PHD and LX200

[johnb]

Hi

Does anyone use PHD to guide a LX200 ?

John B

[Merlin66]

John,

I used PHD to guide my 12" Lx200 Classic for many years, both in Alt-Az and on a wedge. I used an OAG. No issues, no problems.

How can I help you?

[johnb]

My astro club has a 16 inch wedge mounted. I plan to use it for imaging so will use my trusty ST80 and QHY5 with PHD. Are there any good phd settings to start with for guiding.

Regards

John b

[Merlin66]

No, not really. 99% works from memory with the PHD defaults.

Are you considering an OAG??

There's a significant difference between the 400mm guide fl and the 4000mm Lx fl.

[johnb]

Not initially was just going to use the st80 which is mounted on the top of it with the qhy5 to start with. Oh and my 450D and see what results I get. I have no idea what I will get ?

John b

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I am here: http://tapatalk.com/map.php?1bucxs

[johnb]

Looking here : Field of view Calculator<script src="title2.js"></script>

and selecting the scoep and my 450d it seems I may get some interesting images

John B

[Merlin66]

The real problem is the slow f10 basic fr. A suitable reducer can improve things but still a challenge.

(It's OK for spectroscopy!!)

[johnb]

The real problem is the slow f10 basic fr

and the the implicatiions of that are ? (im still learning)

John B

[Merlin66]

The f10 ratio is very "slow" and requires lengthly exposures compared with a "fast" system ie the f5 of the ST80.

Fitting a x0.63 reducer to the Lx will improve things a little and also give a wider field of view.

Check out the freeware CCDCalc - this will clearly show you various DSO objects as they will appear in your camera.

[johnb]

lengthly exposures

i see so with my Skywatcher 250 i was typically doing 300 sec exposures I guess by default the with the LX200 they will increase somewhat unless I get the reducer

Your help is appreciated.

John B

[ollypenrice]

...more than 'somewhat,' I'm afraid. F10 is four times slower than F5.

Olly

Edit...on extended sources, that is, in case anyone was about to launch a rocket my way!!

[johnb]

more than 'somewhat,' I'm afraid

I saw advantages in using this scope, its in the observatory, pier mounted, short set-up time etc, however folk don't really seem enthusiastic ?

John B

[johnb]

well having issues getting PHD to drive the Meade LX200 - guess its a setting just not sure where ? Pointers ?

Regards

John B

[Merlin66]

John,

What issues are you seeing?

Are you able to calibrate?

[johnb]

Not getting anything, PHD is working and getting a good star etc, im guessing it maybe an ASCOM thing. when i try manual control via PHD it does nothing ?

John B

[Merlin66]

How is the guide camera connected? If you use the QHY5 direct connect to the CCD port the signals should be OK.

If you use the QHY to the PC then a serial to the mount it needs to be LX200 protocol....

Again, is PHD completion the calibration stage???

[johnb]

No PHD is not calibrating.

I have the lead from the QHY 5 going to the AutoGuider port on the LX200 and then from the QHY5 via USB for the PHD.

PHD sees a good star and PHD Mount is set to On Camera

Thanks for the help

John B

[Merlin66]

OK

The PHD non calibration is due to the lack of control signal getting through the mount.

(You can double check this by using the manual PHD controls)

May be the ST-4 cable??

[johnb]

I have changed the cable an used the Manual Output and nothing so I guess at least I know were the issue is, just not sure how to solve it ?

John B

[Xplode]

We have the same telescope in my astronomy club and i got it up and running with guiding.

We are using the RS232 port and it works without problems except the connection in the port is a little bad so i have to unplug-plug the connector sometimes.

We're using Ascom with LX200Classic/POTH Handset to connect to the scope.

With this we can connect to the scope from several programs at the same time.

Guidecam is the same as you have, QHY5.

Cameras we have tried are 5D MKII and 450D, there's a little vignetting on the 5D MKII because of the 1.5" restriction in the visual back of the LX200.

I guess we will get the same problem with a focal reducer on the 450D when i get around to test it.

For imaging from the computer we use BackyardEOS.

There's 3 unmodified pictures from this setup here: Gjøvik og Toten Astronomiske Forening

The stars aren't perfectly round so i'm guessing mirror flop and/or guidescope mount flexure is the cause.

If you get your setup up and running i'd like to compare results and settings in PHD.

Ole Alexander