I want to wedge without tears

[Chunky Wheeler (Chris)]

Hi everyone,

I have a Meade 12' LX200R in alt az mode on a nice sturdy pier in my Sirius 3.5m dome. I have used it happily for two years like this, but of course lack the ability to take long exposures.

I did buy a Meade field de-rotator some time back, but have never felt confident with it. In any case, it's really only any good if you are using an off axis guider.

I have a nice new shiny Meade super wedge lying in the corner of my observatory (metaphorically speaking of course) waiting for me to summon up the courage to put it under the 'scope.

I say I lack courage because I have not heard one good report from anybody over the years about how easy it is to install wedges, and what a good result it was when they did.

One person I know experienced a spectacular failure in installing it making the thing work, and ended up selling the whole kit and caboodle in disgust.

He now has German Eq. Mount and several refractors, and has never been happier. However, I would have to say he doesn't- and never did, do visual work.

I enjoy visual as much as photography, and therefore need the big aperture that my 12" gives me. I lovethat scope! I would like to take some long exposure pikkies as well to show the wife.

Can anyone help with an idiots guide to installing and successfully operating a Meade Super wedge? In other words comprehensive instructions, tips and advice.

All comments welcomed.

Thanks a zillion.
Chunky

[[1ponders] (Paul)]

Hi Chunky. While I have had some experience with a wedge on both an 8" LX200 (portable) and a 10" LX200 (pier), its been a while. I've since decided (a few years ago now) that an eq mount is for me. That doesn't mean that the wedge didn't work, I did find it fiddly at first to learn. I also found it did take me some time to setup accurate when I wanted to travel away from home.

If you can learn to drift align, especially using a webcam and software (I'm a K3CCDTools fan for this) the polar alignment of the wedge isn't a major drama. In fact the basics are no difference than for an eq mount.

One thing I did experience being wedge mounted was significant damping down times, and the setup had very little tolerance of disturbances, hanging and dragging wires mainly, but even light gusts of wind could disturb the mount significantly when imaging. I imagine with a 12" the problems would be amplified. However I know of at least one IIS member (thunderchildobs) who had a wedge mounted 12" doing supernova surveying.

I found the biggest issue with polar aligning the LX200 with a wedge was not the wedge itself, but the painful alignment process needed for the Autostar. Not intuitive, not straight forward (well that just describes the whole software to a T for me ) and I believe, a real challenge for many inexperienced astronomers to identify sigma octans in a finderscope, let alone an eyepiece. Fortunately there are work arounds available.

[rogerg (Roger)]

Wow, I have never realised it can be such a problem. Is the main problem with the alignment/electronic procedure/configuration of the LX200R?

My situation with the LX200 Classic is perhaps different..

1) Put the wedge on the pier such that the wedge is facing the southern pole. Set altitude to roughly the right value
2) Put all the bolts through the wedge to the pier and tighten the centre one
3) Put the top bolt in to the base of the LX200
4) Lift the LX200 up and on to the wedge such that the bolt hooks in place
5) Tighten that top bolt somewhat but not completely
6) Put the other bolts in to secure the LX200 to the wegde and tighten all 3 bolts
7) Turn on the LX200 and set mode to Polar
8) Synchronise on one star
9) Perform polar alignment using drift or other methods.

It is much easier with two people, especially when lifting the LX200 up and securing the bolts, as giggling the LX200 to the right position can be required.

An understanding of polar alignment is essential.

Any changes you make to the polar alignment of the wedge are best done while you watch a star in the eyepiece or camera such that you can accurately compensate for any slack or backlash in the wedge mechanics and such that you can accurately quantify the movements you are making to speed up your alignment process (so you know for example if you moved the star half way across the FOV last time and it improved drift by half next time you can move the star half way across the FOV twice and you’ll be a good way towards good alignment).

Once aligned and permanently on the wedge each night I (with LX200 classic) simply sync on one star.

I find it’s best if I tweak the alignment once every 6 months to keep it good.

If you don’t have a permanent setup then I imagine setting up a wedge every night might be a bit of a task when it’s a 12” LX you’re having to lift up on to it.

Roger.

