Guiding an LX90-8" on the Meade Equatorial wedge

[Captain Tweaky]

About 4 years ago I bought an LX90-8" and with it I also bought the Meade Equatorial wedge - which I subsequently got rid of!!! I'm now thinking of going back to the LX90 to use it for imaging and buying another wedge.

BUT I seem to recall having issues guiding this set-up as there is not a guide port on the LX90. Can anyone please tell me how you connect-up the guide 'scope and camera to guide the LX90 using the equatorial wedge. I do have an HEQ5 Synscan Pro and for a while mounted the 8" OTA for imaging on that mount, but it really was not very successful as it was all a bit too heavy. Hence the idea of revisiting the great Meade equatorial wedge!!

Any ideas would be most welcome

[Captain Tweaky]

I have just discovered that Meade now do an Autoguider Port Module for LX80 and LX90 for £40 from Telescope House - does anyone have any experience of this device in conjunction with the equatorial wedge?

[Astroboffin]

Hi,

I too have the LX90 and guide with it very well, contrary to popular belief these fork mounted scopes will image very well on a wedge, but you MUST, and I can't stress this enought, balance it perfectly on the two axis, with the tube horizontal to balance the equipment on the back, and with the tube straight up to balance the piggybacked guide scope, so invest in a proper meade balance kit.

Now onto the guiding, there are two ways of doing this,

1. You can use a meade APM909 module, if you have one, this gives you an ST4 guide port, if you haven't got one, which I guess you haven't, then we will move onto the second, and in my opinion as I have tried both ways, the easiest and best method.

2. For this method you need,

Computer

Ascom software, with the Meade classic and autostar driver loaded, these are on the ascom site.

Guiding software such as PHD, which I use

Guide camera, with drivers, both native and Ascom

Cable to connect from a USB port on PC to the AUX socket on the bottom of the handset, (don't connect to AUX on base of scope) you will have got one of these with the scope, but you may need a USB so serial port adapter, this will enable you and the guiding software to control the mount.

So connect the guide camera to the computer also, so you should now have two cables connected to the computer, one from the guide camera and one from the base of the Autostar handset. No ST4 cable needed, as this uses a newer method called pulse guiding commands, which many people, including me, find much better.

So assuming you have set up the scope and done an align procedure, and you are pointing and tracking on a star, let's start guiding.

Open PHD and from the mount drop down list at the top, select Ascom and your Meade classic and autostar driver, from the list.

Then assuming your guide camera drivers are installed, both the native driver and the Ascom driver both of which should have come with the camera, click the camera icon at the bottom and select your camera from the list.

Then click on the mount button next to the camera button and that will connect to the mount, then click the target button to start

Then you should see some stars on screen, if you use the cursor and select one it will but a box around the star, and the software will run a calibration routine, this is to check the orientation of the camera (you can put the guide camera on the scope Andy way round you like it does not matter)

As soon as the routine has finished the box around the star will change colour to green and it will start guiding by computing the movement of that star and sending relavent commands down the cable to the handset, to tell the mount to move in whichever direction to keep the star centred.

The other icon in PHD is the brain icon, and there are some setitings in there, but for now leave them as there default, unless you have problems, then you will,need to read the instructions to learn about those settings.

Hope that gives you an idea to get started.

I am by no means an expert, but trust me when I say it can be done quite easily and I have gotten 15 minute subs with nice road stars, but as said before, balance is the key, and it must not be ignored.

Regards

AB

[Astroboffin]

If you have any issues when trying this, then let me know and I will try and help, as it WILL work, but it might be trial and error at first, with the settings as they can vary for different people depending on guide camera, and guide scope being used.

Regards

AB

[Astroboffin]

I have just discovered that Meade now do an Autoguider Port Module for LX80 and LX90 for £40 from Telescope House - does anyone have any experience of this device in conjunction with the equatorial wedge?

Yes these do work, but like you say it is £40 and if you get one, all that I said above will still stand for guiding with that, the difference will be one less cable going from mount to PC, as you will connect camera to PC and camera ST4 port to that new module, but a few of the settings in PHD will,be slightly different, apart from that the procedure will be the same.

It is cheaper to do my option, but both will work, and like I said earlier, a lot of people will say that pulse guiding gives better results that ST4 guiding, but that is a matter of opinion, and for our scopes I will always stick to the pulse guiding method.

Regards

AB

[Captain Tweaky]

Astroboffin - Very many thanks for your comprehensive explanation and offer of assistance.

