Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_comet_46p_winners.thumb.jpg.b3d48fd93cbd17bff31f578b27cc6f0d.jpg

Trevor-Austin

LX90 polar alignment driving me crazy.

Recommended Posts

So I have an LX90 fork mounted with Meade wedge.

Setting the wedge correctly and setting polar home so Polaris is at the center of thecwyepiece with handles and finder painting down.

1 star align with Polaris seems fine, then slews to several stars below the horizon.

I can't find any instructions, my manual is useless.a wedge is available follow instructions, but there aren't any. 

All of the decent videos are for lx200 and use the method I've tried, but it just doesn't work.

I don't want to drift align, for now, I just want a simple enough alignment as meade expected, but I can't make it work .

What am I missing? Any help very much appreciated.

The instructions on the 497 are also useless. Adjust the RA within 180 degrees of the hard stops, well of course I have no hard stops.

So should I set to polar home before turning on? Then turn on and align? 

Please save my remaining hair.

Share this post


Link to post
Share on other sites
Posted (edited)

High Trevor, as you say the manual is only good for starting a fire :grin:

There used to be hard stops so you had to rotate the mount  both ways to make sure it was centred before starting up.

Make sure you're set to Polar mode in the hand controller.

Check time and location are correct.

Just set it up with the wedge slope towards North and the fork arms pointing North, the zero RA marks aligned, aim the scope at Polaris parallel to the forks, if you can still see through the upside down finder adjust the alt / az bolts to get Polaris in the FOV, use something like a 26mm eyepiece and get Polaris in the scope FOV, loosen the RA lock and rotate the forks and adjust the bolts to get Polaris to rotate in the FOV this will get you pretty well polar aligned without resorting to the hand controller.

When finished it's good to park it before switching off then set it up the same parked position next time before you switch it on and then it shouldn't be far off aligned, GoTo a handy bright star which hopefully will be in the finder scope FOV and centre it using the hand controller, centre it in the scope eyepiece, once centred hold down the enter button for 3 seconds and the display should say " press enter to sync " press enter and you're good to go.

After this if you're going to be imaging it's best to use PHD to polar align it.

Dave

 

Edited by Davey-T

Share this post


Link to post
Share on other sites
23 minutes ago, Davey-T said:

High Trevor, as you say the manual is only good for starting a fire :grin:

There used to be hard stops so you had to rotate the mount  both ways to make sure it was centred before starting up.

Make sure you're set to Polar mode in the hand controller.

Check time and location are correct.

Just set it up with the wedge slope towards North and the fork arms pointing North, the zero RA marks aligned, aim the scope at Polaris parallel to the forks, if you can still see through the upside down finder adjust the alt / az bolts to get Polaris in the FOV, use something like a 26mm eyepiece and get Polaris in the scope FOV, loosen the RA lock and rotate the forks and adjust the bolts to get Polaris to rotate in the FOV this will get you pretty well polar aligned without resorting to the hand controller.

When finished it's good to park it before switching off then set it up the same parked position next time you start and then it shouldn't be far off aligned, GoTo a handy bright star which hopefully will be in the finder scope FOV and centre it using the hand controller, centre it in the scope eyepiece, once centred hold down the enter button for 3 seconds and the display should say " press enter to sync " press enter and you're good to go.

After this if you're going to be imaging it's best to use PHD to polar align it.

Dave

 

So do you not do any of the autostar alignments? 

I have noticed if I do it like this then if I press the mode button for a few seconds then the readings are not at 90degs and 0 but any random numbers, or do I need to turn it off and back on again after setting polar home so they reset?

Just to be certain, at polar home the ota should be pointing at eight angles to the base and wedge directly at polaris and the handles and finder aiming towards the ground.

Time and date is from gps using starpatch plus I also have the lnt module added.

In alt as it all works perfectly, so I'm sure it's my understanding:)

Is there a reason from that position that 1 star align points below the horizon for the alignment star?

 

Share this post


Link to post
Share on other sites
Posted (edited)
19 minutes ago, Trevor-Austin said:

Is there a reason from that position that 1 star align points below the horizon for the alignment star?

Usually an indication that the time / date / location is wrong, have you got it set to daylight saving ? I have my LX200 on UT ( universal time ) but don't know if that option is available on the LX90.

