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The club meeting was held on Tuesday April 12, 2005 at 7pm, in the Hualalai Conference Room at Keck Headquarters in Waimea, with Craig Combes facilitating. Approximately 30 persons attended the meeting, including a large contingent of astronomy students from Hawaii Preparatory Academy (HPA).

Started with introductions. Matt and the HPA students brought a 16" Meade Newtonian reflector. They would like to donate it to WHAC for use in public outreach and education. It was donated to HPA by a retired airline pilot in Kona. Matt said that the students are in his astronomy class, and that he is soon to retire from teaching the class. His students will conclude the semester by demonstrating their knowledge of the night sky by pointing out 35 objects in the night sky! A teacher from Waikoloa Elementary mentioned that they have a telescope they offer for use by WHAC. It is presently "on Al Honey's porch", but can be reallocated to WHAC. Most of the others in the crowd were familiar faces.

Craig Combes was the moderator for the Gear Talk Show and Tell part of the meeting.

• Scott Hartman shared a laser collimator that has optical crosshairs to easier make good alignment. It was bought from LaserMax about 4 years ago, and retails for ~$400. Interested persons can learn more at oemlasers.com
  
• Howard Yamasaki shared two things. First, a hard-case travel kit to organize eyepieces and other observing equipment. Second, the Coronado Personal Solar Telescope (PST). Allan uses his PST at least once, and often twice a day, to observe solar phenomenon. The PST is a 1-angstrom hydrogen-alpha solar telescope. This allows the observer to see prominences, filaments, and other details invisible without the narrow-band filtering of hydrogen-alpha. The PST costs $500, which is very economical as many HA systems run into the many thousands of dollars. More information about the PST can be found here
  
• Craig Combes shared the main carbon fiber components he has completed for his ultralight 16" telescope which he is building. He mentioned that the ultralight optics are being fabricated. It will be interesting to follow the progress of his telescope. No word on when first light may occur.

Carlton Lane then took to the stage to introduce a few featured web sites for the month. Carlton shared a few comments further clarifying his talk from the last meeting regarding the Extrema of Sunrise and Sunset. He recommends interested persons go to the Naval Observatory site for more information.
Carlton's main theme for astronomy web sites of the month was images from Cassini. There are two sites that offer a large collection of images, which show what you would see if you were orbiting Saturn. They are: NASA and the Cassini Imaging Lab.

Laura Kraft then presented The Sky This Month Laura used Starry Night Backyard and a pre-made "movie" tour of prominent events of the coming month. The main event for the upcoming month is the penumbral eclipse of the Moon which starts the evening of April 24 through the early first hours of April 25. The eclipse starts at 10pm HST, but will not be darkest until midnight. The eclipse concludes at 2am. Observers will see a darkening of one limb of the Moon. The Lyrid meteor shower would be a fine show normally, but this year will be washed out by the bright Moon.

Doug then facilitated several pieces of club business.

• After brief discussion, it was decided to table any decision as to what to do about the 16" telescope that HPA delivered to WHAC.
• Doug announced he is taking a 6-month leave of absence, and needs to transition his club duties to others. He is already transitioning the web site duties to Laura Kraft.

Remy Cabanac was the featured speaker of the night. He spoke about gravitational lenses and their importance to modern-day astronomy. He detailed the three classes of gravitational lenses: strong lensing, weak lensing, and micro-lensing. Strong lensing is where you see multiple images of the same object. Einstein's Cross is a classic example of a strong lens. You can make your own lens here.

Weak lensing is where there is a perturbation of the background objects, but not so strongly as to create multiple images. This type of lensing can be thought of as a distortion of the background. Micro-lensing is lensing that occurs with small objects; small being things like star systems. A small star passing in front of a larger star will lens the light of the larger star, resulting in a brightening of the overall system. This can be used to determine masses of the system. There are about 100 known micro-lenses.

Remy closed by sharing how important gravitational lenses are: they allow astronomers to probe for invisible mass in the Universe, they act as giant magnifying lenses for more distant objects (the "free telescope" effect) and provide an alternative way to measure the Hubble parameter.


Craig Combes concluded the formal part of the talk and the meeting at ~8:45pm. This was followed by informal discussions and inspection of the 16" telescope.