From the Director

Rex

 

 

 

by Rex Parker, Phd director@princetonastronomy.org

AAAP Member Survey Summer 2019. There were 78 responses to the survey sent a month ago (out of 100 total members). The Board will be reviewing the results and using them in making decisions for the future. The survey will remain open through August 21 at this link if you haven’t yet responded: https://www.surveymonkey.com/r/Z2MNWPH

It’s encouraging that 61 respondents own an astronomical telescope, 48 come out to the WC Observatory at least once a year, and 33 would likely participate in the proposed Gravity Hill star party (see below).

Hold the Date: Sept 27-28 Gravity Hill Star Party. Plans are being developed for a AAAP member star party, a new twist on the StarQuest theme of years past – stay tuned for more information later this summer.

Performance Test – AAAP’s ZWO294 Astro Camera. I borrowed the ZWO ASI294-MC PRO camera from the Observatory to see how good it can be, especially when hooked up to a “large but fast” scope. The ZWO is a technological marvel and illustrates why CMOS sensor technology continues to displace the CCD in astronomy applications. The ZWO294 camera features a CMOS Bayer-matrix (RGGB) color sensor, the Sony IMX294. The sensor itself is relatively large at 19 x13 mm (so-called 4/3-inch sensor with diagonal 23mm), key to wider-field images. The pixel array is 4144 x 2822 (11.3M pixels) at 4.6 um size. The camera has 14-bit native bit depth, very fast download rate, low read noise, and cooling to ~35 deg C below ambient to reduce dark current noise. Results below confirm that the newer-gen CMOS color cameras are a revolutionary step forward for electronically assisted astronomy (EAA).

My ZWO test was carried out on a bright moonlit night in mid-July with pasty, hazy skies. I even left the deck light on here at home and could barely see the stars. But I gave the camera a whirl using my AG Optics modified-Dall-Kirkham 12.5” reflector telescope at f/5 (0.75x focal reducer on native f/6.7 scope, FL = 1610 mm) on a Paramount-MX running TheSkyX. For these images I didn’t even need to guide. The ZWO camera sensor was cooled to -10 deg and the gain set at default/mid-range deep sky setting. Below are unprocessed JPEGs of screen shots showing what you’d see as live images in real-time with the ZWO. These are all 15 second “live” subframes with stacking going out to only 3 or 5 min.

I do not think SharpCap is the way to go here as the camera control program. I found a much better software program in terms of ease of use, color balancing, and stability of output – for the ZWO as well as the SX Ultrastar. Software Bisque recently developed a “Live Stack” mode in their Camera Add-On to TheSkyX which we have at observatory. It works great, is simpler, and overall better than SharpCap with the ZWO in my opinion.

We can do this at the observatory with the Celestron-14 using a Celestron f6.3 focal reducer (and presumably flip mirror so eyepiece is still available). I really hope that Keyholders give it a tryout (and yes, I did return the camera to the observatory :>).

M13 Globular Cluster in Hercules, ZWO294 – 15 sec live image stacked for 3 min

M16 Eagle Nebula in Sagittarius, ZWO294 – 15 sec live image stacked for 5 min

M27 Dumbell Nebula in Vulpecula, ZWO294 – 15 sec live image stacked for 3 min

Cirrus Nebula East in Cygnus, ZWO294 – 15 sec live image stacked for 5 min

Skynet Project Renewal. Payment has been completed and the new contract is in place now for another two years of Skynet. Two years ago we began this project to bring AAAP members access to remote astrophotography. Skynet was created by Dr Dan Reichart of the Physics and Astronomy Dept at the University of North Carolina, Chapel Hill. The internet-based queue scheduling program runs on a computer at UNC which accesses a system of observatories they created for remote imaging. This system, the Skynet Robotic Telescope Network, comprises more than a dozen telescopes around the world at observatories in Chile, Australia, Italy, Canada, and US. Each telescope is set up with tracking mount, CCD camera, and filters for remote color image acquisition. Tutorial videos are available to help a user get up and running.

Whether you’re a first-time astronomer or seasoned observer, Skynet’s easy-to-use yet powerful interface allows you to get images of celestial objects from the Messier and NGC deep sky catalogs. Skynet also includes a basic image processing program “Afterglow” that runs on the server, so you don’t need any special software on your PC. You also can download and process your images locally with your own programs like CCD Stack or Maxim DL if you like. While there are limits on the length of exposures, Skynet is a great way to get onto the learning curve for astro-imaging and understanding how the modern practice of astronomy works. Current AAAP members who have used the system will have new credits added to their accounts. If you are interested in a Skynet account, or already have an account and want additional credits, please send me an e-mail note at director@princetonastronomy.org.

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