If using the Meade polar aligning thingy it should be set up with the wedge slope towards north, the control panel towards north and the scope pointing up and north  at 90 dec' then when you press the button to polar align it should find Polaris.

I think there may have been a version that started with the scope pointing south at 0 dec and then it flipped itself over to Polaris.

I have the wedge instructions somewhere, I can copy them and PM them to you if you like.

Dave

Edited by Davey-T

Share this post


Link to post
Share on other sites
10 minutes ago, Davey-T said:

Usually an indication that the time / date / location is wrong, have you got it set to daylight saving ? I have my LX200 on UT ( universal time ) but don't know if that option is available on the LX90.

If using the Meade polar aligning thingy it should be set up with the wedge slope towards north, the control panel towards north and the scope pointing up and north  at 90 dec' then when you press the button to polar align it should find Polaris.

I think there may have been a version that started with the scope pointing south at 0 dec and then it flipped itself over to Polaris.

I have the wedge instructions somewhere, I can copy them and PM them to you if you like.

Dave

I would appreciate that yes please. Especially as mine doesn't have the azimuth bar for fine adjustment or anything missing either, just not there. Ah, dst forgot that, is that a setup setting?

It just confused me auto selecting out if view stars. I am only testing in daylight but it should know that? But dst I forgot!!!

When you say controls towards north the lx90 controls are in the fork arm, not the base, so shouldn't the forks be parallel to ground?

If needs be I can try the south at 0 too. Couldn't be any worse, lol.

Just to confirm again though, polar home setting scope powered on or off?

Share this post


Link to post
Share on other sites
2 minutes ago, Trevor-Austin said:

Just to confirm again though, polar home setting scope powered on or off?

Sending instructions shortly, hope they make sense :grin:

Dave

Pic of mine scope pointing south if you can make it out through the mess of cables.

Meade.png.a22506a95520ecef4e5d4843a7c2817d.png

Share this post


Link to post
Share on other sites

Instructions PMd.

Dave

  • Like 1

Share this post


Link to post
Share on other sites
11 hours ago, Davey-T said:

Sending instructions shortly, hope they make sense :grin:

Dave

Pic of mine scope pointing south if you can make it out through the mess of cables.

Meade.png.a22506a95520ecef4e5d4843a7c2817d.png

So that is the OTA pointing due south, at 0 degrees? and forks parallel to the ground and pointing north? I like cables :) mines as bad especially with the mini PC attached to the Forks and the battery pack on the opposite fork.

Share this post


Link to post
Share on other sites

WOW, hold on there.   Firstly, I have an LX-90 with a wedge.   There's loads of things that can be going on......

As I don't know anything about your kit apart from it being an LX-90 , it's on a wedge, and we're in the visual observing part of the forum.  I'll make no other assumptions.

 

1. Don't use internal power, ever.

The batteries simply don't last long enough to be of any use and it'll get "motor unit faults" which are simply frustrating as it should say "batteries are not powerful enough"   Use an external battery anything over 7Ah, for the scope itself only should see the end of any power problems.

2. Train the scope.

This is worth doing,  setup your scope in Alt-Az mode (leave out the wedge) in daytime.  Set the Telescope targets to Terrestrial and point at something in the distance (further the better, and with a reticule eyepiece if you have one) then run through the drive training routines.  (I used a flagpole that's about 5 miles away)

This will properly train the motors of the scope, so that it's pointing accuracy is much improved.

3. For visual observing don't bother with the wedge.

The scope is much more stable when used without the wedge.     If you are sure you want to use the wedge though go ahead.  Either way, make sure that you tell the Autostar that you are using the wedge there's a setting in the Setup menu for it.

4. Make sure that you have your location entered properly.

This will help the pointing accuracy

5. Make sure that the date and time is entered properly too.

6. Make sure that you set "Targets" to astronomical.  That will enable the scopes tracking.

 

For the alignment process, I do the following....

 

1. Setup the tripod and add the wedge.

2. Level the tripod, making sure that the wedge has the lifted up part "facing north"    i.e. the part of the wedge that hangs over the edge of the tripod is on the southern side.    Or more to the point, is on the same side as the equator.

3. set the elevation for your latitude, it'll help to get you close.

4. Add the fork mount and OTA.   Point the scope so that it's in line with the fork, it should be pointing towards polaris.

5. release the RA clutch, and whilst looking through the scope look at how the stars move.   The closer you are to alignment the tigher circles the stars will move.

