Are there any PMX PE measurements yet?

[cventer]

Thanks for response. I am posting my CCDSoft logs here attached to this.

I am pretty sure now that the graphs I postd on Bisque site are showing the dec drift and seeing and not RA and PE.

When I look at the raw data one of the correction streams seems to be a very straight line with oscillations around +1 and -1 pixels.

The other is also straight (with drift) but more osciallations that look more like a repeating pattern which suggest this is actualy my RA.

If so then I am concerned as this shows my uncorrected PE as being terrible (+8.4/-3.8) arcsec which seems not right either for this mount.

i was unsure of camera orientation when I tooks this so be curious if someone can tell from this data which axis is my RA and which is DEC.

[cventer]

Originally Posted by frolinmod

Not really. I saw your graphs. They look good. That little amount of DEC drift is of no consequence to PE measurement. However, you really should improve your polar alignment (if that's what's causing the DEC drift) for obvious other reasons.

I need to check this, but dont think I have too bad a drift as far as I can see. The star stayed in a 50x50 pixel box for 30 minutes with ease. In fact in 30 min it maved a max of around 8 pixels

[gregbradley]

Originally Posted by cventer

I need to check this, but dont think I have too bad a drift as far as I can see. The star stayed in a 50x50 pixel box for 30 minutes with ease. In fact in 30 min it maved a max of around 8 pixels

Then your polar alignment must be sensational as that is not easy to do.

Greg

[frolinmod]

Originally Posted by cventer

In fact in 30 min it maved a max of around 8 pixels

Oops, okay, then. In that case, during normal operation, Protrack might eliminate that. You're not allowed to use Protrack when measuring PE, of course.

[cventer]

Can someone who has done this before please review my log. Right now it looks like my mount is out of spec in terms of PE unless I am looking at wrong axis which I don't think is the case.

[gregbradley]

I opened up the file in Precision PEC. After the data is fitted (drift removed and scaled correctly) your data is -2.8 to +2.8 with the vast bulk of it between -1.4 to +1.4.

You have 4 large spikes that take it out to 2.8 from the 1.4 band. So its average is more like 3 arc secs and including the spikes you get 5.6 arc secs which is below their spec. As I recall their spec is 6 or so isn't it?
So I take it you have at least 4 rough spots on your worm and it may be only 2 that repeat. What is the period of the worm? About 4 minutes?

I could compare it with my PME's curve if you like.

As I recall my PME was about 3.5 arc secs peak to valley. I don't recall seeing the spikes but when autoguiding there is definitely a period where the guide errors go up a bit for about 20 seconds.

Greg

[cventer]

Thanks Greg

Can you post a pic of the scaled data in precision pec ?

Seeing was also really bad as you can see by all the spikes in the dec axis . Sounds like it just needs to run a few cycles.

I used the excercise mount feature today and had it run for nearly an hour slewing RA and dec from hard stops so that should help some.

I will try agian another night if these clouds ever clear.

[gregbradley]

Excuse my ignorance but how do you do a screen shot?

Greg.

[gregbradley]

As I recall the manual says not to do a PEC run in poor seeing. It would give an wrong PEC curve. What you want is typical seeing, usual conditions so the curve matches what is most often the actual.

Greg.

[cventer]

Depends on what OS you use.

In windows 7 there is a little tool in Accessories menu called snipping tool. Just draw a box around the screen with this tool and it grabs it.

Other way in any OS is simply when you have the screen showing. press left Alt key and the Prnt Scrn key at same time. This copies the active window into memory.

Open up photoshop and select new. It will create a new canvas the size of what you captured in memory. Hit paste or Ctl-V and screen will appear in photoshop. Do the normal save for web thing and you are done...

Seeng was not great but also not the worst it gets. It was probably a little higher than normal but not that far off.

I thought these programs were supposed to be able to remove seeing as a factor for the most part.... ?

Originally Posted by gregbradley

Excuse my ignorance but how do you do a screen shot?

Greg.

[gregbradley]

Hi Chris,

I used the snipping tool.

See the attached.

Greg

[gregbradley]

And the final PEC curve that would be uploaded into the PMX on board memory:

Greg

[cventer]

Thanks Greg,

Although looking at that data I am pretty sure its loaded the wrong axis. That looks like DEC drift data and seeing to me. Plus my image scale was 1.82 which makes things a little worse.

Gues its shows the seeign was pretty bad though jumping around by anywhere from -2.8 to +2.8

Cheers
Chris

[gregbradley]

Hi Chris,

It looks like my PE graph. My data had a drift in it as well.

Greg.

[gregbradley]

I receive my PMX tomorrow. I'll have it up and running fairly quickly. So I can compare notes with you. Also some clear nights in the forecast are coming up.

Greg.

[cventer]

Nice

You must be very excited. But owning an ME you already know what you are getting in terms of quality.

Did you get a tripod for your as well ?

[frolinmod]

Speaking of tripods, I've had my Rob Miller TRI36H tripod partially out in the sun for several months now. The top part has been covered, but the bottom half has not. The bottom half is becoming sun bleached. It's turning pink.

I think you can see this fairly well in the attached images.

[cventer]

Interesting to know that re miller tripod. My Miller tripod arrives tomorrow. The accessory package arived last week and legs tomorrow. The micro levelers are the new enhanced ones and are works of art.

[gregbradley]

I have a solid steel "portable" pier that I will use. At my dark site I have a pier embedded in concrete.

I will bolt the aluminium adapter plate to the pier plate to mount the mount.

My home observatory was designed for 2 setups, the CDK17 on a PME and the steel pier
with refractors.

So the Miller tripod is fading in the sun?

Greg.

[Mighty_oz (Marcus)]

Originally Posted by cventer

Interesting to know that re miller tripod. My Miller tripod arrives tomorrow. The accessory package arived last week and legs tomorrow. The micro levelers are the new enhanced ones and are works of art.

Pics please hehe