Tuesday, 14 February 2012
How to set up a guiding system for your EQ5 mount on a budget.
If like me you own a Sky watcher EQ5 mount and want to have a cheap guiding system so you can do longer exposures for astrophotography then you are in luck. Here I explain what you need to do this and how to go about it, so if you want to have cheap guiding system for your EQ5 mount read on..
First of all lets take a look at the parts you will need to make up this guiding system if you own an EQ5 mount.
Here is a picture showing the items that you need to get, which are.
The Sky watcher Dual Axis motor drive kit from any local telescope supplier note it must be the Dual axis kit not the single RA right ascension kit.
Next you will need to buy two items from shoe string astronomy which are an ST4 port conversion kit and a GPUSB adapter which stands for Guide Port USB adapter.
Next on the list is a webcam suitable for astrophotography, I used a Logitech Quick cam pro 4000 and to this added an adapter so it can be used in a normal telescope focuser. Both adapter and webcams are available on the net from many suppliers.
Lastly you will need two 5m cables for the ST4 port and the webcam and a laptop that is running the free software called PHD which stands for push here dummy, it is free to download and is easy to use with a good user manual.
If you have the sky watcher 10x50 finder scope as I did then you will have everything you need not forgetting your SLR camera and T.Adapter mine is a Canon 350d.
The cost for all those parts is roughly about 200.00 as I already had the webcam laptop and camera.
Once you have got all the parts you need the first step will be to get parts 2 and 3 in the above picture the dual axis kit and the ST4 port put together.
This is very easy to do so don't be put off if your not the type of person who is used to a soldering iron and wiring diagrams I can assure you that it is dead easy to add the ST4 port to the dual axis motor kit and only takes about 40 minutes to do, so lets show you how its done. There is a manual with good instructions but here is how I went about it.
This is what the ST4 port kit looks like and we will be soldering it on to the dual axis control pad and once again its very easy to do.
First of all we need to gently prize off the buttons on the dual axis controller.
Simply ease them off with a couple of small screwdriver underneath them and they pop off.. now that was not hard was it.
Then undo those 4 screws that hold the top on and remove it so you reveal whats underneath ohhh scary..
Ok take a deep breath and undo those two small silver screws on each side of the left and right buttons and then gently lift back the plate like so...
There you go not so hard at all, next bit is to feed the ST4 port wires through the cable holder then to solder on the wires, at this point I was getting scared take a deep breath and carry on its easy peezy and you don't even need any solder just a solder iron.
First get a hand drill and a drill bit and drill a hole in the casing as in the picture below. I just held the casing between my legs and drilled it by hand.
Ok now that the hole is ready you feed the ST4 cable through it and clamp it in postion as I have done here.
That done we now heat up the soldering iron and using the manual as our guide we solder the wires on to the correct points. I simply layed the wire on the point and pressed with the soldering iron till it was soldered on there is plenty of solder on the points so no need to add more. It was easy to do but it is useful to have a pair of tweezers with you. Here is the finished solder job, I am rubbish at this kind of thing.
Well done you have now added your ST4 port to your dual axis motor kit! Just screw every thing back together and when your done it will look like my picture below. I have made a neat little holder for it out of an old cutlery holder cut to shape.You can see the two wires running to the dec and ra axis motors and the new
ST4 port wire coming out next to the power supply. The gray wire is my ST4 cable plugged into the new ST4 port that will then go to my GPUSB adapter and that will plug into my laptop. If your confused see the next diagram which shows you the connection lay out of all the parts.I put a cable tie around the wires from the ST4 port to tidy it up.
This diagram shows you how all the parts fit together.
Now that we have the ST4 Port on our dual axis control pad test it all out to make sure everything all works ok if not check your soldering and make sure nothing has come away from the solder points. Now having done that we can move on to getting the webcam sorted out.
THE WEBCAM AND FINDER SCOPE CONVERTED TO A GUIDE SCOPE.
This again is very easy to do, I am using a quick cam pro 4000 webcam but you can search around the net for others if you like and the adapters are easy to get on line as well. I had a 10x50 skywatcher
First steps, the webcam needs to be taken apart and the adapter put in. So we begin buy taking the webcam apart.
Ok now its all apart remove the camera lens buy gently unscrewing it.
Now we offer up the adapter from Morgans, but there is a problem. The Adapter does not fit! Fear not though it is just a simple case of trimming down the barrel on the camera so that we can reach the screw thread inside a matter of removing about a quarter of an inch with a sharp craft knife blade, helps to heat it slightly so it cuts through the plastic easy.
