New System a Start for Assembly

avandonk · #1 24-03-2012, 02:51 PM

Luke Belleni just dropped off the pier adapter and modified bits for the side by side unit for the new PMX mount.

Bert

Paul Haese · #2 24-03-2012, 07:22 PM

I have to ask Bert, what is the deflection like with that pier? To my mind is the idea that the pier of that size would deflect considerably. Perhaps I am wrong, but with the gear you have on board there may be some and that might be a problem you will need to sort later down the track.

That aside I am glad to see you getting the new gear altogether.

avandonk · #3 24-03-2012, 09:01 PM

Thanks for your concern Paul. Here are a couple of images of the pier. It just does not deflect or have nasty harmonics.

The eight bolts at the bottom allow the pier to be adjusted level without any extra stuff at the top. This gives about 2 or more hours past the meridian so no flips are needed.

The four almost full length tapered gussets ensure that there is no bending at the base. This is where the bending moment is at a maximum. A pier can be considered as a vertical spring pendulum and will have a harmonic frequency depending on load and stiffness. The taper gives the system a low 'Q' so any high frequencies from mount motors or fans will be damped.

I have had about 40+ kg on the EQ6 without any problems. It was SN10 with a focal length of 1150mm.

If I do notice any flex I will just get a new pier made with a larger diameter tube.

Bert

Paul Haese · #4 24-03-2012, 09:43 PM

Yeah tapered gussets is what I have on the pier down at the observatory. That all seems to gel and now that I can see the gussets that changed my mind considerably. I did not see those before. Thanks for pointing that out.

Mighty_oz (Marcus) · #5 24-03-2012, 09:44 PM

Tiss a thing of beauty there Bert

Be nice to see it all working. Are u going to run the cables thro the mount ?

cventer · #6 25-03-2012, 11:36 AM

Bert

Looks good bert.

What side by side setup is that ? Looks very interesting.

Where did you buy this setup ?

gregbradley · #7 25-03-2012, 11:54 AM

Great looking mount and setup.

Your mount seems more red than mine. Mine is more of a pink/red. I read there were some problems with the anodising with some early models so perhaps they either changed anodisers or changed colours slightly. Unless its simply the white balance in your camera.

Greg.

avandonk · #8 25-03-2012, 01:18 PM

Quote:

Originally Posted by cventer

Bert

Looks good bert.

What side by side setup is that ? Looks very interesting.

Where did you buy this setup ?

I got it from here Chris

http://www.starstuff.com.au/

Luke Belleni from Starstuff made the side by side. It is very robust and very well made. I have never seen flexure even with a Meade 10" SN on the EQ6.

He has a PME himself and has designed a double dovetail bar that fits into the standard versa plate of both the PME and PMX. You will need to rotate the versa plate by 90 degrees to get full mount travel.

He is helping me by making all the bits I need to set up the new system. He is not cheap but that is because it is high quality equipment. He is based in Melbourne and is quite happy to design custom equipment.

Well worth a look. If you like I can put up some images. He has good images on his site.

Bert

avandonk · #9 29-03-2012, 10:30 AM

A bit more progress. The mount is now controlled by the software. The correct coordinates and hemisphere have been set. I actually read the manual to get this far or when all else fails RTFM! Luke Belleni showed me how to get started. Although we could not get far as it was very cloudy.

The pier has been accurately levelled with a builders level and the small level on the PMX agrees with it. I have just put my finderscope on for the present which is a F1.8 16 to 160 mm Canon zoom with GstarEX camera. This will make a 'rough' polar alignment far easier.

I sent the mount over most of my visible sky and the objects selected for goto did appear on the finderscopes screen at low magnification.

It is obvious to me I need to play with the mount alot more before I fully understand it. The sophisticated features of the PMX are too numerous to understand quickly or easily.

Any advice gratefully accepted.

Below are a few images showing more detail of the side by side and the finderscope.

