PME Commissioned ... finally!!!

[marc4darkskies (Marcus)]

After waiting an eternity for the clouds to break I finally managed to finish commissioning my new PME.

Raw uncorrected PE of this mount is only +-0.8 arcsec!! I repeated the measurement several times to make sure too! The corrected PE seems to be lost in seeing noise but PrecisionPEC suggests +-0.5 arcsec.

I also did a 300 star TPoint model. This will get me to within 10 arcsecs RMS of any target using TheSkyX (which I can't use in anger yet because my Laptop is too old and slow ) or 13 arcsec in TheSky6 (after mimicking as much as I could from TheSkyX's model). Polar alignment is close enough!

See the screen grabs at the bottom of: http://www.pbase.com/gailmarc/paramount_me

Now I can get back to imaging!! Woo Hoooooo!

Cheers, Marcus

[pmrid (Peter)]

Congrats Marcus. They look the goods don't they. I can't wait 'til my PMX arrives. Which leads me to ask a question. When I mounted my Titan, I had to shorten my pier by about 400mm so I wasn't standing on stepladders. Now at 700mm, it is just about right for my short little legs.
Did the PMA require a similar 'shortening' of your pier?
Peter

[marc4darkskies (Marcus)]

Originally Posted by pmrid

Congrats Marcus. They look the goods don't they. I can't wait 'til my PMX arrives. Which leads me to ask a question. When I mounted my Titan, I had to shorten my pier by about 400mm so I wasn't standing on stepladders. Now at 700mm, it is just about right for my short little legs.
Did the PMA require a similar 'shortening' of your pier?
Peter

No. As it turned out, my 1.06m (42 inch) pier was about the right height. The PME was very close to the same height as my old EM-400. In fact the setup is closer to the ideal height for my dome.

Yeah, that PMX is a good buy for sure - you'll love it! Make sure you post plenty of pictures when you get it!

[strongmanmike (Michael)]

That uncorrected PE sounds very good....nearly as good as my NJP

In reality as an imager, I imagine you will rarely need that level of pointing accuracy..? but good to have when you do.

Top stuff

[g__day (Matthew)]

Very, very impressive stats!

[marc4darkskies (Marcus)]

Originally Posted by strongmanmike

That uncorrected PE sounds very good....nearly as good as my NJP

In reality as an imager, I imagine you will rarely need that level of pointing accuracy..? but good to have when you do.

Top stuff

True enough ... but if you've got it, flaunt it!! Besides, it brings a smile to your face when you can slew to the opposite side of the meridian and have your target smack bang in the middle of the FOV .

Seriously though, anything that removes just a little bit of fiddling from your workflow (ie (re)acquiring and centering your target from night to night) is a bonus!

Cheers, Marcus

[gregbradley]

Wow, you really got your mount setup beautifully Marcus.

I tried using PemPro demo to fit a PEC. I got a PEC curve but its upload to PME option did not work as it said to do. Or at least I don't think it did.

How did you find Precision PEC? Pempro claims to be more accurate because of a few things it takes into account. But of course if you can't upload it when done it isn't is it?

How did you do your polar alignment - CCD drift alignment? Or did you use T-Point and follow its recommendations?

I improved mine recently and am back to round stars. I was getting slightly eggy stars for a while.

One thing that helped was I entered the time more precisely using my iphone's clock.

And using a 15 point T-point polar alignment recommendation.

I think I need to do a 50 point model and see what the recommendation is to tweak it a bit more. Automapper may be just the tool. Is it hard to set up?

Greg.

[marc4darkskies (Marcus)]

Originally Posted by gregbradley

Wow, you really got your mount setup beautifully Marcus.

I tried using PemPro demo to fit a PEC. I got a PEC curve but its upload to PME option did not work as it said to do. Or at least I don't think it did.

How did you find Precision PEC? Pempro claims to be more accurate because of a few things it takes into account. But of course if you can't upload it when done it isn't is it?

How did you do your polar alignment - CCD drift alignment? Or did you use T-Point and follow its recommendations?

I improved mine recently and am back to round stars. I was getting slightly eggy stars for a while.

One thing that helped was I entered the time more precisely using my iphone's clock.

And using a 15 point T-point polar alignment recommendation.

I think I need to do a 50 point model and see what the recommendation is to tweak it a bit more. Automapper may be just the tool. Is it hard to set up?

Greg.

PrecisionPEC was simple and uploaded the PEC curve to the PME without issue. Given it's such a small PE I was surprised it fitted a curve so well.

