Thursday, June 30, 2011

Almost in focus

Today I used the laptop to focus and then switched to live view for the exposures so I could use the camera's superior histogram:

Click to enlarge

Wednesday, June 29, 2011

Got half of it

I guess the "bottom" half is better than nothing:

Click to enlarge
I'm still wrestling with this camera. I managed to get it focussed this time with the use of a laptop but there was no usable data in the red channel of any of my exposures. This image is from the green channel!

Crystal clear the next two days. Stay "tuned"...

Saturday, June 11, 2011

Best solar image yet

Update: I've reprocessed this shot. The result is here.

Today I went through my last round of imaging and found that everything below 1/100 of a second was clipping in the brightest area. So I reprocessed my 1/100 sec exposure in Photoshop, stretched and sharpened it in Registax (I'm running Windows 7 with a Parallels virtual machine on a Mac in OS 10.6.7), then did some final tweaking in Photoshop. I used the Shadows/Highlights feature to reduce the limb darkening. (I use it all the time for the photos on this blog. It's a simplified version of the features used for HDR).

Here's the result:

Click to enlarge
Note that the spots are much darker now. A gap in the histogram is filled in now, too. I think this is as much as I'm going to get out of this one. It's supposed to be very clear Monday. Maybed I'll take some more pictures...

Wednesday, June 8, 2011

2mW Green He-Ne laser tube

I never thought I'd see one of these at a price I could afford:

Click to enlarge
The last time I bought a green (543.5nm) Helium-Neon laser tube it was only about .2mW so this is quite a jump in power. At 19 inches it's the longest He-Ne tube I've ever seen. I have diode laser pointers that are more powerful but the beam is nowhere near as well collimated.

I bought it on eBay from Meredith Instruments (check out their active auctions—their web site is here). They still have nine five left as I write (they started with 35). They were kind enough to include clips and a ballast resistor with it. I used the power supply I got with the last auction I won.

I made the stand out of scrap wood, hot glue and some paint. Don't look to closely at it. I put more a lot work into the picture. Well, now that I look at it I realize that I have the ballast resistor on the cathode instead of the anode but it works anyway.

Sunday, June 5, 2011

Building a Tesla coil part one—the kit

Thanks to all the time I've wasted playing around with my solar telescope my Tesla coil kit has been sitting here gathering dust.

I bought a microBrute kit from Eastern Voltage Research. It's a sophisticated solid-state design with no neon sign transformers, no huge capacitor made out of plate glass and no spark gap.  The kit is almost complete and a great value. It includes the coil forms and even a torroid.

Not included are a base, a cooling fan, and IEC sockets for the AC cords (I'll add those to the base I'm going to make).

Note that this is NOT a project for beginners. Although the instructions are quite good and give you the color code for each resistor, I wouldn't recommend this for your first outing with a soldering iron. For example, look at the box full of parts in the picture—can you find a .01µF capacitor or a 1N4128 easily? Note that the IGBTs that drive the primary coil are easily damaged by heat and primary/secondary arcing. Replacements cost $18.82 apiece at Mouser. You'll have to mount the PC board on some sort of base with a fan (not included) blowing directly across the heat sink. To top it all off, you'll be using mains voltages right on the PC board and the HV discharge from the secondary could seriously burn you.

If you just want to see some sparks and light up florescent tubes from a distance I recommend the smaller kit they offer. If, on the other hand, this isn't enough of a challenge they do make the miniBrute...

So far I've only started stuffing the PC board. Next I'll have to build a jig for winding the secondary and do the actual winding.

To be continued...

Saturday, June 4, 2011

Things are getting better

Yesterday I managed to find a sweeter spot on my camera's imager and there just happened to be a huge prom to focus on. Here's the result (click to enlarge):

I have a large number of exposures to play with now. Stay "tuned"...

Thursday, June 2, 2011

Working on it

Good imaging still eludes me. I'm seeing lots of interesting stuff and I've gotten plenty of tips on how to photograph it but I'm still not there yet.

I went out with my new (old) laptop the other day and got a few exposures before it locked up. After about the fourth time it was so hot I didn't dare go any further. It was well over 90°F at that point.

I have some more gadgets on the way so I may have more to tell before long. We'll see.

In the meantime I've false-colored some spots:

Uneven illumination is the problem here. It's had to get right on the sweet spot:

Hot and hazy tomorrow. We'll see—or not, as the case may be.