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 176 of 195 
Orion Telescopes

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Intermediate
Orion StarBlast 4.5 Imaging Reflector Telescope Optical Tube
$149.99
 
Accepted Payment
In Stock
  • An astonishingly affordable astrophotography-optimized reflector telescope
  • Substantial 4.5" aperture primary mirror and very fast f/4 focal ratio produces stunning astrophotos with short exposure times.
  • Fully illuminates small-chip CCD astrophotography cameras
  • Compact, lightweight, easily transportable, and works well with 1.25" telescope eyepieces for observing
  • Offered as an optical tube assembly only, tube rings and other accessories sold separately


Learn more
Item #  09974

If you're looking for an exceptional telescope for astrophotography that won't cost you big bucks, then check out this affordable alternative. We've optimized the optics of our popular short-focal-length Orion StarBlast 4.5 Imaging Reflector Optical Tube to give a fully illuminated field of view with the Orion StarShoot Deep-Space Imager and similar small-chip astronomical charge coupled device (CCD) cameras. The result is a compact imaging telescope with a price that will please the budget-conscious astrophotographer — beginner or expert — and with the performance that will give pricey refractors a run for their money.

With its big 4.5" parabolic mirror and fast f/4 focal ratio, the Orion StarBlast 4.5 Imaging Reflector Optical Tube provides exquisite, high-quality images and it's simply the most affordable astrophotography-optimized telescope in the market. Unlike refractors, the Orion StarBlast introduces no chromatic aberration with negligible coma. The fast focal ratio also minimizes exposure time and guiding errors.

To achieve 100% illumination with the StarShoot Deep Space Imaging Camera, we slightly widened the secondary mirror and extended the focal point further out in the focuser. The short focal length provides a wide field of view for imaging with small-chip charage coupled device (CCD) cameras. While the telescope works with standard 1.25" eyepieces (Sirius Plossl recommended) some wide-field telescope eyepieces may require the use of an extension tube to reach focus.

At only 3.7 lbs, the StarBlast 4.5 doesn't require a heavy mount and it transports easily to your favorite site. The 1.25" focuser accepts 1.25" telescope eyepieces for visual use as well.

The Orion StarBlast 4.5 Imaging Reflector Optical Tube is offered as tube assembly only, with no accessories.

Warranty

Limited Warranty against defects in materials or workmanship for one year from date of purchase. This warranty is for the benefit of the original retail purchaser only. For complete warranty details contact us at 800-676-1343.

Warning

Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.

Product Support
Visit our product support section for instruction manuals and more
  • Best for viewing
    Brighter deep sky
  • Best for imaging
    Deep sky
  • User level
    Intermediate
  • Optical design
    Reflector
  • Optical diameter
    114mm
  • Focal length
    450mm
  • Focal ratio
    f/4.0
  • Optics type
    Parabolic
  • Glass material
    Soda-lime plate
  • Eyepieces
    None
  • Resolving power
    1.02arc*sec
  • Lowest useful magnification
    16x
  • Highest useful magnification
    228x
  • Highest theoretical magnification
    228x
  • Limiting stellar magnitude
    12.9
  • Optical quality
    Diffraction limited
  • Finder scope
    None
  • Focuser
    1.25" Rack-and-pinion
  • Secondary mirror obstruction
    47mm
  • Secondary mirror obstruction by diameter
    41%
  • Secondary mirror obstruction by area
    17%
  • Mirror coatings/over-coatings
    Aluminum & Silicon Dioxide
  • Mount type
    Optical Tube without Mount
  • Astro-imaging capability
    Lunar, planetary & long exposure
  • Tube material
    Steel
  • Length of optical tube
    18.0 in.
  • Weight, optical tube
    3.7 lbs.
  • Other features
    Secondary mirror w/47mm minor axis
  • Warranty
    One year
Orion Reflector optical tube assembly
Dust cap
Starry Night special edition software

Orders received by noon Pacific Time for in-stock items ship the same business day. Orders received after noon will ship the next business day. When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available. You have the option in check out to request that your order ship complete, if you'd prefer.

How can I check the collimation of my reflector?
Collimation is the process of adjusting the telescope's mirrors so they are perfectly aligned with one another. Your telescope’s optics were aligned at the factory, and should not need much adjustment unless the telescope is handled roughly. Mirror alignment is important to ensure the peak performance of your telescope, so it should be checked regularly. Collimation is relatively easy to do and can be done in daylight. To check collimation, remove the eyepiece and look down the focuser drawtube. You should see the secondary mirror centered in the drawtube, as well as the reflection of the primary mirror centered in the secondary mirror, and the reflection of the secondary mirror (and your eye) centered in the reflection of the primary mirror. If anything is off-center, proceed with the collimation procedure. The faster the f/ratio of your telescope, the more critical the collimation accuracy.

