Tuesday, June 3, 2014

A Getaway Under The Stars!

One of the perks of working part-time at Kitt Peak National Observatory is that I know who to ask permission for after-hours access.  One of my co-workers at my Mirror Lab job was talking to me about where to hold an evening observing session, and since I help facilitate events for the local astronomy club, we got permission to use the picnic area, about 1.5 miles below the summit of Kitt Peak.  It is a great site - dark skies, cool temperatures (about 6500 feet elevation), flush toilets, a nice pavilion with picnic tables, and the employee association arranged use of their gas grill too.  The only disadvantage for your average Tucsonan is the 80 minute drive back to town after a late night of summer observing, where it doesn't really get dark till after 9pm.  But after temperatures approaching 105F in Tucson, I was looking forward to jacket, or at least long-sleeve temperatures at elevation!

I promised to have the picnic area open when the observatory grounds closed to the public at 4pm since the picnic area has been closed because of the fire danger this Spring (it has been extremely dry).  I needed to drive out in the peak of the heat to get the key and check in with the night time crew.  They convinced me to bring along a radio "just in case", and I opened the gate right at 4pm.  Staff scientist John Hill arrived minutes later and set up a hydrogen-alpha solar scope, so we had a nice view of  solar prominences coming off the sun's limb.  I set up a pair of cameras to work on a time-lapse of the mountaintop with the VLBA (Very Long Baseline Array) busily working in the foreground.  Once people started arriving, we set up the grill, had a real feast, and set up a few scopes for the night time viewing.  An interesting side note - the fire alarm sirens went off - easily audible from a mile away, which would have really worried us, but thanks to the radio I had, found that the electronic monitoring at the 4-meter was misbehaving, causing a false alarm.

As the sun set and it started getting dark, I shut
down one of my cameras to take some lunar photos.  The crescent moon was beautiful next to Jupiter in the west and I took a 4-frame mosaic through my Celestron 14" that was assembled with Microsoft ICE into the assemblage here.  Of course, the original files are heavily down-sized for the image at left, so just one of the frames is shown here at right.  I'm no expert at identifying features on the moon, but I believe that the large walled plain at left is Mare Crisium, the Sea of Crises.

Of course, one of the coolest things to see when there is a young moon such as this, is to expose a little longer and record the "earthshine".  When the moon is new or a thin crescent like this, from the moon the earth is fully illuminated, so an exposure of a couple seconds will record features on the moon not directly lit up by the sun.  At left here is a 2 second exposure of the southern cusp of the moon.  The exposure is long enough to show the normally bright rayed crater Tycho at top center, here lit up by the nearly full earth.  Also seen at the very top just off the limb is a moderately bright star in Gemini.  The other really neat thing shown in this longer exposure are a couple mountains apparently separated from the sunlit cusp of the moon.  They are tall enough that they are lit up obliquely partly from behind - it is kind of neat to see it in close-up...

Finally it got dark and the 3 scopes got put to
good use by the 20 or so that attended.  Roger had an 8" diameter triplet refractor he had just finished and was enjoying "first dark light".  He also helped Phil in building his 10" Newtonian, then my 14" was available too.  Favorite among the views were Omega Centauri, a spectacular globular cluster, the planets Jupiter, Mars and Saturn, and a multitude of galaxies.  I split my time pointing the 14", tending to the lone camera still shooting the stars over the Observatory, and using my newer T3 camera at its higher ISOs to take snapshots of our observing session.  At left is one of the observers checking out the Ring Nebula, M57 with my C-14 taken with a 30 second exposure with the 16mm F/2.8 fisheye lens.  This was taken at 11:30 and we still had a good-sized crowd working the eyepieces...  A little later, I used the same lens rotated vertically to take a 4-frame panorama assembled here at right.  The view of our edge-on Milky Way galaxy is still the most amazing sight that can be seen - and you don't even need a telescope!

Finally you get to see the results of 2 cameras shooting 1400+ frames, providing a continuous 6+ hour time line from about 4:30 to 10:40.  For the daytime shots 3 frames/minute were taken, slowing to 2/minute when fully dark to allow exposures up to 25 seconds.  The VLBA dish is part of a 10 telescope array scattered from Mauna Kea, Hawaii to the Virgin Islands and synthesizes a signal as if it had a dish nearly the size of the earth!  It was extremely busy, looking at dozens of objects, none for very long as you can tell from how much it is moving.  As the sun sets and it gets dark, the bright star Vega is the first to come out, then eventually the 3 stars of the Summer Triangle and the Milky Way rises over the Observatory and the glow of Tucson 45 miles distant.  At least 6 satellites are seen in the early evening sky, including an Iridium Flare that I was going to look for, but missed, though the camera got it towards the top of the frame.  You can watch it in this viewer, or go to full-frame and high resolution for maximum detail.

It was a great evening - cool temps and spectacular skies!  It was tough to call it a night, but we finally shut it down and left about 12:30.  After returning the keys, we made it home by about 2am - just a little bit of a late night for us!  I think the general consensus is to try it again next year - fun stuff!

1 comment:

Anonymous said...

Sounds like it was a great event, and some much needed time away from the heat! How lucky that you know just who to call to make things happen. I'm glad it was a clear night for you and that you got some nice observing done!