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Mesu 200 with sitech ii controller


ncjunk
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Hi everyone,

Following on from my original review of the mesu 200 with argo navis and servocat controller i thought i'd post a review of the mesu with the sitech.

When i last left you i had a mount with a dec that i couldn't get to work, and probably made worse, after the delivery company threw the mount around in transit and a controller that had no usefull automation on it's ascom driver, in fact i don't class it as an ascom driver as its next to useless.

The argo navis servocat combo really was a manual babysit it configuration needing someone in the observatory.

Servo cat AN pros:

Excellent goto accuracy

Great hand controllers

Fantastic 1 star alignment

Smooth operation

Easy to use.

Cons:

Ascom driver has no functionality

No park

No possibility to automate it

No meridian flip

In fact its a waste of time connecting it to a pc.

But if you dont need or want to use a pc the setup was a joy to use giving you less things to go wrong.

So now we come to the mesu with sitech servo controller ii.

It has a fully functional ascom driver thats more than just an ascom driver, think Eqmod here and you've got it nailed. It even has a simplified skyview so you dont have to connect to a planitarium.

The setups a little bit noisier than the servo cat but seems very solid. After installing the software and drivers i was able to connect and control the mount first time. The array of options is truly magnificant.

Part 2 to follow later- alignment and goto acuracy.

Regards.

Sent from my GT-I9003 using Tapatalk 2

post-1827-137529415143_thumb.jpg

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So as your stone age time travel Time Team friend I get to say...

I agree!

SOMEONE IN THE OBSERVATORY????? What, you mean a Nerd?? Oh God!!!! Probably some small bald bloke in his his sixties. Yuk!!! The kind of halfwit who can find Stephan's Quintet in a Yob. No, what are they called? Snob? No, Dob. That's it, Dob!

Now joking apart (for the benefit of those raised on smiley faces Neil and I share a joke!) let me tell you just why I love, no LERVE, the Sitech for the Mesu; Yves is modern man and he might one day sell me his old version. I'm already swooning.

Heh heh.

Olly

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Hey! I wrote leters on actual paper! Had to use a typewriter as well.

But i was also in the first generation brought up on computers ahhh zx81 where art thou?

I'm pre-smilies and sadly had email and internet at uni when it all kicked off in the early 90s i didnt realise it was a big thing i just thought it was blumming usefull and it was obvious everyone should be doing it...like astronomy!

Sent from my GT-I9003 using Tapatalk 2

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Neil could you put some screen shots of the software in action please :)

Ok, It´ll take a little while as I´ll be fighting the workmen for control of the power socket whilst being attacked by two screaming kids. Hopefully tonight!

Its worth noting you can download the driver and it will run in simulation mode if it can´t connect to any controller. So you can set it all up and have a play with carte du ciel and it works exactly as if a mount were connected.

Sorry for being a dimwit - Can it run on EQMOD then?

No it can´t run Eqmod Sara, I mentioned it to give most people an idea of the kind of control you have with the sitech driver. I think a lot of people know Eqmod and comparing the Sitech ascom driver to eqmod, although functionality differs, is a good comparison as they both do similar things. Both have:

Polar align

Park

n star synchronisation

Easy to connect to

Control of mount via push buttons

Guiding via Ascom driver or guide relays

The sitech controller Ascom driver also has:-

Skyview map- a small planitarium that shows star positions and telescope position.

PointXY- Models the mount characteristics based on selection of star positions

Scripting- you can set scripts to go to position XY wait x time then to position RT, wait etc.

PlatesolveXP - calculates position from a ccd image and allows you to sync (download of star catalogue required)

Effectively the Sitech ascom driver is an Ascom driver and Telescope mount control software and configuration tool all in one with lots of features. It can alter the tracking rate to compensate for mount errors and polar alignment errors once you have Modelled the mount characteristics using PointXY and a minimum of 16 reference stars.

I tried doing an alignment last night and found I hadn´t revised the manual enough. You must pay attention to the Goto, Sync and polar align sections of the manual and re-read a number of times for it to sink in. There are to sync modes "Initial Offset" where you go to the first star such a Viga and then select "Initial Offset". This effectively syncs the sitech to the sky, it moves the position of the sky within the controller so it lines up with where it thinks it should be.

