Date   

Re: Problems with park

Roland Christen
 

In a message dated 10/15/2001 5:51:06 PM Pacific Daylight Time, plw@...
writes:


In RA, instead of moving 90 degrees (west?) and pointing vertically
downward, the counterweight shaft moves about 120 degrees and ends up
on the west side of the mount. The DEC movement is about three
quarters of the way around the axis (270 degrees) and leaves the
scope pointing south but below the horizon.

Start the mount by syncing on a known object like the sun. Then scroll down
to the 3 park locations and choose park 3. Wait for the mount to go to the
proper orientation, and if it's not quite right, move it manually until the
counterweight shaft is pointing straight down and the scope is pointing
north. Now press menu, press Park 1, and the scope should slew to the proper
position. Do the alignment with the bubble level, and press Park 2. The scope
should now slew to the eastern horizon. When you are all done with your
evening's observing, send the mount to one of the three park positions, one
that you will re-create the next time out. Failure to do this step will
result in the mount not being in the proper position for Park 1 (or which
ever you leave it in), because it will start out at the last position that
your scope was pointing to (this in fact may be the case why you could not do
the routine properly). The last position that you left the scope in is
recorded in the memory, and it is not necessarily Park 1, as with the old
program. The only way now that the scope will start from Park 1 is if you put
it there before shutting off the power.

In future keypad upgrades we plan to put in a "Start from Park 1" feature so
that it will always start from this position, regardless of where you left
it. This feature is only for field use of course.

Roland Christen


Re: TheSky Linked to AP900GTO

Ron Wodaski <ronw@...>
 

I had a problem like this when I was using a USB to serial converter as the
serial port for the mount. There was either noise or some other factor
(interruptions???) that was causing the mount to move at a non-sidereal
rate. This causes trailing during exposures.

In that case, I verified that the mount connection was the problem in the
same manner -- disconnect the mount, and it tracks accurately. I removed the
USB to serial converter, and used a PCMCIA serial port instead, and the
problem went away.

I don't know if this is the same problem being described (the symptoms are
the same, but the causes may be different), but it's another data point.

Another problem I've been seeing lately is that there may be a conflict
between getting enough cycles for serial communication and camera
communication. This is true even with non-mount serial communications. I am
wondering if the problem under discussion is possibly related to that. If
so, perhaps we are past the time to move away from parallel port
communication, or additional buffering is needed to establish more reliable
communication.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: chris1011@... [mailto:chris1011@...]
Sent: Monday, October 15, 2001 12:00 PM
To: ap-gto@...
Subject: Re: [ap-gto] TheSky Linked to AP900GTO


In a message dated 10/15/2001 10:54:14 AM Pacific Daylight Time,
louie@... writes:


If you turn on a debugging option in The Sky, you can see how
frequently The Sky polls the mount. Is it possible that the load
servicing the serial I/O is preempting the software driving the servo
motors on the mount?

If "The Sky" is minimized, or another program like CCDOPS is placed fully on
top, then the polling stops. Either way, even if the mount is polled, it
would not interfere with the guiding function. The guiding signlas come
directly from the CCD camera and are sent directly to the guider port. There
could possibly be some interaction between the two programs which are
running
simultaneously on the laptop, and which do share some common files.

Roland Christen








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Re: TheSky Linked to AP900GTO

Louis Mamakos
 

In a message dated 10/14/2001 10:53:02 AM Pacific Daylight Time,
sreilly@... writes:


If in
fact, as it does appear, this is the case then it should be well noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not if
these are the results.

Good question. I have also contacted SBIG and asked them if they knew about
this problem since I also experienced random tracking errors with my ST10E
and "The Sky" attached to my mount thru the com port. They said that they had
heard of some interaction, but that it was so random in nature that they were
not able to track down the problem. It may be the type of computer you are
using. My IBM Thinkpad does not do this with Windows 98, but my older AST
laptop with Windows 95 does cause random errors. I had warned about this
problem some months ago when I suddenly had many ruined images whenever I had
The Sky up and linked to the mount. At that time I suggested that you de-link
the program, and even pull the com port cable so that no extraneous commands
can be sent to the mount during imaging and tracking.

Roland Christen
An interesting experiment would be to run The Sky on a different computer
than the one which is imaging. That might help determine if the
load The Sky puts on the computer is affecting the CCD guiding image
acquisition and tracking.

Alternatively, if the problem persists, then it might be that the
periodic traffic from The Sky is affecting the servo controller on the
mount. If you turn on a debugging option in The Sky, you can see how
frequently The Sky polls the mount. Is it possible that the load
servicing the serial I/O is preempting the software driving the servo
motors on the mount?

louie


Re: TheSky Linked to AP900GTO

Steve Reilly <sreilly@...>
 

Roland,

Also should any backlash settings be on when this is done?

Steve

Steve Reilly wrote:


Thanks Roland,

I had seen that message with the de-link info at the end of a long reply
and that is when I tried this. I'm sure you have mentioned this before
but I can't seem to find it. What software do you use to aquire your
images, I seem to think it was the Win version of CCDOPS. Also, PE
training, the manual says using a ST4 or STV will give an accurate PE
recording. Will the tracking chip on the ST8E suffice being used through
the C11 ota? Can you explain what parameters to use to get a good PE.
Position of mount, time of exposure, tracking speed, aggressiveness
setting ect..? I hate to beat this horse to death but I just don't seem
to get a good recording and I know the mount is more then capable. I
have done a very good drift alignment so I'm already partly there.
Thanks again for the info.