6. once in the polar home position, turn on the mount and do a two star alignment.

 

At this point everything should be running pretty much spot on.   The pointing accuracy isn't perfect, so whilst the targets may be a little off after a slew, you shouldn't ever be too far away from the target.

 

As I do astrophotography, I've switched to using a camera in my piggy backed guide scope.  This makes my alignment much easier as I can use the Polar Alignment tool in SharpCap Pro.   But that's another story.

Share this post


Link to post
Share on other sites
Posted (edited)
6 hours ago, cjdawson said:

WOW, hold on there.   Firstly, I have an LX-90 with a wedge.   There's loads of things that can be going on......

As I don't know anything about your kit apart from it being an LX-90 , it's on a wedge, and we're in the visual observing part of the forum.  I'll make no other assumptions.

 

1. Don't use internal power, ever.

The batteries simply don't last long enough to be of any use and it'll get "motor unit faults" which are simply frustrating as it should say "batteries are not powerful enough"   Use an external battery anything over 7Ah, for the scope itself only should see the end of any power problems.

2. Train the scope.

This is worth doing,  setup your scope in Alt-Az mode (leave out the wedge) in daytime.  Set the Telescope targets to Terrestrial and point at something in the distance (further the better, and with a reticule eyepiece if you have one) then run through the drive training routines.  (I used a flagpole that's about 5 miles away)

This will properly train the motors of the scope, so that it's pointing accuracy is much improved.

3. For visual observing don't bother with the wedge.

The scope is much more stable when used without the wedge.     If you are sure you want to use the wedge though go ahead.  Either way, make sure that you tell the Autostar that you are using the wedge there's a setting in the Setup menu for it.

4. Make sure that you have your location entered properly.

This will help the pointing accuracy

5. Make sure that the date and time is entered properly too.

6. Make sure that you set "Targets" to astronomical.  That will enable the scopes tracking.

 

For the alignment process, I do the following....

 

1. Setup the tripod and add the wedge.

2. Level the tripod, making sure that the wedge has the lifted up part "facing north"    i.e. the part of the wedge that hangs over the edge of the tripod is on the southern side.    Or more to the point, is on the same side as the equator.

3. set the elevation for your latitude, it'll help to get you close.

4. Add the fork mount and OTA.   Point the scope so that it's in line with the fork, it should be pointing towards polaris.

5. release the RA clutch, and whilst looking through the scope look at how the stars move.   The closer you are to alignment the tigher circles the stars will move.

6. once in the polar home position, turn on the mount and do a two star alignment.

 

At this point everything should be running pretty much spot on.   The pointing accuracy isn't perfect, so whilst the targets may be a little off after a slew, you shouldn't ever be too far away from the target.

 

As I do astrophotography, I've switched to using a camera in my piggy backed guide scope.  This makes my alignment much easier as I can use the Polar Alignment tool in SharpCap Pro.   But that's another story.

I've finally sorted it.

everything is perfect in alt az and the battery pack I use is a 13500ah that also runs my PC last over half a day running the PC and the scope:)

However I use starpatch for gps.on my handset it all looked good when it gets the GPS reading, but after about 20 attempts at polar alignment I noticed that the time was jumping ahead exactly 7 Hours even though gps showed fine. Disconnected the GPS and the lnt and set the time manually looked a little better but not good but at least time was correct. Then I deleted the site I had created for my location, rebooted with lnt and gps connected and the time stayed correct. Must be a bug in starpatch somehow with my custom location and only in polar mode.

As soon as I deleted my custom site, actually modified Birmingham , it all works as expected.

And luckily tonight looks really clear so a full test in a couple of hours.

Why I didn't get the problem in alt az my mode I have no idea.

Edited by Trevor-Austin
  • Like 1

Share this post


Link to post
Share on other sites

And damn, last night was a complete write off, I've just contacted Opticstar who were very helpful and going to look into it for me.

This is my current situation, I can't try again as my wedge for some reason doesn't have the azimuth control so I have to hold the scope undo the screws and move it while trying to look at the eyepiece then do them up without moving it, nigh on impossible I found last night, so I am going to make the Azimuth fine control and add it before trying again.

My telescope is approximately 10-13 years old and is an 8" LX90.
I have added the LNT device to it and a patched firmware from a business called Starpatch(.ca) so my firmware is labelled 43GG.