Bert

Paul Haese · #10 29-03-2012, 09:31 PM

Bert to get pretty accurate polar alignment, follow the rountine using the SkyX. That is select a star and tell the mount to slew and when it stops move the mount in az and alt. That gets you pretty close to the mark. Then do a Tpoint run and follow the Tpoint recommendations to move the mount.

avandonk · #11 30-03-2012, 10:23 AM

Thanks Paul.

I have set up a 100ED with a GstarEX as well as the finder. Cloud last night stopped further progress.

Yes another four leads trailing but this is only temporary. I am getting to old and lazy to chase an eyepiece around on a goto mount.

The sky finally cleared early this morning and I spent some time accurately aligning the finder with the 100ED. This means I will be sure that the star in the field of the 100ED is the correct one when it comes to adjusting altitude and azimuth of the mount.

Dawn arrived before I could start to do a 'rough' polar alignment.

This gives me another day to try and ingest the information in the manual.

Bert

DavidNg (David) · #12 30-03-2012, 11:54 AM

Quote:

Originally Posted by Paul Haese

Bert to get pretty accurate polar alignment, follow the rountine using the SkyX. That is select a star and tell the mount to slew and when it stops move the mount in az and alt. That gets you pretty close to the mark. Then do a Tpoint run and follow the Tpoint recommendations to move the mount.

Hi Paul,

After doing a TPoint run and following the TPoint recommendation to do polar alignment adjustment of Az/Alt, do we have to run the Skyx as if "from scratch" again? ie sync with a star and adding sample points again? I did follow the mount Az/Alt adjustment, however the scoping pointing was still miles off. Thanks in advance
David

avandonk · #13 30-03-2012, 12:27 PM

Quote:

Originally Posted by DavidNg

Hi Paul,

After doing a TPoint run and following the TPoint recommendation to do polar alignment adjustment of Az/Alt, do we have to run the Skyx as if "from scratch" again? ie sync with a star and adding sample points again? I did follow the mount Az/Alt adjustment, however the scoping pointing was still miles off. Thanks in advance
David

I was going to first drift align the mount and see what happens. It is facile to just adjust azimuth and elevation of the mount on one star as it depends on where it is. It is all about othogonality or independant variables.

You can adjust azimuth on a star near the meridian and it will not move. Conversely adjust elevation on a star near either E/W horizon and it will not move.

Drift alignment is the opposite of this.

Bert

DavidNg (David) · #14 30-03-2012, 12:47 PM

Hi Bert,

I am new in every aspect of astronomy. After spent many nights and tens of hours of drift alignment following often contracted instruction from webpages, I managed to have fairly still star on illuminated reticule over more than 10 mins at both North/equator star (for Azi) and West (for alt), from then I tried TPoints run, quite accurate on almost every slew....then the trouble, I followed the Tpoint recommendation to adjust the mount azi/alt (off over 100arcmins), back to SkyX...every star slew is far far off...My drift alignment and TPoint seemed fighting each other. Please help... I want to get this alignment business over and go on to do other more interesting things..

David

cventer · #15 30-03-2012, 01:56 PM

Gents

Provided your location (LAT , LONG and time) are correct then you can rely on T-Point to tell you how to Polar Align.

Homing the mount first syncs the mount to where it should be. Delete all syns in bisque TCS then just point to a star using SkyX somewhere between east and due south above 45 degrees but below 90.

The scope will get close to this without a full model. Use the mounts ALT and AZ settings to center the star you just pointed to. This will get you within a few arc mins.

Once done then send mount home again. Now start your t-point polar alignment run. Move to a star again center it in cross hair or CCD and sync (better still take and image, inage link and plate solve it) then sync on the photo. You then go into t-point add on and add about 9 - 12 more targets all on same side of meridean. then click supermodel button. It will calc your offsets and tell you which way to move the PMX knobs. This will get you to sub arc min.

Once you have don this once you then need to delete the t-point model and the sync and start again. ie send mount home, slew to a star, sync, then start another 12 points t-point run. Follow instructions again on knobs.

