The telescope continues...

Soooo - I may have built another telescope and not documented the process at all. Which is a bit of a problem as I now have a folder full of CAD files with really odd, but meaningful, names (like: "SlottyThings.ipt", why did my past self do this to me!). Luckily I have some nice work in progress photos, even if my in depth description may be a bit lacking.

The telescope is a 76mm Newtonian reflector with a potentially equatorial mount. The optical tube, and mount were built using the university laser cutter. Unfortunately I am not yet skilled enough to make the mirrors, mirror cell, tripod or eyepiece myself, so they had to be purchased/scrounged.

The optical tube with the two cheaty elements, the secondary holder and the primary cell. I like the fact that it looks like a big ray gun!

Tube clad in a sheet of black fabric to guard against light pollution, with two points of interest. One, the photo is from before the final mount was assembled so the telescope is attached straight onto the tripod. This was way too shakey and has not been done since. Additionally, you can see the £5 telescope in the bottom right corner! Safe to say the new telescope is incomparably better.

Drama shot, now with proper mount. There have been a couple of modifications since this photo to stiffen up the mount and tripod, but essentially the telescope still looks like this.

Of course no project would be complete without an even more ambitious project to follow it. Thus, "Operation Sandra Voi", the plan is to produce a mosaic image of the moon by stitching together lots of smaller images. My eyepiece's field of view is quite limited, so this is the only way I can produce a complete picture of the moon, and hopefully it will look really good when it is done: I can always go back and re-image sections that are either incomplete or of poor quality after a first pass.

"Sandra Voi" is named after one of the lighthuggers from Alastair Reynolds's Revelation Space series, only mentioned in passing a couple of times, it is an exploration ship just as hopefully the project will help me explore astronomy (ha ha, maybe I should have come up with a cool acronym instead). The naming scheme does leave me with a bit of a problem as I haven't thought of a cool enough project to call "Operation Nostalgia for Infinity" yet...

Photo, apologies for any confusion, due to the optics of the telescope the image is flipped, I also have no idea about the rotational orientation! I am fairly sure that it is the boundary between the Mare Serenitatis and Mare Imbrium, with a fairly faint Copernicus crater at the top of the image.

Preliminary mosaic with a nice template in the background kindly provided by good 'ol NASA.

the £5 telescope

Sooooo - haven't posted in a while, but I think this one will be the first of many in the near future.

The title is true (approximately), on the day I built the telescope I spent less than £3.50 - but I already had convenient tubing and tape lying around.

Long story short, I decided to have a rather strong coffee on Tuesday morning and that evening, having buzzed around all day, I had built myself a 75mm aperture refracting telescope. Why? Well I have always enjoyed looking through my dad's telescope back home, pointing it at Jupiter, Venus, Mars, the moon and whatever else happened to be along my line of sight. I have been having withdrawal symptoms ever since coming to uni, but my recently completed work for the ESA "fly a rocket program" (more on that in another post) tipped me over the edge.

How did I do it? Search up refracting telescope on google and you will get all sorts of lovely diagrams, adverts, pictures and links to educational websites. Trawling through this lot left me with two impressions: 1. Whatever I built wasn't going to produce pretty images - the colours would blur away from the centre of the image, the image would be flipped and shapes may end up distorted as well. 2. Magnification is done at the eyepiece (the place where your eye goes) - a good goal for the main telescope-y bit is to get it as large as possible, both in diameter (to get as much light), and length (as this counters 1.), but these are both limited by the lenses you use.
Off I went to find a nice big lens to put at the front of my telescope, the correct name for this lens is the 'objective'. Hundreds of years of gradual improvements to telescope design started pretty much immediately by getting rid of the standard convex lens as the objective, instead using all sorts of wonderful shapes to limit colour blurring.

HA HA HA. 

75p later I have myself the greatest abomination of an objective lens in the form of a wilco magnifying glass. At 75mm across it is not the biggest lens, but it is a lot bigger than my eye which is actually the important bit. Another ~£1.50 later and I have myself a pair of small binoculars from a charity store, ready to be killed and resurrected as my eyepiece. None of this is going to work fantastically, but all I want to do is not have only my eyes to look at the stars with.

So having spent the entire day polishing my new objective lens I rushed home to begin construction!! The key thing I was concerned about with the focal length of each of my lenses (including the ones from my binoculars). This simply involved pointing a lamp into the lens from a long way away, and then looking to see where the image came out clearly on the other side:

As you can see I had lots of fun with little pieces of tape, the first black piece after the big lens marks the focal length of that lens while the white pieces were used to measure the distance from the target to my eye.

One of the key mistakes I made at this point was to check for magnification. This being my first recent foray into optics, I really didn't want to manage to make an incredibly convoluted way of looking through a cardboard tube, with all benefits brought by the lenses cancelled in some way. As all I wanted to do was see some of my favourite nighttime targets a bit more precisely, I didn't really care how much magnification I got, simply that it was more than none. Thus I spent ages with the white bits of tape, checking angular sizes of things with and without the lenses, only to realise later that magnification comes primarily from the eyepiece, which usually like to sit very near the focus of the scope - which simplified the design immensely.