Steve

chris1011@... wrote:

In a message dated 10/14/2001 10:53:02 AM Pacific Daylight Time,
sreilly@... writes:

If in
fact, as it does appear, this is the case then it should be well noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not if
these are the results.

Good question. I have also contacted SBIG and asked them if they knew about
this problem since I also experienced random tracking errors with my ST10E
and "The Sky" attached to my mount thru the com port. They said that they had
heard of some interaction, but that it was so random in nature that they were
not able to track down the problem. It may be the type of computer you are
using. My IBM Thinkpad does not do this with Windows 98, but my older AST
laptop with Windows 95 does cause random errors. I had warned about this
problem some months ago when I suddenly had many ruined images whenever I had
The Sky up and linked to the mount. At that time I suggested that you de-link
the program, and even pull the com port cable so that no extraneous commands
can be sent to the mount during imaging and tracking.

Roland Christen



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Re: TheSky Linked to AP900GTO

Steve Reilly <sreilly@...>
 

Thanks Roland,

I had seen that message with the de-link info at the end of a long reply
and that is when I tried this. I'm sure you have mentioned this before
but I can't seem to find it. What software do you use to aquire your
images, I seem to think it was the Win version of CCDOPS. Also, PE
training, the manual says using a ST4 or STV will give an accurate PE
recording. Will the tracking chip on the ST8E suffice being used through
the C11 ota? Can you explain what parameters to use to get a good PE.
Position of mount, time of exposure, tracking speed, aggressiveness
setting ect..? I hate to beat this horse to death but I just don't seem
to get a good recording and I know the mount is more then capable. I
have done a very good drift alignment so I'm already partly there.
Thanks again for the info.

Steve

chris1011@... wrote:


In a message dated 10/14/2001 10:53:02 AM Pacific Daylight Time,
sreilly@... writes:

If in
fact, as it does appear, this is the case then it should be well noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not if
these are the results.

Good question. I have also contacted SBIG and asked them if they knew about
this problem since I also experienced random tracking errors with my ST10E
and "The Sky" attached to my mount thru the com port. They said that they had
heard of some interaction, but that it was so random in nature that they were
not able to track down the problem. It may be the type of computer you are
using. My IBM Thinkpad does not do this with Windows 98, but my older AST
laptop with Windows 95 does cause random errors. I had warned about this
problem some months ago when I suddenly had many ruined images whenever I had
The Sky up and linked to the mount. At that time I suggested that you de-link
the program, and even pull the com port cable so that no extraneous commands
can be sent to the mount during imaging and tracking.

Roland Christen



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Re: TheSky Linked to AP900GTO

Roland Christen
 

In a message dated 10/15/2001 10:54:14 AM Pacific Daylight Time,
louie@... writes:


If you turn on a debugging option in The Sky, you can see how
frequently The Sky polls the mount. Is it possible that the load
servicing the serial I/O is preempting the software driving the servo
motors on the mount?

If "The Sky" is minimized, or another program like CCDOPS is placed fully on
top, then the polling stops. Either way, even if the mount is polled, it
would not interfere with the guiding function. The guiding signlas come
directly from the CCD camera and are sent directly to the guider port. There
could possibly be some interaction between the two programs which are running
simultaneously on the laptop, and which do share some common files.

Roland Christen


Re: TheSky Linked to AP900GTO

Roland Christen
 

In a message dated 10/15/2001 8:41:25 AM Pacific Daylight Time,
sreilly@... writes:


Also should any backlash settings be on when this is done?

No. You are of course not recording any dec data, so there is no point in
trying to tune this axis fro zero backlash.

Roland Christen


Re: TheSky Linked to AP900GTO

Roland Christen
 

In a message dated 10/15/2001 8:39:10 AM Pacific Daylight Time,
sreilly@... writes:


Can you explain what parameters to use to get a good PE.
Position of mount, time of exposure, tracking speed, aggressiveness
setting ect..?
My setting would be 1 second or faster exposure (use a moderately bright star
to do this), agressiveness of .5, guiding speed of .5x, do only on a night of
low or very low atmospheric motion. For me this occurs just before sunset, so
I use a neutral density filter to knock down the sky brightness and guide on
a bright star like Vega or Deneb.

Roland Christen


Re: azimuth adjustment

Roland Christen
 

In a message dated 10/13/2001 5:56:56 PM Pacific Daylight Time,
chris@... writes:


But the question still stands- are there any disadvantages of a
single-rod design?
The two rod design makes it easier to remove the mounting from the base
plate. Also, there is always a bit of backlash in the single rod design.

Roland Christen


Re: TheSky Linked to AP900GTO

Roland Christen
 

In a message dated 10/14/2001 10:53:02 AM Pacific Daylight Time,
sreilly@... writes:


If in
fact, as it does appear, this is the case then it should be well noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not if
these are the results.

