as long to download light frames when using maximDl vs. ccdsoft (time from exposure end to ready for next frame). that "twice as long" seems to be coming from 'reading'. however, when taking flat frames (really just short light frames), the 'download' time (read+download) is what i expect for my STL-11000 (about 34sec bin 1x1). when 'downloading' (read+download) regular light frames (900s, for example), it takes 62-65s.



what is going on? (using maximdl 5.18 but it has been that way since i first tried 5.12)



thanks



Lee



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#48562 Feb 22 2:50 PM

Hey Lee - It's not actually Maxim that's 'reading': this is a transfer of the CCD well data to a temorary buffer in the camera, which is subsequently downloaded. The buffering decreases readout errors during downloading and is therefore a 'good' thing. Less sophisticated cameras, such as my Orion SSP, don't have such a buffer and download directly.



Tony



astrophotography: gemmacaelestis.ca/astro.html ----- Original Message -----

From: lmbuck2000

To: MaxImDL@yahoogroups.com

Sent: Wednesday, February 22, 2012 11:06 AM

Subject: [MaxImDL] reading vs. downloading in maximDL







can someone explain what is going on in maxim when it is 'reading' a light frame vs. 'downloading' it. i notice it takes twice as long to download light frames when using maximDl vs. ccdsoft (time from exposure end to ready for next frame). that "twice as long" seems to be coming from 'reading'. however, when taking flat frames (really just short light frames), the 'download' time (read+download) is what i expect for my STL-11000 (about 34sec bin 1x1). when 'downloading' (read+download) regular light frames (900s, for example), it takes 62-65s.



what is going on? (using maximdl 5.18 but it has been that way since i first tried 5.12)



thanks



Lee











[Non-text portions of this message have been removed]



----------------------------

#48564 Feb 23 5:36 AM

Hi Lee;



Have you tried changing the Readout Mode to "Fast" instead of "normal"? I change that on my Parsec camera and it will bypass the "reading" mode using my camera. Just a thought, hope it will help.



Denny

--- In MaxImDL@yahoogroups.com, "lmbuck2000" lmbuck2000@...> wrote:

>

> can someone explain what is going on in maxim when it is 'reading' a light frame vs. 'downloading' it. i notice it takes twice as long to download light frames when using maximDl vs. ccdsoft (time from exposure end to ready for next frame). that "twice as long" seems to be coming from 'reading'. however, when taking flat frames (really just short light frames), the 'download' time (read+download) is what i expect for my STL-11000 (about 34sec bin 1x1). when 'downloading' (read+download) regular light frames (900s, for example), it takes 62-65s.

>

> what is going on? (using maximdl 5.18 but it has been that way since i first tried 5.12)

>

> thanks

>

> Lee

>



----------------------------

#48568 Feb 23 1:04 PM

What kind of camera are you using? MaxIm is only reporting that a read is occurring. It is your camera which is treating these different exposures differently.



Tony



astrophotography: gemmacaelestis.ca/astro.html ----- Original Message -----

From: lmbuck2000

To: MaxImDL@yahoogroups.com

Sent: Thursday, February 23, 2012 11:35 AM

Subject: [MaxImDL] Re: reading vs. downloading in maximDL







i have not tried different read modes. i was concerned faster read modes would degrade image quality. i won't mess with it now while i'm getting some good imaging time this week, but will check it out further next week.



tony (and denny) -- regarding the reading phase, what i don't understand is maxim IS doing something while reading/downloading. if i take a 15min light frame, bin 2x2, maxim will spend 52seconds 'reading' that frame and about 13s downloading it. if i take a 10sec sky flat (nothing different other than exposure time), maxim will spend 1 sec (or less) reading and 13s downloading. WHY?



there is no type of calibration being done but maxim is making a decision to 'read' the 15min (or 30min) exposure differently than it does a 10sec exposure... i would like to know what it is doing while "reading" and how it decides a 15min light frames needs 52s to 'read' while a 10s one only needs 1s to read -- it's the same amount of data.



i used ccd autopilot to run the session. it measures "download time" as the time passed from start of exposure to file saved minus exposure time. if doing image capture with ccdsoft those download times are roughly 13-14s for 2x2 binning and 34-36s for 1x1 binning. when using maxim, about 52sec gets added to those times due to 'reading'. i can measure them with the stopwatch while observing the sessions, too.



thanks for your input.



Lee



--- In MaxImDL@yahoogroups.com, "Denny" dhill955@...> wrote:

>

> Hi Lee;

>

> Have you tried changing the Readout Mode to "Fast" instead of "normal"? I change that on my Parsec camera and it will bypass the "reading" mode using my camera. Just a thought, hope it will help.

>

> Denny

>











[Non-text portions of this message have been removed]







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#48572 Feb 23 3:18 PM

the camera is an SBIG STL-11000M.



the notion that the camera alone is making different decisions based on exposure time is not consistent with the fact when using ccdsoft this mysterious 52s of read time does not exist (regardless of exposure length). so somewhere along the way, if the camera is making a different choice, there must be some software interaction helping it make that choice. in my case, the only variable is ccdsoft vs. maxim. maxim is definitely a more complex program and it is entirely possible/likely there are settings i don't know about or understand. from what i have been able to figure out, specifying fast download options is not recommended for best quality images.



