Frosty Drew Observatory: Our Equipment
The Frosty Drew Observatory has numerous telescopes and accessories for viewing the skies above thanks to generous supporters, members, and grants. Below we explain some of our more popular telescopes and accessories that you are sure to see on our publicly open nights. At the center of our astronomical operations is our Ash dome, an 18 foot enclosure that houses our main telescope and serves as our central hub on nights open to the public. The dome was erected in 1986 after the site was realized for its fantastically dark skies. Since its opening in 1986 Frosty Drew Observatory has been a local icon for astronomical observation.
- Meade LX200 16"
Our center piece is a Meade Schmidt Cassegrain LX200 16" (4064 millimeters) telescope yoke mounted on an alt-azimuth pier. It was installed in July of 1999. You can keep up with its accomplishments in the Meade LX200 Life List. The words Schmidt and Cassegrain are the names of telescope designers who created this basic type of telescope. A Cassegrain telescope has a hole in the mirror at the back end of the telescope. This allows the eyepiece to remain at a convenient level and easy to reach. A Schmidt telescope uses a thin glass plate at the front of the telescope to correct various optical distortions (aberrations). The combination of these two designs allows a long focal length to be folded into a relatively shorted tube. A 16 inch Newtonian telescope (straight through design) with an f10 focal ratio would be over 13 feet long. This would be extremely awkward to use in a dome with a 9 foot radius. The Schmidt Cassegrain design folds this into a barrel about 3 feet long. Our telescope is about 7 feet long because of dew shields and attachments.
Our old telescope cluster had a clock drive which could keep pace with the stars, but for near Earth objects (the Moon, artificial satellites, a few asteroids and comets) their high relative speed made tracking them a matter of continual hand adjustments. Our Meade LX200 telescope can keep pace with almost every object in the sky except objects moving faster than 4 degrees per second (meteors and rocket launches). It has three independent rotations, around the horizon, up and down, and even turning instruments and eyepieces to keep the same view. All of this is controlled by an embedded computer coordinated with an external computer for locating objects.
- Questar 3.5
Mrs. Camilla Lee of Narragansett donated her step father Ryder Henry's 40 year old Questar telescope. The telescope has been repeatedly sent to the factory in New Hope Pennsylvania for cleaning and improvements. This 40 year old telescope has many of the features of a much newer instrument. The optics of early Questars were unmatched in their day and still compare very positively with the best modern optics.
- The Art Guarino Telescope - 10" Dobsonian
- Art Guarino, one of Frosty Drew previous Directors of Astronomy had donated his 10 inch Dobsonian with fine Park Optics. Art had manufactured this telescope himself using basic materials that are easy to come by and inexpensive to acquire. It is frequently in use outside the Observatory and offers alternative views of celestial objects. On a mild summer evening you may find Art sitting next to his telescope answering questions about its construction.
- 8" Orion Dobsonian
- Brown University in Providence had donated to Frosty Drew this old 8 inch Orion Dobsonian telescope. This telescope has fantastic optics considering its age and lack of modern accessories. Visual observation in this telescope rivals the performance of The Art Guarino Telescope. This telescope can be frequently found setup outside the Observatory on Friday nights offering vies of Deep Sky Objects, Comets and other dimmer objects.
If the computer only controlled the speeds so well it would be impressive but it does lots more. It knows the position of about 64 thousand deep space objects including all the planets. It determines the position of the telescope on the Earth to an extremely precise angle. It keeps track of the time, and controls all the attachments of which we have many. With a little help from the standard PC attached by a communications line, it can extend the number of deep space objects to over 19 million including newly discovered objects (comets, novae and new artificial satellites). Not bad for a computer that manages to tuck itself away in the base of the telescope's mount.
We can connect a CCD imaging system (the modern replacement for photography) to the PC. With the CCD the telescope can form detailed images on the PC's screen. This CCD is equipped with a filtering system that allows us to make color images as well as black and white.
- We have a fine selection of top quality eyepieces and their accessories. Augmenting the eyepieces are diagonals (both 45 and 90 degrees), tele-extenders, Barlow lenses (eyepiece magnifiers), a framing reticule (like cross hairs), and colors and special purpose filters of all kinds. We have flip mirror attachments to allow us to flip between the CCD and the eyepieces. We even have an electric focusing mechanism that allows us to individually adjust the eyepiece for each person using the telescope.
We haven't totally forgotten traditional photography. For managing photography or CCD imaging we have an off axis guidance system. We have a camera piggyback adapter, a guide telescope, T-adapters and ring adapters for our Nikon camera. To keep the telescope in good balance with all of these various weight attachments we have a self contained counterweight system.
Special software controls all these functions. Some of it allows us to direct the telescope to anything in the sky, even new found objects like supernova and first time comets. The rest of the software manages the CCD imaging device. We are able to show real time images of what the telescope is seeing. This software allows us to enhance images and to convert light seen through filters to color pictures.
About the only function we do not have is the ability to view the Sun. There are solar filters and hydrogen Alpha line filtering for Meade telescopes, but these tools are best left to qualified adults. In line with our goal to provide family oriented viewing, we have chosen to avoid solar viewing considering the very small potential risk to children.