Beverly Hills Observatory

Astronomy from Beverly Hills, MD 21214!

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Building the North Dome

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Building the First Dome

 

The first building was designed and built during the summer of 2006. It is an octagonal building roughly eight feet across made largely of plywood with a dome whose shape was inspired by the WYNN observatory on Kitt Peak in Arizona. The key advantage to the dome’s design is that it is all made from flat surfaces. Essentially there are five squares and four equilateral triangles in the design, mounted on an octagonal upper section that has wheels mounted to it’s bottom side allowing the dome to rotate. The top and side piece were replaced by hinged (top) and removable (side) door panels that allow an almost 40-inch wide “slot” for the telescope to look through.

Dome #1

Here’s an early shot of dome #1 nearing completion in July of 2006.

The telescope in dome #1 (which I refer to as “Rig #1”) is the better of the two otherwise identical appearing telescopes in every way. The differences are not large, but discernible. An SBIG ST8xme camera with a grade-1 chip (1530×1020 9-micron pixels) has been used with this ‘scope since September of 2007. The vast majority of data acquired have been images, mostly through a “clear” filter. The camera is equipped with an automated five-position filter wheel containing standard B,V,R, and I filters. However, since the bulk of what I observe are fairly faint cataclysmic variable stars I make the trade-off of being able to go a magnitude or so fainter at the expense of not being able to reduce the magnitudes to a standard system. For the most part these data are used for timing of periodic phenomenon in these systems, a goal whose requirements can often be served without precise color information. On the best nights here I can often achieve 1% photometry of objects as faint as 15.5 magnitude using 60-second exposures.

This camera can also be attached to an SBIG Self Guiding Spectrograph (SGS). Using the stock 600 line/mm grating the instrument is capable of a spectral resolution of around 2 Angstroms, and can acquire decent signal-to-noise over about 800 Angstroms in a single image. The little bit of work done using the SGS has been to observe a few long-period pulsating variables (Mira-type) in the 0.5 to 0.7 micron range. For the most part I am still assessing the capabilities of the instrument and, frankly, searching for projects which might benefit from those capabilities. By combining sets of three or more 30-minute exposures I’ve achieved 20-to1 signal-to-noise for red stars as faint as 12th magnitude. I tend to concentrate on the red part of the spectrum due to the camera’s higher quantum efficiency in the red and because my primary wavelength calibration source, a Neon gas tube, has most of it’s lines in the red. I also have a Mercury tube for the occasional foray into the bluer regions, at the expense of less precisely calibrated wavelengths and much reduced sensitivity.

What I refer to as “Rig #1”, the Celestron 14-inch f/11 telescope in the first dome.

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The StarFarm Observatory

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For whatever reason (including lack of creativity) every time I build a new observatory I call it The StarFarm.  It goes way back to when I used to publish my own little “zine” called “The StarFarmer’s Almanac”.  I guess it’s fitting that in these more technologically enlightened times that I instead direct my literary efforts towards a blog.  I’m sure just as many people will read this as ever read “The StarFarmer’s Almanac” (as many as a few).

The StarFarm Throughout the Years

12.5 inch scope at Bill Nigg's Place

In 1977 The StarFarm was an open field in southwestern Michigan where I would set up my 12.5-inch newtonian.

Throughout the years the StarFarm has experienced several incarnations.  The first was an open field where I would set up my 12.5-inch newtonian telescope.  The field was property owned by a friend’s parents.   There was a small barn where I stored the telescope and would drag it out to the field when I wanted to use it.  It was located about 20 miles SW of Kalamazoo, Michigan under some really nice and dark skies.  The only problem was that I did not own a car at the time and so had to ride my bike about 15 miles each way or try to induce another member of the local astronomy club (the Kalamazoo Astronomical Society) to drive out there with me for an evening of deep sky observing.

This was Blaine Roelke’s observatory building west of Taneytown, MD, the day we moved the newly-completed 17.5-inch reflector into the dome.

