Astronomy
Astronomy Picture Of the Day on your Android
I spent the last week or so learning Android programming. I find it important, in the learning of a new programming tool, to write something with clear specifications. This forces you to work on the best solution instead of using easy to code work-arounds.
The specifications are:
- The application should allow the user to read the Astrophotography Picture Of the Day published by NASA at http://apod.nasa.gov/apod on it’s Android device
- The application needs to be compatible with Android 1.5 (SDK #3)
- The user should be able to access the APOD for any date since june 16th 1995
- The user should be able to directly access the APOD of the current day
- The user should be able to navigate to the previous and next APODs
- The user should be able to navigate to the previous and next APODs with fling gestures
- The user should be able to view the picture in full size by clicking the preview picture
- The user should be redirected to the APOD website when clicking on the full size picture
These were the initial requirements … I will add some more stuff in the upcoming days:
- Change the full size picture activity from a WebView to an ImageView. This will allow the implementation of the OnClickListener callback and the re-use of the image bitmap in memory.
- Caching of the APODs on the SD card. This will save bandwidth, an important issue when using mobile networks.
- Adding a splash screen while loading the first APOD. Since loading the images can take a while on mobile networks, a splash screen with a spinner would look more professional.
The actual version of the project is published on my Github at the following address:
https://github.com/pchretien/APOD Feel free to fork, copying is not stealing!
2012 Venus Transit
We had a perfect weather all day long and 15 minutes before the transit started, dark clouds rolled in and ruined the show! I got these two shots before the sun completely disappeared behind the clouds …
I also uploaded some pictures of my camera and binoculars with the solar filters. I built the binoculars filters using old plastic bags and BAADER solar filter sheets. Adding a plastic rim to the filters helps fixing it to the binoculars or camera.
My camera rig if composed of an old and cheap 60mm refraction scope and my trusty Canon 20Da. I used a standard T-Ring to connect both together.
We made it a family event … good thing we had a soccer ball with us!
1 Comment »
2012 Venus Transit
A quick reminder … Don’t miss the last Venus Transit until 2117! It starts today (june 5th) at 22:09UTC. Venus will be visible against the solar disk for about 6 hours. The transit ends at 04:49UTC.
More of my pictures of the 2004 Venus transit on my astrophoto website at astrophoto.ca.
2004 Venus Transit
1 Comment »
Stars Trackers
I posted these two barndoor mounts on Thiniverse a few days ago. One is manually operated while the other is motorized.
Manual Stars Tracker kit:
http://www.thingiverse.com/thing:11376
Manual Stars Tracker
Motorized Stars Tracker kit:
http://www.thingiverse.com/thing:10756
Motorized Stars Tracker
Since I have not that much time on my hands, I decided to merge both projects so that I can chose between the portability of the manual version and the ease of use and accuracy of the motorized version.
The new manual version looks pretty much like it’s ancestor with some minor modifications. The length of the device has been cut in half and some minor bugs have been fixed.
New version of the manual Stars Tracker
I am now working at motorizing this new version of the manual Star Tracker. I want to make it simple to switch from the manual to the motorized version by reusing as much parts as possible.
I ended up today with this motor support that should replace the actual wheel of the Star Tracker.
Motor Mount for the Motorized Stars Tracker
I am using the same type of attachments as the frame of the Makerbot. This technique is pretty cheap and allows strong assemblies using plastic and wood.
Next step will be to design a coupling to attach the motor to the 1/4″ threaded rod of the tracker. I think I’ll use the same type of coupling as the Reprap 3D printer.
1 Comment »
First Light
I took my first picture, during the holiday, using my new motorized scotch mount. The following is a 2 minutes shot of the cygnus constellation region centered on the North America nebulae. The brigth star near the nebulae is Deneb.
Camera: Canon 20Da
Lens: Canon EF 17-40mm 1:4 Ultrasonic
Exposure: 2 minutes at ISO1600
Mount: Fixed tripod with motorized scotch mount
North America Nebulae
No Comments »