Good question. I have also contacted SBIG and asked them if they knew about
this problem since I also experienced random tracking errors with my ST10E
and "The Sky" attached to my mount thru the com port. They said that they had
heard of some interaction, but that it was so random in nature that they were
not able to track down the problem. It may be the type of computer you are
using. My IBM Thinkpad does not do this with Windows 98, but my older AST
laptop with Windows 95 does cause random errors. I had warned about this
problem some months ago when I suddenly had many ruined images whenever I had
The Sky up and linked to the mount. At that time I suggested that you de-link
the program, and even pull the com port cable so that no extraneous commands
can be sent to the mount during imaging and tracking.

Roland Christen


Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Ron Wodaski <ronw@...>
 

I point the scope within +/- 15 degrees of the celestial equator. I know
that at my location the steadiest skies are going to be happening around
1-3am, so that is the best time to do the recording. If the skies don't
steady, then I just do it another night.

I live and die by 0.5x correction speed; it's the only speed I use. It's
fast enough to get the job done, and slow enough not to overdo things too
often. It's right in the middle of the tracking speed, and thus as far from
backlash as possible <joke!>

I use the STV for most of my guiding these days, even with the ST-8E. It's
just more convenient. I am using an f/6 achromat (Brandon Birder) as my
guide scope. Despite the obvious bloat from chromatic focus shift, it works
great with the STV. If my guiding is at least 0.4 to 0.5 arcseconds average
as reported by the STV, I'm going to get a good PE recording. You could of
course do this through your main scope and with the imaging chip of your
camera, but I find that recording PEC at a long focal length with a
sensitive guider tends to record too much noise from seeing and hysteresis
(interactions between the guide corrections and the noise).

I like to use a fairly bright star, but not too bright as I use a ten-second
guide exposure for recording PE. Some folks have told me I'm crazy to do
this, but my results are great so I ignore that. <g>

The proof is in the pudding, so I like to do at least a 2-3 minute, but
preferably 5-minute test exposure unguided (with really careful polar
alignment, using TPoint in my case) to verify that there isn't any PE effect
in my images when playing back PEC. You of course have to use a long enough
focal length to get good data on this, or the high resolution of the STV.

There's no reason with a quality mount not to get several minutes of
unguided exposures with round stars with PEC playback active using focal
length in the 1000-2000mm range. Once you get to this point, guiding is a
minor tweak at long intervals.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Steve Reilly [mailto:sreilly@...]
Sent: Sunday, October 14, 2001 6:24 PM
To: ap-gto@...
Subject: Re: [ap-gto] RE: [SoftBisqUser] Re: TheSky Linked to AP900GTO


Ron,

Would you care to explain your full process for the PE recording. Where
you aim the scope, tracking speed, exposure times, etc... I will be
using my ST8E for recording.

Steve

Ron Wodaski wrote:

Those numbers are average total error over 8 samples. I used the STV to do
the measuring. The one thing I had to get absolutely right to get this
kind
of accuracy was a really good PE recording; things really started to fall
into place once I had that.

I capture nearly every guiding session to disk, and I really should do a
statistical analysis of it.

The best guiding happens on the best nights, of course. I have been
fortunate to have had above-average seeing conditions with high frequency
this fall. But the winter storms are in, and I may not have another clear
night for months. I have good seeing at this location more often than at
any
other location where I've observed or imaged. I think it is because I live
at the N end of a very long agricultural valley, and there just aren't
very
many places to retain heat or generate rising plumes. This contributes to
my
good numbers.

It also doesn't hurt to have the system set up so well that I can go 2-3
minutes unguided at 2800mm. <g> A good PE recording was what finally got
me
to that point, too.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Richard Seavey [mailto:seavey@...]
Sent: Sunday, October 14, 2001 1:56 PM
To: ap-gto@...
Subject: Re: [ap-gto] RE: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Ron, what is your definition of "total guiding accuracy" and how do you
measure it? I am surprised at the very low guide errors you are getting.
I
have been trying to reduce my guiding errors for some time, and haven't
come close to the performance you seem to get. I have tried the ideas from
the many threads on this subject, and now think maybe the error limits of
my system has been reached??

I am using TheSky5, CCDSoft5, 1200GTO, ST-8E and a 3000mm focal length for
guiding and imaging. I use the "autoguider.log" data from CCDSoft5 along
with Excel to graph the errors and to calculate the standard deviations of
the data. I can't seem to get below 0.4 arcsec RMS and 1.2 arcsec
peak-to-peak after trying hundreds of combinations of guide parameters and
under various seeing conditions. For some reason, Roland's
technique of disabling one guide direction for DEC corrections was not
very helpful.

Have I reached the point of being limited by noise from seeing and other
effects? Steve's observations on possible effects from using "TheSky"
are
very interesting and I'll test them if the clouds ever go away! Comments
anyone?

Richard

"..... This turns out to be true, although the seeing must
> be darn good to get that accuracy. Depending on seeing, when using a
fast
> achromat I get 0.2 to 0.4 arcseconds of total error during guiding. I
need
> to do a few other things to achieve this, described below. Compare this
to
> using an f/8.3 fluorite (Tak FC-60), which yielded 0.8 to 1.5 arcsecond
> accuracy at essentially the same focal length....."

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Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Steve Reilly <sreilly@...>
 

Ron,

Would you care to explain your full process for the PE recording. Where
you aim the scope, tracking speed, exposure times, etc... I will be
using my ST8E for recording.

