So please enlighten me to the visual side that I don't regularly do.
thanks,
...paul.
p.s. Dave T. hopefully next year's Starfest will be non-raining, so I
can look thru your scope.

Hi Paul,

First you would enable a mode in the hand box that will enable the

points and build a model from them. You then slew to your first

not centered you center the object in the eyepiece and click Synch

correction point is then added to the pointing model. As you go

visual objects the pointing model becomes more accurate each time

point.

If you are not interested in having a pointing model or are using

model then you wouldn't use this feature. I think that building a

improves pointing accuracy as you observe would be pretty painless.

Comments?

-Ray

Ray --

One of the things I always hated about Meade's AutoStar was that

so complicated that you never quite knew what it was doing. From

I've read online, the same thing could be said for the CGE

So while I like the idea of a self-learning pointing model, I'd

want an easy indication to tell whether it was on or off, and an

way to zero out the model.

On a side note, do you know if moving-primary mirror flop is

enough for the model to handle?

Cheers,
-- Jeff.



________________________________

From: ap-gto@... [mailto:ap-gto@...]

Behalf Of Ray Gralak
Sent: Wednesday, February 28, 2007 10:36 PM
To: ap-gto@...
Subject: RE: [ap-gto] keypad pointing models. Was: Re:

ME vs. AP 1200GTO



Hi Paul,

First you would enable a mode in the hand box that will

the collection of
points and build a model from them. You then slew to your

target. If it is
not centered you center the object in the eyepiece and click
Synch (or RCAL). A
correction point is then added to the pointing model. As you

through more
visual objects the pointing model becomes more accurate each
time you add a
point.

If you are not interested in having a pointing model or are
using an external
model then you wouldn't use this feature. I think that

a model that
improves pointing accuracy as you observe would be pretty
painless.

Comments?

-Ray

> -----Original Message-----
> From: ap-gto@... <mailto:ap-gto%

[mailto:ap-gto@... <mailto:ap-gto%40yahoogroups.com> ]
> On Behalf Of Paul Mortfield
> Sent: Wednesday, February 28, 2007 10:14 AM
> To: ap-gto@... <mailto:ap-gto%

> Subject: Re: [ap-gto] keypad pointing models. Was: Re:
> Paramount ME vs. AP 1200GTO
>
> Hey gang,
> maybe I'm just missing something here from the visual

>
> I occasionally use my mount for visual usually after an
imaging
> session and remove the camera and ya its a hassle to drag

a PC in
> the cold so I too prefer the keypad. The objects were

in the
> field if I stayed on the same side of the meridian. And

so, if I
> did a meridian flip, I'd goto any bright star on that

a RCal
> and I'm good to go for the majority of objects on that

the
> meridian. If its still off, RCal on a bright star in that
target's
> constellation and off you go again.
>
> The biggest problem with doing a handpaddle model is how

you
> going to enter a pointing model into the handpaddle, ie,

star
> would have to accurately be centered in a cross hair

(don't
> rotate the diagonal) then recorded. To do a good all sky
model,
> you'll need a bare minimum of 30-50points. I just can't see
sitting
> there and entering all this data, visually by hand. For
imaging and
> a fixed imaging train, there's wonderful tools to
automatically do
> that and do 100 points while you grab a bite of food.
> Also, if you're using an SCT and don't keep the mirror

from
> day1, then its impossible to model the sky due to mirror
flops,
> rotating the diagonal and making sure you're always

on axis.
>
> In the field, the polar scope has always gotten me so close
that I
> don't bother drifting and again, usually a Sync in the
beginning and
> RCal if needed later on is all thats necessary. A little

finder
> scope or telrad makes everything so simple just in case.
> For imaging in the field, I'm not gonna waste precious dark
time
> running a model, since usually I'm only grabbing 1-3

night.
> That way using the laptop/planetarium program its even

to RCal
> near the target. I also make use of Maxim's centering
capabilities
> talking to the mount and once again the target is where I

it in
> a matter of seconds.
>
> So please enlighten me to the visual side that I don't
regularly do.
> thanks,
> ...paul.
> p.s. Dave T. hopefully next year's Starfest will be
non-raining, so I
> can look thru your scope.
>
>
>
>
>







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

Comments?

