Date   

OT: C-11 mod

observe_m13
 

Yes, this is similar to what I was going to do but Roland replied that
it would be better to support the metal ring attached to the mirror
and not "push" directly on the mirror as has been done there.


--- In ap-gto@..., "Joseph Schaefer" <joegstargazer@...>
wrote:

I found on the web a good page that documents the Celestron C11
Modification by Roth Ritter.
http://www.rothritter.com/C11_Project
Joe

--- In ap-gto@..., "Hap Griffin" <lgriffin@> wrote:

I've been imaging lately with a 10" Orion Newtonian and an Orion
ED80 on an
AP-1200 mount and autoguided by an SBIG ST-402. However, I've
been wanting
to add a longer focal length scope to the mix for imaging
galaxies.
Obviously, I'd love a big R-C, but after finally finishing the
observatory
( http://www.machunter.org/griffin_hunter_observatory_2.html ) the
funds are
a bit depleated so I picked up a carbon fiber C-11 on Astromart
for now.
Wanting maximum versatility in focal lengths without having to
change the
scope mounts around, I built a 1/2" thick aluminum plate and
mounted both
the 10" and the C-11 on it. At the same time, I came across a
deal on a
Takahashi FS-102NSV that I couldn't pass up (always wanted a Tak
refractor)
and replaced the ED-80 with it for the low FL imaging.

So, here it is...all three scopes on the AP-1200. Believe it or
not,
everything balances nicely and the mount tracks like a champ with
over a
100-pound load. Gotta love the AP-1200 for shear quality!

http://www.machunter.org/hapsequipment.html

Hap Griffin
www.hapg.org


Re: AP 1200 - bump against the counterweight shaft

werner.pribil
 

Hello Geert, Rick and Mark !

Thank you for your answers and your descriptons. I see that I am not
the only user of the AP 1200 with such a problem.
To put an isolation foam to the end of the shaft is a very good idea
and I will do it soon.

I would like to know whether such a bump can damage the mount,
especially when the tracking rate is attuned to "sidereal"
As you did not mention any damage at your mount, it seems to be no
problem to the AP 1200.
What is your estimation respectively your experience ?

ThankĀ“s
Werner





--- In ap-gto@..., "Geert Vandenbulcke"
<geert.vdbulcke@...> wrote:

I must have bumped my head against the AP1200 counterweight shaft
at least
three or four times up to now (and about the same with my previous
mount).
Taping some tube isolation foam to the end of the shaft may be a
good idea
even if it doesn't look nice!

Geert Vdbulcke
Belgium

_____

Van: ap-gto@... [mailto:ap-gto@...] Namens
Rick
Wiggins
Verzonden: maandag 2 juni 2008 22:55
Aan: ap-gto@...
Onderwerp: [ap-gto] Re: AP 1200 - bump against the counterweight
shaft



Hi Werner,
I too have tried moving my AP1200 with cranial persuasion. I have
found that the hand controller is much more pleasant and accurate!
Mine happened when setting up the mount and during the adjustment I
had removed the foam that is usually wrapped around the weights and
end of shaft. In my case the new counterweight stop screw (with
sharp squared-off edge caught my forehead and machined a new aging
line into my head complete with crimson fountain. I nearly passed
out and luckily my friend administered first aide and after an hour
or so, could resume work.
Thanks, Rick

--- In ap-gto@yahoogroups. <mailto:ap-gto%40yahoogroups.com> com,
"werner.pribil" <werner.pribil@>
wrote:

Hello !

Yesterday I had my first observing session with my AP 1200 (the
tracking rate at the main menu of the keypad was sidereal). The
telescope was pointed in eastward direction, so the counterweight
shaft
pointed down to the ground in a northward direction.
At the end of my session I picked up a book from the ground
and when I stood up I striked with my head against the safety
stop
at
the end of the counterweight shaft. In the first moment I did not
know
what had happened and I had to sit down immediately. Now I have a
little bump on my head.
Can somebody tell me if this little accident can damage my AP
1200,
especially the worm and wheel adjustments of R.A. or the both
Dec.lock
knobs. Or is this collision no problem for the AP 1200.

