Of Pu’u and Perseids

Pu’u dot the landscape of the Island of Hawai’i. Pu’u, (pronounced poo-oo) is an interesting Hawaiian word that can mean hill, bump, pimple, wart, or any similar concept, but in this case generally means cinder cone. These reminders of the volcanic origins dot the sides of the big volcanoes like pimples on the face of the island. They are everywhere and each has a traditional name. Locals have used them since the dawn of civilization on the islands to give directions, describe legal land boundaries and name roads throughout the island.

Learning your way around the island is often learning the names of the Pu’u. I use them to mark my progress along my morning commute to work and note the weather above Wiamea. A large pu’u stands above the end of Saddle Road where it turns into the center of the island and another pu’u marks the intersection of Saddle Road and the Mauna Kea access road that climbs to the summit winding through the pu’u that cover the flanks of the mountian. Keck Observatory itself sits on the rim of Pu’u Hou ‘Oki.

The West Hawaii Astronomy Club’s dark sky observing site sits directly beside a small pu’u that goes by the name of Pu’u Kuainiho in a unit of State DLNR land named for Pu’u Anahulu. Nothing fancy, a large gravel lot just off a major state highway, but far anough off to avoid the headlights. Easy to find along the road from Waimea to Kona. It sits at about 2,000ft elevation, high enough to be above most of the low altitude tropical haze. Being in the rain shadow of a 14,000ft peak the site offers surprisingly reliable weather, it is often cloudy in the evening but almost always clears after dark. The only real issue is the often heavy formation of dew and some ground mists that will plague observers. The site is a comprimise between fairly decent skies offered by lower elevations here in Hawaii and the truly spectacular observing that can be had from sites high on the side of Mauna Kea at 9,000ft. The only issue is that those perfect Mauna Kea skies are accessed by a rough hour long drive up Saddle Road and are often windy and quite cold. Sometimes a warm site 15min from home on a good road wins the toss.

This time the target was meteors, a shower I had often not observed because it generally occured in the middle of Tucson’s rainy monsoon season. But a dark sky with no Moon and access to a decent dark site a few minutes away was simply too attractive. Except, of course, for the 2am setting in the alarm clock. I had expected a few other observers to be out for the peak, but when I got to the site I was alone. No matter, nothing new for me. I had brought along the Losmandy mount and the DSLR for a little attempted meteor photography and a lounge chair for relaxed meteor observing.

Set the mount up, a quick polar alignment with a polar scope good enough for wide field photography, bolt the camera on and let it go. Just lie back in the chair with a couple blankets and I am set!

OK, start the show now…

…I must have waited five minutes for the first meteor.

But meteors did appear. A few dim ones widely scattered and a few bright ones from time to time to annouce that something out of the ordinary was going on. I kept a few rough counts to do a quick estimate of rates using the camera’s shutter interval as a timer. I would get three to five every five minute interval giving rates of around 30-60ZHR. Nothing spectacular, just a decent show as the Perseids are so well known for. Though after the true Leonid meteor storm I witnessed in Tucson a few years back anything else does seem a little tame.

As for the photographs? A careful examination of every photo shows a staggering number of meteors were captured by my extensive photographic effort. I had to painstakingly go though each photo to come up with a grand total of…

zero.

I did get a nice photo of the Perseus-Cassiopea region of the Milky Way however…

Cassiopeia and Perseus
Cassiopeia and Perseus region of the outer Milky Way, Canon 20Da, 14 5min exposures stacked, M31 and the Double Cluster are easily visible

Unaided Vesta and a Moonbow

See a naked eye asteroid? Why not? I had never seen an asteroid with the unaided eye before and here was a good chance. Was it worth setting the alarm clock for 2am? Sure, you cannot answer that with a no if you are truly an amateur astronomer.

Off goes the alarm… wife starts grumbling… throw a few things in the vehicle… a few more complaints from my wife now up and awake… feed the cats… A kiss… and off into the dark. I setup at the end of the development where the streetlights have yet to be turned on, at the end of a dead end road surrounded by lots that have been graded but not yet built on. While setting up the gear I discover I am not quite alone, listening to hooves clattering up the road towards me. Someone riding by moonlight? No, just three feral donkeys that wander past. Later, the calm was broken by a male donkey being, ah, quite energetic, just up the hill, and willing to tell the world about it.

Conditions could have been better, Jupiter was a swimming ball, so much for a little planetary viewing to pass the time awaiting moonset. Transparency was only so-so with the usual low altitude tropical haze and the occasional cloud scudding through. So just sit back and enjoy the night for a while, and try to ignore the loud braying that occasionally disturbed the otherwise peaceful night.

As I waited for the moon to set I noticed a bank of clouds approaching from the northeast. The usual cloud bank over the Kohala volcano was reaching out a little further than it usually does. This was a bit of a concern, when the trade winds are blowing this cloud bank usually forms over the Kohala and with it a heavy misting rain that drizzles constantly in Waimea. I looked about at my gear and decided to cover some of it up in case this cloud bank got closer.

And it did, and as usual the mist was falling ahead of it driven by the steady breeze. Combine a wall of mist and a setting bright moon and the unexpected can occur. I looked out to check the cloud’s position and quickly did a double take. Hanging there in the wall of mist was a beautiful, ghostly moonbow. Grab the camera time!

