The following are documents among the papers of Prof. Edgar Everhart, who served as Director of Chamberlin Observatory from ca. 1972 to 1986.
After his death in the early 1990s, his wife Libby continued to manage their mountaintop observatory [Chamberlin Field Station, obs code 707] at Dick Mountain near Bailey Colorado, until her health failed in 2003. The family then requested that the telescopes be moved to the University of Denver, where they will be used to support student projects. We are slowly assembling a biography of Prof. Everhart, and welcome contributions to the story by all who knew him. --R.Stencel, Director
Chamberlin Observatory Annual Report March 1982 by Prof. Edgar Everhart, Univ. Denver Most of you know that the 20" Clark Refractor has needed serious repairs = and was inoperable for two full weeks this month. The polar axis would = not turn, and at first we were afraid it was jammed, which would be = something we could not fix without many thousands of dollars. However, = Fran Ohmer and I found that the trouble was a frozen control shaft which = was geared to the polar axis, a shaft 1.375 inches in diameter that = could not be lubricated. We believe it last saw oil in 1892. This part = was singularly hard to remove. We couldn=92t push it out because the = polar axis was in the way, and when we tried to pull it out we broke a = gear instead. Finally we realized that if we took off enough parts we = could take out the part with its housing. This required a major = disassembly of the control shafts and handwheels. This meant that all = the control console that Van Nattan built some 20 years ago and all the = wiring had to come off, and we won=92t be able to put it back without = extensive rebuilding. The broken gear was of 7 pitch, an obsolete size, = but Erv Hofman of the Physics shop was able to mount the ring of teeth = on a new web and hub and thus fix it. Fran Ohmer and I installed grease = and oil fittings so this will not happen again, and we put the telescope = back together. There have been about 12 man-days in this repair and we = still are not finished with the wiring and the replacement clock mounts = and shelf. However, the telescope is back in service. At Chamberlin Observatory's Field Station near Bailey there is a = 16-inch f/5.5 reflector set up for astrophotography and a station for = hypersensitizing film. The limiting magnitude on stars under ideal = conditions and with 2415 film is about 21.5. There is a comet tracker, = which is a device t hat lets one track on a comet, letting the stars = trail. One can track on an invisible comet, which is usually the = situation. A most important addition to Chamberlin=92s Field Station is = a measuring engine, built locally, but very accurate. This measures the = positions of stars and comets on a negative to errors of tenths of = arc-seconds. In linear measure this is to about one micron which is one = millionth of a meter, or about 40 millionths of an inch. If you knew = your latitude and longitude to the same accuracy as we measure positions = in the sky, you would know your position to be within 20 feet on the = surface of the earth. So far Chamberlin has sent in 24 comet positions to the Smithsonian = Astrophysical Observatory that have been published. We are told that = these are as accurate as any they receive. Starting in 1894 Professor = Howe made many visual measures of the positions of comets with the 20" = refractor, using ring micrometers and other visual devices that are now = obsolete. Professor Recht, the second director made less such measures, = but he did publish extensive study of periodic comet d=92Arrest about = 1943. Now Chamberlin observatory is back in the tradition of measuring = and publishing accurate comet positions. Just this Tuesday morning we = tried to be the first to recover the same P/Comet d=92Arrest now 6 = returns later. We don=92t see it on the negative=97it is still too = faint. Next month we=92ll try again. Edgar Everhart, Director Chamberlin Observatory 1984 Report Our famous and venerable telescope has been the centerpiece for our = Public Nights. The Tuesday night programs have been conducted by Fran = Ohmer and Scott Siegel, and the Thursday night programs by James Rafert. = One difficulty has been with the telephone reservations There has been a = shakeup in personnel at the University with new and inexperienced = operators taking the calls. Worse yet, the University is totally = changing its telephone numbers, and it is difficult to know what number = to call. For now 871-3222 seems to be working. The old number 753-2070 = is no longer answered. We have made some progress in identifying new = people to work as Public Night instructors in relief of our present = instructors. The extension course in astronomy, taught so successfully by Andrew = Gassmann, disappeared when the extension office was closed, and the New = College which replaced it has not revived the course. The observing = laboratories of the Descriptive Astronomy course have been handled by = Andrew Gassmann as usual. The Observatory has continued to serve as meeting place for the Denver = Astronomical Society and the L5 Society. The research and scientific observations have all been carried out at = our Chamberlin Observatory Field Station .During the last 12 months 68 = accurate positions of 23 different individual comets, along with 4 = positions of asteroids, have been sent to the International Astronomical = Union. Scott Siegel helped with the