AP-400 and ST7 calibration


sreilly@...
 

Steve,

The only suggestion I could make is to check the guiding speed that you
have the mount set to. I sometimes forget and get bad readings.
Aggressiveness on my CG-11 is set for 7/8 with RA/Dec set for 5 sec. I
also made a "L" shaped board that butts up to the dovetail plate and
rests on the flat bottom of my ST-8 to make sure the camera is straight.
If polar alignment and balance is good then this should be close. Also,
try calibrating on a close brighter star outside you FOV for the object
if nothing but dim stars are available. After calibrating, move back to
your object and pick the brightest star available on the guide chip. You
can also switch to the imaging chip to calibrate then switch back but
this takes longer due to the downloading time. Hope this helps.

Steve


Steve Leikind wrote:


This may be one for the SBIGUSER list, but here goes. I tried
calibrating my ST7 self-guider chip for my new AP-400 and ran into a
problem. During the calibration process, the calibration star
snip


Terry Johnson <tjohnson@...>
 

When calibrating, make sure you have the GTO keypad slew speed set to .5 or
1.0 or the slew speed will be to high during calibration and the mount will
slew off the chip during calibration.

...Terry Johnson

----- Original Message -----
From: "Steve Leikind" <sleikind@...>
To: <ap-gto@...>
Sent: Wednesday, June 28, 2000 9:55 AM
Subject: [ap-gto] AP-400 and ST7 calibration


This may be one for the SBIGUSER list, but here goes. I tried
calibrating my ST7 self-guider chip for my new AP-400 and ran into a
problem. During the calibration process, the calibration star
consistently moved off the chip meaning that I could not calibrate.
I tried a number of calibration settings, but not seemed to work
Things were pretty well balanced before I attempted calibration and
polar alignment seemed pretty good. I made sure the ST7 was lined up
with the RA axis per SBIG's recommendation.

I had previously used my ST7 with an LX-200 and had no difficulty
self-guiding. Obviously the AP is a different mount and requires
different ST7 settings. I did not get to spend much time working on
this, but thought I would post this to see if anyone as any
suggestions.

-Steve


------------------------------------------------------------------------
I wonder if Eddie will be mad?
http://click.egroups.com/1/6000/7/_/3615/_/962211317/
------------------------------------------------------------------------



Ron Wodaski <ronw@...>
 

With the AP mounts, getting the backlash compensation set correctly is very
important. I recommend doing through this process:

* Verify that end play of the worm and gear mesh are correct.
* Visually set backlash compensation using the mount speeds recommended by
AP in their docs. Whatever backlash setting you use, it should be just
slightly _under_ corrected; you can add any small degree of additional
correction in your camera control software if it includes that feature. It's
just important that you don't go too far. <g>
* Test your backlash settings using your camera control software. Verify
that the movement is equal in RA and Dec, or nearly so. I have found that
this test is more sensitive than the visual test, and will pick up
over-correction very reliably. Verify that the amount of motion is
proportional for varying movement times. That is, if you move the mount for
two seconds in RA, and then for 10 seconds, you should almost exactly 5X
greater movement in the second case. This test will pick up any uncorrected
or overcorrected backlash.

Now calibrate using .5X sidereal; you should get good numbers.

Ron Wodaski

-----Original Message-----
From: Steve Leikind [mailto:sleikind@...]
Sent: Wednesday, June 28, 2000 9:55 AM
To: ap-gto@...
Subject: [ap-gto] AP-400 and ST7 calibration


This may be one for the SBIGUSER list, but here goes. I tried
calibrating my ST7 self-guider chip for my new AP-400 and ran into a
problem. During the calibration process, the calibration star
consistently moved off the chip meaning that I could not calibrate.
I tried a number of calibration settings, but not seemed to work
Things were pretty well balanced before I attempted calibration and
polar alignment seemed pretty good. I made sure the ST7 was lined up
with the RA axis per SBIG's recommendation.

I had previously used my ST7 with an LX-200 and had no difficulty
self-guiding. Obviously the AP is a different mount and requires
different ST7 settings. I did not get to spend much time working on
this, but thought I would post this to see if anyone as any
suggestions.

-Steve


------------------------------------------------------------------------
I wonder if Eddie will be mad?
http://click.egroups.com/1/6000/7/_/3615/_/962211317/
------------------------------------------------------------------------


Herb and Paula York <ztrmann@...>
 

As you probably know you must set the hand controller to 1 or .5 to
calibrate. You can set the hand controller to 1 for calibration and then set
it to .5 to track. It also works at .5 and .25. If you left your hand
controller to 12X or 600X etc this may be why it is moving off the chip or
if your polar alignment is bad.
Thanks
Herb
http://www.buytelescopes.com
Anacortes Telescope and Wild Bird
(360)588-9000

----- Original Message -----
From: "Steve Leikind" <sleikind@...>
To: <ap-gto@...>
Sent: Wednesday, June 28, 2000 9:55 AM
Subject: [ap-gto] AP-400 and ST7 calibration


This may be one for the SBIGUSER list, but here goes. I tried
calibrating my ST7 self-guider chip for my new AP-400 and ran into a
problem. During the calibration process, the calibration star
consistently moved off the chip meaning that I could not calibrate.
I tried a number of calibration settings, but not seemed to work
Things were pretty well balanced before I attempted calibration and
polar alignment seemed pretty good. I made sure the ST7 was lined up
with the RA axis per SBIG's recommendation.

I had previously used my ST7 with an LX-200 and had no difficulty
self-guiding. Obviously the AP is a different mount and requires
different ST7 settings. I did not get to spend much time working on
this, but thought I would post this to see if anyone as any
suggestions.

-Steve


------------------------------------------------------------------------
I wonder if Eddie will be mad?
http://click.egroups.com/1/6000/7/_/3615/_/962211317/
------------------------------------------------------------------------