Werner




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Re: New rig

Joseph Schaefer <joegstargazer@...>
 

I found on the web a good page that documents the Celestron C11
Modification by Roth Ritter.
http://www.rothritter.com/C11_Project
Joe

--- In ap-gto@..., "Hap Griffin" <lgriffin@...> wrote:

I've been imaging lately with a 10" Orion Newtonian and an Orion
ED80 on an
AP-1200 mount and autoguided by an SBIG ST-402. However, I've
been wanting
to add a longer focal length scope to the mix for imaging
galaxies.
Obviously, I'd love a big R-C, but after finally finishing the
observatory
( http://www.machunter.org/griffin_hunter_observatory_2.html ) the
funds are
a bit depleated so I picked up a carbon fiber C-11 on Astromart
for now.
Wanting maximum versatility in focal lengths without having to
change the
scope mounts around, I built a 1/2" thick aluminum plate and
mounted both
the 10" and the C-11 on it. At the same time, I came across a
deal on a
Takahashi FS-102NSV that I couldn't pass up (always wanted a Tak
refractor)
and replaced the ED-80 with it for the low FL imaging.

So, here it is...all three scopes on the AP-1200. Believe it or
not,
everything balances nicely and the mount tracks like a champ with
over a
100-pound load. Gotta love the AP-1200 for shear quality!

http://www.machunter.org/hapsequipment.html

Hap Griffin
www.hapg.org


Re: AP 1200 - bump against the counterweight shaft

Roland Christen
 

In a message dated 6/3/2008 1:39:29 PM Central Daylight Time,
werner.pribil@... writes:


I would like to know whether such a bump can damage the mount,
No, it cannot.

Rolando


**************
Get trade secrets for amazing burgers. Watch "Cooking
with Tyler Florence" on AOL Food.

(http://food.aol.com/tyler-florence?video=4?&;NCID=aolfod00030000000002)


Re: Dumb question

karl.perkins@sbcglobal.net
 

Hi Jim,

You may have downloaded only the manual for the mount.
The instructions for the location setup is in the keypad manual:

http://www.astro-physics.com/tech_support/mounts/keypad_v412.pdf

Hope this helps.

Karl Perkins

--- In ap-gto@..., "jimhp29401us" <thefamily90@...> wrote:

O.K., we figured it out. Talked him through it using Skype. The PDF
download on the AP site does not appear to me to be the entire
manual.
Is there one available that I can point him to?

Jim


Re: New rig

observe_m13
 

Ahhh, well that sort of explains it. I think it will be insufficient
for my C-11. I think I will go with Roland's suggestion and install
some bolts in the back plate so that they can actually contact the
metal plate attached to the mirror.

Rick.

--- In ap-gto@..., "ccoop974" <ccoop974@...> wrote:

This looks like what Hap has installed on his scope:
http://www.sciencecenter.net/hutech/misc/focuslk/index.htm
Hutech has been selling them for quite some time now I think.
Hap is the only person I have ever heard commit on how they work.
Steve

--- In ap-gto@..., "Rick Wiggins" <rickwiggins@> wrote:

Hi Hap,
Are you sure that it is a mirror lock? The Celestrons have a focus
lock, but to my knowledge, there is no mirror lock available. My
understanding is that it takes a significant amount of work to
install a mirror locking mechanism on a Celestron which includes
penetrating the back plate, installing screws that push on the
mirror mount, etc.
Thanks, Rick

--- In ap-gto@..., "Hap Griffin" <lgriffin@> wrote:

I picked up the C11 used on Astromart, so I don't know the origin
of the
mirror lock/focuser. But it seems to work great. Once I get the
mirror in
a location where the Feathertouch has a good range with my
camera,
I just
lock it and it seems to stay put OK.

