Mesu 200 PA

[Mcrogers1]

I must have something set wrong in PHD2 or I didn't run guiding assistant long enough. The graph above was ran only about 6 minutes. I'll try another iteration with a 15 minute run and see what I get for PA error. From what guiding assistant states it turns off PHD2 pulse guide to the mount while it runs. Using PHD2 drift align tool you can choose to run it guided or not if I'm correct by disabling guide output by clicking on the brain icon. I may swap from the 644mm FL refractor to the 1625mm RC to get a better PA.

My star profile has good FWHM numbers and my SNR is good but the HFD number is around 5 with the number in parenthesis being 30. 

I'm not using a sky model and will using ACP for the horizon and pointing accuracy. 

Anyway, I have a dialogue started with Lucas now and I'm sure we'll get it sorted. It's nice to be a able to talk to the manufacture directly.

[Mcrogers1]

Question for Mesu 200  PHD2 users. When you do your initial cal and it finishes the east/west and north/south move does it state that it's clearing backlash?

[Davey-T]

Usually only says clearing backlash when starting the Dec calibration.

Dave

[Zakalwe]

2 hours ago, Davey-T said:

Usually only says clearing backlash when starting the Dec calibration.

Dave

^^Thats what mine does as well. I guess that there will a setting in the Brain somewhere to alter that behaviour as the Mesu has no backlash. I've never looked though, to be fair.

[Davey-T]

Shouldn't think it mattered if there's no backlash to clear anyway ?

Dave

[Mcrogers1]

Here is what the guide graph looks like after 10 minutes. Of course this is a FL of 644 and I will have to switch to the long FL to get PA dialed in. 

[Mcrogers1]

I guess I spoke to soon because after 15 minutes this is what happens: The RA line goes off the screen and I can't get it back by adjusting the Mx RA. Went as high as 5000. The star went that far out of the box and kept on moving. I don't know what caused this. Restarted guiding and it was good for a few minutes then this over and over.  No cable snags. Guiding assistant was ran for 10 minutes and had .4 arc minutes of error.

[swag72]

The guiding in the first screen looks great!! The jump in RA that you experienced *could* be the jump that a few of us are experiencing. Without fiddling mine comes back and settles down....... If it is that, I do believe that there is light at the end of the tunnel to resolve that

[Mcrogers1]

I hope so but my RA line is off the screen even with the y axis set to 16 and it  doesn't come back. It starts moving in RA and the star moves a lot between each guide exposure.

[swag72]

My RA jump is between 75-100" so would be WELL off the PHD screen too!! 

I use PHD Log viewer and you can see a screen grab of how much the RA jumps.

 

 

[kirkster501]

I shall be following this thread in earnest when I get my MESU in the next few weeks.  Mount-less at the moment and have missed a lot of clear skies between Xmas and NY

[gnomus]

3 minutes ago, kirkster501 said:

I shall be following this thread in earnest when I get my MESU in the next few weeks.  Mount-less at the moment and have missed a lot of clear skies between Xmas and NY

Maybe clear, but only a couple have been any good.  (Hoping tonight will be an exception.). I doubt you'll regret the Mesu.  Most seem to be working well.  I hope those who have issues will get them fixed soon.

[Davey-T]

On 01/01/2017 at 07:10, Mcrogers1 said:

I guess I spoke to soon because after 15 minutes this is what happens: The RA line goes off the screen and I can't get it back by adjusting the Mx RA. Went as high as 5000. The star went that far out of the box and kept on moving. I don't know what caused this. Restarted guiding and it was good for a few minutes then this over and over.  No cable snags. Guiding assistant was ran for 10 minutes and had .4 arc minutes of error.

Max RA setting usually just keeps ramping up higher and higher because the mount isn't responding to the pulses.

Dave

[Mcrogers1]

I was able to run for 30 minutes last night without problems before the clouds moved in.

My refractor is messed up because after a 5 second exposure the stars at the edge look like lines and distorted towards the center in from the edge. PA error shouldn't be a factor at that short exposure. I have to swap to the RC for more testing because the refractor doesn't provide a good testing platform right now. 

I just noticed that my string attached to the Polemaster cap was not secured and could have snagged on a bolt on the Mesu and caused the runaway RA above.

This can be a frustrating hobbie but a fun and worthwhile one.

[Mcrogers1]

Got 2.5 hrs guiding without problems tonight before the clouds attacked again. This weather I swear.

[Mcrogers1]

Hello,

Ran guiding assistant for 704 secs and this is what I have with the 1625 FL. The RA drift rate is pretty high. The guide graph is after 2.5 hours. If I can get round stars at the sub lengths I'm aiming for then I don't think to chase a super flat guide graph will be worth it. I don't know how much the FWHM numbers will impact the PA drift aligning but I can't get much better than 5 no matter where I slide the X2 on the OAG shaft. Might have to upgrade to a MOAG because it has fine adjustment for guide camera position. The sub is a 30 minute HA without a good focus or any type of calibration done.  I did notice that when moving the mount I have to recalibrate PHD or the RA will run away. I set SGP to recalibrate on target changes and it seems to be fine after that.