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F.L. Whipple Astronomy Day, March 26


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Event: Fred Lawrence Whipple Observatory Astronomy Day

Location: F. L. Whipple Observatory Visitor's Center, Amado, Arizona, about 60 miles from home.

Weather: 70 at sunset, upper 50s when we quit around 9:30 PM. Zero cloud cover, two or three brief gusts of wind.

Seeing and Transparency: Both very good, occasional snaps into moments of sharp steadiness.


18" f/5 2286mm Teeter Telescope newtonian truss dob, Sky Commander DSCs

Lunt LS60THa/B600 60mm H-Alpha solar telescope on Orion Atlas EQ-G mount

Astronomy Days are periodic public outreach events sponsored by the Smithsonian's F.L. Whipple Observatory Visitor Center and put on by Green Valley's Sonora Astronomical Society with some assistance by members of the Tucson Amateur Astronomy Association.

This is always an enjoyable event to support; a tremendous family entertainment and education opportunity. Key events for this event were the Visitor Center opening at 5:00 PM: several of us set up white light and H-Alpha telescopes for safe solar viewing from 5:00 PM to sundown; a Night Sky Network information and demo table set up by SAS; an informal lecture at sunset presented by Observatory staff; and night sky observing with SAS and TAAA volunteers. I'm not sure how many volunteer amateurs we had setting up, but I counted about 15 near me. We had a full complement of instruments set up, with a 20" truss dob, my 18" Teeter, and just about every type of reflector, refractor, and SCT in all sizes.

This was a busy day for me. Susan and I started off the day by doing the Spring trimming and pruning of the ground plants around the yard. I proceded with a demo on how not to use hedge trimmers, ending up with a lacerated finger bleeding like a garden hose. Eventually got it patched up, but a real nuissance. After the "don't do this" demo, I headed over to Catalina State Park to meet with Bill Lofquist and the Park Manager, Steve Haas regarding future collaboration for public events at the park. After we were done, I headed down to Whipple, about an hour's drive.

Arrival and setup went well. This was my first try with the Lunt solar scope. I mounted it on my Atlas EQ-G, way over mounted. Since I hadn't done solar work in the past and just showed up near sundown, this early setup was really convenient, not having to squeeze in late. As I was setting up the Atlas and Lunt, I noticed Derald Nye set up already on Jupiter; just as he does at the Grand Canyon Star Party, showing off the daytime views of the moon and planets.

The solar experience was a great success. I was set up next to a person from SAS (forgot the name!) who had an 11" Celestron SCT with a white light filter, and showing the artifacts on a mildly active disk in two different forms was a great teaching experience. Lots of feathers around the limb in Ha, with several active regions in the Ha matching the sunspot groups in the white light. Three very big surprises for me. First, the number of visitors. The local community turns out in force for these events at Whipple. I stopped counting at well over 100 at my scope in about an hour and a half. Second, people seemed to have no trouble at all seeing the fine detail on the solar surface, and the detailed feathery activity on the limb. Finally, a prominence shot out of the disk around forty minutes before I shut down at dusk. People were genuinely excited about the views, and comparing the results with the white light images on the 11".

With the disk on the horizon, I took down the solar scope and mount and unloaded the 18". As always, the gorgeous cabinetry of Rob Teeter's work of art drew accolades. I plugged in the battery for the cooling fans, and setup of the big dob was nominal except for an excessive amount of time required for collimation. Last night I was set up with the 18" in Saguaro Park West for the periodic Pima County Natural Resources Parks and Recreation Evening Under the Stars. The entry road into the site has a lot of extremely high speed bumps, and what ever the speed, the load in the truck is really jostled heavily. This cause quite a bit of misalignment of the secondary. Eventually it all came together.

Our setup area is at the base of the huge Whipple 10 meter gamma-ray reflecting telescope. This instrument is always on alert for gamma ray events, and several times during the late afternoon the big dish slewed around to grab data from active events as alerted. Very interesting!

As the sky darkend I did a little sky tour for the thirty or so folks gathered around my scope. I pointed out the stars as they popped into the twilight, and did a pointing tour of Sirius and Canis Major, Betelgeuse and Rigel, then the rest of Orion as elements popped out, Castor, Pollux, and Gemini, Regulus and Leo, The audience was great; they seemed to enjoy the mix of mythology and cosmology. A very enjoyable half hour walk around the sky as constellations became visible.

I moved over to Orion to check the nebula and the sky conditions prior to doing a DSC alignment. Never got a chance to leave it! I did the talk for this gorgeous item, which was extremely impressive at 104X. Six stars in the Trapezium were easily viewed and, as always, the greenish, shimmering, multilayered diaphenous curtain of nebulosity produce a continuous stream of Oh Wows. Over 200 visitors and two hours later, with only a half dozen folks in the area, I went over to Saturn. It was still pretty low for this long dob, requiring a bit of a bend down at first to get to the eyepiece. VERY nice. I jumped up to 254X and we got four moons, and, when the seeing would snap through stability, crisp zonal banding on the planet to go with a sharp ring shadow across the disk. We stayed on it for about 45 minutes, and the difference in the view as Saturn climbed out of the mud was striking. We ended up with most of us flatfooted, one or two needing a step on the ladder. Wonderful way to end the evening.

After the visitors had departed and we were packing up, I went over to The Whirlpool for a look. Still a bit low to get the best experience, nevertheless it showed much of its spiral detail. A half dozen of us looked at it, then time to pack up and depart.

I really have to thank Sonora Astronomical Society, and F.L. Whipple Visitor Center, for always doing so well at putting on these events. They are very uplifting, and worth every minute to be involved and getting the public feedback.

Pictures to come.

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VERITAS - Whipple

Quoting the above link on VERITAS and the 10M Gamma Ray Reflector:

"The Whipple collaboration pioneered the Imaging Atmospheric Cherenkov Technique (IACT) for the detection of Very High Energy (VHE) gamma rays. The Whipple 10 m gamma-ray telescope is located at the Fred Lawrence Whipple Observatory in Southern Arizona in the United States. The predecessor to VERITAS (Very Energetic Radiation Imaging Telescope Array System), this telescope has been in operation since 1968 and detected the first TeV gamma-ray source, the Crab Nebula in 1989 (Weekes et al., 1989).

The Davies Cotton designed reflector holds 248 hexagonal mirrors and provides a total reflecting area of 75m^2. The camera is located at the focal point and contains 379 PhotoMultiplier Tubes (PMTs) and has a field of view of ~2.6 degrees with an angular resolution of 0.117 degrees. The telescope operates between 300 GeV and 10 TeV.

The primary emphasis of the collaboration's research effort is the search for and study of gamma ray sources in the energy range of 100 GeV - 10 TeV. The telescope's primarily concern is long term blazar monitoring in the search for interesting or increased activity and it also acts as an alert system for the VERITAS array. For the observing season 2010/11 a number of known TeV blazars including the High frequency BL Lacs (HBLs) Mrk421, 1ES2344+514, 1ES1959+650 and 1ES0229+200 will be observed and the nightly lightcurves will be posted here and updated regularly. As blazar monitoring is on-going we encourage multiwavelength observations."


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