Lee

--- In MaxImDL@yahoogroups.com, Tony Peterson tpeterso@...> wrote:

>

> What kind of camera are you using? MaxIm is only reporting that a read is occurring. It is your camera which is treating these different exposures differently.

>

> Tony

>



----------------------------

#48573 Feb 23 4:26 PM

Lee,

I use a couple STL11000's via MaxIm which don't have the behavior your

describing. In both MaxIm and CCDSoft

download is in the 30 ~ 33 second range (1x1). I checked my MaxIm

settings, which I have not altered from default, and did notice the

download priority was set to 'very high"



Just some info for ya,



Tom

On 2/23/2012 3:18 PM, lmbuck2000 wrote:

>

> the camera is an SBIG STL-11000M.

>

> the notion that the camera alone is making different decisions based

> on exposure time is not consistent with the fact when using ccdsoft

> this mysterious 52s of read time does not exist (regardless of

> exposure length). so somewhere along the way, if the camera is making

> a different choice, there must be some software interaction helping it

> make that choice. in my case, the only variable is ccdsoft vs. maxim.

> maxim is definitely a more complex program and it is entirely

> possible/likely there are settings i don't know about or understand.

> from what i have been able to figure out, specifying fast download

> options is not recommended for best quality images.

>

> Lee

>

> --- In MaxImDL@yahoogroups.com mailto:MaxImDL%40yahoogroups.com>,

> Tony Peterson tpeterso@...> wrote:

> >

> > What kind of camera are you using? MaxIm is only reporting that a

> read is occurring. It is your camera which is treating these different

> exposures differently.

> >

> > Tony

> >

>

>





[Non-text portions of this message have been removed]



----------------------------

#48574 Feb 23 7:24 PM

OK, obviously this is above my pay grade. Maybe send a ticket to MaxIm support.



t



astrophotography: gemmacaelestis.ca/astro.html ----- Original Message -----

From: lmbuck2000

To: MaxImDL@yahoogroups.com

Sent: Thursday, February 23, 2012 6:18 PM

Subject: [MaxImDL] Re: reading vs. downloading in maximDL







the camera is an SBIG STL-11000M.



the notion that the camera alone is making different decisions based on exposure time is not consistent with the fact when using ccdsoft this mysterious 52s of read time does not exist (regardless of exposure length). so somewhere along the way, if the camera is making a different choice, there must be some software interaction helping it make that choice. in my case, the only variable is ccdsoft vs. maxim. maxim is definitely a more complex program and it is entirely possible/likely there are settings i don't know about or understand. from what i have been able to figure out, specifying fast download options is not recommended for best quality images.



Lee



--- In MaxImDL@yahoogroups.com, Tony Peterson tpeterso@...> wrote:

>

> What kind of camera are you using? MaxIm is only reporting that a read is occurring. It is your camera which is treating these different exposures differently.

>

> Tony

>











[Non-text portions of this message have been removed]



----------------------------

#48575 Feb 23 7:26 PM

thanks, tom. i will look into that one. i have it set to normal now since it's difficult to get control of the laptop when it was set higher. but that only really matters from some preliminary frame and focus setup i might be doing. most of the time it's hands off so the higher priority would not get in the way. session already in progress tonight but will check it out tomorrow, for sure.



don't know how that would explain a 15min light download behaving so differently from a 5sec flat, but it's worth checking out.



thanks



Lee

--- In MaxImDL@yahoogroups.com, THouse look-up1@...> wrote:

>

> Lee,

> I use a couple STL11000's via MaxIm which don't have the behavior your

> describing. In both MaxIm and CCDSoft

> download is in the 30 ~ 33 second range (1x1). I checked my MaxIm

> settings, which I have not altered from default, and did notice the

> download priority was set to 'very high"

>



----------------------------

#48577 Feb 23 9:46 PM

I also use STL11k.

Usually I get the 33s download.

But, sometimes I get the reading then download, which takes much longer.

Seems to happen with long exposures.

.

Dale





---------------

From: THouse look-up1@...>

To: MaxImDL@yahoogroups.com

Sent: Friday, February 24, 2012 2:26 AM

Subject: Re: [MaxImDL] Re: reading vs. downloading in maximDL







.



Lee,

I use a couple STL11000's via MaxIm which don't have the behavior your

describing. In both MaxIm and CCDSoft

download is in the 30 ~ 33 second range (1x1). I checked my MaxIm

settings, which I have not altered from default, and did notice the

download priority was set to 'very high"



Just some info for ya,



Tom

On 2/23/2012 3:18 PM, lmbuck2000 wrote:

>

> the camera is an SBIG STL-11000M.

