I have been a little impatient while waiting for the skies to clear to try out the new scope and in the meantime I have been reading anything I can locate on astroimaging, including using modified a webcam, so naturally I thought “Why not ?” and figured I would give it a go.  Of course doing this will void the warranty of any camera used.  Most sites recommend using the older model CCD based webcams however these are not readily available here, the selection to be found in Indonesia consists of Logitec or Logitec, so I went with Logitech :). I decided to go with the lowest model (cheapest) HD version I could find which ended up being the Logitec C270 which is 720p with a CMOS sensor.  CMOS sensors have reportedly improved significantly over the last few years so hopefully this will be up to the task.  the key aim in the modification is to remove or move the LED from the main circuit board, remove the lens from the camera (the telescope will become the lens) exposing the sensor  and, finally, providing a means of attaching the camera to the telescope.  This last can actually be the most time consuming.  Ideally there are commercial adapters available that screw into the lens mount, however these can be pricey and I don’t have ready access to one.  An alternative is a canister from 35mm film however this take time to locate in this digital age therefore I am using a bit of cut plumbing pipe instead.

Removing the back camera support will reduce weight and make it easier later.  Many sites recommend just using pliers to snap it off, however I considered this a bit of a risk to the main body housing and it is simple enough to remove properly.  Removing the cover indicated in the photo will expose the phillips head screw which holds the pivot shaft in place.  After removing this screw, the pivot shaft can be pushed out and the back support then comes off easily.

 

Next is to remove the front fascia which can easily be done with a fingernail using the slot underneath, or with the aid of a  small flat head screwdriver.  I took some of these photos after the original modification using another C270 I had at work which is why you can see the support arm still attached here.

 

 

With the fascia removed, there are 3 small screws which need to be removed to remove the front faceplate, However I would suggest holding off on doing this until later as it is going to be necessary to cit into the molding of the faceplate to enable the piece of pipe to sit flat.  If you have already removed the lens then you run the risk of damaging the sensor.

 

 

As mentioned, I am using a cut piece of cheap 32mm (1 1/4″) plumbing pipe to simulate an eyepiece holder.

 

 

 

To limit reflection in the pipe, I have covered the inside with black electric tape to begin – it was handy.  If it proves to be too shiny then I will look at other alternatives.  I looped the tape over the end which will insert into the telescope so as to limit the possibility of scratches from the cut end and I will build up layers of tape around the circumference if needed to give a good fit.

 

The raised section of the faceplate needs to be cut back to recess the holder and allow it to sit as level as possible which is important so as to have the sensor focus plane correct.  As the holder is 32 mm, this recess needs to be 16mm from the centre of the lens.  I found that the first line of holes for the microphone was just about the right spot.  I then rounded the corners to accommodate the tube.  Be careful to remove dust and fragments before removing the lens in the next part.

 

Removing the faceplate to expose the underlying circuit board reveals A) the LED, B) the lens and C) the microphone.  The LED, if left as is, will flood the sensor with light, therefore it needs to be modified or removed.  Initially I removed the LED by desoldering.  Testing the camera showed that it worked fine with the LED removed.  Some say that you can just break (crush) the LED however I haven’t tried this myself so can’t vouch for it.  After testing with the LED removed, I decided to replace it on the outside to provide an indicator that the camera was operating (I admit I stole this idea 🙂 ).  Doing this, I was only able to locate a green LED and it is very bright so I may well remove it again if it proves problematic.  The lens can now be removed by simply unscrewing it.  The microphone we don’t need to worry about.

Replacing the faceplate, the tube is currently attached, centred on the sensor as well as possible, using black electrical tape to be able to test and make further modifications as need.  Once it is working as well as possible I will then consider gluing it in place or, if i have been able to locate one, change to a lens mount adapter.

 

 

Update

Since completing the modification above, I have had the opportunity to test it out – on the moon of course as that is the largest and easiest object to locate in the night sky.

  

These pictures were generated using my skywatcher ED80 with a 2x barlow.  There were some issues in the colour balance and vignetting so I converted the final images to monochrome as I am not all that competent in Photoshop yet.

I have been thinking that the issues found in the original videos and images were possible mis-alignment of the homemade 1.25″ nosepiece, putting the sensor plane off in relation to the image plane, and additional unwanted reflections off the shiny electrical tape used to line the nose piece. Therefore I located a commercial webcam nosepiece online (ebay) for $12 and ordered it.  After waiting around 2 month it finally arrived – the joys of Indonesian mail services !

 

Fitting the new nose piece wasn’t quite as simple as I hoped as the nose piece is threaded for an older style webcam and the newer style C270 has a much smaller lens housing and aperture in the front fascia.  This was solved by drilling out the fascia slightly to just be able to thread the adaptor in – the plastic of the fascia was threaded by the metal thread on the adaptor with just a little pressure.  This is still not a perfect fit as there is a gap between the adaptor and the lens housing however I am hoping that this will have the alignment better then the previous arrangement.

Unfortunately, thanks to the continual overcast skies in Jakarta for the last several months I have not yet been able to test this newer version.  Once I can test, if any further modifications are required then I am thinking this will likely be in the way of drilling out the fascia further so that the adaptor can fit further into the camera body in which case the threaded section will sit over the lens housing on the circuit board.