Last updated: 18 November 2005

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This page is for user comments and information of a general nature or items applicable to all LXD55 models. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me and I'll post them. Please use an appropriate Subject Line on your message. Thanks.

Subject:	re: Autostar & 1240 focuser
Sent:	Saturday, November 12, 2005 18:17:44
From:	richard seymour (rseymour@wolfenet.com)
You asked:
1) What autostar signals drive the [focuser] motor.
2) Specifically there are 4 speeds, which means prob 4 signals.

But the answer is quite different.
(a) the autostar does not drive the motor, it drives itself.
(b) the motor box contains a small circuit card which talks
 to the autostar, and has a PIC to generate the pulse-width-modulated
 (PWM) signals which actually drive the motor.
(c) the focuser is plugged into the AUX port on the telescope's base.
(d) that socket has 4 wires: +12v, ground, and a bidirectional
 clocked I2C databus system. One of the signal wires is "data",
 and the other are "clock" signals, telling both ends when the
 data line contains valid data.
(e) the four speeds arise from the Autostar sending an addressed
 data packet telling the PIC chip to go at "speed 1" thru "speed 4".

You could replace the -motor- with one which draws less than 1 amp
and can withstand 12 volts.  But you cannot replace the entire
unit without developing an interface which speaks a modified IIC
bus protocol, and which will respond to the (undocumented)
Autostar commands which ask "are you there?", and which will
respond to the Autostar commands to "move at speed (and direction) XX"
and "stop!"

have fun


From:	Ancel Bhagwandeen (mosaicmerc@yahoo.com)
Thanks ....undocumented protcols.....don't have time to reinvent this


Subject:	Autostar & 1240 focuser
Sent:	Thursday, November 10, 2005 09:23:40
From:	Ancel Bhagwandeen (mosaicmerc@yahoo.com)
Great info on the wen page for AT.
I just got a Meade SN8-AT UHTC/LXD 75. I've been advised that the 1240
focuser will work once I mod it to mate with the Focuser shaft....
Would you be able to guide me to info that detalis...
1) What autostar signals drive the motor.
2) Specifically there are 4 speeds, which means prob 4 signals.
I want to determine if other solutions can be designed based on the
Autostar signal to the motor.

I have on hand a 5 rpm gear head DC reversible motor (6VDC) . I would
like to drive it with the built in AT controller. So I made need to
build an interface to convert the signals to voltage or maybe a simple
voltage divider if the AT just delivers differnt drive voltage to the
thx for any help
Ancel Bhagwandeen BSc Ind Eng.
Mike here: Hadn't heard about the 1240 focuser so can't answer directly. The Autostar #497 will control the Meade Electric Focuser models #1244 and #1247 for the ETX line.
Subject:	LXD-75 Collimation Laser Question
Sent:	Thursday, November 10, 2005 09:14:27
From:	Scott Lytle (s.lytle@sbcglobal.net)
I need to collimate my LXD-75. I am going to purchase a laser collimator
and do not know which is better. I can purchase a Zhumell that MSRP's
for $99 for $55. It appears to be the same as the Orion Deluxe Laser
Collimator that sells for $80. My question deals with the quality of
Zhumell's products. I just don't know what quality their product are vs.
Orion or Meade. Any input would be helpful as I do not want to sacrifice
quality for price!
Thank you for your time,
Scott Lytle

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