Important announcements

	Our next meeting will be on Friday, November 13, at 7:30 at Poricy Park in order to accommodate our speaker, Dr. Michael Corcoran, of the High Energy Astrophysics Science Archive Research Center, Goddard Space Flight Center, Greenbelt, MD. Dr. Corcoran will discuss his work on x-ray emissions from the star Eta Carinae, and its implications on our understanding of the star. We also will have scopes set up on the lawn in front of the hall where you can observe Jupiter and Saturn without the usual glare from the moon. Both will be well placed for observing after the meeting, as will the beginning parade of winter constellations.
	Please pay your membership dues if you have not already done so. Dues are $15.00 for membership. You can also send your check to: S*T*A*R Astronomy Society, Inc. P O Box 863 Red Bank NJ 07701
	One of the club's biggest expenses is printing and mailing this newsletter. If you have internet acces and would like to save the club time and money (and save trees at the same time), send e-mail to mikel@att.net , and I'll stop sending you a paper copy. Instead, you can get the newsletter on-line at http://home.att.net/~mikel/star.html .
	Got an idea? Would you like to write an article for the Spectrogram about it? See http://home.att.net/~mikel/star/author.html for article submission guidelines, or ask me for a paper copy at the November meeting.

Events

	There will be a public solar observing session hosted by our own Ralph Marantino and Saul Moroz on Sunday, 11/1, on the Poricy Park lawn, starting at 1:30 PM. All are invited.
	The Leonids are coming! 11/16-17, all night. Very fast meteors (44 mps), large storm predicted. For more info, see http://www.skypub.com/meteors/meteors.shtml

Notes from October

by Penny Fischer

We were treated to crystal clear skies (though gibbous waxing moon) at October's S*T*A*R meeting. Many scopes were set up on the front hill, which happens to have a great horizon line. The meeting was moved to the main room of the nature center, to accomodate the large attendance..

First item discussed was the South Jersey Star Party of two weeks ago. Dan stated that we had more members there (18) than any other star party we've attended to date. Also, a S*T*A*R meteor shower watch may be arranged for the Leonid shower. Check our web bulletin board at /cgi-bin/starbbs.pl for updates under "S*T*A*R Activities".

A motion was made to have the club's two 10`` mirrors ground and figured for $225 each, and it passed with virtually no "nays" to be had.

A new session of "Stimulating Saturdays" is in the works in Rumson, and Dan, Kay, Don, David Britz and myself have volunteered to do 1 hour fun classes for children between the ages of 4th-6th grades. In return, the school will again donate $400 to our club.

Mike Lindner showed his homemade scope off next. This amazing piece of craftsmanship features a cradle counterbalance system, and Teflon furniture slides as bearings and Formica strips also on the altitude. The secondary spider is made from hacksaw blades which can be adjusted for collimation.

Many of the parts Mike got at the local Home Depot and even salvaged some stuff which was slated for the dumpster!

Penny announced David Segelstein is our new Astro Equipment bulletin board Moderator. David is the person to ask for advice on equipment, along with a great group of people to discuss anything equipment-wise with. You can also use this forum if you are looking to buy or sell equipment!

Mike Lindner was announced as the new Spectrogram editor. You can find thenewslettero-line at http://home.att.net/~mikel/star.html .

Our guests were Ralph Marantino and Saul Moroz, new S*T*A*R members who bring with them many years of observing experience, particularly solar observing. Ralph is a former UACNJ president, and Saul is past membership chairman for the Jenny Jump Observatory. They are both involved with the Amateur Astronomers' Association of Princeton.

Ralph began with the bare bones of solar observing equipment, but learned an important point. After ten years of observing the sun, he says you should have about 45X for optimum resolution and observing. Also, the best time to observe sunspots is in the AM, before heat makes the image blurry.

Ralph showed us a mylar filter, which is very inexpensive, but shows a blue image of the sun. If this is not aesthetically pleasing, you can thread a #21 orange eyepiece filter on, and get almost a true-color image of the sun. Saul and Ralph also think the #21 is the best colored filter for lunar observation, showing the most detail and contrast.

Many other filters (progressively more specific and expensive) were shown off by Ralph and Saul. A solar observing slide show presentation followed.

Ralph and Saul will be conducting a solar observing session on Sunday, November 1st, on the Poricy Park lawn, starting at 1:30 PM. Anyone interested in learning more about this astronomical hobby is invited to attend.

The meeting wrapped up with at least thirty people observing out on the front lawn, with plenty of scopes and still mostly clear skies.