Tracking will not run until you have done an "initial offset" sync. So you get to the star do an initial offset so tracking starts. Then center the star and press "initial offset" again and you have your 1 star alignment done.

you then have Cal star inits which are:-

"Instead of "shifting the sky", which effectively the Offset Init does, the Cal Star inits load the

hour angle, declination, primary axis angle, secondary axis angle into a "matrix". As soon as the

2nd star is "loaded", the polar transformations are performed to convert between the telescopes

primary and secondary axis, and the Hour Angle and declination of the object(s). If you have a

mis-aligned equatorial telescope, your goto's will be accurate, even though you're mis-aligned,

after you load the 2nd star. Cal Star inits are also the type of inits that are used when you do

your mount modeling using the Point XP modeling tool"

I made a right pigs ear of it last night by not understanding the difference and then choosing two stars which were incorrectly positioned. I ended up calibrating it incorrectly and the mount sat there oscillating on its own. After re-reading the manual I now know where I went wrong and I think I should not have had the stars either side of the meridian. 1 should be at the meridean but not past it and the other at 30 deg.

If you have an observatory I think this is a very very powerfull controller once it´s set up.

More updates to come when the weather clears and I can correct my alignment mistakes from last night.

Edited by ncjunk
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You are going to have fun with this Neil - and I mean that in a good way! The two different 'inits' (initialisations) are a little confusing at first. I think of them this way:-

1. CalStar Inits are those used for sky modelling and although these can be added manually (the more the merrier) the automatic sky modelling script supplied with the software does a great job of doing this for you - quite magical to watch it automatically slewing in the most efficient manner and carrying out a plate solve before moving on to the next region of sky. Don't forget to produce a horizon map first unless you are lucky enough to have 360 degrees of uninterrupted horizon!

2. Offset Inits are used at the start of a session and simply tell the mount where on the sky model you are currently pointing - only one is required. This is just a safeguard in case the mount has been knocked since it's last 'park'.

I use both the built in Skyview chart and Cartes du Ciel but prefer the latter as I have been using CdC for years with EQMod and I am completely on home territory.

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Give me a nice brass winding handle any day...

Anon.

There's a lot to be said for that too which is why I still have an ArmStrong rotation system for my dome - it ensures that as a minimum, I am out there enjoying it all every fifteen minutes!

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Give me a nice brass winding handle any day...

Anon.

I'm getting a restraining order on you if your not carefull. One more mention of "the good old days" and i'm off :D (i hope you understand smilies...)

Sent from my GT-I9003 using Tapatalk 2

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You are going to have fun with this Neil - and I mean that in a good way! The two different 'inits' (initialisations) are a little confusing at first. I think of them this way:-

1. CalStar Inits are those used for sky modelling and although these can be added manually (the more the merrier) the automatic sky modelling script supplied with the software does a great job of doing this for you - quite magical to watch it automatically slewing in the most efficient manner and carrying out a plate solve before moving on to the next region of sky. Don't forget to produce a horizon map first unless you are lucky enough to have 360 degrees of uninterrupted horizon!

2. Offset Inits are used at the start of a session and simply tell the mount where on the sky model you are currently pointing - only one is required. This is just a safeguard in case the mount has been knocked since it's last 'park'.

I use both the built in Skyview chart and Cartes du Ciel but prefer the latter as I have been using CdC for years with EQMod and I am completely on home territory.

Thanks for the input steve,

Its definately confusing at first. I also have to figure out what to do when connecting to ACP which also has a mount modelling database.

I could have a mount model running off of another mount model if i'm not carefull

Sent from my GT-I9003 using Tapatalk 2

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Will be following this thread closely (see my thread re me getting a Mesu yesterday) ...you lot already have a head start understanding ascom and eqmod ...I have used neither with my up to now G11 with 'push to' Argo Navis. :huh:

I have the SiTech Quick Start Checklist but a step by step guide with screen shots would be fantastic.

Tom

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Last night I managed to find a clear spot pointing west and performed a polar alignment using

the built in routine.

The first part of this sequence is to perform a number of syncs to stars.

On the sitech software select the "GoToSync" tab and then the "Star" tab.

In the window that pops up chose the star you want to sync to.

post-1827-0-48990400-1375516300_thumb.pn

Now select GoTo and the mount will slew to the target ( or you can manually slew the mount using the buttons under the "Scope" tab or the hand controller).

Center the star and then select "Sync" and the following screen will pop up with a timer counting down on one of the buttons.

post-1827-0-27077600-1375516453_thumb.pn

As we haven´t done any syncs yet the countdown timer will appear as additional text in the "Simple Offset Init" button, number 1 on the picture.