I used a smaller 30 star TPoint model to do the polar alignment. Your PA would have to be pretty bad to yield out of round stars! What guiding software were you using?

Yes, accurate time on your PC is critical. Download NMEA time (small cost) to connect to an internet time server. It will update your clock when you start up and then you can set it to update regurlarly - I set mine to update every hour.

AutomapperII is very easy to use ... and it's free!

Cheers, Marcus

[batema (Mark)]

Hi Marcus,

If you want conversation then please don't invite me to look at your set up as I would happily sit there for hours just staring and dreaming at that amazing looking set up. You must be thrilled. Well done and thanks for all the photos.

Mark

[[1ponders] (Paul)]

I can really appreciate this photo Marcus, wholeheartedly and completely
http://www.pbase.com/gailmarc/image/132296221
http://www.iceinspace.com.au/forum/a...se.php?a=87502

what a beautiful setup.

[gregbradley]

Originally Posted by marc4darkskies

PrecisionPEC was simple and uploaded the PEC curve to the PME without issue. Given it's such a small PE I was surprised it fitted a curve so well.

I used a smaller 30 star TPoint model to do the polar alignment. Your PA would have to be pretty bad to yield out of round stars! What guiding software were you using?

Yes, accurate time on your PC is critical. Download NMEA time (small cost) to connect to an internet time server. It will update your clock when you start up and then you can set it to update regurlarly - I set mine to update every hour.

AutomapperII is very easy to use ... and it's free!

Cheers, Marcus

Hi Marcus,

No I disagree, PA can be close and still get eggy stars at 3 metres focal length. I have drift aligned it at times and gotten it very good and still get slightly eggy stars in 10 min subs. Mind you they are only medium eggy but not good enough.

Everything is easier at 1 metre focal length. At 3 metres round stars are a bit harder to achieve even with the PME. It needs to be setup just right but of course it is capable of it. I had it setup pretty nicely and I must have bumped into the scope a few times (its at one of those heights!) and also I installed an autodither plugin in CCDsoft and that affected the autoguider and took me ages to find out why things were going pear shaped with guiding.

I redid PA and it is close at the moment. I also accidentally erased the existing PEC curve and then tried Pempro. It created a nice curve but I couldn't get it to upload. I suppose that is a question for the Pempro group. It seems rather fiddly as a program and has lots of steps. But it may be the way to go and just go through the learning curve.

Guiding software is CCDsoft. I use a MMOAG with an ST402. It is a good setup although the connection between the 402 and the MMOAG is weak and a possible source of flexure. I may get a proper screw connector. I was also advised a simple parfocal ring on the 402 nosepiece helps.

You need Pinpoint as well as Precision PE. I may get those and go through a similar routine you have. It would be worth it long term.

Also now you have a large Tpoint model you can activate Protrack and get even better tracking.

My mount is also about +/- .8-1 arc second PE. I saw this a few times as I recorded PEC. The scale was +/-1.5 arc sec and the graph didn't go more than about 1/2 way to the limit.

The PME seems to be pretty tolerant of balance being such a beefy mount but I have seen errors from a lack of balance at times. It can be balanced horizontally and be out of balance at 30 degrees.

You must have wireless internet in your observatory? I don't have an internet connection in my observatory. I have a wireless modem but it didn't extend that far. Time off the iphone I imagine would be accurate to the nearest second. Updating it every time may be a good idea. I'll have to check to see if the computer's clock goes off over time. My time was off by about a minute when I updated it off the phone. It seemed to make a noticeable difference.

Greg.

[marc4darkskies (Marcus)]

Originally Posted by batema

Hi Marcus,

If you want conversation then please don't invite me to look at your set up as I would happily sit there for hours just staring and dreaming at that amazing looking set up. You must be thrilled. Well done and thanks for all the photos.

Mark

Cheers Mark. Right now all I can do is stare at it ... the weather won't let me do anything else

Originally Posted by [1ponders]

I can really appreciate this photo Marcus, wholeheartedly and completely
http://www.pbase.com/gailmarc/image/132296221
http://www.iceinspace.com.au/forum/a...se.php?a=87502

what a beautiful setup.

Ahhh ... kindred spirits!

[OzRob (Rob)]

Originally Posted by gregbradley

It created a nice curve but I couldn't get it to upload. I suppose that is a question for the Pempro group. It seems rather fiddly as a program and has lots of steps. But it may be the way to go and just go through the learning curve.

