Hubble Ultra Deep Field (subset)

F E B R U A R Y
2 0 0 5


An electronic publication of The West Hawaii Astronomy Club -



Club Officers:

   Presidents:
        Craig Nance,
        Craig Combes,
        Doug Summers
  Secretary:
        Laura Kraft
  Observatory Sponsors:
        CFHT,
        W. M. Keck


















































This website is currently maintained by Doug Summers

Keck Uranus AO image

WHAC logo


E-mail: whacmail@yahoo.com

 


January 2005 Club Meeting Report


January, 2005 (Keck-HQ) Club Meeting Agenda
Introductions & Member ProfilesDoug Summers10 mins
GearTalk Show&Tell All*15 mins
Featured Web Links Scott Hartman15 mins
The Sky This Month Craig Nance15 mins
Club Business All 15 mins
Talk - Titan Science & HuygensDr. Antonin Bouchez 30 mins
"Techniques" - Telescope Performance TuningDoug Summers15 mins

Doug called the meeting to order at 7pm. Approximately 15 persons attended the meeting. Started with introductions. Went around the room and first-time attendees were asked to introduce themselves and speak about their interest in astronomy. Prior attendees were asked (in the interest of time) to just give their name, whether they have a telescope, and where they live. (i.e., "Shui, no, Waimea") During the "Gear Talk Show and Tell" part of the meeting, Craig Combes showed a pair of small, high quality binoculars. An other individual (one of the Conrads?) demonstrated a spotting scope for whale watching, but also good for observing. It has a mechanical lever to flip between narrow and wide fields. Wiley Knight from CFHT showed an equatorially-mounted refractor telescope. The mount was found on Saddle Road years ago, was in storage for a long time, and eventually fixed up. An Orion Telescopes short-focus refractor was bought and installed on the mount. Craig Nance shared a book "Exploring the Moon Through Binoculars and Small Telescopes" by Ernest Cherrington. This book is an excellent tour guide for learning about and exploring the Moon. It is available through Amazon for $13.57. There was an informative side-discussion about using cross-polarizing filters for observing the fuller Moon phases. Doug shared a red light for astronomy that he recently got. It is worn like a miner's lamp. Please remember to bring a piece of gear to each meeting...this is very enjoyable and a learning experience for everyone! We intend to make the show and tell a part of every meeting.

Scott Hartman then presented the Featured Web Link part of the program. He shared two web sites: The site http://www.atm.dal.ca/~boschat has a seemingly endless list of astronomy links. Scott then shared the Heavens Above web site: http://www.heavens-above.com It is a fantastic site, having loads of information about satellites, Iridium flashes, and even a simple, interactive star chart. These links will be added to our "links" page.

Craig Nance then presented an overview of the night sky. The evening sky highlights for the next month are Comet Machholz and Saturn as the lone evening planet. It was mentioned that the Deep Impact probe will be launching from Florida tomorrow and will encounter/smash Comet Temple/1 on July 4! (note: the spacecraft was successfully launched and is on the way!) For now, Temple/1 is an impossibly faint object in Gemini. For the morning sky, Jupiter is prominently placed. Mars is near Antares.

The featured speaker of the night then took the stage. Dr. Antonin Bouchez is a researcher with Keck with particular expertise on LGS/AO. He is also a long-time researcher of Titan. He summarized what is presently known about Titan, and what the Huygens probe will do. Some of the highlights of his talk are: Titan is a large moon. It has the most Earth-like atmosphere of any object in the Solar System. It has a thick nitrogen atmosphere. Instead of oxygen, Titan has argon (?) and methane as the secondary constituents of the atmosphere. The atmosphere is about three times as thick in height as the Earth's atmosphere, and has a surface pressure 1.5 times that of the Earth. The Huygens probe will enter Titan's atmosphere at 16-minutes past midnight Hawaii time Thursday night/Friday morning. The probe will spend about 2-1/2 hours in its descent and landing/splashdown on the surface. Dr. Bouchez hopes to detect the entry of the probe into Titan's atmosphere using NIRC2 on Keck2. He calculates that the "trail" of the probe entry will be approximately double the brightness of the reflected sunlight. If all goes as planned, human understanding of Titan will be revolutionized by the probe. The main risk for the probe is whether the batteries have power and the probe "wakes up" as designed. He also showed a very recent picture of the moon Iapetus taken by Cassini. There is a very curious ridge of material that is found completely around the equator of that moon.

