In a message dated 8/7/2008 12:20:28 PM Central Daylight Time,
hewholooks@... writes:

I just need confirmation that my reasoning is correct, and I will try
the setting of min motion = 0.034 pixels with the software. Seems
like a very small amount of movement to use as a trigger for a guide
correction, and I may be trying to compare apples to oranges here.
Currently I am using 0.2 pixels min movement, which would be an
equivalent min movement setting of about 0.06 seconds in other
software.

With your scope configuration, 0.2 pixels is probably fine.

Rolando


**************
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With the eFinder and Sbig remote guide head, I used 0.05 for the min, and
1.50 for the max. The eFinder is only a 100mm f/l 'scope' so these numbers
are very small. Guide rate is 1x and I have not tried anything else on this
mount. I have not found the best settings yet to use with my 60mm
guidescope.

Here is my test image from the other night under very poor transparency.
The image itself is not very good, but the stars are nice and round. This
was with a C9.25 @ F/10 2350mm f/l, ST2K, 9 x 10 min Lum 1x1, and 6 x 4 min
ea RGB 2x2.
http://www.doghouseastronomy.com/pix/M57LRGBF10.jpg

So I am anxiously waiting for galaxy season again :)

Dean

In a message dated 8/7/2008 10:16:12 AM Central Daylight Time,
llp41astro@... writes:

Roland,
What about shorter focal lengths? Should the .01 and .1 min/max
numbers be a direct ratio of the focal length 3000mm and any shorter
focal length. For example for 1050mm should these numbers be .03
and .3 (3000/1050)?

You can experiment. If you have very steady skies, you can leave the min move
at .01 seconds. The shorter your focal length, the longer you would want the
Max move setting, especially if you are dithering. To take an extreme example,
if your guider pixel scale is 10 arc sec per pixel and you dither 5 pixels,
you will take forever moving 50 arc seconds between each exposure at 1.5 arc
sec max move command (that would be .1 sec max move setting at 1 x).

Rolando


**************
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In a message dated 8/6/2008 11:08:24 PM Central Daylight Time,
kattnerk@... writes:

Yaeh, I do what I'm told as well. I always use 1X, but have been
told on other forums I should be using .5X or .75X.

Don't listen to them. 1x guiding and min move of .01 seconds will work. In
bad seeing just set the agressiveness to a lower value or reduce the max move
limits or both.

Rolando


**************
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In a message dated 8/6/2008 11:08:24 PM Central Daylight Time,
kattnerk@... writes:

http://tech.ph.groups.yahoo.com/group/ap-gto/photos/view/1b58?b=1

Very nice shot!

Rolando


**************
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In a message dated 8/6/2008 8:12:30 PM Central Daylight Time,
alan_voetsch@... writes:

My situation is different than most as I run an ST-4 as a standalone guider
(no computer in the obs). Most times I guide at 1X, but there have have been
times when things are just too 'jumpy' (corrections are large and go from
one extreme to another) to do that so i drop it to 0.5X. Then there have been
times when I assumed that because it worked last night that I'd just use 0.5
again, but I end up having to move it to 1X. Go figure,,,

You can do the same thing by dropping the agressiveness to 50%. That way the
mount will operate at peak efficiency with minimal delay in Dec (when it needs
to reverse) and you avoid chasing the seeing. Guiding at slower speeds
reduces the mount's ability to respond.

Rolando


**************
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budget? Read reviews on AOL Autos.

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In a message dated 8/6/2008 7:39:49 PM Central Daylight Time,
kattnerk@... writes:

Are you also saying that we should autoguide at 1X? Everyone else
says autoguide at 0.5 or 0.75 sidereal. Not trying to be
argumentative, but don't understand the why?

Yes, autoguide at 1x. No reason to guide at slower speeds. For long focus
systems (above 3000mm), set min move to .01 and Max move to .1 seconds. This will
give you 0.15 arc sec to 1.5 arc sec per iteration. You will not need to go
slower than 0.15 arc sec per iteration with any setup. The atmosphere just
isn't that steady. The slower .5x and .25x speeds are for hand guiding. When you
are hand guiding, you really cannot reliably push the direction buttons for 10
miliseconds. The best a person can do is about 0.1 seconds, so we provide the
slowest speeds for that reason.