If you start to oscilate. ie one run says move 2 tics then next says - 2. Then half what it tells you. So if it says 2 ticks west. Do 1 tick west. Eventually it will report no more adjutsment needed and you are done.

its fast and accurate. No need to drift align anymore.

avandonk · #16 30-03-2012, 02:32 PM

Thanks Chris

When all else fails I stick to what I know!

bert

CDKPhil · #17 30-03-2012, 02:34 PM

Quote:

Originally Posted by DavidNg

Hi Bert,

I am new in every aspect of astronomy. After spent many nights and tens of hours of drift alignment following often contracted instruction from webpages, I managed to have fairly still star on illuminated reticule over more than 10 mins at both North/equator star (for Azi) and West (for alt), from then I tried TPoints run, quite accurate on almost every slew....then the trouble, I followed the Tpoint recommendation to adjust the mount azi/alt (off over 100arcmins), back to SkyX...every star slew is far far off...My drift alignment and TPoint seemed fighting each other. Please help... I want to get this alignment business over and go on to do other more interesting things..

David

Hi David,
If you use T point to do a polar alignment it will align on the refracted pole.
My procedure for a portable set up is as follows.

Get a North South line via a shadow when the sun transits the meridian.
you can get the transit info from Sky X. Make sure your long/lat, time and date are correct for you location. This should get you in the ball park of true South.
Adjust the PMX altitude to match you latitude.

Home the mount.
Make sure you clear any existing Syncs and T point Model.
Slew to a star that is within 5 degrees of the Pole and 5 degrees of the meridian.
Do not use any controls. To centre the star, only use your altitude and azimuth adjusters.

Once this is done I home the mount, then slew to a bright star near the equator, centre it and sync on it.

Form here I do a new T point calibration.
Start by selecting stars that are near your sync star. After about ten to 15 stars I swap to the other side of the meridian and do the same.

Press the Super model button.
I then check the polar alignment report. and make the adjustments that it recommends.
After the adjustments, I home the mount, clear the sync and the T point model, re select a bright star near the equator centre it and sync on it.
Then I do another Tpoint calibration run. This time I do about 50 stars and re check the polar alignment.
Every time you adjust the altitude or azimuth you must clear your existing sync, re sync and redo your Tpoint model.

A few nights ago I ended up with 9 arc second pointing after doing this procedure. (That was after 150 points.)

I hope this helps.

Ps I had already written this and I noticed that Chris had already posted an answer. I thought I would post it anyway. It pretty much says the same thing.

Cheers
Phil

DavidNg (David) · #18 30-03-2012, 02:43 PM

Quote:

Originally Posted by cventer

Homing the mount first syncs the mount to where it should be. Delete all syns in bisque TCS then just point to a star using SkyX somewhere between east and due south above 45 degrees but below 90.

Many thanks for your advice cventer. On page 67 of the The Paramount MX user guide (step 7 of quick polar alignment) recommends to chose a "bright star within 5 degrees of the pole or 5 degrees from the meridian", looking through the eyepieces, I would never be able to identify correctly such star. Can I use any star as you have described?

Thanks

DavidNg (David) · #19 30-03-2012, 03:07 PM

Thanks Phil,

I will try again if Sydney clouds clear up. More questions please (I have so many).
Once you have the polar alignment greatly satisfied, does your mount atl reading agree with your location site? eg.. 33.6 for Sydney. And sometime the SkyX will not slew to particular region with slew limits error. Is there a way to overcome the limit restriction? and if so will it cause any damage to the mount/scope?
regards
DAvid

cventer · #20 30-03-2012, 03:14 PM

Quote:

Originally Posted by DavidNg

Many thanks for your advice cventer. On page 67 of the The Paramount MX user guide (step 7 of quick polar alignment) recommends to chose a "bright star within 5 degrees of the pole or 5 degrees from the meridian", looking through the eyepieces, I would never be able to identify correctly such star. Can I use any star as you have described?

Thanks

Pretty much. Choose something thats more south. ie somwhere between se and south is fine. and anything above 45 degrees and this will get you close enough. if you can get higher ie between 60 and 90 degrees than thats better but dont agonize ovr it. Its just to get you close. before your run the t-point model