[floyd_2 (Dean)]

Hi Chunky,
interestingly, I was in the same situation as you a while back. I had a lovely new ultrawedge sitting in my shed for about a year. My fear of finding sigma octantis from the suburbs, polar aligning in general etc held me back, so I continued on in Alt/Az mode for far too long. I even considered a field de-rotator rather than using my wedge.

I finally decided to give the wedge a shot, and much to my surprise, have never looked back. I agree that damping times on a wedge could be much better. Given that you're in an obsie, factors like breezes etc should be less of a problem. If you keep your cable management spot on, you can minimise any problems there too.

I also think that the wedge, straight out of the box, is far from being smooth. I greased mine up and it made a huge difference. There are a few pages out there written by people who have done various things to their meade ultrawedges to improve their performance.

I say - give it a go. What have you got to lose? Ask a friend to help you get your scope mounted up on the wedge. A 12" is too heavy for one person to mount comfortably.

I used the plum bob at solar noon method to mark true south on my observing platform and it was spot on. If I wheel my 10" LX200GPS out and align it on my North South line, I get Sigma Octantis in the finder every single time. Even in the suburbs, you'll very quickly get the hang of finding sigma. It's not hard at all.

I used these two links as my How To for polar aligning on a wedge. It made the whole process simple and straight forward.

Link 1
Link 2

Take a read of both links - they're good value.

Dean

[DavidTrap (David)]

With my limited experience with a wedge and an LX-90, I can support what Paul says about K3CCD tools. I had great success in achieving polar alignment with it.

My method was to roughly align the scope on the tripod and then fire up K3CCD tools to do a drift alignment. Once the polar alignment was spot on, I would run the "polar align" sequence on the Autostar. I would reliably be rewarded with a "<5" to the pole" for my efforts. If that was all done carefully, I had no problem with GOTOs.

I've since moved onto a much higher quality mount, but the GOTO isn't as good as the Meade. I've only used the AP mount a handful of times (weather and work are such a pain), so I'm still learning, but it is not as reliable for placing objects centre field. It is my understanding that the Meade does have some "modelling" to improve pointing, but the current AP software doesn't.

DT

[AndrewJ]

Gday Paul
Re

I found the biggest issue with polar aligning the LX200 with a wedge was not the wedge itself, but the painful alignment process needed for the Autostar. Not intuitive, not straight forward (well that just describes the whole software to a T for me http://www.iceinspace.com.au/forum/....milies/lol.gif ) and I believe, a real challenge for many inexperienced astronomers to identify sigma octans in a finderscope, let alone an eyepiece. Fortunately there are work arounds available.

If you have properly drift aligned your mount, then the above is irrelevant.
For a Meade scope, you just start a std polar one star align.
When it says centre Sig Oct, you just hit enter,
you dont even bother to look in the EP.
Centre the second star and you are off and running.
Couldnt be easier

Andrew

[Chunky Wheeler (Chris)]

Very encouraging Andrew. Thanks for responding (to Paul actually). Its confidence building to know that there is help available just for the asking.

Chunky

[Chunky Wheeler (Chris)]

Thanks for your comments David. I shall take note of them.
Chunky

[Chunky Wheeler (Chris)]

Great stuff rogerg. Interestingly, you don't seem to park your 'scope after use each night--but the following night do a one star alignment.
I find being able to park is one of the many joys of having a fixed mount in an observatory. When the wife switches the TV on to watch 'The Bill' etc.....I'm out of there and looking at the stars in seconds, thanks to the park function.
To put the record straight, putting the wedge on the pier and the 'scope on the wedge I have always thought of as being the easy part. The difficult part (so those who have gone before tell me....up until this forum that is) is aligning on the SCP and balancing the scope according to what you have put on it- and vice versa. In the alt az mode when viewing only, weight distribution is not critical, and I can put stuff on the scope and take it off almost at random ( as I do all the time---I like trying out different combinations of stuff. For example last night I was experimenting to find out which gave you a better DSLR photo shot of the planets through eyepiece projection--an off axis guider or a flip mirror. I was surprised to find that, at first outing, about the same) .. It seems to me that once you have committed to a certain set up and weight distribution with a polar aligned wedge, you may have to stick with it for a while, unless you are prepared to spend a lot of time doing it over again with your new set up. Or am I being a girlish worrier?
Chunky

[Chunky Wheeler (Chris)]

Originally Posted by floyd_2

Hi Chunky,
interestingly, I was in the same situation as you a while back. I had a lovely new ultrawedge sitting in my shed for about a year. My fear of finding sigma octantis from the suburbs, polar aligning in general etc held me back, so I continued on in Alt/Az mode for far too long. I even considered a field de-rotator rather than using my wedge.