The reason to always calibrate at the fastest guide speeds is to minimize the
reversal delay time. That way you will get the most accurate guide parameter
numbers. If it takes .5 to 1 second to reverse Dec at 1x, it could take up to
4 seconds to reverse at .25x. Then if you compound this error and calibrate
for only 5 seconds, the Dec motion after reversal will only register 1 second of
actual movement. The resultant parameter number for Dec will be 5 times too
small and the loop gain will be 5 times too big. This will cause hunting,
oscillation or instability in Dec.

Rolando


**************
Looking for a car that's sporty, fun and fits in your
budget? Read reviews on AOL Autos.

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Took my Mach1 to the Queensland Astrofest (10 days) where it behaved impeccably.
However attempts to polar align with the PAS4 failed hopelessly. Several experienced
persons tried, one in particular who had used the "Losmandy" PAS with excellent
results, commented that the reticule did not resemble that to which he was accustomed.
The mount was eventually aligned with K3CCDTools, very accurately, and for all the
week took 4 minute unguided images with perfectly round stars, it would probably have been
OK for 5 or 6.
I phoned Scott Losmandy today and gather that graticules are now on his spare parts list.
I am going to send him a copy of one of the pages showing the AP graticule for him to
compare to his current graticule, it certainly does not look like the one I had with a
Losmandy mount.
As an aside no -one could reconcile the view through the PAS when the scope was
so accurately aligned with K3CCDTools - nothing made any sense at all.

Yaeh, I do what I'm told as well. I always use 1X, but have been
told on other forums I should be using .5X or .75X. I seem to
achieve decent results. I'm at .62asp image scale and use .017 as a
min move and .133 as a max. What do you use?

Here's an M51 pic using those settings.

http://tech.ph.groups.yahoo.com/group/ap-gto/photos/view/1b58?b=1



--- In ap-gto@..., "Dean S" <dean@...> wrote:

I just do what I am told, and it works :)

I too had been battling DEC issue similar to the OP. I have a new

1200.

I have finally talked with enough people, including Roland and

Howard, Tom

Davis, Sam Bruce, Joe Mize, etc, that I finally understand what

does what,

and I am now getting smooth guiding. Mine was doing the slow drift

away

with a sudden jump back and I at first thought it was stickion but

after I

tweaked my Minimum and Max move settings I have it settled down

very nicely.

I wonder if your settings have accidentally been changed since it

changed

so suddenly? Not sure who actually started this post as it has

merged into a

couple different issues I think.

And I am now guiding with an eFinder, doing 60 sec calibrations,

and am

finally for the first time since I have owned the mount, am able to

get nice

round stars with 10 min exposures with an image scale up to

about .65

arcsec/pix.

Dean Schwartzenberg



----- Original Message -----
From: "astrokattner" <kattnerk@...>
To: <ap-gto@...>
Sent: Wednesday, August 06, 2008 8:39 PM
Subject: [ap-gto] Re: DEC strangeness

Are you also saying that we should autoguide at 1X? Everyone else
says autoguide at 0.5 or 0.75 sidereal. Not trying to be
argumentative, but don't understand the why?

thanks,

Ken



--- In ap-gto@..., chris1011@ wrote:

In a message dated 8/4/2008 4:14:47 PM Central Daylight Time,

bob@

writes:

Why 1x? Even at nearly 3000mm?

You MUST calibrate at 1x. If you calibrate at lower guide speed,

I

guarantee

you will have problems.

Rolando


**************
Looking for a car that's sporty, fun and fits in your
budget? Read reviews on AOL Autos.

(http://autos.aol.com/cars-BMW-128-2008/expert-review?

ncid=aolaut00050000000017 )

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8/6/2008

4:55 PM

I guide at 1X on my Mach1. However, I do keep it under control by setting the Max Move in CCDSoft to .3 secs.

Using 1X, I normally have guide corrections in the .01 sec to .03 sec range, as seen in my guide logs. I am using an ST-8XME, but am using the Remote Guide Head thru an E-finder for guiding.

I am imaging thru an 816mm FL Apo at prime focus.

Bill

I just do what I am told, and it works :)

I too had been battling DEC issue similar to the OP. I have a new 1200.

I have finally talked with enough people, including Roland and Howard, Tom Davis, Sam Bruce, Joe Mize, etc, that I finally understand what does what, and I am now getting smooth guiding. Mine was doing the slow drift away with a sudden jump back and I at first thought it was stickion but after I tweaked my Minimum and Max move settings I have it settled down very nicely.

