Category: Hardware

One Giant Leap

On By Site StaffIn Hardware, ProcessingLeave a comment

We are pleased to report that the Cosmoscope has recently acquired an instrument from Starizona in Tucson, AZ. Both the optics and display software are manufactured by ZWO Co., Ltd, out of the town of Suzhou in Jiangsu province in China, making for an affordable first system for the Cosmoscope.

The optics of the new system are said to be the equivalent magnification of a 1200 mm telescope on a full-frame 35mm camera sensor. That is, the field of view is very nearly one degree wide – roughly pinkie finger width at arm’s length. This makes the instrument suitable for not only many common deep space objects, but also for lunar and even solar imaging.

This small instrument will debut in the Cosmoscope’s remote outreach missions and is likely to remain mobile on its carbon fiber tripod rather than permanently mounted on a pier in a dome. After becoming familiar with the instrument, Cosmoscope staff hope to become proficient in Open Broadcaster Software, a suite for switching video and images to be “broadcast” live on YouTube.

It will be obvious to some readers that the online presentation may be considered similar to Slooh, or other subscription-based telescope access websites. Cosmoscope services are intended to remain free, and broadcasts will be presented live via YouTube, with staff taking requests on object selection via live chat and providing context where possible. It should be emphasized that staff are interested amateurs, only, and hope to learn from audience members as well!

Images will be “stacked” in real-time for live YouTube guests, with every frame increasing the contrast and resolution of the image as time goes on. At any given time of year the sky targets that are bright-enough for such real time viewing are limited, and so further processing will be accomplished in the open source Siril image processing suite and possibly in commercial software as such demonstrations become appropriate.

We look forward to presenting images from first light in this space very soon. Thank you for your interest!

Images from ZWO website. No infringement intended. We’ll replace with our own original images, soon!

A Space of our Own

On By Site StaffIn HardwareLeave a comment

Although we think the Cosmoscope is a credible public service simply by aggregating access to sites across the globe, it’s reasonable for the community to expect us to work toward our own remotely controlled observatory.

Telescopes are best located at altitude and far away from city lights. Kansas obviously offers no mountaintops, but there are locations where skies are conspicuously dark. Even within a short drive of the Cosmosphere we believe we can find a suitable dark sky location for a modest observatory capable of the sort of medium-length exposures required for “live” viewing.

Rather than invest in university-class, relatively exotic hardware, we propose to make best use of high-end consumer equipment from mass manufacturers. As an example, myt_grossCelestron’s 11-inch telescopes are put to good use by remote telescope operator Slooh. Colorado-based manufacturer Bisque makes equatorial mounts for less than $10,000 that achieve pointing accuracies near those of truly professional equipment. Digital camera manufacturer Diffraction Limited offers units with various combinations of resolution and sensitivity.

An advantage of the “pro-sumer” approach is obviously the economies of scale of the development sbigof this hardware, but also the expertise and ingenuity of a large user base. Much of this equipment comes with computer control software already anticipating remote use via internet protocol.

Another possibility to be considered is the local School District’s observatory dome already within view, or nearly so, of the Cosmosphere itself. We suspect there are maintenance issues that would be more expensive to solve than starting from scratch, but – depending upon the bragging rights any given stakeholder might seek – there maybe a remarkably quick path toward a Cosmoscope-operated dome! A caution that school observatories located in other than the ground floors of their buildings (certainly not anchored to bedrock) are notoriously bad about building vibration marring images. (The Mabee Observatory at Bethel College exhibits this weakness, we’re told.) If the HVAC system in the building could be temporarily disabled during Cosmoscope hours, this could be a solution, as could moving the dome and any existing equipment to a dark sky location.

Narrowband Imaging

On By Site StaffIn HardwareLeave a comment

With a little original research on our part we’ve uncovered some good news for the immediate future of visual astronomy. Elsewhere on the Cosmoscope site you’ll see reference to narrowband astroimaging. This is the technique of selecting for specific “colors,” known to be emitted by deep-sky objects, while filtering out man-made light sources.

Traditional street light glow in the sky has been particularly easy to filter out because these light sources were frequently sodium-vapor or mercury-vapor lamps emit at very specific color frequencies quite different from the dominant colors in emission nebula. These are clouds of gas being energized by stellar radiation, and then re-emitting that radiation as specific colors associated with the atoms involved. The most prastronomik_uhc-e_transevalent of these atoms emitting in the visual spectrum are hydrogen and oxygen.

So, here’s the good news: We were aware that the white LED lights replacing streetlights nowadays are actually a combination of blue LEDs and phosphors absorbing some of this blue and re-emitting it (very much like nebula) at longer wavelengths, balancing out the blue to create white. (If this is a new concept to you, it’s worth a read. Ingenious.) Anyway, we had heard that these phosphors were rather “sloppy,” emitting across many, many colors, rather than just a few that are easy to filter out.White_LED (1) It turns out that by lucky coincidence, the color of doubly-ionized oxygen falls between the blue LED emission and the phosphor re-emission! Note the two charts here produced for different purposes. The yellow lines in Astronomik’s chart are the “colors” of interest. The bottom chart is the color curve for white LEDs. Note that the LED curve dips right at 500nm – the frequency…, the color… of interest! This is a teal, right between green and blue. The other color of greatest use  – a red – is the stronger of two hydrogen colors, at 656 nm where the phosphor color curve quickly decreases in intensity.

So, it’s still possible to protect a camera element from man-made light (somewhat) by taking pictures through filters specially “colored” to filter light we don’t want. Although the sheer number and candlepower of LEDs may ruin the sky for visual observers, telescopes can still narrow their attention to these key colors.

This isn’t a perfect situation, and phosphor choices may change in the future, but for now we still can turn a semi-urban telescope location into a site that is much darker for the purposes of photographing certain classes of astronomical objects. This should allow images captured at a Cosmoscope-owned site to produce world-class results with “pro-sumer” scale instruments. We look forward to finding out!