Care & Cleaning of Aluminized Mirrors

by Kay Sears (reprinted from Cluster, 1/74)

Owners of telescopes utilizing aluminized mirrors and flats are continually in search of the best way to clean the delicate surfaces. I have found that the method recommended by the Coulter Optical Company [which has since been bought by Murnaghan Instruments Corp - Ed.] produces the cleanest surface of any procedure I have ever used.

Coulter advises that the aluminized and overcoated surface is the most delicate part of the mirror, but with reasonable care and usage it can be expected to last up to ten years. Somewhat shorter life expectancy may be experienced in atmospheres containing corrosive salts and contaminates. They point out that the coating should not be touched with the hands or any object except when cleaning. If very dusty, gently brush with a camel hair brush. (Be sure the hair ends are not cut, but are of a natural taper. Use of cut hair produces fine sleeks on the coating). Keep the telescope capped when not in use. Store the tube horizontally to prevent settling of particles on the mirror surface. When the mirror becomes excessively dirty, carefully clean as follows:

With the mirror resting face up on a towel in the sink, turn on the cold water and play a gentle stream of water onto its face. This will loosen some of the particles and wash off unattached dust. Dip a wad of cotton in a mild detergent solution. Surgical cotton or engravers cotton may be used...engravers is less expensive. Gently swab the entire mirror surface. Keep the water going while doing this so as to wash off the detergent solution as you clean. It is very important not to let the surface dry or bead as water marks will be formed. Keep the gentle stream of water going.

After swabbing the surface with detergent solution flush the mirror with the gentle stream of water. Dip one half of a cotton swab into isopropyl alcohol. At the time you place the swab on the mirror surface, turn off the water. Now swab the entire surface with this alcohol saturated swab. CAUTION: Do not turn the swab over or dissolved skin oils will deposit on the mirror. Immediately take a dry swab and wipe gently. Keep changing cotton swabs until the surface is totally dry.

Coulter has used this method for many years and it has proved itself to be the best. They caution that laundered towels or cloths should not be used for wiping the mirror. The residual detergent in the cloth will cause waterspots and a film that is impossible to remove without recoating. Lens cleaners should not be used.

[Ed. note:] David Segelstein reports trying the method advocated by QSP (i.e. pouring acetone on the mirror after rinsing to prevent water spots) with excellent results.

All Yew Want to Know About Dew but Were Afraid to Ask

by Kay Sears

What is dew, and why should amateur astronomers be concerned about it? Dew has brought an early termination to more observing sessions than perhaps any other single factor. It is a fact of life and is something we all must face when we take our equipment out to look at ``what's up there''. But what dew we know about dew and how dew we prevent it from ``dewing us in''?

In order to understand dew we should understand a few of the things thrown at us in every weather report, like humidity, relative humidity and dewpoint.

HUMIDITY- In our atmosphere there is always present a quantity of invisible water vapor mixed with other gases. The absolute humidity is the mass of water vapor present per unit volume at any given temperature. Warm air can hold more water vapor than cold air.

RELATIVE HUMIDITY -The ratio of the absolute humidity to the maximum quantity of water vapor that could be present at that temperature is the RELATIVE HUMIDITY, and is expressed as a percentage.

DEWPOINT -The temperature at which the air becomes saturated and can hold no more water vapor is called the dewpoint. As the air temperature is lowered the relative humidity increases. At the dewpoint the Relative Humidity is 100%and the air can hold no more water vapor. Some moisture is squeezed out of the air, falling to the ground or condensing on cold surfaces. Lowering the temperature further merely squeezes more water out of the air, but the relative humidity remains at 100%.

You hear these terms every day if you listen to the weather report, and what astronomer doesn't?

The relative humidity may be found by measuring the temperature difference between simultaneous readings taken with an ordinary thermometer and a thermometer having a wetted and amply ventilated bulb, then using a lookup table or applying a rather complicated formula. An easy to remember example of this formula says that at 70 degrees F if the relative humidity is 50% (that is, the air contains only half of the water vapor it is capable of holding) and if the temperature is decreased only 20 degrees fahrenheit the air will become saturated and some of the water vapor will be condensed into liquid water. This is what causes rain to fall, fog to form and dew to spoil our telescope viewing.

Consider a typical summer evening of observing in NJ. When we arrive at our observing field at sundown the temperature is 70 degrees and the RH a comfortable 50%. We set up our scopes and wait for darkness to set in.

After the sun sets in the west we marvel at how clear the sky could be tonight. When the sun drops below the horizon it no longer warms our ambient air and things begin to cool down. By the end of twilight the temperature has dropped 5 degrees. We check out the first stars to appear, and settle in for a night of super observing. After an hour of observing the temperature approaches 50 degrees and we slip on a jacket against the cold. When we return to our scope we can only see a blob of light in the eyepiece! We shine a light on our eyepiece and it looks like it came from a steam kettle. What happened?

