Frequently Asked Questions

How do I store my telescope?

It is unnecessary to separate the optical tube and the mount when storing the telescope. It can be stored in one unit in a clean, dry, and dust-free environment. If it has to be stored outdoors, cover it with a heavy-duty plastic cover to prevent it from getting wet. Make sure that the dust cap for the front of the telescope and the cover for the rear opening are on. Accessories should be stored separately in a box, with all their caps on. Some people do store the reflecting telescope in two parts, leaving the telescope tube up side down on the ground to prevent dust from settling down on the primary mirror. However, it is not proven that it really helps.

How do I safely transport my telescope?

The telescope can be transported in 2 main parts--telescope tube and mount. Loosen the thumbscrews on the tube rings and remove the telescope tube from the mount. We suggest removing the accessories (finderscope and bracket, and the eyepiece) from the optical tube. Cover the telescope tube and the eyepiece with their caps. It is also convenient to remove the fine-adjustment control cables and counterweight rod/counterweights. Accessory tray should be removed in order to transport with the 3 tripod legs closed. The telescope can be transported in a vehicle without a problem. Padded insulation can prevent scratches on the tube but it is not necessary. The mirrors may go out of collimation after a bumpy ride but collimation would be required after transportation anyway, with or without padding.

Should I use colour filters?

Colour filters, which usually thread into the eyepiece barrel, are almost a necessity for viewing planetary detail. By using an appropriate colour, you can highlight a specific planetary feature. This often allows you see two to three times as much detail as in an unfiltered view.

Should I get a motor drive with my equatorial mount?

A motor drive is necessary for many types of astrophotography, but it is more than just a convenience for visual observation as well. At 200x magnification, the Earth's rotation will move an object out of your field of view in about two seconds. A Right Ascension motor drive will keep an object in the centre of the field where the image is the best without producing the objectionable vibrations experienced with manual tracking. Adding a Declination motor drive and a hand controller allows you to guide for astrophotography.

What is the advantage of a large aperture telescope?

The larger the aperture, the higher the practical magnification limit. Since more light is collected and brought to focus by a larger aperture telescope, fainter objects can be seen with it than with smaller apertures. Under good seeing conditions when air is not turbulent, a larger aperture objective gives higher resolution, letting you see finer details.

I’m trying to collimate my reflector but all I see at the back of my telescope is 3 Phillip’s-head screws. Where are the 2 sets of screws?

Your optical tube is probably covered with a metal back plate. The 3 Phillip’s-head screws are there to hold the metal plate in place. Loosen them and remove the metal plate. You should be able to see the back of the primary mirror and 2 sets of screws around it.

Which mount should I buy for my telescope?

If your instrument is for land use only, select the alt-azimuth mounting, but if its for astronomical or dual use, the equatorial mounting is the best choice. Make sure that the mounting you select is strong enough to carry the telescope you've chosen. Heavier or longer telescopes need stronger mounts to be stable at high magnifications. When in doubt, over-mount the instrument; choose the mount one size up if you want extra stability.

The image with my low power eyepiece is clear, but my high power is fuzzy. What's wrong with it?

There's probably nothing wrong with the eyepiece: you have probably exceeded the resolving power of your telescope. A television set looks clear 10 metres away, but up close you can see the imperfections.

Which eyepiece design is best?

This often asked question is quite irrelevant, as different design's performance varies with different telescopes. Different eyepiece designs have various characteristics. For example, and expensive widefield design is not required for planetary viewing, where the only important thing is maximum contrast. A Plossl or Orthoscopic would probably be best, but almost all design s are good performers on-axis for any f/ratio. Telescopes with F/ratios>10 are quite tolerant of simple low element eyepieces up to 55 deg. A.F., but telescopes <6 are a different matter. Off-axis performance requires powerful correction to properly image the highly convergent beam. Each eyepiece and telescope performs as a system, and their image can only be evaluated as much.

How much power does my telescope have?