guiding or measuring of several of = these and did all the work on one comet position by himself. Two = periodic comets have been recovered by Chamberlin Observatory recently. = We were first to photograph Periodic Comet Pons-Winnecke, 1983 Jan 12, = two days before the next photograph, which was by Honda of Japan. On Nov = 3 and again on Nov 7 we recovered Periodic Comet Taylor and have the = sole credit for this one. There were 4 unsuccessful attempts to recover = this comet over a 2-month span before we finally found it. This is the year of the International Halley Watch, and there is a = possibility of using the 20-inch refractor to do useful work on = near-nucleus studies of Halley=92s Comet. These would probably be a = program of short-exposure nucleus photographs, something the 20 inch = should do well. We should form a team on this. Edgar Everhart, Director Chamberlin Observatory 1985 March 23 Chamberlin Observatory Annual Report There have been significant changes in the Public Night program. After = 25 years of service with the Tuesday Night Program, Francis Ohmer has = retired. He won the 1981 director=92s citation. Happily, he will = continue to help with the maintenance of the telescope, and last week he = installed a repaired sidereal clock on the telescope controls. Now Mr. = Richard Rew will be on Tuesday Nights. Both these men have been helped = immensely by Mr. Brian Rickard, a young man who has already given = several months of excellent service. We have nothing but good reports on = Brian. After operating the Thursday Night programs very faithfully for 6 years, = James Rayfert has resigned. Anticipating this, we trained Allen Rosen = and Marcia Rainy in this work. Allen, one of our Junior members who will = go to college this fall, has already assumed major responsibilities in = this regard. I have been well impressed by his competence. We are happy = to see Marcia Rainy bringing her experience on planetarium lecturing to = us. Mr. Dave Trudeau and Mr. Steve Innes, former and present presidents = of the DAS, are helping on Thursday nights. Dr. Howe, the first director, was very active in making visual = measurements of comets from the 1890=92s to the 1920=92s with our 20" = Alvan Clark refractor. He took a particular interest in Comet Halley in = 1910, Now your third director is also busy measuring comets with 16" = reflector at our field station. In the past year there are 23 accurate = positions for comets. The latest one would make Dr. Howe particularly = happy. Last week we got a position for Comet Halley when it was between = 20th and 21st magnitude. This is about 10-1/2 months before perihelion, = whereas in 1910 no observatory found it more than 8 months before = perihelion. To the best of our knowledge, this is the fourth = photographic position reported and the second in this country. The = guiding for our recent photograph was done by John Briggs, recently an = editor for Sky and Telescope, but now living in Colorado. The = identification and measurement were by myself. This work at our field = station is now supported by a National Science Foundation Grant. Last June my wife and I traveled to Rome where I gave a paper on a way = to compute orbits by numerical methods at an International Astronomical = Union Colloquium. Then we went on to Garching, just outside Munich, = where I gave two short papers at the International Halley Watch meeting. With the end of the school year last June, I retired from teaching, but = retain directorship of the observatory and continue at the field station = doing astrometry of comets and mathematical research in celestial = mechanics. Edgar Everhart, Director 10/86 MEMO TO: Herschel Neumann FROM: Edgar Everhart RE: New associate director for Chamberlin >From the recent talks and exchange of letters it has become evident that = I am physically unable to continue direction of the relations of the = Denver Astronomical Society with DU. I think I should continue as = director because of past scientific publications that are still = continuing. You suggested we appoint an Associate Director who will be = responsible for DAS concerns and mentioned Frank J. Murcray as a = possibility for this. This has my full approval. The appointment could be made now. If the = idea in my other memo is O.K., it could be his first action. It could be = announced at the annual DAS banquet in March. DU is paying me $7200/yr now and according to the original letter $3000 = of this is for directing Chamberlin. I would estimate that $2004 of this = accounts for liaison with the DAS and $996 for research and = relationships with the astronomy world. Thus DU could reduce my salary = to $5196/yr right now or $433/month. The amounts above have been = adjusted $4 to make the monthly payment come in even dollars. For John Briggs the idea is to give him 9 credits for Physics 7300 = Special Topics: Astrometry of Comets with me as instructor=97Winter = Quarter. This would be on a grad/undergrad level because of his = experience in this field. The NSF contract would pay him enough to more = than cover the $1890 tuition. The $4200 balance of my salary, factoring out Chamberlin, could be = allocated for teaching occasional courses, being on certain Phd = committees. Jay James and Mark Gealy, carrying on research to DU=92s = credit, carrying on a scientific correspondence with astronomers, and = running a NSF grant that brings in $9000 in overhead to DU in the first = of two approved installments. I hope this