Hap

----- Original Message -----
From: "Rick K" <JunkMailGoesHere@>
To: <ap-gto@...>
Sent: Thursday, May 29, 2008 6:49 PM
Subject: [ap-gto] Re: New rig


Hi Hap,

Where did you get the mirror lock? I have had an external
Feathertouch
focuser on mine for years (not the knob replacement kind, the
full
blown 2" modified crayford type) and eventually gave up on
trying to
get the mirror to sit still. It has sat in a case ever since. I
have
always contemplated taking it apart and adding three bolts in
teh back
plate of the OTA, spaced at 120 degrees, with matching cups
siliconed
to the back of the primary that the mirror would draw back onto
with
enough force to hold it firmly yet not enough to distort. Never
had
the time to get around to it though. If someone has a decent
mirror
lock that actually works, it would be worth having a look at.

Rick.


--- In ap-gto@..., "Hap Griffin" <lgriffin@> wrote:


----- Original Message -----
From: "Rick K" <JunkMailGoesHere@>
To: <ap-gto@...>
Sent: Thursday, May 29, 2008 12:42 PM
Subject: [ap-gto] Re: New rig


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

In a message dated 5/28/2008 8:50:04 PM Central Daylight
Time,
lgriffin@ writes:


So, here it is...all three scopes on the AP-1200.
Believe
it
or not,
everything balances nicely and the mount tracks like a
champ with
over a
100-pound load. Gotta love the AP-1200 for shear quality!

http://www.machunter.org/hapsequipment.html
Impressive looking setup. Nothing wrong with a C11 for
small
faint
galaxy
imaging.

Rolando

. . . other than the inevitable &*(%$ mirror flopping around!

Rick
This carbon fiber C11 has a mirror lock and an external
Feathertouch
focuser. It held focus for over three hours last weekend with
the
temperature dropping about 20 degrees.

Hap Griffin
www.hapg.org


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

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see http://groups.yahoo.com/group/ap-gtoYahoo! Groups Links



Re: Dumb question

jimhp29401us
 

O.K., we figured it out. Talked him through it using Skype. The PDF
download on the AP site does not appear to me to be the entire manual.
Is there one available that I can point him to?

Jim


Re: Dumb question

jimhp29401us
 

I may have set things up so that it skips the initail set-up and goes
straight to "location". Not sure. Thanks again for your help.

Jim


Dumb question

jimhp29401us
 

I sold my AP 900 GOTO. My buddy (in London) says when he powers
up "Location" comes up. It is obviously set to me location. He has no
manual but is downloading from the AP website. Can you tell me how he
should proceed to put in his location?
Thanks,

Jim


Re: New rig

ccoop974
 

BTW Hap, What anti-dew system did you put on the secondary of your Newt?
Thanks,
Steve

--- In ap-gto@..., "ccoop974" <ccoop974@...> wrote:

This looks like what Hap has installed on his scope:
http://www.sciencecenter.net/hutech/misc/focuslk/index.htm
Hutech has been selling them for quite some time now I think.
Hap is the only person I have ever heard commit on how they work.
Steve


Re: New rig

ccoop974
 

This looks like what Hap has installed on his scope:
http://www.sciencecenter.net/hutech/misc/focuslk/index.htm
Hutech has been selling them for quite some time now I think.
Hap is the only person I have ever heard commit on how they work.
Steve

--- In ap-gto@..., "Rick Wiggins" <rickwiggins@...> wrote:

Hi Hap,
Are you sure that it is a mirror lock? The Celestrons have a focus
lock, but to my knowledge, there is no mirror lock available. My
understanding is that it takes a significant amount of work to
install a mirror locking mechanism on a Celestron which includes
penetrating the back plate, installing screws that push on the
mirror mount, etc.
Thanks, Rick

--- In ap-gto@..., "Hap Griffin" <lgriffin@> wrote:

I picked up the C11 used on Astromart, so I don't know the origin
of the
mirror lock/focuser. But it seems to work great. Once I get the
mirror in
a location where the Feathertouch has a good range with my
camera,
I just
lock it and it seems to stay put OK.

Hap

----- Original Message -----
From: "Rick K" <JunkMailGoesHere@>
To: <ap-gto@...>
Sent: Thursday, May 29, 2008 6:49 PM
Subject: [ap-gto] Re: New rig


Hi Hap,

Where did you get the mirror lock? I have had an external
Feathertouch
focuser on mine for years (not the knob replacement kind, the
full
blown 2" modified crayford type) and eventually gave up on
trying to
get the mirror to sit still. It has sat in a case ever since. I
have
always contemplated taking it apart and adding three bolts in
teh back
plate of the OTA, spaced at 120 degrees, with matching cups
siliconed
to the back of the primary that the mirror would draw back onto
with
enough force to hold it firmly yet not enough to distort. Never
had
the time to get around to it though. If someone has a decent
mirror
lock that actually works, it would be worth having a look at.