Steve

Ron Wodaski wrote:


Those numbers are average total error over 8 samples. I used the STV to do
the measuring. The one thing I had to get absolutely right to get this kind
of accuracy was a really good PE recording; things really started to fall
into place once I had that.

I capture nearly every guiding session to disk, and I really should do a
statistical analysis of it.

The best guiding happens on the best nights, of course. I have been
fortunate to have had above-average seeing conditions with high frequency
this fall. But the winter storms are in, and I may not have another clear
night for months. I have good seeing at this location more often than at any
other location where I've observed or imaged. I think it is because I live
at the N end of a very long agricultural valley, and there just aren't very
many places to retain heat or generate rising plumes. This contributes to my
good numbers.

It also doesn't hurt to have the system set up so well that I can go 2-3
minutes unguided at 2800mm. <g> A good PE recording was what finally got me
to that point, too.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Richard Seavey [mailto:seavey@...]
Sent: Sunday, October 14, 2001 1:56 PM
To: ap-gto@...
Subject: Re: [ap-gto] RE: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Ron, what is your definition of "total guiding accuracy" and how do you
measure it? I am surprised at the very low guide errors you are getting. I
have been trying to reduce my guiding errors for some time, and haven't
come close to the performance you seem to get. I have tried the ideas from
the many threads on this subject, and now think maybe the error limits of
my system has been reached??

I am using TheSky5, CCDSoft5, 1200GTO, ST-8E and a 3000mm focal length for
guiding and imaging. I use the "autoguider.log" data from CCDSoft5 along
with Excel to graph the errors and to calculate the standard deviations of
the data. I can't seem to get below 0.4 arcsec RMS and 1.2 arcsec
peak-to-peak after trying hundreds of combinations of guide parameters and
under various seeing conditions. For some reason, Roland's
technique of disabling one guide direction for DEC corrections was not
very helpful.

Have I reached the point of being limited by noise from seeing and other
effects? Steve's observations on possible effects from using "TheSky" are
very interesting and I'll test them if the clouds ever go away! Comments
anyone?

Richard

"..... This turns out to be true, although the seeing must
> be darn good to get that accuracy. Depending on seeing, when using a fast
> achromat I get 0.2 to 0.4 arcseconds of total error during guiding. I
need
> to do a few other things to achieve this, described below. Compare this
to
> using an f/8.3 fluorite (Tak FC-60), which yielded 0.8 to 1.5 arcsecond
> accuracy at essentially the same focal length....."

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Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Ron Wodaski <ronw@...>
 

Those numbers are average total error over 8 samples. I used the STV to do
the measuring. The one thing I had to get absolutely right to get this kind
of accuracy was a really good PE recording; things really started to fall
into place once I had that.

I capture nearly every guiding session to disk, and I really should do a
statistical analysis of it.

The best guiding happens on the best nights, of course. I have been
fortunate to have had above-average seeing conditions with high frequency
this fall. But the winter storms are in, and I may not have another clear
night for months. I have good seeing at this location more often than at any
other location where I've observed or imaged. I think it is because I live
at the N end of a very long agricultural valley, and there just aren't very
many places to retain heat or generate rising plumes. This contributes to my
good numbers.

It also doesn't hurt to have the system set up so well that I can go 2-3
minutes unguided at 2800mm. <g> A good PE recording was what finally got me
to that point, too.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Richard Seavey [mailto:seavey@...]
Sent: Sunday, October 14, 2001 1:56 PM
To: ap-gto@...
Subject: Re: [ap-gto] RE: [SoftBisqUser] Re: TheSky Linked to AP900GTO



Ron, what is your definition of "total guiding accuracy" and how do you
measure it? I am surprised at the very low guide errors you are getting. I
have been trying to reduce my guiding errors for some time, and haven't
come close to the performance you seem to get. I have tried the ideas from
the many threads on this subject, and now think maybe the error limits of
my system has been reached??

I am using TheSky5, CCDSoft5, 1200GTO, ST-8E and a 3000mm focal length for
guiding and imaging. I use the "autoguider.log" data from CCDSoft5 along
with Excel to graph the errors and to calculate the standard deviations of
the data. I can't seem to get below 0.4 arcsec RMS and 1.2 arcsec
peak-to-peak after trying hundreds of combinations of guide parameters and
under various seeing conditions. For some reason, Roland's
technique of disabling one guide direction for DEC corrections was not
very helpful.

Have I reached the point of being limited by noise from seeing and other
effects? Steve's observations on possible effects from using "TheSky" are
very interesting and I'll test them if the clouds ever go away! Comments
anyone?

Richard




"..... This turns out to be true, although the seeing must
> be darn good to get that accuracy. Depending on seeing, when using a fast
> achromat I get 0.2 to 0.4 arcseconds of total error during guiding. I
need
> to do a few other things to achieve this, described below. Compare this
to
> using an f/8.3 fluorite (Tak FC-60), which yielded 0.8 to 1.5 arcsecond
> accuracy at essentially the same focal length....."





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Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Richard Seavey <seavey@...>
 

Ron, what is your definition of "total guiding accuracy" and how do you measure it? I am surprised at the very low guide errors you are getting. I have been trying to reduce my guiding errors for some time, and haven't come close to the performance you seem to get. I have tried the ideas from the many threads on this subject, and now think maybe the error limits of my system has been reached??

