PRESIDENT/EDITOR’S REPORT

This is a rather small issue of Nova Notes, because you didn’t send me much stuff!

Lots of astronomical events happened this summer (the General Assembly, Nova East, Starfest, etc.), but no one has written me anything? Take this as a not-so-subtle hint to put fingers to keyboard and write me some stuff for the October issue.

Last issue I told you that the Halifax Centre has a "home page" on the Internet’s World Wide Web (http://apwww.stmarys.ca/rasc/rasc.html). After mailing the June issue, I made the effort of putting it on the WWW, too. I received some favourable comments and so I intend to do the same from now on. You will likely find it there before you receive the paper copy in the mail.

So many of you are getting “wired” that it makes sense now to compile a centre e-mail list, so I believe we will add a blank on this year’s membership renewal form for you to write it in. If you are a "life" member, just e-mail your address to me. Before I close, I encourage to take note of the "Executive Members Needed" notice on the back page.


TOUR NIGHT

BY DAVID TURNER

Saturday, July 15th, 1995, with clear skies and no wind to speak of. Time for another Saturday night tour at the Burke-Gaffney Observatory of Saint Mary's University. The tall ships are in port this weekend, and perhaps they will prove to be more popular than the heavens. It is still broad daylight as I arrive on campus about an hour and a half prior to the 9:00 p.m. starting time for the Observatory tour. A couple of graduate students are playing catch on the front lawn of the McNally Building. Graduate student Gary Gidney is assisting me this evening. When he arrives at my office around 8:30, we both walk over to the Loyola building to make sure that Room 155 is open, then take the elevator to the top floor in order to check on things in the Observatory itself. We turn on lights for the visitors, open the dome, remove the front end cap from the telescope, and turn on the power for the telescope drive. The computer is "fired up" to bring Dave Lane's Earth-Centered (sic) Universe (ECU) up and running. However, it is too early to set the telescope on an object. Sunlight is still streaming into the dome!

At 8:49 p.m. Gary and I watch through the west-facing window of the Observatory's warm room as the Sun slowly sinks beneath the horizon. The weather is ideal for observing, but that is no guarantee we will have lots of visitors. Upon our trip back down to Loyola 155, Gary and I find only a mother and father with their young son waiting for the tour to begin. Just after 9:00 p.m. a few more visitors arrive. I kill a bit of time by asking a few questions of the visitors. "I guess that we might as well go up to the telescope," I mutter to Gary, so we collect the few people on hand and begin the trek to the elevator. On the way we collect about another half dozen visitors who are wandering around in the hallways. This is typical of our Saturday tours, although the elevator is actually relatively crowded on the way up to the top floor. I count over a dozen people in addition to Gary and myself. It is now shortly after 9:00 p.m., less than half an hour into evening twilight. "It's a good thing that we still have a sidereal clock on the control panel," I think to myself, "otherwise it might be tough trying to locate anything in this bright sky." Discovery #1: there is no longer a sidereal clock on the control panel.

The visitors are left with Gary in the warm room as I go into the dome by myself in order to find something to set the telescope on. I recall that Mars and Jupiter are still in the early evening sky, and spot a relatively dim Jupiter off in the southern sky. "Okay now, this should be easy," I mumble. "Let me just point the telescope at Jupiter, and we'll be all set to begin." I rotate the dome slit off to the southwest, shove the telescope roughly in the direction of where I spotted Jupiter, then climb the ladder so that I can view the sky through our Telrad finder. “Yep, there she is all right,” I mutter to myself. “Let's just power up the old Telrad so that I have some setting circles to use for centring......” Click ........ click ... click ........ click ... click ........ "What the.....!” Discovery #2: the red setting circles on Telrad finders are not visible during the early portions of evening twilight!

All right, so I can't use the Telrad to centre the telescope. There are still several other finder scopes that I can use. Fortunately, I have already taken the dust caps off a couple. After jostling the telescope around a bit, I finally locate Jupiter in the large finder. The telescope axes are clamped, then I slowly bring Jupiter to the centre of the cross-hairs of the finder. I clamber down from the ladder in order to plop an eyepiece into the telescope. Nothing but bright blue sky is visible. Of course, there is no guarantee that the telescope is focused for viewing, so I set the focus rate on high and power the focus motor back and forth. Nothing. I climb back up the ladder to look through the finder. "Hummm, if I remember right, the finder scope is not properly aligned with the telescope. Now where was it relative to the field centre that the proper alignment was located?" I try several settings of the telescope, climbing up the ladder with the hand paddle in order to move the telescope, then back down the ladder with the hand paddle in order to look through the eyepiece. Umpteen unsuccessful settings later I am beginning to panic. There are over a dozen people out in the warm room waiting patiently for the show to begin, and I still haven't been able to set the telescope on Jupiter. Tick ... tick ... tick ... tick ... "Boy, these people must be getting rather anxious. Let me try another finder." I now centre Jupiter in the small finder telescope, and go back to the eyepiece. Success! A much out-of-focus image of Jupiter is slowly brought to the centre of the field as I stab at the various slow motion controls on the hand paddle. Then the image itself is focused. "Okay, Gary, you can send them in now. And you can also synchronize ECU on Jupiter itself."