Rick.


--- In ap-gto@..., "Hap Griffin" <lgriffin@> wrote:


----- Original Message -----
From: "Rick K" <JunkMailGoesHere@>
To: <ap-gto@...>
Sent: Thursday, May 29, 2008 12:42 PM
Subject: [ap-gto] Re: New rig


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

In a message dated 5/28/2008 8:50:04 PM Central Daylight
Time,
lgriffin@ writes:


So, here it is...all three scopes on the AP-1200.
Believe
it
or not,
everything balances nicely and the mount tracks like a
champ with
over a
100-pound load. Gotta love the AP-1200 for shear quality!

http://www.machunter.org/hapsequipment.html
Impressive looking setup. Nothing wrong with a C11 for
small
faint
galaxy
imaging.

Rolando

. . . other than the inevitable &*(%$ mirror flopping around!

Rick
This carbon fiber C11 has a mirror lock and an external
Feathertouch
focuser. It held focus for over three hours last weekend with
the
temperature dropping about 20 degrees.

Hap Griffin
www.hapg.org


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

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



Re: AP 1200 - bump against the counterweight shaft

Geert Vandenbulcke <geert.vdbulcke@...>
 

I must have bumped my head against the AP1200 counterweight shaft at least
three or four times up to now (and about the same with my previous mount).
Taping some tube isolation foam to the end of the shaft may be a good idea
even if it doesn't look nice!

Geert Vdbulcke
Belgium

_____

Van: ap-gto@... [mailto:ap-gto@...] Namens Rick
Wiggins
Verzonden: maandag 2 juni 2008 22:55
Aan: ap-gto@...
Onderwerp: [ap-gto] Re: AP 1200 - bump against the counterweight shaft



Hi Werner,
I too have tried moving my AP1200 with cranial persuasion. I have
found that the hand controller is much more pleasant and accurate!
Mine happened when setting up the mount and during the adjustment I
had removed the foam that is usually wrapped around the weights and
end of shaft. In my case the new counterweight stop screw (with
sharp squared-off edge caught my forehead and machined a new aging
line into my head complete with crimson fountain. I nearly passed
out and luckily my friend administered first aide and after an hour
or so, could resume work.
Thanks, Rick

--- In ap-gto@yahoogroups. <mailto:ap-gto%40yahoogroups.com> com,
"werner.pribil" <werner.pribil@...>
wrote:

Hello !

Yesterday I had my first observing session with my AP 1200 (the
tracking rate at the main menu of the keypad was sidereal). The
telescope was pointed in eastward direction, so the counterweight
shaft
pointed down to the ground in a northward direction.
At the end of my session I picked up a book from the ground
and when I stood up I striked with my head against the safety stop
at
the end of the counterweight shaft. In the first moment I did not
know
what had happened and I had to sit down immediately. Now I have a
little bump on my head.
Can somebody tell me if this little accident can damage my AP
1200,
especially the worm and wheel adjustments of R.A. or the both
Dec.lock
knobs. Or is this collision no problem for the AP 1200.

Werner




No virus found in this incoming message.
Checked by AVG.
Version: 8.0.100 / Virus Database: 269.24.4/1477 - Release Date: 1/06/2008
17:28



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Mijn Postvak In wordt beschermd door SPAMfighter
486 spam-mails zijn er tot op heden geblokkeerd.
Download de gratis SPAMfighter <http://www.spamfighter.com/lnl> vandaag
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Re: Flexure Solved

hewholooks
 

Thanks Roland. I shared that specific shot just to show the tight
stars, but since I enjoy showing off, I also shot M101 that night.
Stars aren't as tight, but I still like it for other qualities.

http://tinyurl.com/4s6wff

That's the last one. Promise.

