The setup of the AS-GT mount is similar to the N5i in that I can swap optical tubes, have velcroed (?) the I/O Net Edgeport to the mount, reducing cable clutter (single cable to the computer), and am using the same camera & software. The difference is that the mount itself is heavier, and I generally take off the OTA & counterweight for transport. When the ST80 is on, I can carry the entire thing minus the counterweight, but it is awkward.
As you can see, I have the fabled Celestron Port Expander which provides 2 AUX ports as well as a PC port which I use for both programming the mount's motor controllers (I'm a beta tester) and for driving NexRemote via a single cable. Just like with the N5i, I don't have to use a hand control to run the telescope.
In place of the hand control, I've rubber banded my STAR2000 dongle so I can self/autoguide the mount. The serial port from the dongle goes to the serial port in the Edgeport. The USB cable from the camera goes to the Edgeport. And, the programming cable from the PC port goes to the Edgeport. Then it is one USB cable to the telescope and I'm good to go.
Something I've started doing lately is to forego using an eyepiece completely. Everything is done via the MX916 camera. Less stuff to cart out! YES! I've had good luck with objects falling on the chip. However, for the occasion when it doesn't, a quick plate solve with PinPoint LE and a synch in MAXIM and I can use an ASCOM program to do the GOTO. Then I can realign on the object I was looking for in the real hand control and get both ASCOM and the real HC closer to fine.
SOFTWARE : Everything is the same as it is for the N5i so you can see that page for software info.
Celestron has released updated motor control firmware on October 7, 2004 which will address issues with backlash in particular, and tracking rate as well (in addition to things about runaway slews, etc. which never really were an issue for me.) You should apply this update at your earliest convenience if you've had issues with mount behavior.
AUTOGUIDING :
This is a topic that seems to be of great interest to folks considering the AS-GT as a platform for imaging. Well, here's all I can tell you at this point. I'm not a great imager and I'm even less of an autoguider. I think I have the principles down pretty well, but I need more practice. That said, with no attempt to do a good polar alignment, using beta everything , I was able to produce these crappy images with the following parameters :
(1) Eyeballed polar alignment
through hole in mount
(2) Made no attempt to use proper motion on alignment stars for autoalignment
(3) By the time the M31 area and the Capella shots were taken, heavy dew
was on the lens of the scope and I mean HEAVY.
(4) I did attempt to balance the scope by moving the weight up or down depending
on side of meridian
(5) ST80 F/5 with MX916 camera straight through with (gasp!) Orion Ultrablock
filter
Image Scale : 5.87 arcseconds/pixel (more or less)
Field of View : 55.8 x 75.9 arcminutes
(6) Maxim DL/CCD software
(7) 0.5 second guiding exposures
(8) backlash in ALT 20/20, AZ 10/10 for M31 area and then 15/15 for Capella
(9) 75% sidereal in ALT autoguide rate, 50% of sidereal for AZ
Just remember that for each full exposure time, only half of the exposure goes toward the image. The other half is for guiding. So, a 10 minute guide produces a 5 minute image. But still, gotta guide for the full 10 minutes to make it work!
So here's an unguided image (no dark subtraction) so you can see the elongation.
Next I'll show two stacked guided images :
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I took 3-10 minute images back to back and while the first two were great, the 3rd kind of lost it. (See below)
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Why Capella? There was so much dew that I was having trouble finding stars that would show up in 0.5 second guide images. You can see the cool way the light shines through the dew.
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Not
much difference between the unguided image and the 10 minute self-guided
image
For
Capella, I took 23-4 minute self-guided images back-to-back. The first
half produced OK images and the second produced excellent images. Still,
the first half were good enough to stack because a nice median combine
would round out the stars.
In general, when things were going well, I could keep X within +/- 0.5 pixels and Y within +/- 1 pixel. Still Y took some odd excursions at times, up to 5 pixels! Hower, considering the fact that I made zero attempt at good polar alignment, the guider had to work really hard to guide the mount, and the mount responded rather well.
Autoguiding isn't easy because there are so many factors that have to be controlled. But it seems the mount is heading in the right direction.
I have also autoguided with a 5" SCT at F6.3 using a MX916 and STAR2000 with Maxim DL successfully. You can see more autoguided images in the image section. In fact, I found the 5" SCT at F6.3 easier to calibrate than the ST80 at F5. Some of me thinks the mount likes the higher weight. I have autoguided successfully w/o doing a "polar alignment" routine from the hand control as well as after doing one. It is easier to guide when the routine has been done, but it is also possible to simply be "close" and still guide. YMMV.