The mount is not tracking at this point so press the "Simple Offset Init" button, without worrying if the star is exactly centered, and the point will sync and tracking will start. We can now move the star so that it is centered and then redo the "Initial offset sync".

We have now synced the sky model in the controller so that it is moved to match where the mount is pointing.

Next need to load some cal points by selecting 2 stars and syncing them. 1 star at around 30 deg near the equator, above or below, and then another on the same side of the equatorial line but near the meridian NOT PAST IT. if you read the instructions in the manual the first description is for an EQ mount telling you to do syncs either side of the meridian DONT DO THAT. The mesu is a GEM and the GEM instructions state both stars on the same side. (guess who misread and tried an EQ polar align....)

Part 2 next where we sync two stars fiddle around in the dark a bit and repeat....then realise the clouds come in and start swearing...

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After the initial sync the gotos now should be acurate enough for the polar align and tracking is working.

Select your first star for the alignment, I used Arcturas for both the initial sync and the 1st Cal sync.

Perform a Goto and center the star. Select the "GoToSync" tab and press "Sync".

Now press button "2", shown on the attached picture, to perform "Load Cal Star No. 1"

post-1827-0-52083500-1375517586_thumb.pn

Now select the second star from the menu,Perform a Goto and center the star. Select the "GoToSync" tab and press "Sync".

Now press button "2", shown on the attached picture, to perform "Load Cal Star No. 2"

We now have the two sync points ready for polar alignment. To perform the alignment select a star for performing the alignment on.

This star should NOT be near the zenith, or the east or west horizon. I picked a star near to my 2nd sync point as it fitted these criteria.

I performed a GoTo to the Star and then performed a "Simple Offset Init" (see previous post for details). Now we can go to the "Features" tab and select "Polar Align". The following screen appears:

post-1827-0-23893400-1375518048_thumb.pn

Click "Yes" to perform the Alignment. The scope will now be moved by the controller and when it stops we can manually re-center the star, using the mechanical adjusters...those brilliant bolt/screw thingies (you can tell i´m a software engineer and not mechanical).

Center the star and clear the cal points.

I am not 100% clear on the next bit as the help says to press "Clear all Inits" without helping fools like me find it....it´s probably obvious...

So I went to the "Scope" tab and pressed the "PointXP" button (Shown in Green on the attched picture):

post-1827-0-08519200-1375518890_thumb.pn

I then pressed the "Clear Terms and Cal Stars" button, with the star still centered, and after selecting "Yes" to delete all terms and cal points I then pushed the "Write Config" button.....not sure if this is correct but it all worked.

Then you can repeat the polar align as many times as you want. The above seemed to work as the next Polar alignment had the stars appearing on the CCD sensor.

Tonight I´ll try to model the mount by doing the 16+ Cal points (25+ is better), Hopefully I´ll not touch it after this.

There may be errors as this was "Extreme" forum posting whilst being shouted at by two small children for milk, toast and a film....no not that film Dad!...this films scary....the other film!

Edited by ncjunk
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Make sure you install the latest version of the Sitech Ascom driver. Version 90P, version 90A the park and unpar doesn't load the parameters correctly for the pointXP when unparking. Version 90P works fine.

Sent from my GT-P5110 using Tapatalk 2

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Thanks for that Neil...When I open SiTech.exe the version at the top is VO.90P so it looks like I have the right one.

Dan on the SiTech forum had to send me some sort of driver yesterday as I couldn't get any comm port to work... it worked and I now have control of mount.

Am sat in obs now reading the SiTech manual on my laptop while trying things on the obs/scope PC. :icon_confused:

This thread of yours will be very useful when I am past the basic stuff.

Just posted a question on the Mesu forum re encoder click setting in servo config.

Tom

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You shouldn't have to change any encoder settings, are you having problems?

Another thing that may catch you out is if you slew to a star using planitarium software like carte du cieles then be carefull to sync using carte du ciel. Dont sync using the ascom driver. Basically sync with the same software you did the goto with. I did a goto on carte du ciel and synced using the ascom driver which had the previous star set. Basically i said arcturus was where Vega was...obviously its bloomin not so it throws the calcs out and the motors start moving until it hits the mount or you estop it (on the goto menu).

Look at how to set your visible horizon, slew to a point that is just on the visible side and press add horizon point (i'll check out the details later) but if you do it during the day within half an hour you can have your visible horizon mapped and your good to go.