-Ray

Hi Jeff,

Sorry, apparently there was a yahoo outage a couple days ago and

stopped coming in for me, so I am just seeing your post.

Norm is correct though. The pointing model counts on repeatability,

unfortunately mirror flop is not always repeatable. Also as Norm

lock down the mirror to counter this type of random error.

-Ray

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
On Behalf Of Norm
Sent: Friday, March 02, 2007 6:17 AM
To: ap-gto@...
Subject: [ap-gto] keypad pointing models. Was: Re: Paramount
ME vs. AP 1200GTO

On a side note, do you know if moving-primary mirror flop is
predictable
enough for the model to handle?

Unfortunately, I do not know of any model that can take mirror

into account...there are too many variables as to when the flop
takes place and therefore impossible to model. The errors MUST be
repeatable! The only way to eliminate the problem is to use a

mirror.

Norm

--- In ap-gto@...
<mailto:ap-gto%40yahoogroups.com> , "Jeff Young" <jey@> wrote:

Ray --

One of the things I always hated about Meade's AutoStar was

it was

so complicated that you never quite knew what it was doing.

what

I've read online, the same thing could be said for the CGE

software.

So while I like the idea of a self-learning pointing model, I'd

also

want an easy indication to tell whether it was on or off, and

easy

way to zero out the model.

On a side note, do you know if moving-primary mirror flop is

predictable

enough for the model to handle?

Cheers,
-- Jeff.



________________________________

From: ap-gto@...

<mailto:ap-gto%40yahoogroups.com>
[mailto:ap-gto@... <mailto:ap-gto%

On

Behalf Of Ray Gralak
Sent: Wednesday, February 28, 2007 10:36 PM
To: ap-gto@... <mailto:ap-gto%40yahoogroups.com>
Subject: RE: [ap-gto] keypad pointing models. Was: Re:

Paramount

ME vs. AP 1200GTO



Hi Paul,

First you would enable a mode in the hand box that will

enable

the collection of
points and build a model from them. You then slew to your

first

target. If it is
not centered you center the object in the eyepiece and click
Synch (or RCAL). A
correction point is then added to the pointing model. As you

go

through more
visual objects the pointing model becomes more accurate each
time you add a
point.

If you are not interested in having a pointing model or are
using an external
model then you wouldn't use this feature. I think that

building

a model that
improves pointing accuracy as you observe would be pretty
painless.

Comments?

-Ray

-----Original Message-----
From: ap-gto@...

<mailto:ap-gto%40yahoogroups.com> <mailto:ap-gto%
40yahoogroups.com>

[mailto:ap-gto@...

<mailto:ap-gto%40yahoogroups.com>
<mailto:ap-gto%40yahoogroups.com> ]

On Behalf Of Paul Mortfield
Sent: Wednesday, February 28, 2007 10:14 AM
To: ap-gto@...

<mailto:ap-gto%40yahoogroups.com> <mailto:ap-gto%
40yahoogroups.com>

Subject: Re: [ap-gto] keypad pointing models. Was: Re:
Paramount ME vs. AP 1200GTO

Hey gang,
maybe I'm just missing something here from the visual

users.

I occasionally use my mount for visual usually after an

imaging

session and remove the camera and ya its a hassle to drag

out

a PC in

the cold so I too prefer the keypad. The objects were

always

in the

field if I stayed on the same side of the meridian. And

even

so, if I

did a meridian flip, I'd goto any bright star on that

side, do

a RCal

and I'm good to go for the majority of objects on that

side of

the

meridian. If its still off, RCal on a bright star in that

target's

constellation and off you go again.

The biggest problem with doing a handpaddle model is how

are

you

going to enter a pointing model into the handpaddle, ie,

every

star

would have to accurately be centered in a cross hair

eyepiece

(don't

rotate the diagonal) then recorded. To do a good all sky

model,

you'll need a bare minimum of 30-50points. I just can't see

sitting

there and entering all this data, visually by hand. For

imaging and

a fixed imaging train, there's wonderful tools to

automatically do

that and do 100 points while you grab a bite of food.
Also, if you're using an SCT and don't keep the mirror

locked

from

day1, then its impossible to model the sky due to mirror

flops,

rotating the diagonal and making sure you're always

centered

on axis.

