Suggested for: visual and light duty imaging by amateur astronomer, beginning to intermediate who also wish to have the choice of Go To or not over time. Payloads include 80 to compact 130 mm refracting telescopes by Astro-Physics and TeleVue, moderate weight Newtonian telescopes including the 8 inch f/6 made by Orion, Catadioptrics such as as the Orion 150mm Maksutov, the Questar 7 Astro, Meade, up to the Celestron C-9.25; these are all offered by Company Seven. Can be a good alternate, a relatively lightweight mounting for an advanced amateur who is looking to outfit another more convenient telescope.
German Equatorial Mount and Tripod
Right: Click image if you wish to take a 360 degree tour of the Sirius 8 telescope which includes the Sirius mount.
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Overview: The Sirius provides a very good balance of payload capacity, portability, convenience features, and price. This German Equatorial Mount is rewarding to use, and is easily transportable by most teens and adults. When mated to a suitable telescope, the German Equatorial Mount provides:
With an optional Clock Drive and either a Piggyback Camera Mount or a telescope with Camera Adapter the owner is equipped to pursue introductory astrophotography producing results that most amateurs would be proud to put on their wall.
- The capability to easily center and then smoothly track celestial objects as they drift across the sky. This becomes particularly desirable when operating at those higher magnifications necessary to observe some of the brighter deep sky objects, and the more subtle features on the planets.
- Capability to accept electronic single or dual axis tracking drive. This can make the observing session more pleasing for an individual or for any group of people: a family, or with young children, or when sharing with groups of persons who may lack experience using a telescope.
- The German Equatorial Mount facilitates teaching a number concepts in astronomy including the Coordinate System used for Celestial Navigation.
Background and Evolution: Over the recent years the Orion telescope company has developed innovative telescopes and mounts which have come dominate that area of the telescope market that has traditionally served the more demanding beginning to intermediate amateur astronomer. Particularly with the introduction and evolution of the SkyQuest XT6 6" (15cm), SkyQuest XT8 8" (20cm), and SkyQuest XT10 - 10" (25.4cm) Dobsonian reflecting telescopes, Orion became known to provide such good value and performance that most other manufacturers have had to simply give up trying to compete in this area of the market, even though some clones of the Orion product have been misrepresented as the equal of these Orion telescopes. It was because of the good performance of the Orion SkyQuest telescopes, and the customer satisfaction ethic of Orion that Company Seven made the decision that we needed to make the Orion product line available to our customers.
The Earth's Motion The Earth rotates about its axis once full turn over a period of just under a day. This period of 23 hours 56 minutes 04.09053 seconds is called the sidereal period or the period relative to position of the stars overhead. The sidereal period is not exactly equal to one 24 hour day because by the time the Earth has rotated once on its axis, it has also moved along the path of its orbit around the Sun, because of this the Earth has to keep rotating for about another 4 minutes before the Sun seems to be back in the same place in the sky that it was in exactly a day before. As the Earth rotates in space the celestial objects overhead appear to move in an arc across the sky.
Right: Click image if you wish to see an animated movie of the Earth Rotating.
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For an observer located in the Northern Hemisphere objects rise in the Eastern horizon, gradually moving in an arc up and right across the sky towards the South, and then continue moving to the right and down towards the Western horizon. This motion can be observed with the naked eye if one carefully observes the limb of the Moon as it rises or sets behind trees or some other fixed object in the distance, the motion though slow is perceptible. A telescope provides magnifications far beyond that of the human eye, as the magnification of a telescope in increased (25X to 50X, 50x to 100X, etc.) then this motion of an object drifting across the sky will appear accelerated. With a very well designed Alt-Azimuth mount such as that provided on the Orion SkyQuest Dobsonian telescopes it is possible for an observer to track objects by manually guiding the telescope at magnifications of 200X or more, and some people are comfortable at magnifications in excess or 300X.
The solution to the limits imposed by the manually guided Alt-Azimuth mount is the Equatorial Mount. There are a number of designs of Equatorial mount but those which the amateur is most likely to encounter are the Equatorial Fork and the German Equatorial arrangement. More Computer Controlled Fork Alt Azimuth mounts are coming available too where the mount moves simultaneously in two axes to stay on target.