>

> the notion that the camera alone is making different decisions based

> on exposure time is not consistent with the fact when using ccdsoft

> this mysterious 52s of read time does not exist (regardless of

> exposure length). so somewhere along the way, if the camera is making

> a different choice, there must be some software interaction helping it

> make that choice. in my case, the only variable is ccdsoft vs. maxim.

> maxim is definitely a more complex program and it is entirely

> possible/likely there are settings i don't know about or understand.

> from what i have been able to figure out, specifying fast download

> options is not recommended for best quality images.

>

> Lee

>

> --- In MaxImDL@yahoogroups.com mailto:MaxImDL%40yahoogroups.com>,

> Tony Peterson tpeterso@...> wrote:

> >

> > What kind of camera are you using? MaxIm is only reporting that a

> read is occurring. It is your camera which is treating these different

> exposures differently.

> >

> > Tony

> >

>

>



[Non-text portions of this message have been removed]









[Non-text portions of this message have been removed]







----------------------------

#48578 Feb 24 3:04 AM

This is a mystery that has intrigued me for years. I hope that someone from Diffraction Ltd will chime in to give us the answer. My guess, and it's only a guess, is as follows: MaxIm starts an exposure and also starts a timer of the same or maybe slightly less interval. Windows timers can be quite unreliable, and in any event it can't start to download the image until the camera has actually finished, so when the timer expires it starts the 'reading' phase and continues to poll the camera until it's actually ready. Then it changes to the 'download' phase and starts the download. I could be wrong though.



Regards

John Moore

Fleet, Hants, England



----------------------------

#48580 Feb 24 7:43 AM

John, you might be correct, some sort of an internal timer within Maxim.

When this situation first raised its head Maxim told me my computer's timer

was fast and Maxim's timer was correct. That being said, I use Think-Man

internet time service, I can see there's a "small" day to day, and hardly

any in 30mins, time difference but nothing much as 'Reading Chip' indicates

occurs in a 30min exposure.



If you watch your Guider exposures and Corrections they continue while

'Reading Chip' is displayed. That indicates to me something is going on

somewhere, but what?



I first noticed this 'Reading Chip' issue with my 2005 STL11K after SBIG

released a new Driver Update ~2007. Maybe SBIG is doing something

controlled by the Driver, Pedestal calculations(?), which would cause the

'Reading Chip' interval. But why would longer exposures cause longer

'Reading Chip' times? I've not seen anyone address this question directly

to SBIG.



I use Maxim's Default 'High' Download Priority. Since 'Reading Chip' allows

the Guider to continue guiding I don't really care. The 'Reading Chip' time

is minuscule compared to the total exposure time unless taking very short

exposures. To me high quality downloads are what count...joe :)





"May You Go Among The Imperishable Stars"

Joe Mize www.cav-sfo.com

Chiefland Astronomy Village (CAV), Fla

StarFields Observatory, (SFO).

----- Original Message -----

From: "jcmoore_uk" j_moore@...>

To: MaxImDL@yahoogroups.com>

Sent: Friday, February 24, 2012 6:04 AM

Subject: [MaxImDL] Re: reading vs. downloading in maximDL





> This is a mystery that has intrigued me for years. I hope that someone

> from Diffraction Ltd will chime in to give us the answer. My guess, and

> it's only a guess, is as follows: MaxIm starts an exposure and also starts

> a timer of the same or maybe slightly less interval. Windows timers can be

> quite unreliable, and in any event it can't start to download the image

> until the camera has actually finished, so when the timer expires it

> starts the 'reading' phase and continues to poll the camera until it's

> actually ready. Then it changes to the 'download' phase and starts the

> download. I could be wrong though.

>

> Regards

> John Moore

> Fleet, Hants, England

>

>

>

>

---------------

>

> Yahoo! Groups Links

>

>

>

>



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#48652 Feb 29 10:19 PM

Most cameras do not report back the "time remaining" in the exposure (If I

recall correctly the ST-6 did that, but I can't think of any other camera model

that does). Lacking any information from the camera, we have to count down the

time remaining using Windows timekeeping.



Some cameras have a reading stage (transferring data to internal memory but not

downloading), followed by a downloading stage. Others go directly to

downloading. (This either means they don't have an internal buffer, or that it

is capable of simultaneous read/write.)



If the Windows-based countdown timer reaches zero we display "reading" until the

camera tells us it is downloading. This is something of an assumption because

the camera didn't tell us anything. In some cases it is actually true but the

camera doesn't tell us; in others it's caused by some delay in the exposure

processing. It could also be caused by some sort of difference between Windows

timekeeping and the camera's timekeeping.



As far as I can tell the occasional computer differs on the passage of time

compared to the SBIG camera actually doing the imaging. We've never seen it

happen in-house, but I don't believe this has any real impact on the imaging.



Doug



--



Doug George

dgeorge@...



Diffraction Limited

Makers of Cyanogen Imaging Products

www.cyanogen.com/



100 Craig Henry Dr., Suite 202

Ottawa, Ontario,

Canada, K2G 5W3



Phone: (613) 225-2732

Fax: (613) 225-9688



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