Remove the two small screws at the back of the unit that hold the barrel onto the chip here I am removing the second one below the first one at the top part of the unit.
And with the barrel gently removed here is the chip.
Having removed the barrel I trimmed it back a small amount with my craft knife until the adapters thread could reach the thread inside the barrel. I then screwed it in to test a snug fit, then replaced the barrel back onto the unit and screwed in the Morgans adapter.
Now its time to put the casing all back together snug and screw tight the first screw we removed to divide the casing.
Notice we have a rather horrible gap there which dirt and dust can get in so to fix this I used a piece of foam cut a small bit of the end and pierced a hole in the middle that fits nicely around the adapter and seal the gap. I also cut another bit to plug the end of the adapter when not in use to keep the dust out and off the sensor chip.
MAKING YOUR FINDER SCOPE INTO A GUIDE SCOPE THE EASY WAY.
U TUBE VIDEO WHERE I SHOW YOU HOW THIS IS DONE
Turn your finder scope into a guide scope.
Now all of that fits into my converted finder scope here is how that is done simply cut a loo roll to size wrap tightly around a spare eye piece and tape it with masking tape so it gives a snug fit and place the loo roll in a tube of foam pipe lagging.
Now push the adapted webcam into the finder scope and aim it out the window of your house at the unsuspecting chickens. To focus just pull back slightly or push forward slightly and the chickens will never know they are being spied on.
Here is a still frame of the webcam finder scope conversion and the chickens it is filming.
Ok hope you have managed to keep up so far. You will find that the webcam will fit nicely into the finder scope using the loo roll and foam holder and that once you have it plugged into your laptop you can gently push it back and forward to fine tune the focus. You may want to diy your own more sturdy way of holding the webcam in the finder scope but it works ok for me.
Lets do a recap then..
We have added the ST4 port to the dual axis motor control pad and we have got a webcam with the adapter on it so we can put that in the finder scope and use the finder scope as a guide scope. We will use the webcam and finder scope converted now into a guide scope to focus on a star and use that star for guiding with through the free guiding software PHD. Here is a shot of a star that we have found with our webcam and it has been locked onto in PHD. You can see the screen of PHD here with the star that we have locked on to and PHD is using this star to guide with.
Now if you refer back to the diagram showing you how all of the parts fit together we can take a closer look at how when you have it all set up outside, to go about using it all to guide with. Remember that on this diagram we must also add our SLR camera that is attatched to the telescope with a T adapter. If you are completly new to astrophotography and all of this is too much then my advice is take a step back read my blog from its beginning to see the progress made over a year until I got to this stage. If you are feeling confident and are already doing astrophotography then read on..
TAKING IT ALL OUTSIDE AND GETTING IT ALL WORKING.
By now you are wondering if all of this is going to work and what sort of results you will get ie is it worth doing. My answer is yes it is worth doing especially if your on budget and want a cheap guiding system.
SO lets get outside and do some guiding and see the results.
First of all choose a good night to test this all out nothing more frustrating then having it all set up and getting clouds ruining it all.
You will normally put the telescope down and do a polar alingment first take your time over this and get your scope nice and level.
Now with everything set up fire up your laptop and star up PHD.
PHD is simple to use but you will have to tweak a few of its setting to get the most out of it. First of all you hit the camera button and this will select your webcam from the settings next you hit the telescope button and this will connect up to your telescope make sure your GPUSB adapter is plugged in to your laptop and your st4 cable is connected. The next stage is to hit the loop button which will activate your webcam, focus it carefully so that you can see your choosen guide star in this case I was using Beetle juice in the constellation of Orion. You then click on the star and press the PHD button. PHD will then calibrate its self and start guiding.
If you then bring up the graph you can see how the guiding is going, the aim is to get a nice smooth RA and DEC graph going. Here is a picture of my graph after a bit of tweaking to the settings.
I should also point out to you at this stage that you must insure you have removed all the slack out of your mounts gears so you dont have any slack in your dec and ra axis. To help you with this here is a You Tube video showing you how this is done.
Taking the slack out of your EQ5 gears
Once you have got the system guiding with a nice smooth graph you can start your camera having insured it was focused correctly and using a remote timer to take the exsposure.
The final results are show here. I have yet to do more guiding with this system but I am satisfiyed that it works and will allow you to do longer exsposures on a budget. If you want to know more you can find me on the stargazers lounge as Quatermass.
In order we have the first shot a full 5minutes at an ISO of 800
Next is a 6minute shot with the ISO down to 400
Next is a 7minute shot ISO 400
Next is a full 10 minute shot ISO 400
And if you want to follow the very detailed thread on this project please go here