The second StarFarm was near Taneytown, Maryland.  The building, topped with an 8-foot AshDome, was owned by Blaine Roelke and was  located on his property just a few miles from the first large foothills of the Appalachian Mountains.  The skies were pretty dark out there, but it was a 45 mile drive in each direction.   Many were the nights that I’d drive all the way out there only to be clouded out.  Still, it was the first telescope that I actually used for stellar photometry, mostly using an Optec SSP-3 solid-state photometer.  The telescope was a fork-mounted 17.5-inch Newtonian that I’d built using an optics set from a Coulter Oddesy telescope given to me by Joe Patterson.  Joe and I had met while I was a graduate student and he a post-doc in the Astronomy Department at the University of Michigan.   For the most part I observed eclipsing binary stars, to determine their time of mid-eclipse.  The skies were so nice; I actually spent most of the time just observing faint fuzzy objects.

This was The StarFarm as completed, just west of Reisterstown, MD. A 12-foot dome made of Masonite and plywood. It leaked.

The next StarFarm was a 12-foot domed observatory of my own design that was built on property owned by Dave Pesagno, this time just a few miles west of Reisterstown, Maryland, some 20 miles NW of Baltimore.   Blaine had found it necessary to sell his farm in Taneytown in order to take a new job in Virgina, so I needed a new location.  I built the dome in sections in my basement throughout the winter of 1987, finally assembling all the pieces in my back yard in June of 1988.  The lower section of the building was built in late July of ’88 and then the dome sections trucked from my house to Reisterstown in August.  First light occurred in late August of 1988, celebrated by a large star party that included a number of local amateurs as well as bunches of co-workers from the Space Telescoep Science Institute, many of whom had helped me with the observatory’s construction.

This is the 17.5-inch telescope used in both the Taneytown and Reisterstown StarFarms. Mounted on a huge equatorial fork, 2-inch steel axels for declination and 3-inch right-ascension axel. The axels were welded to steel plates then bolted to the 3/4-inch plywood.

The skies at the new location were definitely not as dark as Tayneytown, but the fact that the observatory was now located less than half the distance from me than it had been previously meant I used it a lot more frequently, at lest for a few years.  I built a sturdy holder that helped secure the SSP-3 photometer to the side of the telescope, and found a used IBM-PC with a roomy 10-megabyte drive to automatically log and reduce the data.  It was a huge step up from what I was doing before, which basically amounted to reading the photometer’s digital display into a tape recorder with WWV time signals blasting away in the background as a time standard.  All-in-all this setup worked pretty well and I managed to do a reasonable amout of photometry, mostly of eclipsing binaries, but also of short-period red variables  in the AAVSO’s observing program.   By late 1991, however, for a number of reasons, my interest in the observatory began to wane.  By 1994 I had removed the telescope and eventually discarded all but the primary mirror and diagonal.

It was late in 2005 that I began to consider putting a telescope at home, right where I lived, instead of having to drive somewhere to use it.  By then the 17.5-inch was in pieces stored in a warehouse in SW Baltimore.  I had, in 2000, purchased the house that I now live in, just four miles from the center of downtown Baltimore.   So it seemed that a fast focal ratio reflector was less than optimal.  Besides, I wanted to use a CCD camera on something with a decent clock-drive; some setup that could all be run by computer.   It all pointed towards something along the lines of either a Meade or Celestron SCT (Schmidt Cassegrain Telescope).  In early 2006 I purchased the first of the two Celestron 14-inch telescopes that now comprise the backbone of the current StarFarm

