auto aligning and centring using #497 controller for ETX 125

As the topic suggests I'm having experiencing some frustration with same. I setup level and north; put tube in home position then use auto align (easy). Castor (this time) is close to centre of finderscope but outside field of 32mm plossl. When I try to centre the star the 'scope does so :evil: but immediately corrects to the original (poorly aligned) position. Using the Synchronize function after (poor) alignment yields the same result. I'm sure the solution is simple but everything is easy in hindsight. Give me 20:20 vision WITHOUT going to specsavers please

William --

Have you trained your drives yet? If not, you're probably experiencing the effects of backlash in your geartrain; a Train Drives allows the computer to measure this backlash and subtract it out of subsequent movements. It's under Setup > Telescope > Train Drives on Autostar II; I'd expect to find it somewhere similar on the ETX, but I can't remember exactly.

-- Jeff.

As the topic suggests I'm having experiencing some frustration with same. I setup level and north; put tube in home position then use auto align (easy). Castor (this time) is close to centre of finderscope but outside field of 32mm plossl. When I try to centre the star the 'scope does so :evil: but immediately corrects to the original (poorly aligned) position. Using the Synchronize function after (poor) alignment yields the same result. I'm sure the solution is simple but everything is easy in hindsight. Give me 20:20 vision WITHOUT going to specsavers please

William,

I assume you trained Autostar as per instructions in the manual. I don't think it's backlash as this is just a delay experienced when moving the axis controls. That shouldn't produce what you're experiencing.

Is this a new scope or one purchased secondhand? I ask because this sounds like "rubber banding", a problem believed to have been introduced with Autostar v. 2.1ek with A2.4 Autoloader (don't think it affected all ETXs, just some). It was engineered out of Autostar systems a few years ago. My ETX90EC only started to suffer from rubber banding after I upgraded the firmware over the Internet (not all upgrades have positive effects!) and I eventually sorted it out with a further upgrade.

What happens is that you centre a star or object and Autostar decides it doesn't like where you think it is and it returns the scope to where it originally placed it. Most infuriating! This occurs with alt/az alignment but seemingly not with polar alignment so you could try that and if the problem disappears, then you know it's rubber banding that's affecting your Autostar.

If you bought the ETX125 as a new scope, bring it back to the dealer and ask him to sort it out. Perhaps this scope was lying around in a storeroom for a long time and has outdated firmware. If secondhand, then I suspect you will have to upgrade yourself with the #505 cable set and Meade's free ASU program - www.meade.com/support/auto.html

Gordon

Mike Weasner and Clay Sherrod are two of the foremost experts on ETXs and Autostar. A brief search revealed two interesting pages.

www.weasner.com/etx/autostar/as_info.html
Scroll down to the last topic "Training, Setting Percentages and Rubberbanding"

also: www.weasner.com/etx/techtips/etx_tuneup2.html

Do a search for more links on rubberbanding from the search box on the home page:
www.weasner.com/etx/menu.html

Judging from comments on the Internet, it seems rubberbanding was still a problem for some as late as 2004.

Gordon

If I'm imagining this correctly, then it sounds like a software problem, althoguh I'd train the drives asap, just to eliminate that.
If that fails, then upgrade the firmware.

I texted the same message as above to mike weasner last night and he replied (in less than an hour) giving me similar advice to all your (appreciated) advice. Unfortunately I'm on day (13 hr) shifts at the moment and dont have the daylight to fix the problem. I'll post an update as soon as I address it. ps Where can I get a toucam pro? I've been reading lots positive reports and seeing the photo results here and in other sites.