I am using TheSky5, CCDSoft5, 1200GTO, ST-8E and a 3000mm focal length for guiding and imaging. I use the "autoguider.log" data from CCDSoft5 along with Excel to graph the errors and to calculate the standard deviations of the data. I can't seem to get below 0.4 arcsec RMS and 1.2 arcsec peak-to-peak after trying hundreds of combinations of guide parameters and under various seeing conditions. For some reason, Roland's technique of disabling one guide direction for DEC corrections was not very helpful.

Have I reached the point of being limited by noise from seeing and other effects? Steve's observations on possible effects from using "TheSky" are very interesting and I'll test them if the clouds ever go away! Comments anyone?

Richard




"..... This turns out to be true, although the seeing must

be darn good to get that accuracy. Depending on seeing, when using a fast
achromat I get 0.2 to 0.4 arcseconds of total error during guiding. I need
to do a few other things to achieve this, described below. Compare this to
using an f/8.3 fluorite (Tak FC-60), which yielded 0.8 to 1.5 arcsecond
accuracy at essentially the same focal length....."


Re: GOTO vs QMD. Blurring with Stepper motors?

Ron Wodaski <ronw@...>
 

The moon's of Jupiter are a very sensitive indicator of vibration. They will
show elongation at the _slightest_ vibration.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: vahe@... [mailto:vahe@...]
Sent: Sunday, October 14, 2001 1:19 PM
To: ap-gto@...
Subject: [ap-gto] Re: GOTO vs QMD. Blurring with Stepper motors?


While researching the issue I had an individual tell me
that a major difference is that the stepper motors of the QMD mount
will "blur" fine planetary detail at high mag. under excellent
seeing
conditions. I had heard that you could "see" the stepper motors at
very high mag. but that it was not a problem.
I am not an expert on this, but the QMD's that I have seen had
reasonably smooth motions, smooth enough not to blur the image.
My G11 is the best example of what image vibration can do to the
planetary image, you can see the heartbeat of this mount on the
planets at powers above 200x, threshold detail is pretty much wiped
out, and yes I am familiar with all the recommended fixes, none has
helped. Compared to G11 the QMD's are perfection particularly the
larger ones, the 900 & 1200's.

Thanks,
Vahe



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Re: GOTO vs QMD. Blurring with Stepper motors?

vahe@...
 

While researching the issue I had an individual tell me
that a major difference is that the stepper motors of the QMD mount
will "blur" fine planetary detail at high mag. under excellent
seeing
conditions. I had heard that you could "see" the stepper motors at
very high mag. but that it was not a problem.
I am not an expert on this, but the QMD's that I have seen had
reasonably smooth motions, smooth enough not to blur the image.
My G11 is the best example of what image vibration can do to the
planetary image, you can see the heartbeat of this mount on the
planets at powers above 200x, threshold detail is pretty much wiped
out, and yes I am familiar with all the recommended fixes, none has
helped. Compared to G11 the QMD's are perfection particularly the
larger ones, the 900 & 1200's.

Thanks,
Vahe


Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Steve Reilly <sreilly@...>
 

Ron,

I will defiantly check out what you have said, at least the parts I
think I can.

Ron Wodaski wrote:

That's the part about this that I didn't really understand, since TheSky
shouldn't be sending anything to the mount, as far as I know. Something else
to think about, that I've just been learning about the last few days: lack
of buffering in any download of camera data can lead to some strange and
messy effects. I believe that the issue is that there is a noisy register
involved in the read operation, and as long as the data is downloaded
quickly from the camera, without interruption, there are no significant
consequences from this fact. But if something causes a delay, and there is
no on-board buffer to enable the data to continue to be read, the
interruption will cause an extremely high noise level -- enough to
completely mess up guiding, for example. You might not even see the noise,
depending on the histogram settings, but it can affect calculations
internally.
I see no lines on the screen (15" TFT) on any guider frames.


Just another possibility. I have one computer that I can't run anything but
a camera on because of interruptions during the download of data causing so
much noise. Buffered cameras, like the FLI standard line, are unaffected.
If TheSky sends update location or time signals to the mount, or any
other commands for that matter, I guess it could definitely affect the
guiding operation.

Steve

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Steve Reilly [mailto:sreilly@...]
Sent: Sunday, October 14, 2001 11:51 AM
To: SoftBisqUser@...
Subject: Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO

I agree Roger. It just seems that this would be helpful information up
front. Ron has suggested many good ideas and maybe I'm stubborn, but if
suspending the link makes CCD guiding that much better, seems TheSky is
the problem or at least a fair amount of it. I love TheSky and have had
it for years. Abandon it? Never. But using it differently looks like a
must.

Steve

roger.pittock@... wrote:

Steve

I guess this is necessary for non sidereal objects (planets, comets
etc) but for normal stuff I fully agree with you. Looking back I may
also have suffered this untoward effect. In fact I'm sure I have.
Thank you for bringing it to our attention.

I must try the disconnect and see if my guiding becomes better.

However, to abandon the best planetarium software over this is not
necessary. As you say, the solution is very straightfirward - click
the link suspend icon and all comes right.

