Archive for the ‘Choosing a Telescope’ Category

Choosing a Telescope

Wednesday, June 16th, 2010

The universal telescope made perfectly for everyone that desires to see what is beyond our atmosphere does not exist, so consumers need to prepare beforehand when considering such a purchase. Instead, each type of telescope is manufactured to perform certain functions that distinguish it from other telescopes, making choosing the best telescope somewhat of a challenge for the novice user. The best telescope for the casual observer is one that will assist with obtaining the most enjoyment, while providing the best view of the objects the astronomer wishes to see. It should also conform to the buyer’s interests, needs, and wallet. There are essentially three Categories of telescopes to choose from, each with its own strengths and weaknesses.

The refractor telescope comprised of lenses that gather and bend light, has a tendency to be more on the larger side. This telescope’s bragging feature is that it is manufactured with lenses that allow the light through unobstructed, as opposed to its competition with mirrors. To elaborate, think of a piece of glass opposed to a mirror. Which one allows the light to penetrate better? This unimpeded passage of brightness creates an improved contrast for the viewer, giving the refractor telescope bragging rights in this category. Cleaning is almost unnecessary with this all-encased telescope, and problems with misalignment are almost non-existent. On the pricey side when measured up to other similar telescopes, the refractor delivers some of the clearest visions.

The reflector, hence its name, contains mirrors to gather and refract the light from the northern skies. The reflector’s bragging rights come in the measurement of the aperture, or the circumference of the lens. The higher the aperture, the more light is brought in which results in a superior image. For less money than the refractor, a reflector with a larger aperture can be purchased that provides similar or even higher quality viewing. Because the images that are observed are brighter with a larger aperture, the star gazer can see more objects with the reflector than the refractor. The reflector requires more cleaning than the refractor, but an economical buy, value is the key aspect of the reflector.

The compound telescope is a mixture of the refractor and the reflector, consisting of lenses and mirrors combined. Smaller and much more portable than the refractor and the reflector, the compound telescope is normally considered a smart investment. Although brightness is compromised with this versatile telescope, it boasts clearer images than both the refractor and the reflector. Reasonably priced per comparison, the compound telescope is wonderful for the beginner and should definitely be considered if a particular model within this class is affordable.

A wave of digital telescopes are also available for purchase and are marvelous for viewing with, but the astronomer needs to know where to direct the digital scope to “look” in order to catch a glimpse of their intended destination. For this reason, it would not be the best investment for the beginner telescope user, even though they do deliver excellent viewing.

Starting out with a more basic telescope with average features is the best bet. As desires change and the need to expand to a further part of the universe increases, the more accomplished astronomer can consider upgrading to a stronger telescope that requires more skill. In conclusion, the best telescope theory is simply a myth; whatever best fits your needs is the proper choice.

Building a Newtonian Telescope

Wednesday, June 16th, 2010

The Newtonian telescope dates back to the days of the Newton era, hence the name. Sir Isaac Newton, a British scientist, while playing around with a couple of mirrors and a scope, and eventually created the first reflector telescope in 1668. Amateur astronomers that are interested in building their own telescope normally favor the Newtonian telescope to reproduce because of its simplicity and ease of use.

Refractors and reflectors are the two prominent telescopes used by star gazers today, and these categorizations are derived from the type of light collecting tool the telescope contains. The refractor telescope utilizes several lenses to collect the light into the telescope, while the reflector instead uses mirrors.  When building a telescope at home, the Newtonian telescope is often chosen because of the simplicity of the build. While people think that building a telescope that actually works like an expensive is complicated, it is a fairly straightforward project that can be completed without too much headache once all of the materials are gathered.  The essential steps are below.

1)      Purchase a mirror with the diameter of about 6” to 8” for the objective.

2)      Create an octagonal tube constructed with slender plywood to ensure the telescope is lightweight. Glue eight boards, cut at 1/8” identically, around nine 1/8 octagonal formers each containing a 7¼” diameter cutout.

3)      Pin together all the baffles and the ½” plywood back plate, then cut and sand them into shape. This will guarantee that they are all equal in size.

4)      Cut eight 3 1/3” by 48” boards into 22 ½ degree bevels on the edges. Mark the bevels with the positions of the baffles. Using woodworking glue, glue the bevels to the marked positions.  It is important to check that they are all square and vertical.

5)      Start gluing the boards on carefully to avoid twisting. Glue one on one side, then glue a board to the other side, working around the tube alternating sides. Leave the final board off until the inside is painted and the project is ready to be finished. Give a second coating with PVA glue to strengthen to the joints, then let dry overnight.

6)      Mark the spot where the mirror will reside inside the tube, and drill four holes to accommodate the ½” plywood cell plate.

7)       Apply a coat of blackboard paint to the inside of the tube, and be sure to paint the last board that was left off. While the paint is still wet, throw some sawdust into the tube, coating the entire inside. Shake the excess dust out, and apply a second coat of paint to seal the sawdust in. Let this dry.  Once dry, use a vacuum to clean up any stray sawdust.

8)       Attach the final board to the telescope.

9)      Coat the outside of the tube with sanding sealer, rub it down, and then finish off with a couple coats of glossy white paint.

The finished do-it-yourself at home Newtonian telescope will not only be fabulous looking, it will provide countless hours of viewing pleasure fueled by self accomplishment.  It also allows the user a unique insight on the inner workings of a telescope and this knowledge will definitely help when choosing more powerful models in the future. In addition, a home built telescope is far less expensive than one purchased at the store and if built properly will deliver nearly identical or even clearer images of the solar system for the exploring astronomer.