A telescope has three types of power and they are measured against the performance of a normal human eye. They are magnifying power, light gathering power and resolving power. All three are important but the most important is resolving power. The longer the focal length of a telescope, the more a particular eyepiece will magnify the image. However, there is a practical magnification limit of 2x per mm of telescope aperture. Using an eyepiece which gives a magnification beyond that limit is normally of little use. The amount of light that a telescope can gather depends on size of the aperture and the more light that can be gathered, the better the resolution. What you will see through your telescope will then depend on these three powers. For example, compared to the human eye, and using the 2x per mm rule, a 150mm aperture telescope will have a maximum practical magnifying power of 300x, a light gathering power of 600x and a resolving power of 0.8 arc-seconds.

Where can I find prices for Sky-Watcher telescopes?

We at Pacific Telescope are only able to provide the MSRP (manufacturer suggested retail price) to the public. E-mail our customer service with the telescope units you are interested in to obtain the suggested retail prices. To receive more accurate pricing information, or prices on parts and accessories, we suggest that you contact our dealers directly.

Where can I buy Sky-Watcher telescopes in the U.S.?

Please contact Sky-Watcher USA:

 

United States of America

Sky-Watcher USA

475 Alaska Avenue, Torrance, CA 90503

 

phone: +1 310-803-5953 x 306

fax: +1 310-803-5953 x 306

website: http://www.skywatcherusa.com/

e-mail: JSimon@skywatcherusa.com

Can I buy direct from you?

We at Pacific Telescope do not sell direct to the public with only one exception--the floor model sale. The floor model sales are not held often and will be announced on our web site.

I live in Europe, where can I buy Sky-Watcher telescopes?

You can buy Sky-Watcher products through our European distributor in your area. See a list of the Sky-Watcher distributors: http://www.skywatcher.com/where_to_buy.php

What can I see with my telescope?

Astronomically, you can see the Moon, the Sun if correctly filtered, all of the planets except perhaps Pluto, some surface details on Mars, Jupiter and Saturn, multiple stars, globular and open clusters, bright nebulae, galaxies and nearby galaxy clusters. Terrestrially, there are wildlife, sports, etc., but remember that daytime viewing is often over areas which may radiate heat so that very distant subjects may shimmer.

Where can I buy Sky-Watcher telescopes in Canada?

We have dealers in most provinces in Canada. See the  list of the Sky-Watcher dealers:. 

http://ca.skywatcher.com/_english/05_service/10_dealer.php#alldealers

Will I see objects as they appear in photographs?

Yes and no. Bright objects like the Moon, some planets and some star clusters will show colours and features just like photographs, but faint objects are more difficult. The eye is not sensitive enough to detect colour at low light levels so even bright nebulae appear as shades of gray in small telescopes. Colour films can be exposed long enough to collect light across the visible spectrum so photographs show colours than you don't see visually.

Will a telescope work without an eyepiece?

Not for visual purposes, as the eye cannot process the real image made by the objective. The telescope may be used without an eyepiece for camera and other instruments.

How much magnification can I use with my telescope?

Every telescope is different, but a rough rule of thumb is 30-50X per inch diameter of the objective. A good refractor may, however, use 100X/inch on bright objects, so this is not a hard rule. You can always increase the magnification above these limits, but it is pointless if you're not seeing more. This rule breaks down for larger instruments, as the distortion of the atmosphere limits practical magnification to 300X. See Usable Magnifications.

How do I choose the alignment stars for Two Star Alignment?

Generally speaking, choose an object close to the meridian line as the first alignment star. If you have performed manual mount calibration and are sure that your mount is free of cone error, select any star the SkyScan recommends to you as the second star. Otherwise choose two stars located at the same side of the sky which you will be doing the most observing. This improves the pointing accuracy on this particular side of the sky.

How do I choose the alignment star for One Star Alignment?

Objects with smaller DEC are better suited for One Star Alignment. With the same apparent movement in the eyepiece view, objects with larger DEC move in larger angle in R.A., resulting in less accurate measurement in R.A.

How do I find objects using the setting circles?

Periodicals like "SkyNews", "Sky&Telescope" and "Astronomy" will tell you where the moon and planets are, and the location of all other objects can be found in Star Charts. The quickest way to find objects is to learn the Constellations and use the finderscope, but if the object is too faint you may want to use setting circles. Download the PDF file to find out how to use the setting circles on your Sky-Watcher EQ3-2 (EQ3) and EQ5 (EQ4) mounts, or EQ1 and EQ2 mounts. (You will need Adobe Acrobat Reader to open the file.)