Did you find the special instructions to upload the curve in the help file? If you go the the help file and look under PEC>User's Guide>Program Mount there is a link to the instructions for the PME.

[marc4darkskies (Marcus)]

Originally Posted by gregbradley

Hi Marcus,

... Everything is easier at 1 metre focal length. At 3 metres round stars are a bit harder to achieve even with the PME.

Fair nuff.

Originally Posted by gregbradley

... I installed an autodither plugin in CCDsoft and that affected the autoguider and took me ages to find out why things were going pear shaped with guiding.

That plugin has never worked for me but I haven't tried it in a long time.

Originally Posted by gregbradley

...You must have wireless internet in your observatory? I don't have an internet connection in my observatory. I have a wireless modem but it didn't extend that far. Time off the iphone I imagine would be accurate to the nearest second. Updating it every time may be a good idea. I'll have to check to see if the computer's clock goes off over time. My time was off by about a minute when I updated it off the phone. It seemed to make a noticeable difference.

Greg.

Hmmm, yes, a few SECONDs can make a noticeable difference! I've just recently replaced my wireless connection with an ethernet cable. Wireless is a PITA - frequent dropouts at a mere 20m! Get yourself a GPS unit that has a serial port and outputs NMEA messages. NMEATime will happily decode these - no need for the internet.

[gregbradley]

Good idea. I have a handheld GPS unit. Not sure what output it has. I'll check it out.

You have to have Pinpoint for the automapper to work right?

Did you use the automapper to get your 30 point model? It seems to be the way to go otherwise it is time consuming.

I could probably install an ethernet cable. I could run it under the house and then across the final 12 metres in a shallow trench.
It'd be a total of about 30 metres though.

Thanks,

Greg.

[marc4darkskies (Marcus)]

Originally Posted by gregbradley

Good idea. I have a handheld GPS unit. Not sure what output it has. I'll check it out.

You have to have Pinpoint for the automapper to work right?

Did you use the automapper to get your 30 point model? It seems to be the way to go otherwise it is time consuming.

I could probably install an ethernet cable. I could run it under the house and then across the final 12 metres in a shallow trench.
It'd be a total of about 30 metres though.

Thanks,

Greg.

No. AutomapperII works with CCDSoft and TheSky6. Funny thing was my dome battery ran out of juice before I finished the 300 point model! I had to jury rig a cable from my UPS to finish. I have TODAY removed the dome battery and hooked the dome directly to my main power supply!!

My ethernet cable is 33 meters long (more than I need but I don't have the tools to make a custom length cable). I've had no issues so far.

Cheers, Marcus

[Doomsayer]

If you use boosted gain antennas for your wireless base at the house and at the receptor in your obesrvatory that helps a lot with wireless reliability. I use TheSky6, the 'old' version of Tpoint, CCDsoft, FocusMax and Pinpoint for my PME rig along with CCDAP for automation. Lately I have reverted to drift aligning the PME, but still use Tpoint for goto modelling. As others have recommended if you are using CCDsoft or Maixm, plus Pinoint for platesolving, the freeware AAG Tpoint Mapper is also excellent for mapping stars for automated Tpoint modelling. I have stuck with CCDsoft as its 'direct guide' mode allows direct control of the mount via the serial connection rather than a guider cable.

Greg, I was suffering from eggy stars at times at 2.3m FL using a MMOAG and remote guide head with my STL6303. What sort of errors is CCDsoft reporting when guiding? I suspect a lot of the time I was chasing seeing if conditions were a bit turbulent. Getting the min/max move settings just right can be tricky as the PME is capable of such fine moves. An AOL is on my shopping list for that reason.

I suspect I may have polluted the PEC in the PME at one time. You have to be careful when using PrecisionPEC as it can allow you to append a new curve to an old one already stored in your system - clearing any older PEC data on your PC before doing a PE run is essential. I haven't had trouble with uploading a PE curve to the PME so far - I still use a DB9 serial cable connection rather than the USB connection - I am still running XP Pro so serial is very reliable.

I am contemplating moving my PME to a remote site to get away from the coastal cloud and genrally ordinary seeing. We'll see.

guy

[gregbradley]

Accurate drift aligning is hard to beat because it is the actual thing rather than an estimation of the thing (with models etc).
Like in building there is the object and then there is the measurements of where the object should be. Not necessarily the same at all!

Try putting in the exact time. Check your long/lat/altitude and make sure that is exact. Do you callibrate your guider often?
Is it square to the scope?

