Help please: MESU and PHD2 Backlash does not clear all of a sudden

[sloz1664]

19 minutes ago, kirkster501 said:

Indeed Dave (and Vlaiv). Don't let my issue here put you off.  My MESU has been operating flawlessly since I bought it in 2016 and guides and slews beautifully and has never missed a beat.  I am 100% confident this matter is not the mount, it is IT or balance related.  

Some clear patches about at tea time here in Nottingham.  If they hold for tonight I will be able to Polar Align and do some more testing and fiddling.

 

Hi Steve CO has given a clear night until 11pm 🤞

Just a thought, how are you running your Mesu in sgpro and PHD2. 

Steve

[kirkster501]

Hi Steve,

I connect all the gear in SGP.  I unpark scope and point it anywhere where there is a clear patch of stars.  I do a blind sync first so scope knows where it is pointing.  After the successful blind sync I then I right click my object in sequencer and centre on it to make sure it all works ok; scope slews perfectly and places the object bang in middle of FoV after two iterations within a pixel - it does its plate solve thing and all perfect.  Then I manually start PHD2 and select the star myself and start guiding. 

I then start the sequence and can leave the imaging rig and use my Dob.  True, it repeats some of the above steps.  But I like to do the above steps manually first to make sure all is well.

Meridian flips all worked perfectly.

The only change has been the mount has moved and twisted slightly on the pier - a degree or two max - slightly and the balance was not quite right.  I corrected the balancve and need to do another PA.

Steve

[andrew s]

5 hours ago, Davey-T said:

The fact that the software not being " in house " seems to cause most of the issues, given that all mount control software uses pretty much the same protocol surely it's not beyond the wit of the manufacturer to get a bespoke operating system written, it could then have a built in balancing routine ala 10Micron etal, that would take the guess work out of it as it only monitors the current drawn by the motors how hard can it be ?

Dave

Don't be fooled the software for controlling a mount is non trivial given all the possibilities in mount orientation and errors,  sky pointing - catalogue position v actual position, hardware limits, location on earth and northern v southern hemisphere,  etc etc. In many ways the hardware is in comparison trivial.

Regards Andrew 

[Davey-T]

1 minute ago, andrew s said:

Don't be fooled the software for controlling a mount is non trivial given all the possibilities in mount orientation and errors,  sky pointing - catalogue position v actual position, hardware limits, location on earth and northern v southern hemisphere,  etc etc. In many ways the hardware is in comparison trivial.

Regards Andrew 

Didn't think it was trivial but given the established protocols it should at least be straight forwards.

Dave

[whipdry]

For anyone considering purchasing a Mesu l think the mk2 has a lever system that releases the drive in both RA & Dec. 

 

Peter

 

 

[Skipper Billy]

I have never had any trouble balancing my Mk1 Mesu 200 - I get it close by feel then (with power off) use the tip of my little finger to push the mount in both directions - this gives a good 'feel' for when the pressure required to move the mount is the same in both directions (in RA and DEC). My experience is that its not particularly fussy about spot on balance but I always get it as close as I can.

[kirkster501]

😀IT WORKED!!!!!  IT WORKED!!!!!! Yay!!!! 😀

My PA was not bad anyway I was about 45 arc mins out.  It is precisely set now within a few minutes.  So that was not the issue.  The guide graph is like a pancake tonight.

Pretty sure it was balance that was not accurate enough!

Vlaiv, Steve, Dave and everyone else, have a virtual beer on me  🍻🍺🍷🍹

[kirkster501]

Look at this Ha 3nm Astrodon 5 minute bad boy that just came in    Thanks guys for your help.

[vlaiv]

1 hour ago, kirkster501 said:

Look at this Ha 3nm Astrodon 5 minute bad boy that just came in    Thanks guys for your help.

That looks nice and tight!

[mihaighita]

4 hours ago, kirkster501 said:

😀IT WORKED!!!!!  IT WORKED!!!!!! Yay!!!! 😀

My PA was not bad anyway I was about 45 arc mins out.  It is precisely set now within a few minutes.  So that was not the issue.  The guide graph is like a pancake tonight.

Pretty sure it was balance that was not accurate enough!

Vlaiv, Steve, Dave and everyone else, have a virtual beer on me  🍻🍺🍷🍹

🥳. I'm glad it worked!

[mihaighita]

On 31/08/2019 at 13:12, mihaighita said:

Mesu 200 MK2 solves that. With Mk1 there are ways to balance it perfectly. I use a system of pulleys attached to the center of the rotation axis and measure the force needed to pull in any direction. I also have another idea that I need to clear with Lucas first... The dec motor has a tension adjuster on the top that can be loosen and make the dec axis turn extremely easy. I was thinking to use that for balance and then tighten it again to operate the mount. But I need to see that this will not cause any damage to the motor axis. There is also the possibility to monitor the power needed when you are using the handpad to rotate the dec axis. Note that I am speaking only about the dec axis because the Ra axis is easy to balance due to the much bigger centripetal force. 

 

I had an email exchange with Lucas and he told me that the above tension adjuster method for balancing will surely damage the mount. So, please don't try this!