merits approval. For reading at the DAS banquet at NCAR Mar 22, 1986. This is the report for 1985 of your director of Chamberlin. It is read = by my wife, because I can no longer speak loud and clear. First of all = it was a good year for our venerable 20", with so many DAS people and = public night people seeing Comet Halley. The year 1985 was the best year = for productivity the field station has ever seen. We have reported 36 = precise positions of about 19 different comets. These have all been = accepted and published by now. You know that was Dr. Howe=92s field of = research productivity in with the 20" in the early 1900[s. Some of our = measures have been of exceptional interest. Our several pictures of = periodic comet Giacobini-Zinner in April and May helped Jet Propulsion = Lab prepare a course correction of the ICE satellite that allowed our = space probe to intercept that comet in September. I should say that all this work is carried out at Chamberlin=92s Field = Station near Bailey and is funded by a National Science Foundation = Grant. We were first to recover returning periodic comet Giclas, = photographed a month before any other observatory found it. We were = first in the state to capture Halley=92s Comet, on Mar 14 a year ago. We = were delighted that Sky & Telescope chose our Jan 9, 1986 picture of = Halley for its March cover, and are talking to National Geographic about = their use of it also. At this time I want to pay tribute to the skills in experimental = astronomy brought to this work by John W. Briggs. This young man = appeared on the scene last February when the contract was just starting, = and when my neurological difficulties were beginning. He quickly learned = to use my 16" telescope, mastered the complications of the comet = tracker, the hypersensitization apparatus, and the measuring engine = right away. He seldom makes a mistake, except, of course, when he = forgets to pull the slide covering the film when photographing a comet. = He has been responsible for all the photography and most of the recent = measuring. And now let me confess that I have done a sorry job of liaison between = the DAS and DU. Just when I should have been planning the public Halley = viewing, I was flat on my back in Rose Hospital, and all I could do was = to give the problem to your executive committee. I find that broken hips = or broken ribs, or even loss of balance or even thracheostomys, don=92t = help in getting into historical observatories built in 1890. Both DU and I realize the situation. As of Jan. 1 an associate = directorship has been given to Frank J. Murcray and he is asked to = undertake liason with the DAS and to be responsible for the use of the = observatory in Denver. Frank brings impressive credentials to the job. A = bright young member of the Physics faculty he holds a doctorate in = Astronomy from Harvard. I treasure the friendships and memories of certain DAS members. There is = Fran Ohmer with whom I spent many hours fixing up the drive on the 20". = There is Merrill Manion who always had good advice on DAS problems. = There is Andy Gassman, who looks like Lenin, but is such a good teacher. = I understand that the sarcophagus being chizeled for him out of the pier = of the 20" is not ready yet. Some DAS members with whom I have had = interesting projects or conversations include Bruce Cunningham, Tom and = Linda Dadisman, Jack Eastman, Charles Habenicht, Steven Innes, Kevin = McKeown, Derald Ny, Nancy Pearson, Ronald Polvadre, Henry Rael, Marsha = Rainey, Pat Rasor, Francis and Richard Rew, Allen Hobie, Kent B. Roller, = Alan Rosen, Herb Roth, Brad Schaefer, Scott Siegel, Robert Spencer, Paul = Thayer, Dave Tondreau, Jim Rayfert, Richard Clrement, and of course Bill = Vannattan and Louise Hedricks. Mar 25, =9187 TO: JOHN BRIGGS READ AT DAS BANQUET. This is THE DIRECTORS REPORT. IT IS NOT GIVEN IN = PERSON BECAUSE I CANNOT TALK OR WALK NOR TRAVEL THIS FAR AT THIS HOUR. = Our Dick Mountain field station does ASTROMETRY sponsored BY NATIONAL = SCIENCE FOUNDATION, WE ARE ON THE SECOND AND CONCLUDING YEAR OF THIS = GRANT. Already 41 new positions have been reported and we will do number = of others during the next 4 months. John Briggs has made these = measurements. These are very accurate measures. If you knew your = latitude and longitude as accurately as we report them, you would know = your position absolutely within 20 feet! I digress to show what I mean. = It is about 8000 miles equator to pole and that is 90o of longitude. = This roughly gives 100 miles/degree. Dividing by 60, we get roughly 2 = miles/minute of arc. Dividing again by 60 to get seconds of arc we find = that 200 feet of space on the surface is equal to one second of = longitude. We quote positions to tenths of seconds. There have been other publications: The February Sky & Telescope gave a = long description of our comet tracking system by stepping motors and = computer program we use. We are writing another article for them. Then = in March Astronomical Journal published a technical paper by Edgar = Everhart and Brian Marsden on "The Original and Future Orbits of = Comets." The years when I can do anything are very nearly accomplished and it is = time for me to resign as director. Let me suggest Jul 31 =9287 of this = year as the effective date when the NSF contract will be concluded. I = will stay for life as member of the DAS in which I have had many = friends. I want to wish you all a fine time at the banquet and a good year ahead.