It had been my intention to buy another wedge imminently,  but that was just before I smashed my plate-glass patio door about 2 hours ago. Hopefully, by the time the insurance company and glazing people have sorted things out I shall still have some shekels left to proceed with this little project!! 

In the meantime I can but prepare. You mention a '... proper Meade balance kit ...' - can you point me in the direction of the seller of one of these? I'd not come across this before.

I have all the other bits from imaging with an HEQ5 Pro Synscan and various refractors and have created lots of images with an Atik 314L+ and filterwheel. I should now like to do some distance 'stuff' using the 8" SCT, but I do recall having all kinds of issues trying to guide with the LX90. I shall certainly try the process as you suggest (finances permitting!!) now that I have a little more experience and shall be pleased to call upon your expertise if I have experience any of the issues I had before.

[Captain Tweaky]

Believe it or not Astroboffin - there's not a Meade LX90-8" equatorial wedge to be had anywhere in the country!!!!    - unless anyone who reads this has one for sale!!

[dazza1639]

I've got an orbit wedge it cost me an arm and a leg but worth every penny.

I will be putting it up for sale later in the year when I get a new mount

Darren

------------------------------------------------

Twitter: @SalAstroSoc @Astronut1639 www.salfordastro.org.uk

Nexstar 8 GPS ADM MDS Rings & Counter Weights, Skywatcher ST80 & Synguider, Canon EOS 1000d,

Dew Heaters & 4 Channel Controller, Orbit Wedge, Observatory and not enough clear nights

[Davey-T]

There are other wedge manufacturers but whether it's financially viable only you will know, incidentally if you've deforked the scope realigning it is not simple.

Dave

[Astroboffin]

Astroboffin - Very many thanks for your comprehensive explanation and offer of assistance.

It had been my intention to buy another wedge imminently,  but that was just before I smashed my plate-glass patio door about 2 hours ago. Hopefully, by the time the insurance company and glazing people have sorted things out I shall still have some shekels left to proceed with this little project!! 

In the meantime I can but prepare. You mention a '... proper Meade balance kit ...' - can you point me in the direction of the seller of one of these? I'd not come across this before.

I have all the other bits from imaging with an HEQ5 Pro Synscan and various refractors and have created lots of images with an Atik 314L+ and filterwheel. I should now like to do some distance 'stuff' using the 8" SCT, but I do recall having all kinds of issues trying to guide with the LX90. I shall certainly try the process as you suggest (finances permitting!!) now that I have a little more experience and shall be pleased to call upon your expertise if I have experience any of the issues I had before.

this is the balance kit i use

http://www.rothervalleyoptics.co.uk/adm-mini-dovetail-system-counterweight-kit.html

select the right one for your scope from the drop down list

i had to get an extra weight for mine

AB

[Davey-T]

Balance system here.

Dave

http://www.astro-engineering.com/prod/AstroEngineering/3DCBsystem/AC255-AC123-AC035.html

[Captain Tweaky]

Daren - many thanks for that - I fear it may be outside my price range! :-(

As for the balance kits - thank you kindly for the links, but until I can get a Meade Wedge it's all a bit academic! And Opticstar tell me that they may get them around May time!! Then again they may not!

[Captain Tweaky]

There are other wedge manufacturers but whether it's financially viable only you will know, incidentally if you've deforked the scope realigning it is not simple.

Dave

You've got me a bit worried there Dave. I have deforked it and then repositioned it as close as I could to the original - although there isn't a great deal of adjustment. How does it manifest whether it is aligned properly or not? Once I've been through the star alignment procedure it seems to GoTo and track as well as it ever did.

[Davey-T]

Read a tutorial on the LX200 Yahoo group about carefully marking the position before deforking to make sure it went back in the same place.

You can always knock up a wedge for your latitude out of plywood if you're into DIY

Dave

[Astroboffin]

Here is a good hardwood DIY wedge, made by a guy on here?

The holes under the washers are crescent moon shaped to allow for azimuth movement

Looks good to me, the declination can be altered by the north facing bolt at the front, as there is a nut above and below the wedge, there is a gap between the wedge and the top of the pier, but can't be seen on this image, so the actual wedge is sitting on four large nuts and washers, so as to be able to get perfectly horizontal to start, but I guess the angle of the wedge needs to be pretty close and final adjustment with the bolt.

AB

[Davey-T]

If you are using a tripod you can make the wedge for your latitude and adjust it with the tripod legs, bit fiddly but easier to make it without adjustment if it's only going to be temporary.

Someone posted a pic' of one made from ally recently, bit of a work of art, may have been Peter, will have a look.

Dave