Wedge Line Up

[leon]

Hi Guys,

Last night i fitted my wedge to the peir, and decided to line it up to the SCP.

I'm pretty lucky at home as the tip of the last rung of the TV antanna is exactly due South, and also -37 degrees (Ballarat's Latitude), i know it sounds untrue,but even Ken was amased when he was down here.

Anyway, to make sure it was exactly right i mounted the ED80 exactly center of the wedge and at night fitted the camera, and took 20minute exposures, checking each one, and just moving the wedge a fraction if needed.

This is how it went, and i think i have pretty spot on, check it out.

Cheers leon

[jase]

Yep, looking pretty good Leon.

[5ash]

hi leon am a bit puzzled how you fitted the ed80 to the wedge? with the lx200 set at dec 90degrees (home) position with a low power eyepiece the circumpolar stars (sigma octanis etc) should rotate about the centre of the field of view much like your photos this would be a more precise test. i observe this after i use the iterative one star align to set up my wedge, just to confirm alignment.
regards philip:thumbsup:

[leon]

Hi 5ash

Ok, this is how i went about it, firstly the wedge is home made out of half inch plate steel.
When i made the plate that moves up and down to give the correct latitude, i drilled two holes dead center, one at the top and one at the bottom.
These two holes would hold the tube rings for the ED80, then i mounted the scope in the tube rings, which would now be in the center of the top plate of the wedge.
I corrected the angle to -37 degrees and took the images, and that is where the wedge is pointed.

hope that sought of explains it a bit.

cheers leon

[5ash]

hi leon , from what you say the ed 80 is lying on the plate of the wedge,which is at an angle of 37degrees? if thats so the wedge is pointing in the opposite direction to when the lx200 is on it?
regards philip

[leon]

You mean iv'e got it arse about, well i'll be buggered, :P :rolleyes: can you tell me why the lx200 will be pointing in the wrong direction, according to what iv'e read the control end of the base of the scope should be pointing Nth, which it will be.

Now i'm really confused.:shrug:

Cheers leon :thumbsup:

[5ash]

hi leon,
when the scope is on the wedge in the 90 degree RA home position the scope itself should point at the scp ( scope orientated 90degrees to the surface of the wedge) so that as the dec axis is turned the scp should stay in the centre of the field of view. for this to happen the bottom edge of the wedge should point geograpic south (magnetic south +or- magnetic deviation from true south) and the wedge angle should be 90 degrees minus your latitude.
if you then place your 80ed telescope on the wedge and parallel to the wedge you will not get the pictures you first showed.
regards philip

[leon]

Gee's i'll have to think about this one, according to the info i got of the web, about (Polar Aligning the Lx200 GPS in the Southern Hemisphere ), it states.

Step,1. get familar with your wedge, ok that's easy enough.

Step,2. Setting the Wedge Latitude.

No.1 Find your observing latitude, mine is -37 degrees.

No.2 Mount the wedge on your level tripod or peir.

No,3 Mount your scope on the wedge, ok i didn't do that, but made sure the wedge was pointed correctly at the right latitude.

No.4. Without the scope powered up manually slew the scope so it points straight up towards the sky with the lens/dust cover on, this was my next step after i got the wedge right

No.5 Adjust the scope in the DEC axis with the fine adjustment knob until the DEC is reading your latitude on it's arm Eg -37 degrees.

No.6 Place a spirit level on top of the dust cover and level your scop using the big knob at the rear of the wedge, this process will set the latitude of the wedge to your approximate observing location.
Well, that would not be necessary, i thought as my wedge is set at the right latitude and RA.

After that is all done do all the other stuff, you know drift align etc..

Totally lost now i am.

Anyway, i'll have to think about this some more, obviously i'm missing something.

Cheers leon

[5ash]

your directions sound right and if you were in the nothern hemisphere the thin end of the wedge would point north. however in the southern hemisphere it should point south. this was omitted in your list of steps.
regards philip

[leon]

Hi 5ash, so what you are telling me is that i have to swing the whole wedge assembly 180 degrees, leaving the latitude height at -37 degrees.

i'm sure you right, but it just seems odd to me.

Cheers leon

[beren]

I just set my LX and wedge using the approx lat and compass readings {with magnetic dev accounted for} and then drift align. I don't worry about the Meade polar home pain routine. After drift aligning I choose a star, locate it in the autostar menu, centre it in the eyepiece, hit GOTO then the scope slews a short distance stops and confirms its on the chosen star. You then have to slew back to the selected star hit the sync button hold it until you hear the keypad beep and then everything should be set :D

[leon]

Ah Thanks beren, now iv'e got the idea,thank you, i can see what i was doing wrong.
And yes i know what you mean with the sync idea, those red lines you marked on the image made the brain activate, and i immediately saw the problem

Thanks Heaps,

Cheers leon