I wonder if your settings have accidentally been changed since it changed so suddenly? Not sure who actually started this post as it has merged into a couple different issues I think.

And I am now guiding with an eFinder, doing 60 sec calibrations, and am finally for the first time since I have owned the mount, am able to get nice round stars with 10 min exposures with an image scale up to about .65 arcsec/pix.

Dean Schwartzenberg

Hey Ken,

My situation is different than most as I run an ST-4 as a standalone guider (no computer in the obs). Most times I guide at 1X, but there have have been times when things are just too 'jumpy' (corrections are large and go from one extreme to another) to do that so i drop it to 0.5X. Then there have been times when I assumed that because it worked last night that I'd just use 0.5 again, but I end up having to move it to 1X. Go figure,,,

Alan

Astrophotography: http://www.pbase.com/avoetsch12952
Clear sky clock: http://cleardarksky.com/c/CttrObORkey.html?1

Are you also saying that we should autoguide at 1X? Everyone else
says autoguide at 0.5 or 0.75 sidereal. Not trying to be
argumentative, but don't understand the why?

thanks,

Ken



--- In ap-gto@..., chris1011@... wrote:

In a message dated 8/4/2008 4:14:47 PM Central Daylight Time,

bob@...

writes:

Why 1x? Even at nearly 3000mm?

You MUST calibrate at 1x. If you calibrate at lower guide speed, I

guarantee

you will have problems.

Rolando


**************
Looking for a car that's sporty, fun and fits in your
budget? Read reviews on AOL Autos.

(http://autos.aol.com/cars-BMW-128-2008/expert-review?

ncid=aolaut00050000000017 )

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

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As requested by Thomas Baader, these eyepieces will not be available
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There has been a great deal of discussion regarding the tiny triangular
cutouts in the field stop of the eyepieces. As you can see from the part
descriptions above, we will offer the eyepieces in their original state
or modified (black optical paint covering the triangle cutouts). We
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Please read the information on our website for all the details:
http://www.astro-physics.com/products/accessories/baader/abbe2.htm

Thank you very much for reviewing this information.


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Astro-Physics, Inc
11250 Forest Hills Road
Machesney Park, IL 61115
Phone: 815-282-1513
Fax: 815-282-9847
www.astro-physics.com
Please include this e-mail with your response.

Thanks, Sam. That does help.


--- In ap-gto@..., "Samuel Bruce" <sgbruce@...> wrote:

Kerry,
The Mach1 performs easily and effectively with loads in excess of

45

pounds. This I did with a SCT with a heavy imaging train and a

large

and heavy guide scope piggybacked on top of the main scope. Now

that

being said the load was probably 52 pounds. The key here is that

it

was done on a permanent pier in an observatory with a roll off roof

so

that wind and other gremlins were not factors. I would expect that

the

conditions around the mount will affect its stability more than the
actual weight it carries. In the end I removed all of the extra

wieght

of the guide scope and now just use the SCT alone not becuase of

the

weight bearing performance of the Mach1 but becuase of other

factors

inherent in the use of a seperate guide scope and its mounting
(differential flexure).

Hope this helps. The Mach1 is a remarkable instrument. It has

exceed

every expectation that I had and has become a real motivator in

doing

any form of astronomy that I can do. It is easy to use and best of

all

it is light and easily transportable.

Hope this helps,
Sam Bruce

--- In ap-gto@..., "kerrywaz1" <kerry.williams@> wrote:

I am thinking about buying a Mach1GTO mount. Has anybody pushed

this

mount beyond its rated 45 pound capacity and if so what kind of

results

did you get?

Thanks,
KW

In a message dated 8/5/2008 9:29:04 PM Central Daylight Time,
stardoctor5@... writes:

I should have clarified...I was guiding with CCD soft. I was not
measuring tracking directly, but assumed that the tracking must have
been deteriorating because my guiding was inconsistent (compared to
superlative just a few months ago). I did recalibrate a few times, and
had an excellent calibration graph each time. I tried guiding both
with PEC turned on and PEC turned off. Each time, my errors in X and
Y, updated each 5 seconds, would sometimes stay low (under 0.2) for a
few cycles of 5 seconds, but then jump as high or low as +1.0 or -1.0,
sometimes lingering with the error, sometimes correcting rapidly,
sometimes overcorrecting to the same degree in the opposite direction.
Seeing was pretty good, and there was no wind. These errors seemed
greater near the pole. The errors seemed about the same with PEC on or
PEC off.