Roger

--- In SoftBisqUser@y..., Steve Reilly <sreilly@a...> wrote:
It appears, after a long and tedious search along with trial and
error,
that TheSky while being linked to my AP900GTO mount is grossly
affecting
my tracking ability. What is TheSky sending to my mount when the
slew is
over and CCDSoftV5 is trying to guide. I have a very accurate drift
polar alignment, well balanced C11 scope with a ST8-E and CFW-8.
Tracking at f6.3 while linked to TheSky gives me errors in excess of
1.25 pixels, suspend the link and guide errors are an average of <.3
pixels. I find this to be very disturbing. I want TheSky to indicate
where I am pointing and what my sky looks like. I don't want it to
send
any commands to the scope until a new slew is requested. Is this
unreasonable? Is this just affecting the AP mounts or is this for
all?
Maybe a driver problem. I really wish it had not cost me so much
time
under decent skies with lousy results before this was discovered.
If in
fact, as it does appear, this is the case then it should be well
noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not
if
these are the results.

Steve



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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups.yahoo.com/group/ap-gto

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Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO

Ron Wodaski <ronw@...>
 

That's the part about this that I didn't really understand, since TheSky
shouldn't be sending anything to the mount, as far as I know. Something else
to think about, that I've just been learning about the last few days: lack
of buffering in any download of camera data can lead to some strange and
messy effects. I believe that the issue is that there is a noisy register
involved in the read operation, and as long as the data is downloaded
quickly from the camera, without interruption, there are no significant
consequences from this fact. But if something causes a delay, and there is
no on-board buffer to enable the data to continue to be read, the
interruption will cause an extremely high noise level -- enough to
completely mess up guiding, for example. You might not even see the noise,
depending on the histogram settings, but it can affect calculations
internally.

I've experienced this problem with an ST-9E, and with an FLI MaxCam. My
ST-8E shows the problem at a lower level. Because I've been guiding a lot
lately with an STV, it hasn't occurred to me to check what effects this kind
of noise could have on guider data, but it's worth consideration. I suggest
saving some guide frames and looking at the noise levels. This type of noise
typically shows up as horizontal streaks, sometimes very short and fading to
the right, and sometimes all the way across the frame. They are generally
brighter than normal, but not terribly much most of the time. When really
bad, this kind of noise can make it look like your horizontal lines don't
line up properly. That is the kind of noise that will really screw up a
centroiding calculation!

Just another possibility. I have one computer that I can't run anything but
a camera on because of interruptions during the download of data causing so
much noise. Buffered cameras, like the FLI standard line, are unaffected.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Steve Reilly [mailto:sreilly@...]
Sent: Sunday, October 14, 2001 11:51 AM
To: SoftBisqUser@...
Subject: Re: [SoftBisqUser] Re: TheSky Linked to AP900GTO


I agree Roger. It just seems that this would be helpful information up
front. Ron has suggested many good ideas and maybe I'm stubborn, but if
suspending the link makes CCD guiding that much better, seems TheSky is
the problem or at least a fair amount of it. I love TheSky and have had
it for years. Abandon it? Never. But using it differently looks like a
must.

Steve

roger.pittock@... wrote:

Steve

I guess this is necessary for non sidereal objects (planets, comets
etc) but for normal stuff I fully agree with you. Looking back I may
also have suffered this untoward effect. In fact I'm sure I have.
Thank you for bringing it to our attention.

I must try the disconnect and see if my guiding becomes better.

However, to abandon the best planetarium software over this is not
necessary. As you say, the solution is very straightfirward - click
the link suspend icon and all comes right.

Roger

--- In SoftBisqUser@y..., Steve Reilly <sreilly@a...> wrote:
It appears, after a long and tedious search along with trial and
error,
that TheSky while being linked to my AP900GTO mount is grossly
affecting
my tracking ability. What is TheSky sending to my mount when the
slew is
over and CCDSoftV5 is trying to guide. I have a very accurate drift
polar alignment, well balanced C11 scope with a ST8-E and CFW-8.
Tracking at f6.3 while linked to TheSky gives me errors in excess of
1.25 pixels, suspend the link and guide errors are an average of <.3
pixels. I find this to be very disturbing. I want TheSky to indicate
where I am pointing and what my sky looks like. I don't want it to
send
any commands to the scope until a new slew is requested. Is this
unreasonable? Is this just affecting the AP mounts or is this for
all?
Maybe a driver problem. I really wish it had not cost me so much
time
under decent skies with lousy results before this was discovered.
If in
fact, as it does appear, this is the case then it should be well
noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not
if
these are the results.

Steve



Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/




Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/


Re: [SoftBisqUser] TheSky Linked to AP900GTO

Steve Reilly <sreilly@...>
 

Hey Ron,


Ron Wodaski wrote:

Not sure what your exact problem is. When you use the term "guide" are you
referring to guiding with a CCD camera, or did you actually mean "tracking"?
These are very different issues.
This is guiding with the ST8E.

Also, it would help to know how you are measuring the errors. If you are
guiding, are you saving the guide corrections to disk for analysis? This can
generate a lot of useful information.
Not sure how to save and analyze this info.


If the problem is indeed during guiding with a CCD camera, then here are
some thoughts about working with a high-quality mount.