Construction was very simple:

1. Take cardboard and cut section off with  a length corresponding to the focal length of your objective lens, I tried with a slightly longer tube to begin with but this did not work at all.
2. Cut another much shorter section of cardboard to act as a light shield in front of your objective lens.
3. I then added slightly smaller rings of cardboard inside the two sections at the ends where I was going to put my objective lens to help mount the objective lens and keep it still once the telescope was complete.
4. Then tape the cardboard sections together with the objective lens between them.
5. Now we need to have some sort of mounting for our eyepiece (s). Looking around the web you can see that most mountings allow for the eyepiece to move towards and away from the objective lens to help focus the output image. I took a ring of cardboard with a diameter such that a toilet paper roll could slide through it. I then took a convenient object matching the cross section of my main tube (the end of the tube for when it was a postage tube), cut a hole at its center with a diameter corresponding to my loo paper roll collar, then taped the collar into this hole.
6. Bodge an eyepiece. I am still doing this. Actually looking at eyepiece layouts was a good start, I eventually opted for a Ramsden configuration as this was the best I could do with the lenses available...
   

My conclusions...

£5 for any telescope would be good, but building it has meant that instead of a rubbishy kids second hand novelty scope I have ended up with a passable scope with an alright aperture and plenty of potential. At the moment the telescope mainly just focuses images, without enhancing them too much, but with some more lenses (and a bit of practice) I think that new eyepieces would drastically improve the telescope's performance. The dodgy objective lens reduces the potential utility of the scope: colour bleed and image distortion are utterly pathetic, and this project is missing the crucial element of any true telescope - the mount.

I envision many happy evenings spent looking at random celestial objects with the telescope, but in reality I think my efforts in telescope building may have only just begun...

Lunar Rover progress update

Been a while but here we go!!

So progress on the lunar rover project has been reflective of the once a week meetings - as predicted the comms team merged with control (although there was a proposal to spin off power into its own team).

One of the problems we are facing is that we cannot easily define the boundaries of each team so early in the project. Ideally communications would build the talking bit of the robot, how we get information into and out of the robot including commands, sensor data and possibly images. Control will have to deal with how we use this information on board the rover, including making it move and deploy our sensors. Power will be given a big battery, a bunch of required outputs and told to go sit in a corner and design an interface between the two.

The problem arises when the functionality of one section impact on another. The best example here is the communications potentially impacting on the control system by restricting the amount of information we can feed to the rover.

How do we solve this? It will probably be done gradually, as things start to fall into place the required behaviours of each section will become better defined to the point where sub teams can split off to work on separate project areas.

What has actually happened so far? A bunch of rough proposal work, most teams (including the structural teams) have come up with a rough idea of what they are supposed to be doing and passed on the biggest requirements they can think of to everyone else (including the fact that the payload deployment and drive train will probably mean we have to deal with upwards of 6 motors :| ). Within the control/comms/power team we have come up with some basic control system ideas - and how each have to be supported by the communication and power teams. While Raspberry Pi came up as the immediately obvious solution (you can say it is a proven technology and therefore less risky, as well as being easy-ish to use), someone from the control team found a Commercial Off The Shelf (COTS) piloting and control system, a bit pricey but would certainly solve many of our problems at a stroke.

Our next meeting is tomorrow, so ideally there will soon be lots to write about.

3DS Hardmod and Wii Controller Dissassembly

Hi, Andrey over here.

One of my flatmate's Wii Controllers were in quite bad condition after travelling across Asia for a while....

So I took them apart, desoldered the battery contacts and submerged everything but the PCB in soapy water (to remove gunk and alkaline corrotion). Soon I will reassemble them and hopefully there won't be explosions (hehehe).

Also, a couple of weeks ago, I modified my "New 3DS XL" by soldering four wires to the NAND chip test points. The mod allows to copy the firmware directly from the NAND chip by using an SD card reader. With the firmware backed up, many doors for homebrew open up   ͡° ͜ʖ ͡°)

Just One More Resistor Begins...

Here we go!

So, why the blog?
Well, to display some of the insanely cool projects I have managed to throw together (mainly with others) after only a year of studying Electrical and Electronic engineering (time period growing as we go on).

For example, after only 6 months of electronic goodness myself and three others attempted to make a radio telescope as an entry into a 24 hour hackathon. I actually wrote a post somewhere else (here). Surprisingly we did not do too badly, we were not able to get a high enough angular resolution and the weather on the day prevented us from taking it outside and pointing it at the largest object we could find (the sun).

Other projects included an antweight robot wars entry, and a model rocket accelerometer payload.

Coming in the near future are more robots (including fun with servos), and possibly an internet connected coffee machine...