How do I align the secondary mirror with the collimation cap?

With the collimation cap in place, look through the hole in the cap at the secondary mirror. Ignore the reflections for the time being. The secondary mirror itself should be centered in the focuser drawtube, in the direction parallel to the length of the telescope. If it isn’t, it must be adjusted. Typically, this adjustment will rarely, if ever, need to be done. It helps to adjust the secondary mirror in a brightly lit room with the telescope pointed towards a bright surface, such as white paper or wall. Also placing a piece of white paper in the telescope tube opposite the focuser (in other words, on the other side of the secondary mirror) will also be helpful in collimating the secondary mirror. Using a 2mm Allen wrench, loosen the three small alignment set screws in the center hub of the 4-vaned spider several turns. Now hold the mirror holder stationary (be careful not to touch the surface of the mirror), while turning the center screw with a Phillips head screwdriver. Turning the screw clockwise will move the secondary mirror toward the front opening of the optical tube, while turning the screw counter-clockwise will move the secondary mirror toward the primary mirror. Note: When making these adjustments, be careful not to stress the telescope's spider vanes or they may bend. When the secondary mirror is centered in the focuser draw-tube, rotate the secondary mirror holder until the reflection of the primary mirror is as centered in the secondary mirror as possible. It may not be perfectly centered, but that is OK. Now tighten the three small alignment screws equally to secure the secondary mirror in that position. If the entire primary mirror reflection is not visible in the secondary mirror, you will need to adjust the tilt of the secondary mirror. This is done by alternately loosening one of the three alignment set screws while tightening the other two. The goal is to center the primary mirror reflection in the secondary mirror. Don’t worry that the reflection of the secondary mirror (the smallest circle, with the collimation cap “dot” in the center) is off-center. You will fix that when aligning the primary mirror. Alternative: Some people prefer to remove the primary mirror completely from the telescope when aligning the secondary mirror, especially if the primary mirror needs to be removed anyway to be center-marked. It may help to have no reflections and align the secondary on the edge of the telescope wall.

How do I align the primary mirror with the collimation cap and center-marked mirror?

The telescope’s primary mirror will need adjustment if the secondary mirror is centered under the focuser and the reflection of the primary mirror is centered in the secondary mirror, but the small reflection of the secondary mirror (with the “dot” of the collimation cap) is off-center. The tilt of the primary mirror is adjusted with the larger collimation screws on the back end of the telescope's optical tube. The other smaller screws lock the mirror’s position in place; these thumbscrews must be loosened before any collimation adjustments can be made to the primary mirror. To start, loosen the smaller thumbscrews that lock the primary mirror in place a few turns each. Use a screwdriver in the slots, if necessary. Now, try tightening or loosening one of the larger collimation screws with your fingers Look into the focuser and see if the secondary mirror reflection has moved closer to the center of the primary. You can tell this easily with the collimation cap and mirror center mark by simply watching to see if the “dot” of the collimation cap is moving closer or further away from the “ring” on the center of the primary mirror mark. When you have the dot centered as much as is possible in the ring, your primary mirror is collimated. Re-tighten the locking thumbscrews. Alternative: If you loosen one or more of the bolts too much, it won’t move the mirror. Some people prefer to pre-load the collimation screws by tightening them all down and adjust by loosening each one in turn. This way you don’t run-out of threads and have a loose collimation screw. The disadvantage to this approach is that you have completely un-collimated the scope and are starting from the beginning.

Can I center the secondary mirror under the focuser with the aid of the Orion LaserMate?

You can, but it requires marking the center of the telescope’s secondary mirror in the same way the center of the telescope's primary mirror was marked. This is generally undesirable due to the large area of the supplied collimation targets compared to the total area of the secondary mirror. Since centering the secondary mirror under the focuser is an adjustment that very rarely, if ever, needs to be done, we recommend simply making this adjustment by eye. We’ve tried it both ways and it is just as easy to do it without the Orion LaserMate.

How do I use the Orion Collimation Cap and the mirror center mark?
The Orion collimation cap is a simple cap that fits on the focuser drawtube like a dust cap, but has a hole in the center and a silver bottom. This helps center your eye so that collimation is easy to perform. Orion telescopes that have a collimation cap included also have a primary mirror that is marked with a circle at its exact center. This “center mark” allows you to achieve a precise collimation of the primary mirror; you don’t have to guess where the center of the mirror is. You simply adjust the mirror position until the reflection of the hole in the collimation cap is centered in the ring. The center mark is also required for best results when using other collimating devices, such as Orion’s LaserMate Collimator, obviating the need to remove the primary mirror and mark it yourself. Note: The center ring sticker need not ever be removed from the primary mirror. Because it lies directly in the shadow of the secondary mirror, its presence in no way adversely affects the optical performance of the telescope or the image quality. That might seem counterintuitive, but its true!