* I don't know what your philosophy and approach to guiding is, but I
suggest you consider the following guidelines:

1. Less guiding is better guiding. If your mount has precision gears; has
an accurate PE recording and playback; and is well-aligned to the pole,
guiding really isn't going to help if it happens more often than every 10-60
seconds. The purpose of guiding in such a situation is to monitor for
extremely small errors in gears, PE, and alignment. These small errors can
only show up after long periods of time. Attempting to guide with shorter
guide intervals means you are measuring noise and reacting to it. In the
past, this was harder to do because the guide software did not have the high
precision it does today.
I have tried the PE recording and it didn't seem to help although I
won't swear that this procedure was done right. Basically I had the
scope looking straight up at the zenith and used a star bright enough to
expose for 1 sec during record with the sidereal rate set at .5x

2. It is useful to know the noise level in your system, so that you know
what to discard as noise and what to keep as information. If your measured
noise level (save the guide errors to disk and analyze in a spreadsheet) is
above the level you are trying to guide at, you are going to guide on noise,
and that is going to create problems.
Again, not sure how to do this but willing to learn.


In the past, these were simply not issues because the noise level was way
below the measurements. Just as you can image at a resolution that includes
too much noise (from the seeing), you can also guide at a resolution that
includes too much noise. It's up to you in either case to choose a sampling
rate that filters out the noise.

The revelation for me came using another mount, a Paramount 1100s. The
problem was the same: why am I getting such large guiding errors with such a
good mount? I was guiding with an STV, but the same issues showed up in
CCDSoft. Here is what I did as a comprehensive approach to improving my
guiding with a quality mount and alignment:

* For PE recording, I took much longer guide exposures than most folks do --
10 seconds. Ray Gralak argues with me about the wisdom of that approach, but
I base my preference for this approach on the results I get. By slowing down
the sampling rate for recording PE, I wind up with a very smooth PE
recording that provides very reliable accuracy even at long focal lengths
(2800mm).
Willing to try whatever to get better guiding!


* When guiding, I choose a fast scope over a long focal length. My current
choice for guiding is an 80mm Brandon achromat at f/6. The fact that the STV
can guide at 1 arc second using a 100mm fl. eFinder (which I have validated
by my own tests), means that a 500mm fl. achromat should deliver up to 0.2
arcseconds of accuracy. This turns out to be true, although the seeing must
be darn good to get that accuracy. Depending on seeing, when using a fast
achromat I get 0.2 to 0.4 arcseconds of total error during guiding. I need
to do a few other things to achieve this, described below. Compare this to
using an f/8.3 fluorite (Tak FC-60), which yielded 0.8 to 1.5 arcsecond
accuracy at essentially the same focal length. Today's high-precision guide
algorithms thrive more on fast focal ratios than on focal length.
I have just the C11 and would prefer to image and track using the guider
chip in the ST8 while imaging with the KAF1600E.


* Focus is much more critical with today's guide algorithms. Even a small
shift of focus can lead to a serious reduction in guide accuracy. It is as
though guiding, when viewed as a chaotic system, is extremely sensitive to
the quality of focus. Given the focusers on many guidescopes in use, this
bears watching for most imagers.
I have and use religiously the Optec TCF-s which gives me great focus
control.


* Guide at no more than a 0.5 aggressiveness setting when using a
high-quality mount and excellent alignment. I've guided at a setting as low
as 0.2 successfully, but 0.5 has more ability to respond to the occasional
problem.
I have found that at times my aggressiveness is set between 2 and 8.


* Use much longer guide exposure times than you are used to. This averages
out a whole lot of noise, and avoids troublesome hysteresis.

* If you are NOT using PEC, you should. Why? If you take the time and
trouble to get a superb PE recording under superb seeing conditions, you
will generate less noise by applying PEC than by applying guide corrections
live during poorer seeing conditions. This results in a net noise reduction
in the tracking most of the time.
Again, any PE training for dummies directions? I'm not sure my procedure
is giving me the best results.

Thanks for the time and instructions.

Steve

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Steve Reilly [mailto:sreilly@...]
Sent: Sunday, October 14, 2001 10:52 AM
To: ap-gto@...; SoftBisqUser@...
Subject: [SoftBisqUser] TheSky Linked to AP900GTO

It appears, after a long and tedious search along with trial and error,
that TheSky while being linked to my AP900GTO mount is grossly affecting
my tracking ability. What is TheSky sending to my mount when the slew is
over and CCDSoftV5 is trying to guide. I have a very accurate drift
polar alignment, well balanced C11 scope with a ST8-E and CFW-8.
Tracking at f6.3 while linked to TheSky gives me errors in excess of
1.25 pixels, suspend the link and guide errors are an average of <.3
pixels. I find this to be very disturbing. I want TheSky to indicate
where I am pointing and what my sky looks like. I don't want it to send
any commands to the scope until a new slew is requested. Is this
unreasonable? Is this just affecting the AP mounts or is this for all?
Maybe a driver problem. I really wish it had not cost me so much time
under decent skies with lousy results before this was discovered. If in
fact, as it does appear, this is the case then it should be well noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not if
these are the results.

Steve

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

To UNSUBSCRIBE, or for general information on the ap-gto list
see http://groups.yahoo.com/group/ap-gto

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/


Re: [SoftBisqUser] TheSky Linked to AP900GTO

Ron Wodaski <ronw@...>
 

Not sure what your exact problem is. When you use the term "guide" are you
referring to guiding with a CCD camera, or did you actually mean "tracking"?
These are very different issues.