The mob arrives in the dome and I begin showing them how to view Jupiter through the eyepiece. From the warm room Gary is heard to say, "Okay, I'm going to synchronize the telescope coordinates now." WHRRRRRRRRRRR. I leap to the top of the ladder and catch a quick glimpse of Jupiter in the large finder as it disappears from view. "Gary, what did you do? The telescope is slewing." From the warm room there is a moment of quiet, then Gary hesitatingly speaks, ".....Oooops, .....I think I clicked on the wrong box." "Okay, Gary, then let's stop ECU," I scream. WHRRRRRRRRRRRRR. "Gary, the slew motors are still running," as I state the obvious to a rather hushed group of visitors. "Ummmm, I don't know how to stop the program," comes after another long pause. By now the telescope is starting to point close to the horizon, and I am worried that the cords may get tangled. In desperation Gary and I switch off the computer that is running ECU. WHRRRRRRRRRRR. Discovery #3: switching off the terminal that is running ECU does not turn off the slew motors. I finally reach for the power key and turn off the telescope power itself. WHRRRR ..... KERRRRRCHUNKKKKK! The telescope finally comes grinding to a halt, quite literally!

Peace finally comes to the telescope dome again, and we start from scratch to get the tour running. In another five minutes I have managed to get the group back to viewing Jupiter. This time we synchronize ECU properly, and, after a while, the tour is starting to run very smoothly. The extra screen in the dome itself is proving to be a godsend, since it possible to do a little bit of constellation finding through the dome slit using the constellation outlines of ECU. I point out Cygnus and portions of the Summer Triangle to those visitors who aren't in the lineup to look through the telescope. I also take some time while we are viewing Jupiter to check the alignment of the large finder scope. To my horror I discover that Jupiter is only partly visible on the edge of the field of the large finder scope when it is centred in the telescope. Discovery #4: why was this not made known to tour guides?

By now we have tried a variety of eyepieces and have looked at many different objects, patiently talking about each one in turn to the group. There are three, elderly, gray-haired women in the group who ask several perceptive questions. They are clearly having a good time on this visit to the Observatory. As it starts to get late, one of them begins to ask a variety of questions about Father Burke-Gaffney himself. I am puzzled by their questions, but answer them as best I can. Finally, I ask one of the women, "Why are you so interested in Father Burke-Gaffney?" She looks at one of the other women, and then back at me. She addresses the woman, "Okay, Becky (not her real name), perhaps it's time to reveal your true identity." Why do I not like the sound of this? The other woman turns to me and begins, "Perhaps I should have told you this earlier, but I am a niece of Father Burke-Gaffney. My father and Michael used to have many interests in common. I have come a long way to visit the Observatory named after my uncle." Discovery #5: you can count on everything going wrong only if there is someone important on hand to witness it.


THE ST. CROIX OBSERVATORY SITE:

BY SHAWN MITCHELL, Chair, Observatory Land Search Committee

By the time you read this article, the Halifax Centre will have completed a ten year lease with Annapolis Basin Group, Inc. for the use of a parcel of land in St. Croix for our future observatory. If you have not attended any recent meetings, the parcel of land is located outside of St. Croix on the Halifax side of Windsor on Minas Basin Pulp & Power's reservoir for their hydroelectric dam (see map). Our lease is for a the small peninsula of land indicated on the map.

Now that the Centre has land, it's time to decide what type of facilities we want and can afford! The land search committee has discussed amongst themselves that an observatory with some form of a roll off roof with an attached warm room be built. Several designs have been discussed and a concept plan drawn up (see below). The proposed observatory would consist of three rooms: the first room would be a 12 by 16 foot warm room located in the middle of the structure; on the left side of the diagram is the communal roll off observatory measuring 16 feet by 20 feet. This area would house the Centre's small telescopes (C8, Haverson, etc.) and members personal telescopes. The third room, located on the right side of the diagram, would be a 16 by 16 foot roll off that would eventually house the observatory's main telescope (hopefully a 25” to 30” diameter reflector). In addition to the observatory building, a large concrete pad and some concrete piers would be constructed outside for anyone to use.

WORK TO START THIS SUMMER AND FALL!