Hunter

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

In a message dated 6/1/2008 11:08:31 AM Central Daylight Time,
hewholooks@... writes:


Here's the M92 that I got since solving the issue:
http://tinyurl.com/69edga
Excellent shot. Surprising how well a consumer camera does on deep
sky.

Rolando


**************
Get trade secrets for amazing burgers. Watch "Cooking
with Tyler Florence" on AOL Food.

(http://food.aol.com/tyler-florence?video=4&;?
NCID=aolfod00030000000002)


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


Re: AP 1200 - bump against the counterweight shaft

Wiggins, Rick
 

Hi Werner,
I too have tried moving my AP1200 with cranial persuasion. I have
found that the hand controller is much more pleasant and accurate!
Mine happened when setting up the mount and during the adjustment I
had removed the foam that is usually wrapped around the weights and
end of shaft. In my case the new counterweight stop screw (with
sharp squared-off edge caught my forehead and machined a new aging
line into my head complete with crimson fountain. I nearly passed
out and luckily my friend administered first aide and after an hour
or so, could resume work.
Thanks, Rick

--- In ap-gto@..., "werner.pribil" <werner.pribil@...>
wrote:

Hello !

Yesterday I had my first observing session with my AP 1200 (the
tracking rate at the main menu of the keypad was sidereal). The
telescope was pointed in eastward direction, so the counterweight
shaft
pointed down to the ground in a northward direction.
At the end of my session I picked up a book from the ground
and when I stood up I striked with my head against the safety stop
at
the end of the counterweight shaft. In the first moment I did not
know
what had happened and I had to sit down immediately. Now I have a
little bump on my head.
Can somebody tell me if this little accident can damage my AP
1200,
especially the worm and wheel adjustments of R.A. or the both
Dec.lock
knobs. Or is this collision no problem for the AP 1200.

Werner


Re: New rig

Wiggins, Rick
 

Hi Hap,
Are you sure that it is a mirror lock? The Celestrons have a focus
lock, but to my knowledge, there is no mirror lock available. My
understanding is that it takes a significant amount of work to
install a mirror locking mechanism on a Celestron which includes
penetrating the back plate, installing screws that push on the
mirror mount, etc.
Thanks, Rick

--- In ap-gto@..., "Hap Griffin" <lgriffin@...> wrote:

I picked up the C11 used on Astromart, so I don't know the origin
of the
mirror lock/focuser. But it seems to work great. Once I get the
mirror in
a location where the Feathertouch has a good range with my camera,
I just
lock it and it seems to stay put OK.

Hap

----- Original Message -----
From: "Rick K" <JunkMailGoesHere@...>
To: <ap-gto@...>
Sent: Thursday, May 29, 2008 6:49 PM
Subject: [ap-gto] Re: New rig


Hi Hap,

Where did you get the mirror lock? I have had an external
Feathertouch
focuser on mine for years (not the knob replacement kind, the
full
blown 2" modified crayford type) and eventually gave up on
trying to
get the mirror to sit still. It has sat in a case ever since. I
have
always contemplated taking it apart and adding three bolts in
teh back
plate of the OTA, spaced at 120 degrees, with matching cups
siliconed
to the back of the primary that the mirror would draw back onto
with
enough force to hold it firmly yet not enough to distort. Never
had
the time to get around to it though. If someone has a decent
mirror
lock that actually works, it would be worth having a look at.

Rick.


--- In ap-gto@..., "Hap Griffin" <lgriffin@> wrote:


----- Original Message -----
From: "Rick K" <JunkMailGoesHere@>
To: <ap-gto@...>
Sent: Thursday, May 29, 2008 12:42 PM
Subject: [ap-gto] Re: New rig


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

In a message dated 5/28/2008 8:50:04 PM Central Daylight
Time,
lgriffin@ writes:


So, here it is...all three scopes on the AP-1200. Believe
it
or not,
everything balances nicely and the mount tracks like a
champ with
over a
100-pound load. Gotta love the AP-1200 for shear quality!

http://www.machunter.org/hapsequipment.html
Impressive looking setup. Nothing wrong with a C11 for small
faint
galaxy
imaging.

Rolando

. . . other than the inevitable &*(%$ mirror flopping around!