In the field, the polar scope has always gotten me so close

that I

don't bother drifting and again, usually a Sync in the

beginning and

RCal if needed later on is all thats necessary. A little

50mm

finder

scope or telrad makes everything so simple just in case.
For imaging in the field, I'm not gonna waste precious dark

time

running a model, since usually I'm only grabbing 1-3

targets a

night.

That way using the laptop/planetarium program its even

easier

to RCal

near the target. I also make use of Maxim's centering

capabilities

talking to the mount and once again the target is where I

want

it in

a matter of seconds.

So please enlighten me to the visual side that I don't

regularly do.

thanks,
...paul.
p.s. Dave T. hopefully next year's Starfest will be

non-raining, so I

can look thru your scope.

Also, wouldn't switching from your crosshair eyepiece to your 2 pound
nagler change the pointing model? My point is that each time you
change eyepieces, it could mess up the pointing model - perhaps an
arugment against the need for this on a visual system? However, it
is probably not sufficient enough to worry about, right?

As for making the process user friendly, if AP is planning to add
this to the mount, a user-friendly way to do start the pointing model
would be to ask for how many stars they'd like to begin with (with a
specified minimum to establish at least a semi-accurate model).
Another question that could be asked is which side of the meridian
they'd like to model - East, West, or Both. I say this because I
have found that it needs the same number of points on each side of
the meridian due to the difference in weight and orthogonality.
Where I am located, I seldom view west of the meridian because of
obstructions. Why waste the time failing to calibrate on stars that
you'll never find?

Another problem you'll have with the idea versus practice of
increasing the pointing model accuracy as you observe, people often
think they are on one thing and RCAL/SYNC on it, when it is really
something else. In addition, the user will probably not want to swap
out their good eyepiece with a crosshair eyepiece, refocus, center
the star, add a modeling point, switch back to the good eyepiece, and
refocus. Will they? Human nature steps in and people think they can
guestimate the center and try to add the modeling point with their
good eyepeice. Each of those bad points will mess up the model.

I've been using ACP with my AP1200. ACP comes with modeling
component - no need to buy tpoint. Being automated through the
cameras, you just tell it to do, say 20 points, and let it rip. It
will do 10 points on each side of the meridian, fail on a few that
are behind trees, etc. but it only takes about 5-10 minutes to do it
the unattended way. Doing it by eyesight, which I did with a 60 day
trial version of TPoint a few times, is possible, but you can screw
it up by thinking you're on the right star when you aren't, not to
mention that it will take much longer. ACP doesn't have that problem
of using the wrong star because it does a plate solve for each point.

Lastly, once you have built your model, it is simple math to
determine how far off you are from a good polar alignment. The new
AP software could also do something like what PoleAlignMax does to
tweak your polar alignment. However, you'd have to redo your model
after making those adjustments. The software in the mount is
probably capable of determining from this tpoint-like model to be
able to tell the user to point to a known semi-bright star and center
it. The mount could then move off the star by the amount of polar
alignment error and then ask the user to move the mount in AZ or ALT
to recenter the star without the hand controller.

Other calculations could be performed as well and displayed as status
to the user. For example, some of the TPoint information is the
focuser droop (somehow they can calculate that from the model), tube
flexure, orthogonality error, etc.

The database in the hand controller could be used to find the "n"
brightest stars and then calculate which separation would provide the
best model. Ideally, the first few stars in the mapping run would be
close together and then, as the model improves, it could use stars
much further away.

Another potential issue will be the way we use our AP mounts. We
park them, and come back days later and resynch. The resynch should
update/shift the model, shouldn't it? I just see this as something
not to test and resolve before shipping.

So if this
is an issue for you maybe you need to buy a more solid telescope to
put on your
expensive AP mount! :-).

Hi Dave,

You wrote:

Also, wouldn't switching from your crosshair eyepiece to your 2

nagler change the pointing model? My point is that each time you
change eyepieces, it could mess up the pointing model - perhaps

arugment against the need for this on a visual system? However,

is probably not sufficient enough to worry about, right?