The Equatorial Mount is designed to gradually turn a telescope in the opposite direction from that which the Earth is rotating, at the same apparent speed as the Celestial objects are moving. The motion is so slow that few people can observe the motion, this rotation is only on the order of one revolution per 24 hours! To track precisely, the Right Ascension Axis of the Mount is adjusted by the user so that the axis is parallel to the rotational axis of the Earth. An equatorial mount will provide acceptable results for visual uses if the mount is aligned to within about one ot two degrees of the Celestial Pole. But as you align the Mount more and more accurately then the need to periodically make minor adjustments to center a target in the eyepiece will become less frequent. A very accurately alignment of the mount to the Celestial Pole is most beneficial for those persons who intend to attempt astrophotography or CCD imaging.
Easy to Use? The Equatorial Mount is not the most intuitive arrangement to the novice. But once the telescope is slipped into place, with counterweights added and balancing done in both axes done, and the mount Pole Aligned, with a little practice the system is then easy to use. The German Mount has two perpendicular axes called the Right Ascension (RA, or Polar) and Declination (Dec) axes. When the RA axis is aligned parallel with the Earth's rotational axis, objects can be easily "tracked" as they drift across the sky (due to Earth's rotation) by turning just one axis (RA) instead of two, as is required with an alt azimuth mount. You point the telescope onto an object by simply nudging the tube up or down, and left or right by hand. Once centered onto an object an electronic "Clock Drive" can keep the telescope moving with the object across the sky. And with the ability to track in Right Ascension comes the electronic capability to make fine adjustments in Declination too, since this is a "dual axis" drive system.
German Mounts For telescopes of relatively longer physical lengths, or for improved portability with some mid sized telescopes we suggest you place the telescope onto a German Equatorial mount. The German Equatorial Mount is the design preferred for the physically longer telescopes including the Newtonian Reflector and Refracting telescopes. Incidentally, in Germany the German Equatorial mount is called a "deutsche Montierung" (thanks Georg).
The German mount arrangement has advantages over the fork mounted designs in that:
- the better German mounts are less sensitive to the balance needs of the fork mount
- when working towards the celestial pole while using accessories such as CCD cameras with flip mirrors, etc. fork mounts can bind the telescope and restrict movements
- German mounts allow one to quickly interchange telescopes. One night you might use a larger "light bucket" for small faint objects, then later slide off the light bucket and slip on another high resolution telescope for even better views of planets, or for astrophotographic coverage of wide fields of view.
- the fork mount arrangement can become heavy and unwieldy before the limit of practicality is reached with the German Mount. It is usually quite easy to remove an optical tube from a German Mount and then disassemble the mount too into smaller, lighter weight components for travel.
The telescope will swing from one side of the mount to another as once proceeds to explore the four quadrants of the hemisphere. When using a German Mount with a Newtonian telescope this may at times put the eyepiece at an uncomfortable position however, most Newtonians we offer will come with or have available as options a pair of clamp style Mounting Rings can be loosened so that one may rotate the optical tube to position the Focuser and Eyepiece at more convenient positions.
Made in China: The Sirius was developed for Orion by their manufacturer in China, and then introduced to the US market in 2003. The equatorial mounts and other components made in China for beginner to intermediate amateur telescopes have been evolving into more refined products over the more recent years. Formerly, Chinese made mounts were criticized as being shoddy cheap copies of other makers designs, and lacking refinement; years ago "made in Japan" was synonymous with that view up to about the 1960's. In time Japan got its act together and eventually displaced U.S. manufacturers from the economical amateur telescope market (other market areas too). The Japanese became known as masters of taking ideas from elsewhere, adding their own refinements, and then selling them at modest prices. However, as the Japanese lifestyle became better and more costly, so did the cost of their products. And so by the late 1980's, after the dollar devaluation under the Reagan administration some prominent US manufacturers began the move away from Japanese products to third world nations as sources of labor. Countries making these products came to include Taiwan, Korea, and China. For some years Company Seven refused to offer Chinese made amateur telescopes, mounts and accessories since these often lacked the performance, quality control or refinement of the Japanese products they often mimicked. We always knew that in time some Chinese manufacturers would eventually displace some Japanese sources, as Japan had displaced others and in mid 2001 with the introduction by Orion of the StarMax 127 telescope, Company Seven became convinced China had arrived in the serious beginner to intermediate telescope market.