Rick
This carbon fiber C11 has a mirror lock and an external
Feathertouch
focuser. It held focus for over three hours last weekend with
the
temperature dropping about 20 degrees.

Hap Griffin
www.hapg.org


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

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see http://groups.yahoo.com/group/ap-gtoYahoo! Groups Links



Re: Dec Autoguiding problem

Roland Christen
 

In a message dated 6/1/2008 6:03:24 PM Central Daylight Time,
capitoladude@... writes:


The dec oscillation problem with my AP900 is still ugly as ever.
Your tests of the Dec axis show nothing out of the ordinary as far as the
mechanics are concerned. If it takes 3 seconds for the Dec axis to reverse when
pressing the N-S button at 1x rate, then I would say that your gear mesh is a
bit loose. However, this should not cause wild swings back and forth in Dec.
Maybe I misread your test of the Dec axis and it does not take a full 3 seconds
to reverse. Of course, you would be the one to know since you were there doing
the test and I can only interpret what the result was.

Normally, wild swings are caused by a loop gain greater than 100% (i.e. the
correction commands sent to the mount are larger than the error). This will
result in limit cycling as you have experienced. You can see whether the loop
gain in Dec is too large by looking at the parameter numbers in the Dec axis. If
the parameter number after calibration is always smaller in Dec than RA
(calibration near the celestial equator) then chances are that your loop gain will
be larger than 100%. In that case the mount will always be asked to overcorrect
in Dec with the resultant oscillations.

Two ways to fix this, if that is the cause. 1) increase the parameter number
to be approximately equal to the RA number. 2) reduce the agressiveness in the
Dec axis below 100%. Keep lowering it until the axis becomes stable. Try
setting your Min move to 0 and Max move to 0.3 seconds and then adjust the
agressiveness until the axis is stable. Also be sure that the backlash adjust in the
keypad and in Maxim has been set to zero when you are guiding.

Roland




**************
Get trade secrets for amazing burgers. Watch "Cooking with
Tyler Florence" on AOL Food.
(http://food.aol.com/tyler-florence?video=4&;
?NCID=aolfod00030000000002)


Re: Flexure Solved

Roland Christen
 

In a message dated 6/1/2008 11:08:31 AM Central Daylight Time,
hewholooks@... writes:


Here's the M92 that I got since solving the issue:
http://tinyurl.com/69edga
Excellent shot. Surprising how well a consumer camera does on deep sky.

Rolando


**************
Get trade secrets for amazing burgers. Watch "Cooking
with Tyler Florence" on AOL Food.

(http://food.aol.com/tyler-florence?video=4&;?NCID=aolfod00030000000002)


Mach1 on a DM-6 tripod? (and hello)

richardm123uk <richard.molyneux123uk@...>
 

Hello all,

This is my first post on this group. I am on the waiting list for a
Mach1 and was wondering if I can mount it on my DM-6 tripod or am I
going to have to purchase another tripod when my number comes up?.

Cheers,
Richard


Re: Dec Autoguiding problem

Steve Peters
 

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

In a message dated 3/26/2008 9:10:44 AM Central Daylight Time,
chris1011@... writes:
One more thing: On the AP website under Technical Support, scroll
down until
you get to the heading: "Mount Troubleshooting - For additional
troubleshooting tips, check the mount and keypad manuals." Click
on: "Characterizing the Dec
Axis Motions (09-15-03) - PDF document." Follow the instructions in
this PDF
to determine whether your Dec axis is moving properly. The
instructions should
be plain enough for you to determine if you have a mechanical
problem in this
axis. If so, then we can go to the next step.

Rolando

Hi Roland,

The dec oscillation problem with my AP900 is still ugly as ever. Last
night after trying to image and failing because of the wild dec
fluctuations I did some testing and recorded some results as you had
suggested.

Again, my setup is AP160 refractor on AP900 GTOCP3 (purchased new in
2007), 100mm f/6 guide scope with Orion StarShoot DSI camera for
guiding, MaxIm DL software for guiding and image capture.

