LNT module for Meade LX90 - any info?

[tonybarry]

Hello People,

The Meade LNT module for the LX90 is apparently discontinued.

Does anyone have information on

(a) where can I get one, or
(b) anyone done any reverse eng on the unit (e.g.comms protocol).

Regards,
Tony Barry
WSAAG

[AndrewJ]

Gday Tony

Meade used to make a version that plugged into the Aux Port,
You may find one on EBay/Astromart etc.
We have deciphered the protocol,
but like everything else on the AUX bus,
its a totally non standard I2C format
and covers quite a range of processes.
Other than the RTC inside it, its not much use.
Doing a manual 2 star align is far quicker and easier,
and there are much better red dot finders available quite cheaply.

Andrew

[DavidTrap]

I used mine once and it now sits in the cupboard. As Andrew said the manual alignment is much quicker. Mst important tip is to get you tripod top level - invest in a $2 bubble level.

If you're still keen on buying a LNT, let me know via PM

DT

[acropolite]

+ 1 for manual alignment, I'm with David and Andrew on this one, the best thing I ever did was abandoning the LNT and using Manual alignment, mine had a dinky plastic screen that somehow broke despite my best care.

[tonybarry]

Thank you to Andrew, David, and Phil.

Last night (after I wrote the message to the forum) I went out and did a standard assembly of my LX90-10" ACF and an "Easy Align".

It is my practice to do a fairly exact level on the tripod top anyway (even with the LX90-8" GPS, which did have the LNT). And from experience I know where north is at my place of residence, so it's easy to point somewhere near that. Adding the necessity of levelling the tube was not onerous - it takes perhaps five seconds.

I am OK with using the "Easy Align" instead of Automatic Align. It is faster. But North is not as reliable. And if the tripod level is not correct ... well a two star align will not pick up an ectopic axis. For that, three stars are required, if my geometry serves me aright. The old method with the LNT would appear to pick up an axis error better than a two star align.

Anyway, I remain interested in the whole question. Once again, thank you to Andrew, David, and Phil. Your thoughts are much appreciated.

Andrew, if the protocol has been eng'd, is it worth implementing the LNT bit (apart from the clock) on something like an Arduino? I do a fair bit of AVR programming, and this might be a nice project. If you wished to continue the correspondence (off list) I'll send you my email address.

Regards,
Tony Barry

[AndrewJ]

Gday Tony

I will reply offline for some specific items
but basically, a full autoalign and an EasyAlign
are just a manual 2 star align wrapped in frippery
where "you" arent required :-)
Ie All three methods essentially use the same underlying
alignment algorithms to do the align, its just how/who chooses
the stars that changes.
The LNT module only "assists" you to centre the first star.
After that, anything it did is forgotten.
Basically, the system sets a datum point when you centre the first
star and then calcs the misalignment model when you centre
the second star.
Ie Everything prior to centring the first star is irrelevant
in the final process.
As such, manual 2 star aligning cr@ps on the other methods.

Andrew

[tonybarry]

Thank you Andrew. It's information like this that I wish Meade would publish. I suspect that it took you a good deal of digging to find this out. Your efforts are much appreciated.

Regards,
Tony Barry