Camera, tripod, remote shutter release… dash 50yds to where the big power lines would not dominate the picture… hope not to find the donkeys that are around here somewhere… find a spot on the rocks of the ancient lava flow where I could setup the tripod without endangering the camera or my ankles… in the dark… focus the camera… in the dark… frame… program the shutter release for a one minute shot… fire! Time for two frames before the moonbow faded from sight. A quick check of the frames and victory! Got it!

Waimea Moonbow
Moonbow! 1min, Canon 20Da, 17mm@f/4 with the lights of Waimea at center

With the fading moonbow and the setting Moon I was able to return to my mission objective, Vesta without optical aid. Finding the asteroid was trivial, just starhop up from Jupiter or down from ζOph and there is was. Swung my little TV-76 to the correct location and there it was, right on the location plotted. Easy to see at about 5.5 mag. a little brighter than HIP80793 at 5.6 mag. that was located about 1°sp. Naked eye was tougher, there was a line of 4-4.2 mag. stars coming up from Sco that was relatively easy, but it took averted vision to find Vesta and then only occasionally as it would appear and dissapear before my eye. I was clearly being hampered by the lousy seeing and poor transparency down lower in the sky. I am sure from a better site, possibly up on the side of Mauna Kea without the moonlight it would be quite simple to spot. I will need to try again before this opposition is over. That will have to wait a bit until after full Moon.

Vesta 28May2007
Vesta (marked), Jupiter and Summer Milky Way, 40s, 17mm@f/4, fixed tripod

A Daytime Comet!

C/2006 P1 McNaught is currently passing close to the Sun. At a mere 18 million miles (0.197 AU) from the Sun the intense solar radiation is causing the comet to boil and vent violently. The resulting cloud of gas and dust is reflecting enough sunlight to brighten the comet dramatically. Estimates are placing the comet at mag. -5 or even mag. -6. This is much brighter than even Venus! Some observers are reporting easy unaided eye visibility, but in the sky over Tucson a lot of dust and aerosols in the air are causing a great deal of glare around the Sun. Thus binoculars or a telescope is required to see the comet.

C/2006 P1McNaught
C/2006 P1 McNaught captured with a TV-76 operating at f/5 and a Canon 20Da DSLR, 1/8000 sec, gain at 100ISO. Taken 2:29pm 14 Jan, 2007 and processed with Photoshop. Three frames aligned and stacked in Photoshop to improve the signal to noise ratio.
The challenge is that Comet McNaught is just five degrees east of the Sun. Observing so close to the Sun presents distinct dangers, I do not want to fry my retina! So I carefully positioned my TV-76 on the alt-az mount so that the Sun was just behind the edge of my carport. Thus I could pan around and locate the comet with little fear of direct sunlight down the tube. A few frames with the Canon 20Da turned out OK but not great, those dust and aerosols in the sky and the resulting glare is reducing the signal to noise in the images. The photo to the right is a stack of three images in an attempt to improve the signal to noise, then greatly cropped in and levels adjusted in Photoshop.

The view was better in the eyepiece. A sharp point of the coma with a fan shaped tail. This really looks like a classic comet, I had not expected such a good tail in the bright sunlit sky. This is my first daytime comet, and since the opportunity may not come again anytime soon, this may be my only chance to see one, truly a once in a lifetime event!

Mercury Transit

About a dozen times a century Mercury passes in front of the Sun as seen from Earth. The event is observable with a modest telescope and a solar filter, Mercury can be seen as a small black dot crossing the surface of the Sun. If half of those happen when the sun is below your horizon the average person will have the chance to observe five or six in a lifetime. Since the next opportunity will not occur until May 9th, 2016 I didn’t want to miss this one!

Photographing a Mercury Transit
90mm refractor Violet Haze photographing the transit
I took the day off.

Considering that Mercury never gets very far from the Sun means that most of the time you can observe Mercury it is low on the horizon and is typically seen through a great deal of atmospheric distortion. A transit is one exception to this, during a transit mercury is a sharp disk, very different from the multicolor jello ball that is usually seen.

The 2006 Transit was well timed for observation across western North America, starting just after noontime and ending at 5:09pm MST. This put the Sun high in the sky for all but the last part of the event. Our weather cooperated as well, delivering a cloudless blue sky the entire day in place of the clouds that had been forecast. The air was reasonably steady as well allowing good photographic and observing conditions.

I took advantage of the weather and photographed almost the entire transit, all but the very end when the sun sank below the trees in my neighborhood. I used the Canon 20Da and setup a timer to shoot every 5min. The only issue was the inability to do a polar alignment on the mount when setting up in the middle of the day. The result was I had to manually guide the scope every 10-15 min to keep the sun centered.

I got plenty of good photographic material, enough for a few single photos as well as an animation of the transit. A transit is an impressive demonstration of the scale and arrangement of our solar system. Not hard to visualize the reality of those textbook drawings of planetary orbits after you have had such an opportunity to see the real thing.

No complaints on my second Mercury transit.

Mercury Transit 8Nov2006
The Mercury transit of 8 Nov 2006 in progress. Mercury is about halfway between the center to the bottom, a large sunspot complex is visible on the left edge. Photo with a 90mm APO refractor, a Thousand Oaks full aperture filter and a Canon 20Da camera.