solar imaging with the ASI120MC

I can not believe over a month has gone by since my last blog post...while not good blog form, I have been working almost 7 days a week for the last 6 weeks and having a ball.  As I continue to work alongside some remarkable staff and graduate students in the development of the UA Science: Sky School I am reminded every day why I love my job.  As satisfying as work can be, one still needs time to pursue one's hobbies and I have not had nearly enough time to observe through my telescopes.  Last night I stayed up until nearly 2 AM observing some departing summer objects as well as taking my first glimpses of the year at winter objects such as the Orion Nebula and also at Jupiter.  It was a beautiful night and so satisfying that I still pulled myself out of bed by 8:30 AM to play further....

(Note to self: I am not an astrophotographer...But, apparently I am attempting to play one on TV.)  On a lark last week I decided to purchase my first dedicated planetary/solar imaging camera and try my hand at taking images of the Sun through my Lunt 60mm Hydrogen Alpha telescope.  This morning I captured and processed my first 'reasonable' solar image using my new ASI120MC camera from ZWO Optical.  This little camera has been receiving more than its share of accolades in the amateur community as an incredible value for the money.  At left is an image of the key pieces that come with the camera.  In addition to the camera itself, it comes with a 1.25 inch nose-piece, a USB cable, and a 150 degree lens that allows the camera to be used as an "all-sky" camera. (It also comes with a pre-installed IR cut filter (which is removable), a cable for auto-guiding, and a CD with drivers).  I decided to purchase the color camera to get my feet wet in this imaging business, and the camera also comes in a monochrome version with the only difference being that instead of an IR filter, there is a clear filter installed.

So after downloading the freeware programs Firecapture and Registax, I set things up this morning and began to play with settings and features of the software to try and record a reasonable avi file of the Sun.  In addition to my own issues (which are far too numerous to list), the seeing was just average and there were passing cirrus clouds that kept interrupting my process.  Regardless, the little camera delivered in the sense that there is far more detail present in the captures than my processing skills are currently able to take advantage of.  Further, I really have no idea what the ideal settings are for this kind of imaging in terms of shutter speed, gain, gamma, etc.  The image below is the result of a trial and error process and represents 150 frames aligned and stacked in Registax...Fooling around with the wavelet functions (I do not even know what a wavelet is) resulted in some over sharpening.

Hopefully I'll have some time to research settings and learn from many of the fantastic solar imagers out there that have traveled this path ahead of me.  I do enjoy a modest amount of learning by figuring things out, however, if I can at least know that I am capturing the data in an optimal fashion then I can focus my time on learning to bring out the details from the data.

Crepuscular rays

As I arrived home from work on Monday, I noticed that there were some very nice crepuscular rays in the western sky. These rays, streaming through gaps in the cloud, are columns of sunlit air separated by darker cloud-shadowed regions. While these rays of sunlight appear to radiate outward from the specific point in the sky (where the sun is located), they are actually near-parallel shafts of sunlight, and their apparent convergence is a perspective effect. This is similar to the way that parallel lines will appear to converge at a point far in the distance.  These beautiful rays are commonly seen in the desert skies as a result of our dry atmosphere.  When humidity is high, the light is diffused in the atmosphere making these rays much more difficult to detect.

Click to enlarge

The picture was taken with my Canon T2i and a 24-105mm lens operating at 40mm f/10 with a polarizing filter.  The exposure was 1/200 of a second at ISO 100.

Pausing to remember Dr. King

Today the nation took a moment to recognize a defining moment in our collective civil rights story- and I am thankful that even though much work remains, the moment we commemorate has not slipped from our national consciousness.  Yesterday Ian showed me a couple pictures from his trip to Washington DC last spring- pictures he took standing on the steps of the Lincoln Memorial in the spot where Dr. King shared his dream.  50 years later, for Ian, the importance of the message is not lost.  In fact, it is as relevant as it ever has been as we prepare to stand up against the tyranny and mass murder being carried out in Syria.  There are no easy answers, and as the late Dr. King stated "Injustice anywhere is a threat to justice everywhere.”

I found this video of Dr. King online today, and it is quite prophetic.  It is a part of an interview he did with NBC news in 1967, about 4 years after his "I have a Dream" speech.  It is well worth watching...

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Giant Magellan Telescope mirror 3

Image Credit Dean Ketelsen

Working in education and public outreach in the Department of Astronomy's Steward Observatory at the University of Arizona, I try to keep abreast of the remarkable work that happens at the department's Mirror Lab (or SOML as they call it).  The mirror lab is the only facility of its kind in the world, where we cast and polish mirrors for the worlds largest (such as the Large Binocular Telescope - LBT) and next generation telescopes (such as the Giant Magellan Telescope - GMT).  Currently the 3rd off-axis mirror for the GMT is in the oven, and the glass is approaching/passing melt-point as I write this.  (EDIT: Glass is now melted and smoothing.)  Each of the mirrors for the GMT is 8.4 meters across and in total seven mirrors will work together forming a single mirror over 25 meters in diameter!