Sirius Equatorial Mount: resembles the "Super Polaris" model, a very popular and successful equatorial mount which was made in Japan by Vixen and has been discontinued some years ago. The Sirius equatorial mount is a very suitable choice for use with many of the lighter weight 3 (80mm) to 4 inch (10cm) aperture refracting telescopes, and some Catadioptric telescopes. Its' sound design considering the intended payloads results in almost complete elimination of unwanted vibration and oscillation; the inevitable downfall of many poor telescope mounts. Whereas in many economical telescopes the image seems to bounce around forever after the scope has been touched, this is not the case with the Sirius 8. This mount incorporates a number of features that make it attractive, these include:
1. Quick Release: a female dovetail style saddle is designed into the mount which makes it a simple matter to attach a telescope or lens, or to interchange one instrument for another. With this arrangement a telescope, even one with changing accessory payloads can be easily moved forward and back on the Saddle to attain proper balance in Declination axis of the mount,
2. Slow Motion Manual Controls: the mount incorporates fine geared worm gear sets with large hand knobs on each of both axes to facilitate centering the telescope onto a target, and to permit one to manually guide the mount to keep it on target.
4. The motion on both axes is regulated by clutches which can be adjusted to "buttery smooth" letting you guide the telescope with just the lightest touch from one part of the sky to another. The optional motors made for the Sirius also include clutches to permit the override of the motor while tracking by the manual geared controls. This is a feature normally not provided on mounts of this price, while this may be an option even on more costly alternative mounts.
5. Elevation and Azimuth adjustment to facilitate pole alignment of the mount, manual screw drives are provided. This makes it possible to move the mount head (without moving the tripod) to the left or right, up or down precisely. This makes getting that last, fine pole alignment adjustment easily. And once aligned, these controls have opposing screws that can be brought to bear in order to secure the mount even more rigidly.
6. Setting Circles: engraved with numbers corresponding to the two dimensional "Right Ascension" (R.A.) and "Declination" (Dec.) coordinate systems used by astronomers to navigate the night sky. These help you to learn about the Celestial Coordinate System, and help you to locate objects in the sky by their cataloged coordinates. Company Seven also does offer optional electronic Encoder and digital display devices as aids to celestial navigation which can be added to the Sirius however, most of our customer do not buy these add-ons since they enjoy the thrill of discovery as they learn to "Star Hop" from one object in the night sky to another.
7. Provision to accept optional Pole Alignment finder telescope.
8. The Sirius Field Tripod is surprising for its quality, durability, and rigidity. At first glance, it is a less costly clone of a tripod design that has been widely regarded as the best in the amateur telescope industry. Right down to the stainless steel tubing for the legs and the leg extensions.
When spread and locked the Sirius Field Tripod stands 32 inches (81 cm) high. By pulling out the 9-5/8 inch (24.5 cm) extension section, the Tripod height can be increased up to 40 inches (102 cm). The Tripod when set to minimum height still puts the eyepiece of a 6 or 8 inch reflecting telescope as typically balanced at a height that is about perfect for someone of between 5 foot 6 inch (170 cm) or taller height. The Tripod when set to minimum or extended height places the eyepiece of a 3 or 4 inch refracting telescope as typically balanced at a height that is perfect for most observers comfortably seated or standing.
The Sirius Field Tripod Leg Spreader Bar incorporating a convenient Eyepiece Holder. The Field Tripod Spreader Bar arrangement provides a stress that aids the rigidity of the Tripod, in this way it mimics the industry standard Meade Instruments Field Tripods. The Spreader easily rotates out of the way to permit the three legs to collapse in for storage. But Orion has taken this a step forward by providing holes in the Spreader so that it can hold up to five 1.25 inch and two 2 inch diameter eyepieces or other similar diameter accessories. Furthermore, this tray is held in place by two keyhole shaped screw holes so that customers may easily slide the tray up and out to remove the tray for transport or if desired.
Left: the Sirius 8 Field Tripod Leg Spreader Bar (161,618 bytes).
To keep dew or other contaminants from marring eyepieces stored on this tray Company Seven recommends you keep eyepiece caps in place when these accessories are stored in the accessory holes. And for use in areas of high humidity consider the use of optional dew prevention devices including our highly successful Kendrick heater systems.
