From: email@example.com (richard seymour) In the LX90 Egroup, Janet asked: > They sure don't give much information about the autoguider port > do they? I was hoping that they would at least list compatible > guiders, or the pinouts of the connector. It's exactly the same as the LX200's CCD guider port. Since Meade's descriptor of -that- is beyond confusion into befuddlement, here's my go at it: Looking into the hole on the 909APM, the pinnage is: +-------------+ | 1 2 3 4 5 6 | +----+ +----+ +---+ 1 "NC contact" (not used)(many CCD guiders apply +5v here) 2 - Ground 3 - Left (CCW) 4 - Down 5 - Up 6 - Right (CW) All signals are pulled low (to ground) to assert. So i have become a "wetware CCD" with 4 pushbuttons... They each can tie the pin-2 Ground to any of the pins 3 thru 6 inputs. My megapixel eyeball provides the pushing power. The scope ignores confusing (go left/right simultaneously) inputs. [GoTo] and manual slewing override the CCD input. It only works in Polar. (Why?) The APM also has a Focuser and Reticle connector which i think are specific for the Meade accessories. I don't have them, Clay does. > I assume you have the APM. Would you mind answering a few questions? > What are your impressions as far as it's quality and use? It's a decent lump. Many components inside. Cute mounting. Lacks any external indication of CCD operation. No LEDs. > Is the cable long enough? The cable is a thinner-guage, but a coil cord the same length as my ETX90's Autostar cable. (stretchable to 3 feet, easily) Plugs into the AUX port on the telescope base. > Does it interfere with your access to the focuser, or the visual > back? A little plastic clip screws onto a fitting just below your rear port. The 909APM itself slips onto that, and can be easily removed. It does not -have- to mechanically attach to the scope to work. > Have you used a CCD guider with it yet? I haven't, but i've pushed its buttons... Result: the Guide speed it commands seems to be about -half- of "speed one" on the Autostar. Whereas speed one is "1x sidereal", and pressing the Autostar's anti-sidereal slew key effectively stops the RA drive, pressing the "retard" button (mimicing the CCD) only slows it down. The motor does not go silent. Up/Down (Dec) shows stars slowly entering/exiting the edge of the FOV. I haven't had time yet to time how long it takes to fully cross a measured visual field. The CCD guiding function uses your backlash percentage settings to give the motors a start-up kick if it reverses them. Since it only slows, and doesn't actually -reverse- the sidereal motor, you won't see it in RA motion. But you -will- see it in Dec motion, so you'll have to ensure that your values are correct, or, if anything, under-correct for the backlash. I ran a long-term test with the 909 APM, commanding a continual Upward correction. It appears to move at about a 10 arcminute per clock minute rate. That's 2/3rds sidereal rate. (the 2/3rds sidereal is the **CCD** guide speed effect. Measured in a DEC direction (elevating barrel), with continual input on the "up" CCD pin. Not normal operational tracking.) --dick
Return to the top of this page.
Go back to the Autostar Information page.
Go back to the ETX Home Page.