I finally decided to give the wedge a shot, and much to my surprise, have never looked back. I agree that damping times on a wedge could be much better. Given that you're in an obsie, factors like breezes etc should be less of a problem. If you keep your cable management spot on, you can minimise any problems there too.

I also think that the wedge, straight out of the box, is far from being smooth. I greased mine up and it made a huge difference. There are a few pages out there written by people who have done various things to their meade ultrawedges to improve their performance.

I say - give it a go. What have you got to lose? Ask a friend to help you get your scope mounted up on the wedge. A 12" is too heavy for one person to mount comfortably.

I used the plum bob at solar noon method to mark true south on my observing platform and it was spot on. If I wheel my 10" LX200GPS out and align it on my North South line, I get Sigma Octantis in the finder every single time. Even in the suburbs, you'll very quickly get the hang of finding sigma. It's not hard at all.

I used these two links as my How To for polar aligning on a wedge. It made the whole process simple and straight forward.

Link 1
Link 2

Take a read of both links - they're good value.

Dean

Thanks a million floyd_2 (Dean). You have hit the bullseye............and I can feel a wedging session coming on! Yes, there a no wind problems in my Sirius dome, which by the way, I consider to be the Bees Knees. Cable management with an electrically operated go-to is a problem even without one or two cameras on board. I shall give some thought to that one.
I like the idea of the noon plumb bob. I haven't checked out those two articles yet. If it is not covered, can you give me the good oil please?
Many thanks again.
Chunky
ps It is so long since I last went on IIS that I have forgotten why I have 'Cauliflower Cheese' under my nom de plume. What is it in aid of?

[Chunky Wheeler (Chris)]

Originally Posted by [1ponders]

Hi Chunky. While I have had some experience with a wedge on both an 8" LX200 (portable) and a 10" LX200 (pier), its been a while. I've since decided (a few years ago now) that an eq mount is for me. That doesn't mean that the wedge didn't work, I did find it fiddly at first to learn. I also found it did take me some time to setup accurate when I wanted to travel away from home.

If you can learn to drift align, especially using a webcam and software (I'm a K3CCDTools fan for this) the polar alignment of the wedge isn't a major drama. In fact the basics are no difference than for an eq mount.

One thing I did experience being wedge mounted was significant damping down times, and the setup had very little tolerance of disturbances, hanging and dragging wires mainly, but even light gusts of wind could disturb the mount significantly when imaging. I imagine with a 12" the problems would be amplified. However I know of at least one IIS member (thunderchildobs) who had a wedge mounted 12" doing supernova surveying.

I found the biggest issue with polar aligning the LX200 with a wedge was not the wedge itself, but the painful alignment process needed for the Autostar. Not intuitive, not straight forward (well that just describes the whole software to a T for me ) and I believe, a real challenge for many inexperienced astronomers to identify sigma octans in a finderscope, let alone an eyepiece. Fortunately there are work arounds available.

Thanks Paul,
How are you keeping? I shall be at Duckadang again this year for my annual tutorial from you. I know that wedging is not your favourite pastime, and that the Meade DSI leaves you cold. But we can still be friends............!
Your comments, as always, very helpful. Nice to know you are there ready to field my next 3214 questions. No doubt I shall have one shortly aboout CCD Sky Tools and the SCP.
Chunky

[GrampianStars (Rob)]

Originally Posted by AndrewJ

If you have properly drift aligned your mount, then the above is irrelevant.
For a Meade scope, you just start a std polar one star align.
When it says centre Sig Oct, you just hit enter,
you dont even bother to look in the EP.
Centre the second star and you are off and running.
Couldnt be easier
Andrew

Chris
Ditto
Once polar alligned I unlock and move the tube all the time to change heavy items.
I just turn the scope back on GOTO first star MANUALLY centre via unlocking RA / DEC,
GOTO a known star use autostar to ctre. and sync.
Alls good to go again.

[[1ponders] (Paul)]

Np Chris I'll see you there. Do you want me to save you a seat in the rotunda.