Sent from my GT-P5110 using Tapatalk 2

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Hi Neil

Thats good to know re the horizon.

No I was just looking at the settings ...wasn't going to alter anything...and was curious why one (RA) encoder was set different than the other (Dec)

Had a reply from Steve and his were set different as well so maybe that's how they are set up

One thing I was curious about though was the park.

As it says in SiTech when you have parked the scope and powered off if it moved it will throw settings out.

As the Mesu has no clutches I find that even if well balanced it could be moved relatively easily power off if say removing a camera etc.

I would have thought that with having 4 encoders that if you moved it, power off ,then switched on and selected 'park' it would motor to the park position but it doesn't it just stays where you put it.

I haven't of course yet done an alignment yet ...was just experimenting in the daylight today so maybe I am missing something.....I know the 10 micro and even the new EQ8 can be moved around clutches off and still remember settings.

Tom

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Hi Tom,

You have two types of encoder pulse per rev. and absolute (i might have some terminology incorrect but you'll get the idea). A pulse encoder will provide a number of pulses per revolution so you now how far you've travelled from point A but you can't determine where point A is.

An absolute encoder will have a set patern of bits for each position on it's revolution so each position is unique and you can know where A is and you can look at the position to find B.

We have pulse encoders so if we lose position then we lose the ability to determine where we are and we have to do a sync in order to regain that knowledge. Basically if it gets moved by anything other than the controller the controller won't know where it's moved to and be lost (as it wasnt reading the pulses or direction when it moved)

Now, once we have performed cal. Inits on 15 - 35 stars around the sky then we have mapped a model of the responce of the mount. If we lose position we only have to slew to a known star and do a simple init offset which then matches our model to the mount position and from that point we can carry on as normal.

What myself and Steve do with our mounts is park it so that the levers that lock the axis are next to their slots and then turn off and lock it down. On a start up i can do an simple offset init.

The sitech controller has the ability to use home position switches so that on start up it drives in a set direction until it hits the switches then syncs itself. So hopefully at some point in the future we can figure out how to add these switches to our mounts and add in that functionality.

Hope thatnhelps :blink:

Sent from my GT-P5110 using Tapatalk 2

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Thanks for that Neil

Yes it would be ideal if the required park position coincided with the lock indentations.

However...I want my park position to be at the very lowest the mount will go height wise with the scope on ...so that my roll off roof JUST clears the scope

But in this position the scope doesn't line up with a slot for the locking pin.

I think a good update for the Mesu (I wonder if Lucas reads these forums...not noticed any input from him like the SiTech guys) would be to put multiple notches in the discs instead of just 4 at 90 degree intervals

Tom

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Thanks for that Neil

Yes it would be ideal if the required park position coincided with the lock indentations.

However...I want my park position to be at the very lowest the mount will go height wise with the scope on ...so that my roll off roof JUST clears the scope

But in this position the scope doesn't line up with a slot for the locking pin.

I think a good update for the Mesu (I wonder if Lucas reads these forums...not noticed any input from him like the SiTech guys) would be to put multiple notches in the discs instead of just 4 at 90 degree intervals

Tom

The hooks are only for loading the scope. SInce it went on the mount here, Yve's have never been touched. Why would you want to use them? If you were non-observatory you might use them in the wnd but in an observatory?

Olly

Edited by ollypenrice
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Hi Olly

As Neil said ...to keep the park position proof against nudging.

I need my park position to be at the very lowest available to give roof clearance in my roll off and still max sky view in use.

I have temporarily put a scope on the mount this week just to play with it (only got it on Wed) and not fully balanced it ...and because the Mesu doesn't have clutches when turning the power off it sags down under it's own weight in certain positions

I Know that when I am all up and running with my pier height finalised and dual mount fitted it WILL be all properly balanced ...but it would be handy to swing the locking pin in at ANY park position (well maybe 16 notches instead of 4) so it doesn't move when taking the camera off at the end of the night etc and nudge the roof.

You obviously have far more expertise on the Mesu than me so excuse me if what I have just said is rubbish :smiley:

Tom

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Why would you want to use them?

Because I do outreach here, I get visitors who can all too easily knock the telescope in the small confines of a 7' dome so I use my locks coincident with my park position so that even with a knock I have a good home position to unpark from. If I had a bigger observatory, it wouldn't be necessary.

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