The StarFarm Today

SF

A view of Beverly Hills Observatory from 2012

The StarFarm as currently configured (January 2013) is two domed observatories in my back yard, each equipped with identical 14-inch Celestron telescopes on CGE computer controlled go-to mountings.  The first (referred to as C14#1 or “Rig 1”) is housed in a building of my own design and construction, essentially an 8-foot octagonal building with a rotating dome constructed from various sized rectangles and triangles of plywood.  C14#2 is housed in a Technical Innovators 10-foot ProDome.  Rig #1 has an SBIG ST8xme camera attached to it, along with a set of Custom Scientific BVRI and clear filters installed in an automated filter wheel.  Rig #1 can also be used with an SBIG SGS spectrograph for low and medium-resolution spectroscopy (R=600 and R=2400, respectively).  Rig #2 features an SBIG ST9xe camera, again fitted with an automated filter wheel loaded with Custom Scientific BVRI and clear filters.  The telescopes are run remotely from my study using Remote Desktop, though I do have to visit them every 45 minutes or so in order to turn the domes and to focus; new automated and temperature-compensating focusers are on the short list for new purchases!

The vast majority of the observing time is dedicated to monitoring cataclysmic variables, largely at the behest of Joe Patterson at Columbia University, who donated the optics for the 17.5-inch (see above).  When the cataclysmics are all being quiet I’ll sometimes monitor a few eclipsing binaries to determine times of minimum, usually for the AAVSO (American Association of Variable Star Observers).

Each telescope has it’s own laptop computer.  MaxIm DL is used for camera control and data acquisition.   TheSky 6 is used for pointing the telescope and acquiring targets.  Image calibration is done in Mira UE7 and Mira ProScript; reductions of photometric data are handled by Mira and by IDL 8.01.  Spectroscopic data are calibrated and reduced using IRAF.  I’ve augmented all the above with a number of programs written in IDL, lua, and VBScript.

Having an observatory outside my back door has completely revolutionized how and what I observe.  The night skies here are never dark.  On the best of nights the sky is a deep blue color; on bad nights the sky is orange.  But because the telescopes are so close I use them almost every clear night.  My observing logs show that since the first observatory was completed (Rig #1) in August of 2006, I’ve observed 90-100 nights a year.  Now that there are two complete observatories the task of calibrating and reducing all the data has become the main bottleneck!

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Asteroid 2005 YU55 from Baltimore

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So the earth was “buzzed” by asteroid 2005 YU55 the other night.  A roughly 1000-foot long bit of cosmic debris passing within the moon’s orbit at a distance of 202,000 miles.   At the time that I was trying to catch the object it’s motion against the background stars was almost 500 arcseconds a minute, moving towards the east-northeast.  Since the apparent east-towards-west motion of the stars across the sky due to the earth’s almost 24-hour rotation period (called diurnal motion) is about 897.5 arcseconds per minute, that meant that as far as tracking the asteroid was concerned it would appear to be moving from east to west at somewhat less than half the speed of diurnal motion.  Well, the CGE mounts I use for the telescopes are not able to track something like that.  So that meant I had to set the telescope at a location a few minutes ahead of the asteroid and wait for it to enter the field of view.  Since the telescope would be driven at a speed necessary to keep the star field steady (compensate for the diurnal motion) that meant the object would enter the field of view from the west and track towards the east through the field of view.

My initial attempts to locate 2005 YU55 were failures.  I’d forgotten that the positions I’d downloaded were geocentric positions; that is, where the object would appear against the background sky as seen by an imaginary viewer located at the earth’s center.  In almost any other instance that would get me close enough to assure the object was in the camera’s 8.5-arcminute field of view.  Not this time!  Because the object was so close the location of the observer on the earth’s surface is an important consideration.  In this case the difference in apparent position of 2005 YU55 as seen by an observer on the earth’s surface (the topocentric coordinates) could be different from the geocentric coordinates by a degree or more.  Doh!  So I quickly converted a few of the coordinates to topocentric coordinates (thank you again Jean Meeus!) and viola!

 

A 5-second exposure taken at about 9:11pm on November 8th (that is, 2:11UT November 9th). The field of view is 8.5 arcminutes or about 1/7 of a degree on a side. Taken with C14 rig #2, using a SBIG ST9xe camers.