Plans are under way to start site preparations this fall, this includes surveying the site for a building permit and staking out the locations of the driveway and building. Upon receiving a building permit, brush and trees from the driveway and building area will need to be removed. After this has been completed we hope to have a contractor excavate the driveway and building site and fill and level them with gravel. Once all this work has been completed the site will be ready for members to enjoy at any time. By next spring, hopefully a finalized building plan will be approved and construction of at least the communal roll off and warm room can begin.

Due to delays in getting this article into Nova Notes, some of the planned work on the site has already taken place. The site has been surveyed and the brush in the areas where the driveway and buildings are going has been partially removed, and an application for a building permit has been obtained.

VOLUNTEERS NEEDED!

In order for the Centre to complete this project, the support of all members will be needed both physical and financial. During the September 15th executive meeting a motion to create two new committees will be presented. These two committees will be the Observatory Committee and Observatory Funding Committee. The Observatory Committee will be responsible for designing, building, and preparing the operating policies for the observatory. This committee will require help with the physical labour required to build the observatory and anyone who can help either with the actual work or in acquiring building materials would be greatly valued as a member of the committee. Please volunteer!

The Observatory Funding Committee will be responsible for raising the necessary funds to build and operate the observatory. Members who have experience in raising funds will be needed. Some of the funding opportunities that this committee may examine include a donation drive from current members, provincial and federal funds for education or technology development, and funding from educational institutions.

YOUR SUPPORT IS NEEDED!

Having read this article I hope you have realized that this is not a small under taking but probably the largest project that the Halifax Centre has or will undertake. When completed this observatory will provide members of the centre with a resource that individually they could not afford, a facility capable of doing professional quality research projects, and as a resource for the promotion of the centre and space science education in the region.

You may be wondering at this point what you can do to contribute to this project. Well, there are many things a member can do, for starters there is the need for funds to build the observatory, help in raising funds through tax deductible donations from members or companies. Asking local building supply companies for donations of building supplies such as lumber, nails and plywood, or the use of a back-hoe and dump truck from a contractor. We will also need people to swing hammers, shovel gravel, clear brush, etc. This project is a legacy that we as current members of the Halifax Centre can leave to future members. A plaque with the names of all the people who contribute to the project will be permanently mounted on the observatory so that future members will know who to thank for the use of the observatory.


CONSTELLATION OF THE MONTH: AQUILA

BY JOSEPH YURCHESYN

Lying on the summer Milky Way and separated from Cygnus by Vulpecula and Sagitta, and with Scutum separating it from the Milky Way splendour of Sagittarius and Scorpius, Aquila the Eagle has many offerings at a reasonable altitude for mid-northern latitude observers. Unfortunately, Scutum (Editor’s Note: see the article on Scutum in the last issue of Nova Notes), immediately to the south is home to most of the open clusters in this area of the Milky Way, while Aquila is home to many bright planetary nebula.

The brightest star Altair, at 16 ly's distant, is one of our closest neighbours. It is 1.5 times the size of our sun and 9 times brighter. It also has the fastest known rotation rate, with an equatorial surface velocity of 255 km/s. the star completes one rotation in 6.5 hours, compared to our sun's 25.4 days.

About 3 degrees NW of Altair is the stark and easily observed dark nebula Bernard 142 and 143. These two nebula form a giant "E" shape, some 80' x 50' in extent, through which very few stars are able to shine.

The best planetary nebula is the 12th magnitude NGC-6781, which measures 109" across. It has a low surface brightness, but is detectable in a 4 or 6 inch telescope under good conditions. Lying 3.5 degrees NW is NGC-6804. It is one half magnitude fainter, but is only 31" in diameter, so the surface brightness is much higher. In the southern part of Aquila lies the faint 14th magnitude, 60" diameter NGC-6772 and the smaller 12th magnitude, 20" diameter NGC-6751.

The most brilliant recorded nova to appear in 300 years, burst forth in Aquila in 1918, it being first noticed on the night of June 8th as a 1st magnitude star 6 degrees north of the Scutum star cloud. At its maximum, it was only out shone by the brilliant Sirius. The precursor object was 11th magnitude.

At a calculated distance of 1,200 ly's, the event actually occurred in 700 A.D. The maximum luminosity was 440,000 suns, ranking it among the brightest normal novae on record, which total about 100. Spectroscopic studies revealed successive shells of gas being blown into space at speeds of between 1,600 and 2,200 km/s. A few months after maximum, a gaseous nebulosity was detected, which had a diameter increasing at a rate of 2"/yr. This gaseous shell eventually faded into space and Nova Aquila is now a bluish star of magnitude 11.95 and apparently much smaller and denser than our sun. It took 7 years to fade to back to its normal magnitude state.

Just a little something to ponder, when you next gaze in the direction of Aquila. Now?... If I could just figure out what triggers a Nova?...


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Last Updated: September 13, 1995 by David Lane, President, Halifax Centre.