What the patch does is allow the telescope to believe it has GPS added.  It's quite complicated but works fantastically in ALT/AZ mode.

I have been using the patch for 6 months plus, with zero issues.  However I tried to mount the telescope on a Meade Equatorial Wedge over the last few days for longer astro photography with the plans to add a guider, however I cannot get it even close to working.

The method I am attempting to use is the following;
Set the telescope to level
Add the wedge and ensure it is pointing close to due North
Set the Azimuth plate to approximately correct (mine is 52 degrees 32 minutes)
Mount the telescope with the forks and finder pointing directly down and the OTA pointing directly towards Polaris
Turn the telescope on (tried it with it on before alignment too)
Choose 1 star alignment
I then get asked to get Polaris dead centre using the wedge controls as the scope slews round a little to expose the eyepiece, all seems simple and works fine.
Then it tries to slew to a star for me to align to, at no point does it EVER slew anywhere near to where the named star actually is.
I have tried to manually sync without an alignment, that was also a similar abysmal failure.
I have tried this maybe 30 times and it never gets better. Normally the chosen star is well below the horizon and often as much as 120+ degrees pointing in the wrong direction.

I have checked, the mount setting is polar, the location, time and date is correct, including disconnecting the GPS and LNT module and entering manually, deleting the manual site I had setup, taking it back to ALT/AZ mode again (all perfect)

Things I might be doing wrong;
Am I using the LX200 method wrongly and is that different from an LX90 method? I notice that if I hold my mode button to check drive positioning they are never at 90 degrees and zero as the LX200 guys are in Polar home.
I am going to try with the official meade firmware instead of the patched firmware
I am going to try a full handset reset, in the past that has fixed non working tonight's best tour and a couple of other things.
I could loosen the clutches and set the home position readout to the same as is set on the LX200s by running the motors disconnected until I get the correct readings.

 

Share this post


Link to post
Share on other sites

hmmm.

Let's see if I can help out a little.

 

Firstly, my LX-90 is the EMC version that was sold in 2001, I bought it brand new and have been using it every since.   My Autostar is on firmware 43G, the highest from Meade for the #497 Autostar.

I got a delux version of the wedge.   I believe that the different is the addition of the fine adjustments for the alt and az.  Although they are a bit basic really.

The alt adjustment came in two parts, one attached to the screw holes on the north side of the tripod (opposite one of the legs)

and the other part attaches to the edge of the edge.  This allows you to push the wedge left and right with a screen.

The Alt adjustment is threaded through a bar that goes under the wedge and allows fine control of the altitude.

 

I've got no experient with the LNT stuff.  That said, from memory, I was under the impression that was only designed for Alt-Az use.

 

For setting my scope to the home position, what I do is once the scope is on the wedge.   I use a torpedo spirit level to set the forks so that it's resting on both forks and showing level.  The gap is behind the spirit level hence the use of a long one so that it can rest on both forks without falling through.

I then have the scope pointing directly up at Polaris.

 

From there, do a 2 star alignment.  Make sure that you have the date time, lat and long of the site entered correctly.

And it should work just fine.

 

One final random thought, in the auto star menu I think you can choose which scope the autostar is connected too.   Might be worth double checking that's set to the LX-90.

Share this post


Link to post
Share on other sites
Posted (edited)
6 minutes ago, cjdawson said:

hmmm.

Let's see if I can help out a little.

 

Firstly, my LX-90 is the EMC version that was sold in 2001, I bought it brand new and have been using it every since.   My Autostar is on firmware 43G, the highest from Meade for the #497 Autostar.

I got a delux version of the wedge.   I believe that the different is the addition of the fine adjustments for the alt and az.  Although they are a bit basic really.

The alt adjustment came in two parts, one attached to the screw holes on the north side of the tripod (opposite one of the legs)

and the other part attaches to the edge of the edge.  This allows you to push the wedge left and right with a screen.

The Alt adjustment is threaded through a bar that goes under the wedge and allows fine control of the altitude.

 

I've got no experient with the LNT stuff.  That said, from memory, I was under the impression that was only designed for Alt-Az use.

 

For setting my scope to the home position, what I do is once the scope is on the wedge.   I use a torpedo spirit level to set the forks so that it's resting on both forks and showing level.  The gap is behind the spirit level hence the use of a long one so that it can rest on both forks without falling through.

I then have the scope pointing directly up at Polaris.