Is the LaserMate Collimator dangerous?

The LaserMate emits laser radiation, so it is important not to shine the beam into your or anyone’s eye. During the collimation procedure, it is also important to avoid direct reflections of the laser beam into your eye. Rather, look only at off-axis reflections to determine the position of the laser spot on the mirrors. It is safe to view the laser when it is reflected off a surface that will diffuse the light, such as the bottom surface of the LaserMate. It is also safe to view the reflection off a mirror surface as long as the beam is not directed into your eye. Because of the potential danger from the laser beam, store your LaserMate out of the reach of children.

Does the atmosphere play a role in how good the quality of the image will be?
Atmospheric conditions play a huge part in quality of viewing. In conditions of good “seeing”, star twinkling is minimal and objects appear steady in the eyepiece. Seeing is best over-head, worst at the horizon. Also, seeing generally gets better after midnight, when much of the heat absorbed by the Earth during the day has radiated off into space. Typically, seeing conditions will be better at sites that have an altitude over about 3000 feet. Altitude helps because it decreases the amount of distortion causing atmosphere you are looking through. A good way to judge if the seeing is good or not is to look at bright stars about 40 degrees above the horizon. If the stars appear to “twinkle”, the atmosphere is significantly distorting the incoming light, and views at high magnifications will not appear sharp. If the stars appear steady and do not twinkle, seeing conditions are probably good and higher magnifications will be possible. Also, seeing conditions are typically poor during the day. This is because the heat from the Sun warms the air and causes turbulence. Good “transparency” is especially important for observing faint objects. It simply means the air is free of moisture, smoke, and dust. These tend to scatter light, which reduces an object’s brightness. One good way to tell if conditions are good is by how many stars you can see with your naked eye. If you cannot see stars of magnitude 3.5 or dimmer then conditions are poor. Magnitude is a measure of how bright a star is, the brighter a star is, the lower its magnitude will be. A good star to remember for this is Megrez (mag. 3.4), which is the star in the “Big Dipper” connecting the handle to the “dipper”. If you cannot see Megrez, then you have fog, haze, clouds, smog, light pollution or other conditions that are hindering your viewing. Another hint: Good seeing can vary minute to minute. Watch the planets for a while to pick-up those moments of good seeing.

How do I clean any of the optical lenses?
Any quality optical lens cleaning tissue and optical lens cleaning fluid specifically designed for multi-coated optics can be used to clean the exposed lenses of your eyepieces or finder scope. Never use regular glass cleaner or cleaning fluid designed for eyeglasses. Before cleaning with fluid and tissue, blow any loose particles off the lens with a blower bulb or compressed air. Then apply some cleaning fluid to a tissue, never directly on the optics. Wipe the lens gently in a circular motion, then remove any excess fluid with a fresh lens tissue. Oily finger-prints and smudges may be removed using this method. Use caution; rubbing too hard may scratch the lens. On larger lenses, clean only a small area at a time, using a fresh lens tissue on each area. Never reuse tissues.

Does my telescope require time to cool down?

As a general rule, telescopes should be allowed to cool down (or warm up) before they are used. If you bring optics from a warm air to cold air (or vice versa) without giving it time to reach thermal equilibrium, your telescope will give you distorted views. Allow your telescope 30 minutes to an hour to reach the temperature of the outdoors before using. When brining your telescope from cool temperatures to warm temperatures, leave any protective caps off until the telescope has warmed-up to prevent condensation. Storing your telescope in the garage or shed where the temperature is closer to the outside temperature will reduce cool down times.

How do I take solar astrophotos?

By attaching a camera body to a telescope, in effect using the scope as a telephoto lens, you can take striking photographs of the Sun. Only attempt this if the telescope is equipped with the proper solar filter. Solar filters are coated to a neutral density of 5, which reduces the light about 100,000 times. Depending on the aperture and focal length of your telescope and “seeing” conditions, you will need to experiment to find the best exposure time for your equipment. We recommend starting with an ISO rating of around 400. At prime focus, start with an exposure of about 1/250 second. Experiment with different shutter speeds. When using higher magnifications, longer exposures will generally be necessary. If you are a beginner in astrophotography and need further information, there are books available that cover this subject completely. Do not be discouraged if your first attempts at solar photography are less than desired. The Sun is very difficult to photograph because of poorer “seeing” conditions caused by unavoidable heat currents associated with daytime viewing. The highest possible resolution for any land-based telescope, regardless of location, is about 1 arc second. Ideal seeing for any location will be available less than 5% of the time. It may be some consolation to consider that your results could equal those at professional observatories, as larger apertures and location have little, if any, advantage. During bad seeing conditions, it may help to “stop down” apertures over 5" with an off-axis mask.

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