When I accidentally erased my PEC curve guiding was worse. I just recorded a PEC using the Sky 6 and it looked like the original
(much like a sine wave and gentle not heavy) and that improved things. Check your balance especially at the angle you are most likely to image at. If your setup is top heavy that will shift balance as you change angle. Make sure your mount is level and I take it eveything is stable.

You might try using 1x1 binning on your remote guide head and a brighter guide star if you can find one. I found if I could use 1x1 it got better results than 2x2.

I tried to load Automapper and it came up with an error message saying Pinpoint was not detected and to load it first.

There is an update to Automapper so perhaps I need that but I think I need Automapper in first for the update to work.

My guiding is set to 4 second exposure times. I set min move to .01 and max to .5. If you get an error bigger than .5 its got to be PE or seeing or bad polar alignment. Firstly I use 2x2 binning on the ST402. I pick a star that is reasinably bright but also quite tight looking. I don't usually pick a fat star. I get quite a large difference in guiding errors between guide stars. A tightly focused brightish small star is the go and I use subframing to frame it but not too small so the guider can reacquire the star if cloud interrupts.

I see errors that vary as the seeing and PE go through their cycle but it would look like this:

.1, .2, .4, .28,.5, .05, .4, .66 so a range between high of about 1 and a low of about .05, average would be about .25 at a guess perhaps higher. When the scope is pointing closer to the zenith the guiding errors are noticeably smaller.

I have found this combo callibrates very quickly. In fact its one thing I like about the PME, it takes about 30 seconds to callibrate the autoguider and it almost never fails compared to hell in the past with other setups. So I tend to callibrate more often now and that helps.
I also make sure the 402 is square to the scope as it seems to be knocked out of whack easily.

I think Marcus's approach is good, getting a fairly large model and using its recommendations. The problem I had was I drift aligned using the camera and then did a 10 point T-point model and I followed its directions and it made the guiding worse. So not a large enough model, not accurate enough time would be the cause I assume.

I'd like to a get a big Tpoint model not so much for accurate go-tos as I get close enough to find things but to use ProTrack to gain an extra edge in autoguiding.

With the MMOAG and ST402 I find the camera is not stable in the eyepiece holder of the MMOAG. It can rock. So I adjust it so the stars are round rather than eggy which means it is tilting.

I am going to buy a cheap parfocal ring and attach it to help find focus easily and stabilise the 402 in the eyepiece holder more.

Greg.

[Doomsayer]

Hi Greg
Accurate time is automatic for me since theSky etc draws time from the atomic clock based time servers on the internet - GPS satellites work just as well,
Sounds like your CCDsoft guide errors are similar to mine in their characteristics. I use around 4-5 second exposures plus I find that binning 2x2 helps when seeing is poor. Last time I tested the system the eggy stars had subsided - it seems so rare that I get clear sky to test it, so I can't make any conclusion based on regular experience as yet. I find with calibration that having the star centred and isolated from other stars which might interfere is the main thing.

I always run my PME with a minimum of 60 or so stars mapped either side of the meridian using AAG Tpoint Mapper once I'm satisfied with polar alignment. With only 15 points or less mapped it's actuially difficult to draw accurate conclusions about your model. You need at least 25 or 30 points to get a handle on pointing and alignment with Tpoint in my experience over the last few years. I have done 250+ Tpoint models before, but since I use autoguiding, Protrack is perhaps not so essential. I also suspect my pier creeps a bit with the seasons so redoing a 250+ Tpoint model regularly is not attractive.

I don't seem to have much problem with balance - I regularly check this.
I only run the one OTA and a camera so I guess there's no issue.

I really like the MMOAG but as you say the guider connection can be prone to some tilt. I use am ST402 for autoguiding my EM200 with an E-finder - works really well, assuming the RJ12 connections are behaving. I used to use the ST402 on the MMOAG before I got the RGH so I know what your are talking about.

Pinpoint really is worth the expense - a minor cost in my opinion - plate solving allows so many powerful tasks to be done very accurately and easiily with your mount, scope and camera.

Marcus seems to be well on track - so I'm sure we'll be seeing some outputs soon if the weather behaves.
guy

[gregbradley]

Hi Guy,

I think with all this rainy weather it is entirely possible the slab a mount is mounted on could possibly shift.
In my case I haven't noticed that. My slab is 1000mm deep and 850mm square with lots of steel in it and must weigh
a lot.

My observatory needs a bit of repair already as the wall has bowed slightly making the roll off roof system a bit unstable. I think that is a result of the 40C days and some rain etc plus a bit of sag over time.

Greg.