Also, it would help to know how you are measuring the errors. If you are
guiding, are you saving the guide corrections to disk for analysis? This can
generate a lot of useful information.

If the problem is indeed during guiding with a CCD camera, then here are
some thoughts about working with a high-quality mount.

* First, CCDSoft v5 is much more sensitive and capable than most preceding
software when it comes to guiding. It is cable of finer control, but if you
don't take that into account, you could easily get over-correction. The
better your mount and the better your alignment, the more careful you need
to be in using guide corrections. You can encounter identical problems with
other high-precision guiders, such as the STV, which attempts to guide at
1/30th of a pixel accuracy.

* I don't know what your philosophy and approach to guiding is, but I
suggest you consider the following guidelines:

1. Less guiding is better guiding. If your mount has precision gears; has
an accurate PE recording and playback; and is well-aligned to the pole,
guiding really isn't going to help if it happens more often than every 10-60
seconds. The purpose of guiding in such a situation is to monitor for
extremely small errors in gears, PE, and alignment. These small errors can
only show up after long periods of time. Attempting to guide with shorter
guide intervals means you are measuring noise and reacting to it. In the
past, this was harder to do because the guide software did not have the high
precision it does today.

2. It is useful to know the noise level in your system, so that you know
what to discard as noise and what to keep as information. If your measured
noise level (save the guide errors to disk and analyze in a spreadsheet) is
above the level you are trying to guide at, you are going to guide on noise,
and that is going to create problems.

In the past, these were simply not issues because the noise level was way
below the measurements. Just as you can image at a resolution that includes
too much noise (from the seeing), you can also guide at a resolution that
includes too much noise. It's up to you in either case to choose a sampling
rate that filters out the noise.

The revelation for me came using another mount, a Paramount 1100s. The
problem was the same: why am I getting such large guiding errors with such a
good mount? I was guiding with an STV, but the same issues showed up in
CCDSoft. Here is what I did as a comprehensive approach to improving my
guiding with a quality mount and alignment:

* For PE recording, I took much longer guide exposures than most folks do --
10 seconds. Ray Gralak argues with me about the wisdom of that approach, but
I base my preference for this approach on the results I get. By slowing down
the sampling rate for recording PE, I wind up with a very smooth PE
recording that provides very reliable accuracy even at long focal lengths
(2800mm).

* When guiding, I choose a fast scope over a long focal length. My current
choice for guiding is an 80mm Brandon achromat at f/6. The fact that the STV
can guide at 1 arc second using a 100mm fl. eFinder (which I have validated
by my own tests), means that a 500mm fl. achromat should deliver up to 0.2
arcseconds of accuracy. This turns out to be true, although the seeing must
be darn good to get that accuracy. Depending on seeing, when using a fast
achromat I get 0.2 to 0.4 arcseconds of total error during guiding. I need
to do a few other things to achieve this, described below. Compare this to
using an f/8.3 fluorite (Tak FC-60), which yielded 0.8 to 1.5 arcsecond
accuracy at essentially the same focal length. Today's high-precision guide
algorithms thrive more on fast focal ratios than on focal length.

* Focus is much more critical with today's guide algorithms. Even a small
shift of focus can lead to a serious reduction in guide accuracy. It is as
though guiding, when viewed as a chaotic system, is extremely sensitive to
the quality of focus. Given the focusers on many guidescopes in use, this
bears watching for most imagers.

* Guide at no more than a 0.5 aggressiveness setting when using a
high-quality mount and excellent alignment. I've guided at a setting as low
as 0.2 successfully, but 0.5 has more ability to respond to the occasional
problem.

* Use much longer guide exposure times than you are used to. This averages
out a whole lot of noise, and avoids troublesome hysteresis.

* If you are NOT using PEC, you should. Why? If you take the time and
trouble to get a superb PE recording under superb seeing conditions, you
will generate less noise by applying PEC than by applying guide corrections
live during poorer seeing conditions. This results in a net noise reduction
in the tracking most of the time.

Ron Wodaski
The New CCD Astronomy
http://www.newastro.com

-----Original Message-----
From: Steve Reilly [mailto:sreilly@...]
Sent: Sunday, October 14, 2001 10:52 AM
To: ap-gto@...; SoftBisqUser@...
Subject: [SoftBisqUser] TheSky Linked to AP900GTO


It appears, after a long and tedious search along with trial and error,
that TheSky while being linked to my AP900GTO mount is grossly affecting
my tracking ability. What is TheSky sending to my mount when the slew is
over and CCDSoftV5 is trying to guide. I have a very accurate drift
polar alignment, well balanced C11 scope with a ST8-E and CFW-8.
Tracking at f6.3 while linked to TheSky gives me errors in excess of
1.25 pixels, suspend the link and guide errors are an average of <.3
pixels. I find this to be very disturbing. I want TheSky to indicate
where I am pointing and what my sky looks like. I don't want it to send
any commands to the scope until a new slew is requested. Is this
unreasonable? Is this just affecting the AP mounts or is this for all?
Maybe a driver problem. I really wish it had not cost me so much time
under decent skies with lousy results before this was discovered. If in
fact, as it does appear, this is the case then it should be well noted
so others won't have the same problem. Any explanation would be
welcomed. I would very much like to use TheSky (Level 4 V5) but not if
these are the results.

Steve






Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/