Build a Dobsonian Telescope

Wednesday, June 16th, 2010

Building a do-it-yourself telescope is an eventful project and for the astronomer it can bring hours of enjoyment once completed.  Creating the telescope can be complicated or simple, depending on how in-depth you wish to make the project. The most common do-it-yourself telescopes are refractors made by Boy Scouts or in school in physics class, but this project can be as big as your imagination allows.  Building a Dobsonian telescope can save you up to half off of retail value, but depending on the size desired this project can take up days or even weeks to complete.

Materials and Tools Needed

Mirrors manufactured exclusively for telescopes can be purchased new or used; and can also be obtained through a telescope company’s website if a local dealer is not available.  While there, also pick out a chrome-plated eyepiece that suits your taste.  A tube, preferably made from cardboard and obtainable from construction companies, is also necessary and it should match the mirror size in order for the project come out correctly.  You will also need some exterior grade plywood, paint, PVC coupling, a wooden dowel, a mailing tube, leather scrap (a belt also works), Masonite, Teflon, glue, scrap cardboard, and a variety of screws, nuts, tacks, and bolts.    

The required tools are a hammer, a saw, a drill, a tape measure, a compass, screwdrivers, a nail set, a crescent wrench, an awl, a hole-cutter, and a carpenter’s framing square.

The Construction Process

1)      Start off building the telescope by scouring the tube down and painting it. Acrylic garage floor paint will adhere to the tube and provide some water resistance for those that enjoy star gazing outside.

2)      Construct a tube box, or Rocker box, with the plywood, ensuring the box is perfectly square. Attach the main bearing to the bottom of the Rocker Box using countersunk screws.

3)      Create three flawlessly round circles out of wood, cutting the core out of two. Attach the three circles together with glue and clamp them. This will serve as the base of the telescope.

4)      Spray paint the interior of the tube intended for use as the scope. Create a spider out of thin wood slats and a dowel. Glue the mirror right onto the spider with RVC.

5)      Create a cell using wood and steel fittings.

6)      Fit the mirror into the cell and secure with six metal brackets to ensure stability.

7)      Situate the Rocker Box in position where the telescope is going to reside, and carefully attach the tube to the Rocker Box. 

8)      Make the necessary adjustments to the alignment. 

Alignment may need to be done several times in order to get the best results after the telescope is assembled, but once honed in your do-it-yourself one can perform just as nicely, if not better than store bought models.  Once the telescope is functioning properly, the builder can pat themselves on the back, enjoy the stars, moon, and planets and bathe in a distinct feeling of self-accomplishment.

Beginner Telescope

Wednesday, June 16th, 2010

Gazing at the darkened sky, speckled with stars and moons and planets through a telescope opens up the imagination for skilled astronomers. For a person that has never used a telescope before it may sound difficult to do. For the beginner, maneuvering an instrument may seem tricky and the technology might appear intimidating because of the complexity of the tasks involved. On the contrary, there are telescopes made simple enough for even the beginner astronomer with simple adjustments yet very solid functionality.

There are a myriad of different telescopes available on the market for novice stargazers; they fall under the classifications of refractors, reflectors, and compound telescopes. Coming to a decision as to which telescope is right for the aspiring astronomer will depend on their overall viewing expectations.  Although price is always a factor to some degree while seeking the perfect beginner’s telescope, other options to consider like size and portability will also directly affect the amount of enjoyment obtainable from the model.

The price of anything nowadays is usually a deciding factor in any purchasing situation because of the current economy. Telescopes can range from the inexpensive children’s type telescope that provides only basic views of the sky to the mammoth telescope NASA uses to view distant galaxies in perfect detail, named the Hubble Space telescope. Purchasing a telescope from either end of the price spectrum can ultimately leave the consumer frustrated or disappointed if their skill level does not match the complexities of the product. The more expensive telescopes have a tendency to be more complicated and manufactured for use by the accomplished astronomer, leaving the beginner perplexed due to the advanced options. The expected price of a telescope to start exploring the stars with ranges from $200 to $600; however, used models can often be found at a fraction of that price.

Due to the fact that telescope manufacturers promote their telescopes on the market according to the magnification, people assume that magnification is the most important factor. This cannot be further from the truth. The size of the objective, or the lens, is the primary factor in producing the clearest images. The power of the objective mixed with the focus of the magnification produces the image to the eye. Most skilled astronomers normally work with low magnification to view their favorite spots in the sky because the image actually appears clearer than at a high magnification. For the beginning astronomer, in fact, a magnification between 30x and 50x and an objective between four and six inches is more than enough viewing power.

If the telescope will be used specifically for indoor viewing and moving the telescope to different places is not an option, portability should not be a factor. Refractor telescopes are larger size telescopes, characterized by their use of lenses for an objective. For the astronomer wishing to create the perfect experience by relocating the telescope outside, size and portability will definitely need to be taken into consideration before the model is purchased. Reflector telescopes, characterized by the use of mirrors instead of lenses, are a smaller, more portable version of the telescope and they normally work better for the aspiring stargazer who wishes to view the sky from multiple locations.

The beginner will also want to stay away from the computerized telescopes until they acquire a grasp of the sky and its expansive map. These telescopes require the user to input where objects are in the sky in order to function, and the novice astronomer will not have readily memorized this information. As a beginner, it will be more important to learn the map of the sky with the telescope, instead of learning the telescope and the map separately.