First, I characterized the dec axis motions following the procedure
on the AP website. I didn't use the track log, but here's what I
found in three separate tests. I started at a "middle" position of
X=16, Y=16, then used the North button to move the star to Y=8. then
I pulsed the South button in ~ 1 second pulses. the results show the
movement in the Y axis; X did not change.

Test 1 Test 2 Test 3
Start 8 8 8
Pulse 1 7 8 7
Pulse 2 7 9 7
Pulse 3 10 11 9
Pulse 4 14 14 12
Pulse 5 17 16 14
Pulse 6 -- -- 17

So, it took three pulses before the star started moving south in each
test.

Do these results suggest anything out of the ordinary?

Next, I did the following things. I have posted some screen shots in
the Files area that I will refer to. They're in a folder named AP900
Dec Tests, Files from Steve Peters.

I should also note that I polar aligned using the polar scope only.
However, the polar scope itself was aligned (usingt the thre tiny
setscrews) a couple of sessions ago AFTER I had done a drift
alignment, so it is pretty spot on. Guiding rate was 1x.

1. Calibrated on a star in the eastern sky.
2. Guided on a nearby star. With dec guiding turned on, the dec error
graph was flat for 5 minutes (I didn't take a screen shot of that).
As I've stated before, the mount guides well in the easter part of
the sky. It's in the west and sometimes the south where the
oscillation pattern occurs.
3. Turned off both dec (Y) directions in MaxIm. I began this at 410
time point (see DecOFFbegin_east.jpg). Almost 5 minutes later at 690,
the error graph is essentially flat (DecOFFend_east).
4. At time point 900, I turned both dec directions back on
(decON_east). After a liottle more than 3 minutes, you can see maybe
a half pixel of downward drift.

I realized after all this that you had said to turn on one Y
direction and see what happens. I neglected to do that, so I will
have to go back and do it if having that information would still be
useful to you.

5. Then I slewed the telescope to the western sky and checked "pier
flip," got a guide star and started tracking at time point 1440 with
dec guiding on(see decON_west). You can see the big +2 and -2 pixel
oscillations.
6. Turned both dec guiding directions off at 1800 (decOFF_west). The
dec error graph flattens out.

7. Then, to see if calibrating in the west helped, I calibrated on a
star, then guided on the same star. With dec guiding on, I started at
time point 2370 (decON_west_calib). Again, bad oscillation.
8. At 2670, turned both dec directions off (decOFF_west_calib). The
oscillation stops. There is a slight upward drift of 1.5 pixels after
5 minutes (decON2_west_calib).

So that's pretty much what I've been struggling every time out since
I bought this mount. I've tried numerous tweaks of settings, gear
mesh adjustment, consulting with my imaging friends, etc., all to no
avail. Let me know your thoughts.

Next weekend I may have an opportunity to swap my mount for a
friend's AP900. The rest of my system would be the same, so I will
see if there's any difference in dec behavior using his mount.
Another test I could do (on a different night) would be to try a
different guide camera. And of course I could try a different guiding
program, such as PHD Guiding (although that program doesn't have an
error graph, just a numerical tracking log, I believe).

I will be interested in your comments on the above tests and what you
suggest I try next to get the dec to function properly.

Thanks,

Steve Peters


Re: Flexure Solved

Jerry Lodriguss
 

Hi Hunter,

That is really excellent.

Jerry


At 12:08 PM 6/1/2008, you wrote:
Thanks everyone for your advice with my flexure problems.

As you recall, I had gotten the new Mach1 and since the guiding was
so good, I could now determine that my elongated stars were flexure
and not the mount.

I was advised to junk my side-by-side saddle arrangement and so I
went piggyback with my ST80 on top of my C9.25 with some ADM rails
and rings. Frankly, I was worried about moving the center of gravity
out farther with all that scope and weight on the Mach1, but it has
not batted an eye. I didn't expect to rid myself of all the flexure,
since I was using the SCT, and maybe I didn't, but it's all but
disappeared.
http://hwilson.zenfolio.com/p782801820/

Now I have tiny little round stars, even with an SCT, thanks to the
great guiding and the advice from here.

Here's the M92 that I got since solving the issue:
http://tinyurl.com/69edga

Thanks again,

Hunter


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