Noteworthy features of the Sirius include:
Sirius Equatorial Mount Highlights
- Completely adequate, solid performance
- Adjustable yet smooth friction/drag on both axes
- 3.4 inch (86 mm) Diameter Setting Circles in R.A. and Declination help one find their way around the night sky,
and learn how use the celestial coordinate navigation system developed for astronomy
- Pole Alignment Telescope included with durable protective cover
- Fine geared controls in elevation and azimuth to facilitate a more accurate Pole Alignment
- Adjustable Height tripod with 2 inch diameter stainless steel tube legs, provides Mount Saddle Height range adjustment from about 42 to 61 inches
- Tripod constructed of durable aluminum castings with 2 inch diameter steel tube legs
- Tripod Leg length locking Hand Knobs are positioned inside of leg spread to reduce possibility of breakage, or of tripping the user
- Quick Release Dovetail Saddle Plate accepts telescopes with Dovetail Bar
- Spreader Bar incorporates Eyepiece Holder for 1.25" and for 2" eyepieces or accessories
- Clamp Style Mounting Rings with easy to operate Hand Knobs
- Piggyback Astrophotography Bracket conveniently provided on top of Mounting Ring
- Thread on Counterweight Shaft with Safety Stop.
- Two 7.5 lb Counterweights included, enough counter force to balance telescope even with most common optional accessories. Other weights available.
- Eyepiece height ranges from 58 to 67 inches (147cm to 170cm) with legs extended
- Dovetail Plate provided is 8-1/2 inch (21.6 cm) long
Sirius Equatorial Mount Optional Drive Systems
- Dual Axis Stepper Motors with Drive Corrector - permits completely automated tracking of celestial objects
- Push Button Hand Held Drive Controller with slewing speeds of 2x, 8x, and 16x Sidereal Rate
- Drive can track in either North or Southern Hemispheres
- Declination and Right Ascension control button reversing switches to maintain a comfortable orientation
when making drive corrections while pointing to all quadrants of the night sky
- Battery Pack Provided, accepts eight "D" cell alkaline batteries, or 12 volt D.C. rechargeable pack for operation in the field from provided battery pack
For more information about the Sirius Equatorial Mount download
the Orion illustrated instruction manual from Company Seven's Library.
This download size is 606,874 bytes (in Acrobat Reader ".pdf" format).
To read about the optional True Track Single Axis drive for the Sirius Equatorial Mount download
the Orion illustrated instruction manual from Company Seven's Library.
This download size is 432,670 bytes (in Acrobat Reader ".pdf" format).
These are optional accessories that are not included with the mount that we recommend you consider for your viewing pleasure and long term success:
The mount is available assembled at Company Seven's showroom and delivery is available too. But whenever possible we suggest pickup in our showroom to reduce chances of damage in transit. And of course the Orion One Year Limited Warranty is complimented by Company Seven's own guarantees and service facilities. With proper use and maintenance, there is very little that can go wrong with a mount such as this - if there is a problem then it is likely we will have found it for you and so with the exception of mirror coatings, Company Seven backs our telescopes for life.
- Guide book: "Backyard Astronomers Guide" or "Nightwatch" by Terrence Dickinson, or "Starware" by Phil Harrington. For the novice from age 8 to 15 or so up to adult. Good introductions to astronomy, the use of telescopes, and their accessories. Easy introductions to finding ones way around the night sky.
- Red LED Flashlight such as the Rigel Skylite to help one set up and use a mount, and to read charts or a planisphere without adversely impacting the observers night vision.
- Pole Finder Telescope: Astronomers often use a Pole Alignment telescope in a German Mount as an aid to quickly orient the German Equatorial Mount R.A. Axis onto the Celestial North or South Pole. The eyepiece of this small telescope incorporates a reticle pattern that aids Pole alignment of the Mount in both and the Northern and Southern hemispheres. The Orion Sirius Mount accepts an optional Polar Alignment Finder telescope. This accessory threads into a fitting on the mount head R.A. Axis shaft. For transport the Pole Alignment Finder is protected by a slop on plastic cover as it protrudes visibly from the mount head and would otherwise be vulnerable to (at the least) misalignment from impact damage.
Right: Orion Sirius optional Pole Alignment Finder Telescope. Click on image for enlarged view (19,867 bytes).
If setting up an equatorial mount in a permanent location, then other techniques can be used to gradually "zero in" a mount onto the Pole to obtain even greater accuracy. However, the Pole Finder is an especially desirable aid to quick alignment for people who are transporting the mount from one location to another.
- Extra Counterweights available each of either 4.5 lbs (2 kg), or 7.5 lbs. (3.4 kg), or 11.9 lbs. (5.4 kg.).
- Extra Dovetail Plates are available to permit the quick installation of other telescopes too! Lengths are: 8-1/2 inch (21.6 cm), or 13-1/2 (34.3cm).