New Astronomy Products from Wa'chur'ed Observatory

[Greg Marshall]

Since I retired from a career in designing electronic products (mostly related to imaging), I've often had to rely on the skills learned over the years (and learn some new ones) to solve problems that came up in astronomy. Thinking that my friends in astronomy and astrophotography might benefit from the solutions I developed (and having little else to do), I decided to make some of these solutions available as real products. My intent is not to make a big business from this and it's not likely that I'll ever make money from it - I just want to stay in practice and, hopefully, help people facing similar problems.

So I'm going to tell you about the first 2 products here. Neither of these is very sophisticated and they barely qualify as being "electronic", but I've found them useful.

First, the "Art-Star", an artificial star for collimation and optics testing.

The Art-Star is a battery powered (3 AA batteries) device with variable brightness (about 2.5 magnitudes range), an LED light source (available in white or green), and a 150 micron aperture drilled in a thin steel plate.

The bottom is fitted with a 1/4-20 metal thread, so you can easily mount it on a tripod. The light is normally diffused so that the aperture is very evenly illuminated, but since that is unimportant in some applications, you can remove the diffusion filter, thereby increasing the brightness.

The color choice also depends on the application. To test optics properties affected by wavelength, select the white option. The green device is quite narrow in bandwidth and therefore produces a sharper set of diffraction rings, which may be preferable for collimation.

The introductory price is $30. This standard version (white or green) includes a 150 micron aperture that I make myself using a precision drill bit on a professional milling machine. I then select the best pieces via inspection under a microscope. If you want a different size aperture or one that is even better quality, I can provide a commercially made aperture at just about any size you want. I have not established a price for this option, but it's at least as much as the Art-Star itself!

Next, and of special interest to you imagers, is the "ELF Panel", an electroluminescent light source for taking your calibration flats.

ELF is designed to fit over the end of your scope and has a black felt lining to make it reasonably light proof. That means you can take your flats any time, without bothering others. ELF includes an inverter for the high AC voltage required to drive the panel. The input to the inverter is 12V DC and comes with a power cord for the usual cigarette lighter jack. ELF uses only about 2 watts (for up to 6" diameter), so it can be powered by just about any 12V DC source.

Each ELF is custom made to fit your scope. To make one for your scope I need to know the outside diameter of the front end. Please measure carefully! The standard ELF can be built for any scope with a diameter of up to 5.5". For slightly larger diameters it might be possible, depending on the inside diameter of the OTA/dew shield. The important factor is that the illuminated area is about 5.5".

I am currently in the process of testing the flatness of the ELF panel. Simple methods indicate that it is, indeed, quite even in illumination. However, precise measurement of this property is surprisingly difficult to make. I'll post more information when it becomes available.

The 5.5" (or smaller) ELF is $45. The optional AC adapter is $10. Larger panels can also be made, but are full custom and priced per order.

Please contact me here or at "greg (at) afterlightphoto.com" for more information.

Thanks!

[Greg Marshall]

Thanks, Bob. For others that might be interested in an ELF for 8" scopes, this is, unfortunately, a very inconvenient size. The panels are typically available in metric paper sizes (A3, A4, etc.). The closest size for an 8" aperture is the A4, but since the inside diameter of a typical 8" OTA is around 9", the A4 size is a little too small, forcing you to go to A3, which is much larger than you need and much more expensive. I haven't done all the math to price it out, but it's sure to be well over $100.