Category Archives: General

Redoing the power distribution of my scope

After many years of use, I’ve decided that it’s time to redo the power distribution of my telescope.  The power box project that I did was great at the time, however over the years there a couple of things about that project that didn’t really work out too well.  Here’s the problems that I had with the first version.

Replacing my laptop.

The laptop that I have been using with my scope is over 10 years old.  This isn’t a problem in itself, but there are a few things that are worth noting.

 

  • Sony Vaio VGN-A115ZIt’s power hungry.  The internal battery is worn out, and only lasted about an hour in real use anyway.
  • It’s very picky about the input power, so can’t be run from a 12v DC-DC converter, unless it’s plugged into a car with a running engine (too low input voltage otherwise)
  • The 230v power supply doesn’t work with an inverter. Lucky I have a generic that does work.
  • Inverters are power hungry.
  • It’s just plain awkward to use the laptop in the dark.
  • The laptop has suffered from a HDD failure, so I replaced the drive.  If the laptop needs any work again, it’s not going to be so easy to repair it.

APC Back-UPS ES 700G

So, what of my Netgear ReadyNAS?  Well, I needed a better power supply.   Enter the APC Back-UPS ES 700G.TTOUln6Pvcpf-2fs7vf7JFZA-3d-3d_BigProductImage

 

This UPS should be able to run my NAS for about an hour without mains power.  What’s more, it has a Data power which when used with the supplied cable will attach to a UPS port on the ReadyNAS.   Once that’s done, the ReadyNAS will recognise that the UPS is attached and start working with it.

Using the ReadyNAS configuration I simply set the power threshold two 20%.  This is when the NAS will power down.  It worked right out of the box, and I didn’t need to do much.  This UPS was twice the cost of the PowerCool, but the peace of mind makes it worth the money.  If you look at the UPS, it has provision to power 8 devices, 4 will get UPS coverage, the other 4 will get surge protection only.  Frankley, I’d have been happy with a single power outlet, as I’m not intending plugging anything else into this UPS.

 

UPS fun and games continued.

As I said in an earlier blog post. The Powercool UPS’s are cheap and cheerful, but the USB device in these isn’t supported by my Netgear ReadyNAS.  My ReadyNAS is an important device on my home network as it stores my software library, film library amongst other things.   To me it’s important that this device doesn’t simply loose power if there’s a power cut.  Last week I attempted to power it from a PowerCool UPS – the power part worked fine, but the USB monitoring isn’t compatible between the UPS and the ReadyNAS.   So, the PowerCool is now providing UPS support to my home network.  Yep, if there’s a power cut, my Cable modem, Switches and Routers will stay up until my PowerCool UPS runs out.  I did purchase a second one of these, as I have network gear in two seperate places, so I have one powering a switch, router and cable modem, the other is powering a switch and router.  (basically I have network gear for each floor of my house)

Installing MySQL

MySQL is going to be the back end database for the server.  It’s a fairly good RDBMS (Relational database management system) there are several others to choose from, for my Needs MySql is the database that I’m going to use.

To install MySQL it really couldn’t be much simpler.

log into your linux, using the username and password that you setup with installing.

issue the command

SU
Then enter your root password.  This will give you SuperUser access.

now issue the command

apt-get install mysql-server mysql-client

you will be prompted to enter a password for the MySql root user. note: this is not the Operating Systems root user, the MySql root user will only be able to access the database in god mode.
After the files complete the copying process, you are done.  MySql is installed and running.

Freeing my guidescope

For several years I’ve been using the same guidescope setup.  That is, a SkyWatcher ST80 mounted onto my Meade LX-90.  When it works this setup is great.  With a webcam in the Skywatcher, and a DSLR in the LX-90.  Running K3CCDTools to do the guiding.   My setup has a big and common problem, sometimes I cannot find a star to guide with!

The root cause of the problem is that the guidescope is mounted on my Mainscope using tube rails. The Guidescope is ridgedly tied to the mainscope and cannot be moved outside of a very small area.  At the weekend I was attmpting to take a photo of M51 – The Whirlpool Galaxy.  After aligning the scope and slewing M51 into the field of view, I attempted a photo – 5 min unguided.  This worked reasonable well, there was some star trailing.  It proved that the scope was on target.  I then attempted to put a star into the field of view for my webcam (Phillips TouCam Pro II) this was not successful.  There simply wasn’t a bright enough start in the field of view to register on the K3CCDTools software.  I then loosened off the scope rings as much as I could, but this had no effect, there simply wasn’t enough play to allow me to put a star – any star into the field of view!