These kind of guiding results are more consistent with long period
atmospheric motion than whether REM is on or off. PEM, of course, has nothing to do with
the Dec axcis, so if you were getting similar errors in both axes, it is
going to be due to atmospheric instability. One can have great seeing but slow
undulating motions in the atmosphere that causes a star to wander around.

Ever since CCDs have replaced eyeballs, most of us no longer have any feel
for what is actually happening up above. We see only the result - poor tracking
and guiding, but have no idea what's causing it, so we pursue the nearest
handy thing, which is always the mount. If you are doing 5 second exposures, you
are going to see some atmospheric movement.

As you approach the pole, you can have all kinds of tracking errors and
horiffic periodic error in the worm, and guess what? You will get great tracking
anyway! Reason is that for any given arc second RA tracking error in the mount
worm, the corresponding pixel error gets smaller and smaller, and approaches
zero error as you approach the pole itself. Therefore, using logic, if you are
getting poor guiding the closer you get to the pole, that tells me that you are
experiencing more atmospheric motion down there versus straight above at the
zenith.

Rolando


**************
Looking for a car that's sporty, fun and fits in your
budget? Read reviews on AOL Autos.

(http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 )

Kerry,
The Mach1 performs easily and effectively with loads in excess of 45
pounds. This I did with a SCT with a heavy imaging train and a large
and heavy guide scope piggybacked on top of the main scope. Now that
being said the load was probably 52 pounds. The key here is that it
was done on a permanent pier in an observatory with a roll off roof so
that wind and other gremlins were not factors. I would expect that the
conditions around the mount will affect its stability more than the
actual weight it carries. In the end I removed all of the extra wieght
of the guide scope and now just use the SCT alone not becuase of the
weight bearing performance of the Mach1 but becuase of other factors
inherent in the use of a seperate guide scope and its mounting
(differential flexure).

Hope this helps. The Mach1 is a remarkable instrument. It has exceed
every expectation that I had and has become a real motivator in doing
any form of astronomy that I can do. It is easy to use and best of all
it is light and easily transportable.

Hope this helps,
Sam Bruce

--- In ap-gto@..., "kerrywaz1" <kerry.williams@...> wrote:

I am thinking about buying a Mach1GTO mount. Has anybody pushed this
mount beyond its rated 45 pund capacity and if so what kind of

results

did you get?

Thanks,
KW

Dear Rick, Richard, Ray, and Rolando (from Ruben....hmmm...all R's),

I should have clarified...I was guiding with CCD soft. I was not
measuring tracking directly, but assumed that the tracking must have
been deteriorating because my guiding was inconsistent (compared to
superlative just a few months ago). I did recalibrate a few times, and
had an excellent calibration graph each time. I tried guiding both
with PEC turned on and PEC turned off. Each time, my errors in X and
Y, updated each 5 seconds, would sometimes stay low (under 0.2) for a
few cycles of 5 seconds, but then jump as high or low as +1.0 or -1.0,
sometimes lingering with the error, sometimes correcting rapidly,
sometimes overcorrecting to the same degree in the opposite direction.
Seeing was pretty good, and there was no wind. These errors seemed
greater near the pole. The errors seemed about the same with PEC on or
PEC off.

I will do the following next weekend, weather permitting:
1. Remeasure my tracking, using Pempro, both with and without my Pempro
running.
2. I will recheck my polar alignment, using first my Polar scope and
then finetuning with PEMPRO 2 (which has worked well for me).
3. Then I will create a new curve with Pempro, and let you guys know
the results on tracking.
If you have any other suggestions, please let me know.

Ruben

I am thinking about buying a Mach1GTO mount. Has anybody pushed this
mount beyond its rated 45 pund capacity and if so what kind of results
did you get?

Thanks,
KW

The manual of my AP600 suggests programming PE correction with a guide
camera. Can this be done with a program like PHD Guiding, which
controls the mount through the serial port, or does it have to be done
with a dedicated guide camera which uses the guide port?

Thanks

Don Van Akker