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What do you get when you combine a passion for astronomy, the motivation to evangelize the hobby, and a big field under a dark sky? In this case, you get the newly established Earth, Wind, and Sky Star Party. This was the inaugural year for this star party located outside Barry, IL, which is sponsored by Bill and Becky Saflarski who admittedly "put this star party together in two months" without the support of a local astronomy club or other organization.
Being the inaugural year, the star party did not attract a large number of attendees or any vendors—a direct result of the short planning cycle. Additionally, a few minor logistical issues and a "dynamic" schedule of events kept the organizers busy, but overall things seemed to go smoothly. There is lots of potential for growth, and improvement and this star party will get better each year.
Typically, I attend star parties not for the social aspects, but for the opportunity to use my scope under some dark skies. Do not get me wrong, the social aspect of "star partying" is enjoyable and important, but I do not use it as criteria for judging a star party. If I can meet old friends, make new ones, hear an interesting presentation, and socialize with other amateurs, I consider that a bonus part of the star party experience.
I recorded SQM readings every hour while I was observing, which denoted an average limiting magnitude of 6.3 over two nights. Both nights were rather humid and the humidity exaggerated light domes from nearby cities to the southwest and southeast and made the sky appear gray. On a pristine night, the sky could possibly reach a limiting magnitude of 6.5. Other than the light domes to the south, the rest of the sky appears dark down to the treetop level. The Milky Way draped through the zenith after dark was impressive.
Sometimes you have to ignore that voice in your head and take a chance. Although, attending a first time star party is not exactly a risky venture, everyone is hesitant to be the first to try anything. The first year is in the history books and next year has all the potential to be better than this year. I am adding the Earth, Wind, and Sky Star Party to my list of star parties for next year and am looking forward to see what this grows into.
As I wandered around the IFSP observing field this weekend, I had the chance to talk with several amateur astronomers. Unbeknownst to them, I was on a clandestine mission. One by one, I directed the conversation to logging with the not so subtle question "Do you keep an observing log?" Not exactly a scientific survey as I am sure the margin of error is quite high but the results are indicative of my experiences with other groups.
Only about ten percent of the observers I spoke with keep an observing log of any kind. Of those observers who indicated they kept an observing log; about half record only the names of the objects they view and no other details. The remaining half records various details of their observations on a wide range of media including laptops, PDA's, and paper.
A large portion of the observers who do not keep observing logs say they have no interest in logging, which would "simply turn a hobby into work". A smaller group feels that they do not have a writer’s skill and therefore, could never pen an observation worthy of documenting.
For me, logging my observations and comparing those observations to others made at different times and locations, and with different equipment, adds to my enjoyment of the hobby. I would not expect another soul to derive pleasure from amateur astronomy in the exact same way as I do. However, it does seem odd that in an endeavor like amateur astronomy, with observation being such a keystone, why we are reluctant to record our observations.
In the Internet connected world where facts and photos of the night sky are a few mouse clicks away, why would anyone want to record what they have seen through a small telescope in a light polluted sky? After all, this pales in comparison to the images available from the Hubble Space Telescope and through sources like the Worldwide Telescope.
Here is a well-kept secret that only those of us who log observations regularly truly know and understand. We write, compile, and archive our observations for our use only. I have never written an observation and concerned myself with what others might think. When I write and observation, I do it in as clear and concise of a manner as possible, but only to ensure that I am able to understand my thoughts in the future.
There are no good observations or bad observations. As long as each written observation means something to the author, then the goal is satisfied. My favorite written observation does not come from the journals of Messier, Herschel, or other prolific observers. It comes from a friend who wrote in his observation log while observing M76 with a pair of binoculars “If it was brighter, I could see it.” To me that speaks volumes.
In case you are wondering, I write all of my descriptions and sketches in a weather proof logbook. I later transcribe the text then redraw, and scan the sketches into a MySQL database that stores all of this information, both images and text. This database forms the basis for the observations section of this website.
When you begin an observing session, do you routinely determine the Naked Eye Limiting Magnitude (NELM), which is the magnitude of the faintest star detectable with only the naked eye? If so, how do you determine the NELM value? How often do you measure the NELM? How do your values compare to those of others? Is your head spinning from all of these questions?
I typically measure the NELM at the beginning of an observing session after Astronomical Twilight has ended. At the end of Astronomical Twilight, the Sun has dropped more than 18° below the horizon and no longer influences the brightness of the night sky. While I might record observations during Nautical and Astronomical Twilight, I always wait to measure the NELM until after Astronomical Twilight.
When I measure the NELM, I use a chart of star fields prepared by the International Meteor Organization (IMO). These charts define thirty star fields scattered over the entire celestial sphere. To determine the limiting magnitude, simply count the number of stars visible in the star field (including the stars that define the corners of the star field) and look up the limiting magnitude on the supplied tables. I always choose the star fields that are closest to the zenith to reduce the effects of light pollution and atmospheric conditions.
Last week I purchased a Sky Quality Meter and began experimenting by taking readings of the sky brightness then comparing the calculated NELM from the measured sky brightness to my estimates of the NELM using charts from the IMO. I have only a few data points from my backyard, but I am finding that my NELM estimates from the IMO charts and the calculated NELM based on the sky brightness readings differ by only 0.2 magnitudes (my NELM is 0.2 magnitudes fainter than the calculated NELM) .
While I need to gather many more data points, the initial results are impressive. I typically only make one NELM estimate per observing session due to the amount of time it takes to locate the star field, study the field for several minutes, count the stars, record the results, and so on. For sites that I observe from often, I sometimes have gotten lazy and just go with the estimates I have made during previous sessions. With the SQM, I point the meter at the sky and within ten seconds or less it displays the sky brightness reading. I see this greatly improving my NELM data in the future.
I have posted a new article "Creating a Session Plan" in my “Observe My Way” series. This article covers how to use a planisphere to create an observing session plan for some future date.
For years, I have been using the limiting magnitude formula found in Norton’s Star Atlas without giving it much thought. Occasionally, I thought that I exceeded the limiting magnitude of a particular instrument, but with no quantitative data to support my suspicions, I brushed it off with a "Hummm, that’s odd." mental note. Over the years, as my experience level developed and my note taking improved, I regularly documented cases where I exceeded the calculated limiting magnitude of an instrument, even in less than ideal conditions.
At this point, the geek in me began to scream for an explanation. Do I have Superman vision? Do the physics of optics somehow not work the same in my backyard as the rest of the Universe? Am I employing an excessive amount of "averted imagination" in my observations? On the other hand, perhaps, just perhaps, the limiting magnitude formula is somehow flawed.
Consulting the astronomy books in my personal library and the Internet, I conducted an investigation—albeit a brief one—that revealed no less than six different formulas or methods for calculating the limiting magnitude of a telescope or pair of binoculars. A disclaimer accompanied each formula or method telling the user that in essence “Your mileage may vary.” Essentially, in each case, the limiting magnitude was not a true limit with the expectation that certain individuals under certain circumstances could observe objects from one to two magnitudes fainter than the computed values.
What is the value of having the ability to calculate a limiting magnitude that is not really a limit? I am sure I will be writing more about this subject in the near future as I embark on a quest to discover the basis of determining a true limiting magnitude.
In May 2008, a new storm on the surface of Jupiter gained notoriety. This new storm was unique in that it exhibited a red color similar to the Great Red Spot indicating it was strong enough to lift gas from the lower portions of Jupiter's atmosphere. Alas, this weekend, the new storm met its demise when it collided with the Great Red Spot, which subsequently absorbed the much smaller storm.
Jeff Burton
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