Unless your scope is extremely flimsy this is going to be

is an issue for you maybe you need to buy a more solid telescope to

expensive AP mount! :-).

Besides, the pointing model doesn't need to be accurate to arc-

arc-minute or two is probably accurate enough for visual work,

*could* at times be actually much better than that.

As for making the process user friendly, if AP is planning to add
this to the mount, a user-friendly way to do start the pointing

would be to ask for how many stars they'd like to begin with

specified minimum to establish at least a semi-accurate model).
Another question that could be asked is which side of the

they'd like to model - East, West, or Both. I say this because I
have found that it needs the same number of points on each side

the meridian due to the difference in weight and orthogonality.
Where I am located, I seldom view west of the meridian because of
obstructions. Why waste the time failing to calibrate on stars

you'll never find?

The process I suggested is different. What I proposed is "Sync as

time is wasted.

Another problem you'll have with the idea versus practice of
increasing the pointing model accuracy as you observe, people

think they are on one thing and RCAL/SYNC on it, when it is

something else. In addition, the user will probably not want to

out their good eyepiece with a crosshair eyepiece, refocus,

the star, add a modeling point, switch back to the good eyepiece,

refocus. Will they? Human nature steps in and people think they

guestimate the center and try to add the modeling point with

good eyepeice. Each of those bad points will mess up the model.

Yep, but so what? Arc-second accuracy is not required. A "goodness

could be displayed for each point and any point that doesn't make

fit error is high) is ignored.

I've been using ACP with my AP1200. ACP comes with modeling
component - no need to buy tpoint. Being automated through the
cameras, you just tell it to do, say 20 points, and let it rip.

will do 10 points on each side of the meridian, fail on a few

are behind trees, etc. but it only takes about 5-10 minutes to do

the unattended way. Doing it by eyesight, which I did with a 60

trial version of TPoint a few times, is possible, but you can

it up by thinking you're on the right star when you aren't, not

mention that it will take much longer. ACP doesn't have that

of using the wrong star because it does a plate solve for each

I am very familiar with ACP, but it is irrelevant for this

going to want to disable the AP pointing model when using ACP.

As I said "bad points" can be rejected from the pointing model if

fit very well.

Lastly, once you have built your model, it is simple math to
determine how far off you are from a good polar alignment. The

AP software could also do something like what PoleAlignMax does

tweak your polar alignment. However, you'd have to redo your

after making those adjustments. The software in the mount is
probably capable of determining from this tpoint-like model to be
able to tell the user to point to a known semi-bright star and

it. The mount could then move off the star by the amount of polar
alignment error and then ask the user to move the mount in AZ or

to recenter the star without the hand controller.

I don't think you would want to build a visual pointing model with

few points if your goal is to polar align.

The procedure might be:

1. reset pointing model and add 3-4 points.
2. adjust polar alignment based on polar alignment numbers in the

controller.
3. repeat steps 1-2 until alignment is close enough.
4. Start building your larger visual model.

*OR*, before you build a pointing model you use drift alignment,

accurate than PoleAlignMax (I've done extensive testing comparing

to drift alignment).

Other calculations could be performed as well and displayed as

to the user. For example, some of the TPoint information is the
focuser droop (somehow they can calculate that from the model),

flexure, orthogonality error, etc.

Yes of course. Did you really think that wouldn't be available? :-)

Not only that put the model allows something else I didn't mention:

The Dec/RA tracking rates will be automatically adjusted to the

minimize stellar drift wherever you point (as long as modeling is

that region).

The database in the hand controller could be used to find the "n"
brightest stars and then calculate which separation would provide

best model. Ideally, the first few stars in the mapping run would

close together and then, as the model improves, it could use

much further away.

Another potential issue will be the way we use our AP mounts. We
park them, and come back days later and resynch. The resynch

update/shift the model, shouldn't it? I just see this as

not to test and resolve before shipping.

The RA/Dec offsets are two of the pointing model's terms (the same

have seen in TPoint models).

-Ray