Items of club business were then discussed: Doug asked people who are interested to sign up for club information via email. Reminder that WHAAC is an "electronic club" and all communications are via email. And, that all presentations and links discussed in meetings are found on the WHAAC web site. There is an ongoing discussion regarding the security of email addresses. The concern is that people may not want their emails shared because of privacy concerns and SPAM. Everyone was reminded that the Telescopes and Observing Clinic was planned for both Thursday evening (1/13) and Saturday evening (1/15) at Waikoloa Village Elementary School. Craig Nance lead this. It was originally planned for a single event on 1/13. Due to some confusion and contradictory dates in the local media, it was decided prudent to hold both dates. During these events, we need people to show how to use telescopes and observe, and people who may have telescopes and not know how to use them. The session was planned for 5:30pm, a bit before sunset, with no definite end time. Regarding the March Star Party, Doug suggested that we use the parking area adjacent to the Waikoloa Road/Mamalahoa Hwy junction. Locals will recognize this junction as where the big "Waikoloa Obelisk" stands tall. The site is a good, flat, paved area. Doug tested the site and it is very dark. There is a slight bit of light from vehicles driving south, but this can be mitigated by where we locate our telescopes. The local County Council member, Pete Hoffman, has suggested that we should "squat" on the site. Presently it is a bit trashy and "undesirables" sometimes hang out there. Doug is seeking volunteers to help clean up the site as we further consider this as a deep sky observing option. An hour or two of work should bring it into shape. Doug briefed everyone on a presentation that was made to Keck and other Mauna Kea Observatories for a product called OptiClean. This is a polymer product used to clean precision optics. It is painted on and looks like clear syrup. It dries and can be peeled off the surface. It can remove fingerprints and heavy dust, and cleans to the molecular level! Both Doug and Craig Nance attended the presentation. The inventor hopes to introduce the product to the Mauna Kea observaotories. Doug suggests we offer our amateur astronomy telescopes as test optics for using this product for large optical surfaces. (Note, there has been some dialog with CFHT regarding this subject as well; stay tuned as we negotiate with Keck and CFHT to see if the club can participate in the cleaning trials).

Doug then presented "Performance Tuning of Telescopes". The WHAAC web site has a link of interest: http://legault.club.fr/collm.html This site shows how collimation is a major factor on the delivered image quality of a telescope. Doug promises a detailed talk about this and other tuning topics in the future. Other talks will touch on collimation, coatings health, aperture masks, etc... This meeting's talk was about "seeing doubles". Double stars can be used to determine the image quality of a telescope, and can be used to rate the quality of a night in terms of seeing. Some nights are better than others, and some telescopes are better than others. Average seeing on Mauna Kea is 0.7-arcsec, with a range of 0.5-arcsec to 1-arcsec, sometimes worse. Lower elevations, such as Waikoloa or Waimea, are typically 2-3 times the Mauna Kea seeing. (i.e., a 0.5-arcsec night on Mauna Kea would be 1.5 to 2 arcsec in Waikoloa.) Resolution Background: Dawes Limit is the approximate resolution where a telescope can first detect that a double star is elongated. DL ~ (4.56)/(telescope aperture in inches). Dawes Limit is easy to remember! Rayleigh limit is the point where the two stars of a double are clearly seen as separate entities. RL ~ (5.45)/(telescope aperture in inches). For most purposes Dawes limit and Rayleigh limit are approximately equal. For an excellent primer on the subject: http://www.cloudynights.com/lab/technical/resolution.pdf (again see our web page...it's linked). Doug developed a list of double stars that can be observed and can tell you how good your telescope is performing, along with how good your sky is, once you have some experience rating the sky. Doug's list can be found on the WHAAC web site on the "Links" page. http://www.keck.hawaii.edu/realpublic/whac/links.html On the links page find and select the "Seeing doubles list" located near the bottom of the page. It is an excel spreadsheet. The 7th column of the spreadsheet lists the separation of the double stars. The closer (harder to resolve) ones are at the top of the list. They get easier as they go down. The key is to go outside and find the point where you can no longer resolve the double star. If you can split double stars in the ~1.5-arcsec range or better, your telescope is probably quite good. If you can never split a double less than, say, 4-arcsec, this may indicate a problem with your telescope. Maybe one of Doug's future Performance Tuning talks will uncover your problem! In general, <2-arcsec is a challenge. >2 arcsec doubles should be splittable every night. When observing doubles be sure to use sufficient magnification, but not so much that the image becomes soft. Most people know what is the highest useful magnification their telescope can operate at. In the list, the stars that have asterisks ("*") beside their name are "easy to find". Really, all of the stars on the list are easy, but the asterisk ones are really simple. Get out there and split those doubles!

Meeting adjourned at 8:45pm





Home | Event Calendar | Sky Chart this Month | Club News | Observing Reports | Photo Gallery | For Sale | Astronomy Links | Membership Form (MS word document)

West Hawaii Astronomy Club

Web page last updated: February 4, 2005

~