 

From there, do a 2 star alignment.  Make sure that you have the date time, lat and long of the site entered correctly.

And it should work just fine.

 

One final random thought, in the auto star menu I think you can choose which scope the autostar is connected too.   Might be worth double checking that's set to the LX-90.

Thank you, so I guess I have the basic wedge, missing that bar, I'm going to add it as trying to adjust without it is impossible, basically you have to loosen off then support the whole scope with your arms while looking through the eyepiece then tighten, any small adjustment is impossible.  The alt adjustment is fine, just undo the support a little bit and move left and right so I'll just leave that.

I have checked the scope model, and don't forget it's perfect in alt/az checked the mount 100 times:) and haven't tried a 2 star alignment, but then if it can't find a star from the easy or 1 star I don't suppose it would be any differnt.  Any chance you could try a 1 star or easy and let me know what happen.

Your home position sounds identical to mine, scope pointing directly up at Polaris, where are the handles and finder on your scope then? On the top aiming at you or pointing at the ground like the LX200s have to do in the Northern hemisphere (I think)

Edited by Trevor-Austin

Share this post


Link to post
Share on other sites

I was typing from memory.   It’s the easy alignment that I do with my scope.   I’ll put some photos up of my wedge so you can see how the extra bits look.

 

one more trick, put a cd between the tripod and wedge, it’ll act as a bearing and help make the AZ adjustment easier

Share this post


Link to post
Share on other sites

I just found the manual for the LX-90 wedge on the web.  This is the one that I have, turns out that I don't have a deluxe one after all.  (wasn't sure, and I've had it for years)

http://www.meadeuk.com/pdf/Meade-8-inch-Wedge-Manual.pdf

You can see in the instructions that there are things in addition to the wedge itself that give you alt and az adjustment for your wedge.

  • Like 1

Share this post


Link to post
Share on other sites
8 hours ago, cjdawson said:

I just found the manual for the LX-90 wedge on the web.  This is the one that I have, turns out that I don't have a deluxe one after all.  (wasn't sure, and I've had it for years)

http://www.meadeuk.com/pdf/Meade-8-inch-Wedge-Manual.pdf

You can see in the instructions that there are things in addition to the wedge itself that give you alt and az adjustment for your wedge.

Very similar to mine except I have a bubble level instead of a compass and I am missing items 4,5 & 6 from fig 3.  Or item 4 from fig 1, plus the latitude control is also missing, that's easy to work without but the fine azimuth control is impossible, the OTA is barely held anyway by the adjustment knobs without that bar to support it and in addition supporting the whole weight of the scope while looking through the eyepiece while trying to make mm adjustments and tighten down is close to impossible :)  I am trying to make one from drilled/threaded aluminium bar and some epoxy weld.

Share this post


Link to post
Share on other sites

I can't imagine working with a wedge without either of the alt of Az adjustment.    I know that tweaking in the final seconds of PA is very delicate, even with them.

Share this post


Link to post
Share on other sites

So I made myself a very solid latitude bar 2" steel, andcreated q new site with the correct settings.setup with handles upwards as advised for the LX90 and first time alignment worked perfectlt, at last 

So now I have just one issue left, and this is down to me.

How do you ensure that your OTA is pointing exactly 90 degrees to the forks.latitude and azimuth adjustment is simple.buy I get it all looking 100% spin the OTA as and polaris flies off sideways. The diwc on the fork is useless, it's been moved. Is it just hours of trial and error then set the fork indicator or is their an easier way.........

Share this post


Link to post
Share on other sites

Yep there is a much easier way.  Cheat!

 

For the spinning the OTA thing, you know you are spot on when polaris doesn't fly off.  the closer you are the less that polaris will move.  After that, yes there's trial and error.  There's also the geometry of the mount that can help you.  Look at the part of the fork that's connected to the OTA.   Comming from there, both sides are black metal bars that hold the primary area solidly.     What you can do is line those up with the forks and hey presto, it's in line.    See, it's cheating and it's good enough for when I'm doing stuff visual.

 

I've switched over to using camera, and frankly, I cheat even more.   SharpCap Pro has a polar alignment feature I use my guide camera to do this and all I need to do is get the scope pointing within 5 degress of the pole and it's happy enough to do it's thing.   Takes alot of the guess work out of it.

 

Sounds like you made some major progress with the latitude adjuster :)

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.