After extremely careful inspection, the glass chunks were loaded into the oven a couple weeks ago around the custom built mold, and this past Monday the oven was turned on.  Long time SOML employee and the inspiration for this blog, Dean Ketelsen published a report documenting the casting preparations which I would recommend and can be seen here.  Temperatures have been ramping up over night and maximum temperature of 1165 degrees C will be between 10 and 11 PM local time tonight.  Already, the glass has melted, acquiring the consistency of honey and running down into the mold.  As the oven continues to heat up and rotate at almost 5 rpm the surface will slowly smooth out and the glass will become clear.  Early in the hours of Sunday morning the furnace will begin a slow cool down (continuing to rotate) and around Thanksgiving the mirror will be revealed.

There are several cameras inside the oven (remarkable in and of itself!) that are taking pictures in order that the process can be closely monitored.  Below are images from various temperatures which give you peek into the formation of the mirror, and the changes that occur at increasing temperatures.  You can see subtle changes even between the images from 892 degrees and 900 degrees C as the glass is noticeably transforming from its slumped state to melting.  I'll post a couple updates later today if I have time with pictures later in the process.

Camera 7 showing the edge of the mirror - click the images to enlarge them:

499 C

750 C

892 C

900 C

922 C

934 C

Shifting to camera 5 as the image is clearer...and the glass is now smoothing

990 C

Camera 3 showing a wide angle view at similar temps to above - click the images to enlarge them:

499 C

750 C

892 C

900 C

922 C

934 C

At this point the glass is now smoothing and you can see the reflection of the furnace top in the surface, as well as the very nice honeycomb structure of the mirror mold.

990 C

1012 C

At 1028 degrees C now, you can see the air bubbles that are rising up through the glass as it continues to smooth.

1028 C

UPDATE- 10:25 PM local time (MST) the furnace is now nearly at "high fire" maximum temperature.  You can see in both the edge view and wide view that the glass is clear and smooth.  At 1160 degrees Celsius, the furnace is only 5 degrees from its top temperature.

1160 C

1160 C

This is a short video I shot last year while the furnace was rotating during the high fire day for the second GMT mirror.

UA Science: Sky School!

Having recently changed career paths into the Department of Astronomy at the University of Arizona, I am often asked by friends and relatives how it is working out.  Sometimes the question is straightforward, other times the question comes from a skeptical place and may be a projection of the other persons own fears of change (much more frequent from long time UA colleagues).  I generally give a short answer to the effect that I could not be happier with my new co-workers and that in particular, the projects I am working on are quite challenging and engaging.

One of these projects is now among the most rewarding things I have ever done- establishing the UA Science: Sky School.  I never would have had the opportunity if not for the ideas, hard work and dedication of my colleague and friend, Ben Blonder.  Ben envisioned a residential science school operated by the University, and together we have launched this new program.  In addition to Ben, I am very fortunate to be working with Pacifica Sommers and Rebecca Lipson who also maintain the vision and dedication to the project.  Pacifica , a PhD candidate in ecology and evolutionary biology and a NASA graduate Space Grant Fellow, and Rebecca, a highly regarded middle school science teacher have helped us to create a truly world-class educational experience.  I could go on and on, but this video explains things nicely.

Summer of Beth ~ Part 1

July 16th marked Beth's 50th birthday...and we have been celebrating all summer in various ways.  For the first time, Beth planned to join Ian and I on our annual summer trip to Colorado and I believe she will never miss the trip again.  As Beth was coming along on the (previously 'boys') trip, we figured it was high time to upgrade the experience...and saving you the painful details, we ended up purchasing an r-pod travel trailer.  This is a fairly small trailer (weighing in at 2400 lbs. dry) that can be pulled by our existing Nissan Xterra and it has many luxuries that push the definition of "camping."  At left you can see the r-pod parked at one of our favorite campsites, Woods Lake, just southwest of Telluride.  Below is an image of the lake, about a quarter mile hike from our camping spot.

This is the view of El Diente Peak from our site (a very challenging 14'er to hike):

I'll post more pictures from our trip in successive posts, but here is one of Beth in her birthday cowboy hat, getting into the Colorado spirit.

 Next up...Climbing Mt. Quandry!

Sunset time lapse

I spent the past week in Del Mar California with my family (another longer post to follow), and while there devoted some time to playing with my Canon T2i and the software Magic Lantern (freeware, actually) that I had just installed onto the cameras SD card.  The software is pretty amazing and while many of its features were designed for shooting video there are some neat features for still photos as well.  Seeing how powerful the software is, it makes one wonder why Canon has not directly incorporated many of the ideas into their newer cameras.  While I have just started to scratch the surface of all it has to offer, I did try the built in intervalometer while the sun was setting over the ocean.  The result is the animation below.  Images were taken every 10 seconds using a 24-105mm zoom lens at 32mm, with manual exposure changes as the sun was setting.  Magic Lantern has a feature to automatically ramp the exposure, but that is the next feature I need to explore.