I’m currently in the process of trying to come up with options to solve this “interesting problem”.  The tube rings that I’m currently using are the Astro Engineering AC441 Parrellel rail system with 5″ rings.

So what are my options?

1. Bigger rings?  That should give me more play, so that I can point the guidescope seperately to the main scope.

2. Install the guidescope on it’s own swivling mount?   This way, the guidescope can be seperatly pointed to the closest conveniant guidestar.

3. Get another telescope to use as a guidescope

 

So for my options, the one that is going to solve it without any doubts is option 2.  However, it comes at a price.  I’d need to completely replace the dual rail system with a Dovetail bar, onto the new dovetail bar, I’d install a Skywatcher GuideScope mount.  Then to that, I’d need to source a new set of rings with a dovetail that can be attached to the Guidescope mount.  This will give some movement, but will cost over £300 to implement.

Going for a smaller telescope is also an option.  I could get a 70mm Skywatcher Mercury.  It’s an f/10 scope so matches my LX-90 focual length.  The scope would mount into my existing tube rings.  but there does remain the question of if I can get enough play to make this work, also with the 10mm less light gathering, it may not help when it comes to finding guidestars.

So finally my option 1, get bigger rings.  Currently, I have the 5″ rings mounted on my dual rail system.  There are 7″ and 9″ rings in existance.  With that in mind, I figured that the 9″ rings are going to be too large, and won’t grip the scope.   I’ve just managed to find some 7″ rings, which comes with a complete set of bars too (which means spareparts to me)  This will give a couple of inches of play around the ST80 that I currently don’t have.  With any luck (and yes there will be an element of luck involved here) this will mean that I can mount the ST80 and adjust the position to get me access to a good 30° sweep of the sky, or larger.

If this experiment works out, I’ll be able to point the guidescope at a nearby bright star even when it’s not close to where I can currently point.  There are limits on the amount of distance that I can slew away from the main scope before strange things will start happening, but there should be a star close enough to allow the guider to work.

What will my PI be for?

Raspberry PI logoWhat use is the Raspberry PI for me?   The biggest surprise for this little device is that is has the graphics capability to play full 1080P HD movies. Combine that it’s cheap, low power consumption and yet has enough power to play full HD content.  This device could shape up to be a really nice media streaming device.

 

Indeed that is what the Raspbmc project is all about.  This project is going to be fantastic once it’s out of beta. Just think about this for a moment XMBC running on a PI.  This silent device, yes silent.  No moving parts at all. Providing a way to use the PI as a complete media streaming solution.  This project alone really does take the biscuit.  It’s brilliant.

 

I have a collection of about 150 DVD’s, these are clotting up my living room.  Well actually I already ripped them to be WMV files but they won’t play on the PI, (something about codec licensing)  But having a media centre where I can watch and Film, iPlayer and even use the AirPlay features of my iPhone, this is really going to be something to watch.

Secondbar

One of the defining features of OS X, is that the menu bar is at the top of the screen. It’s not part of the application, or well document that you are working on.  This is all well and good when you are working on a single monitor. But, when you extend your display to a multi monitor setup, a problem appears.  The problem is that the menu bar is at the top of the main display.

 

OK whats the big deal?

Astronomy.cjdawson.com

I made good progress transferring the site from the old template.  There is still more to do, there’s some broken links, some of the images need changing up, some of the gallery items still need to be bought into the new format.  But the majority of the site is there.  Rather than leave the old site up, I decided that was time to update to the new format.  I think it’s better than the old site, much more navigable, and hopefully much more manageable on my part.  Time will tell on that second point, but with the liberal use of templates I think that I’m onto a winner.

Nested Templates

I’m still pulling content across from my current website into the new layout.  After messing about with dreamweaver for most of the weekend, I created a base template that the entire site will be built upon. (see my post New face of Astronomy.cjdawson.com) However, some of the pages have multiple items in each category, so I wanted to have a menu on the left side of the screen for this.  There are several ways to accomplish this, using PHP is one really flexible method, but for now I decided to use nested templates in dreamweaver.   This technique allows me to create a template based on another template.  So, I can use my base template, as a file which is a template for the projects section.  The project section can have it’s own template which is used for the articles.

This method become really cool when I need to make an adjustment to the base template – for example when I decided to alter the way that the section buttons appear.  I simple alter the base template and it will update all the documents for the entire site.   Everything gets processed correctly, and the change is cascaded throughout the entire site with no effort on my part.

The other way to accomplish the same thing is to have the site programmed up using PHP,  I’m sure that eventually I’ll move over to a PHP data driven web layout but for now, having everything processed locally is perfect for me.