As the air temperature falls the temperature of the eyepiece, mirror (or lens), and the entire telescope begins to fall. Less massive parts cool fastest, more massive parts cool slower. Since these objects do not themselves generate heat they give up what heat they have to the surrounding air and to other surfaces [an object exposed to a clear sky can get even colder than the air, because it radiates energy into space - Ed.]. If you touch the tube of your scope you will find it is wet. The mount will be wet, and if the scope is pointing up to the zenith the mirror and diagonal may be wet.

As the temperature of the air around our scope dropped the amount of water vapor it could hold decreased and the Relative Humidity increased from 50%, which it was when we set up. As the air temperature continued to drop the RH increased to 99% as the eyepiece temperature approached 50 degrees. This meant that the air surrounding the telescope couldn't hold much more water vapor, and continued lowering of the air temperature resulted in the water vapor in the air condensing out on the cold surfaces of the eyepiece lens, diagonal, mirror, and the rest of the telescope. These surfaces reached the Dewpoint, the temperature at which the air could hold no more water vapor. Continued dropping of the temperature only resulted in heavier condensation, with RH remaining at 100%.

If there is no breeze the air can become stratified. With the lens slightly above the dewpoint, just a waft of air over its surface can result in instant condensation, caused merely by the air turbulence set up by the movement of your hand, or walking past your scope.

You will notice that your car is wet with dew, the grass is wet, your tent or canopy is dripping on you, and even though your maps are under the canopy the paper is damp. The car, the grass and the canopy are wet because the moisture condensing in the air above and around you falls to the ground, wetting whatever it falls on, even though the temperature at the surface may be slightly above the dewpoint. This will account for some of the wetness on the outside surfaces of your telescope, too.

If your scope is not pointed at the zenith the mirror of a newtonian will probably not be dewed (yet). This is because much of the dew on external parts has fallen from condensing vapor in the surrounding air, and the mirror was not directly in its path. Besides, the mirror is the most massive component in your telescope and cools more slowly, therefore air near its surface is warmer and is still above the dewpoint. Give it a little time, though and it will become covered.

What can you dew about this outrage? There's not much you can dew about falling dew except to cover your equipment until the temperature changes have stabilized. Falling dew is like rain. It forms in the air then falls to the ground. Dewcaps (extensions on the front of your tube)help until you point to high elevations. Heated dewcaps raise the temperature of the air inside the tube, vaporizing moisture falling from above, but require a current source to provide the heat.

When your scope is not in use it should be covered with a tarp or large plastic bag. When the eyepieces are not in use keep them in a heated container. It doesn't have to be much...a six-pack of room temperature coke or beer kept in an insulated picnic bag with your optics will keep your eyepieces slightly above the ambient air temperature. It could even be an insulated box with a heavy slab of metal in the bottom. After you use the eyepieces return them to the container. If you use two eyepieces interchangeably put one in your pocket near your torso or hold it in your hand while you use the other. Do anything to keep the temperature of the eyepiece above the ambient temperature.

Heat the lens or mirror to keep it slightly warmer than the surrounding air. A small fan blowing air heated by small heaters and directed over the mirror can be useful. Don't wipe or blot the lens or mirror surfaces, especially those with anti-reflective coatings, because they are easily scratched with surface grit, and can become stained.

Multi-element air-spaced lenses and objectives can trap liquid moisture between the elements and the only way to remove it is to disassemble the lens elements and bake them dry. This is best done by the lens manufacturer because many of the elements in such a lens must be placed in the same rotational orientation with respect to the other lenses in order for the assembly to perform properly.

Treat your camera with care too. Keep it in it's case until you are ready to use it, then return it as soon as you are finished. Keep lens caps on until ready to focus and make an exposure. Keep a supply of plastic zip food bags to keep removeable lenses in. NEVER bring your camera or lens directly from the cold into a heated room. Put it in a bag and zip it closed while you are outside, then bring it inside. That way, as the lens warms up the RH inside the bag decreases, and there will be no condensation.

How can yew tell when dewing is imminent? Before leaving for the field check the weather forecast of the nearest weather station to get the dewpoint. Now all that's necessary is to measure the temperature at your observing site to see if it is near the dewpoint. If you forgot your thermometer you may have to resort to my tried and true ``cricketometer''. Count the number of cricket chirps in 15 seconds and add 40. The number will be very close to the air temperature. An alternate approach is to note that crickets chirp 72 times per minute at 60 degrees F. For every additional four chirps per minute add one degree to 60 and for every four chirps less than 72subtract one degree. Now there is no need for yew to get dewey.