How do I find objects in the sky?

The sky is mapped out in a spherical coordinate system similar to the system of Latitude and Longitude on the surface of the Earth. On the imaginary celestial sphere, the coordinates are Declination, which is equivalent to Latitude and measured in degrees, and Right Ascension, which is equivalent to Longitude, but measured in hours. The celestial equator is a projection of the Earth's equator onto the celestial sphere. Because the positions of stars and other distant celestial objects, as plotted on this celestial sphere, change very slowly with time, their listed coordinates and star charts are only updated every fifty years. On the other hand, planets change position so rapidly that their coordinates must be obtained from current astronomy periodicals. The setting circles on your equatorial mount can be aligned with the celestial sphere to aid in finding astronomical objects.

Is high magnification better?

Only for some objects, although undermagnification is often a problem, even for experienced observers. The penalty for increased magnification is reduced field of view and brightness; faint objects grow fainter as the magnification is increased This is why larger aperture telescopes are so effective on faint objects; they provide enough light to stimulate the eye at high magnifications. For example, a 4-inch telescope will only view a globular cluster effectively at 80X, and it will appear as a blob. A 6-inch will resolve the outer stars at 130X, an 8-inch will resolve further in at 200X. 10 and 12.5-inch telescopes will make them glitter to the core at 300 and 400X.

How do I polar align my telescope?

For visual use, only a rudimentary alignment of the polar axis of your equatorial mount is required. First, the finderscope should already have been aligned to the telescope by centring a distant fixed object in the telescope's field and then adjusting the finderscope with its adjusting screws until the object is at the centre of the crosshairs. The angle of the polar axis should also be set equal to your Latitude. Now, with the mount approximately level, align the telescope parallel to the polar axis (ie set the Declination axis to 90 degrees), and then adjust the polar axis until the star Polaris (the "North star") appears in the centre of the field of your finderscope. This alignment is good enough for visual observation. If you are trying astrophotography, a more accurate alignment is required, and you will need a polarscope if your mount is equipped for it. For longer exposure times, the mount is usually adjusted using a very accurate star-movement measurement technique called "drift alignment."
Download the detailed information on Polar Alignment.
Download the detailed information on Polar Alignment for EQ1 and EQ2 mounts.

What is polarscope? How do I use it?

A polarscope is a specialized finderscope which is used to align an equatorial mount with the celestial pole. It is usually mounted in a tube which runs along the RA axis. For northern use, it may have a mark for Polaris, the pole star, which is slightly offset from the North Celestial Pole. It must be rotated so that the offset mark of Polaris is correctly aligned relative to the directino of epsilon-Cassiopeia on a line from it (through Polaris) to Alkaid, the end star on the Big Dipper's handle.

How do I take photographs through my telescope?

Most telescopes can be adapted to act as lenses for single lens reflex (SLR) cameras. For the basic technique of "prime focus" photography, all you generally need are a camera body, a T-ring specifically made for your camera body (allows it to connect to a T-thread) and in some cases a combination T-adapter designed for your telescope (supplies the T-thread). This configuration, is fine for terrestrial use, or for the Moon or the correctly filtered Sun, but for fainter astronomical objects you will need to do time exposures using an equatorial mount with a Right Ascension motor to correct for the Earth's rotation. For exposures longer than a few seconds, you should use dual axis motor drives and a hand controller to guide the telescope.

I am observing Jupiter but I only see a shimmering disk. What am I doing wrong?

Astronomers must be patient; you must optimize your observing site and times, as well as your equipment. When you observe the Moon and the planets, and they appear as though water is running over them, you probably have bad "seeing" because you are observing through turbulent air. Always observe objects as high in the sky as possible. Don't observe immediately after sunset and avoid viewing across heat-radiating ground objects such as buildings and parking lots. Let your telescope come to temperature with the surrounding air; sometimes the shimmering is due to "tube currents" within the telescope tube. Try to enhance planetary detail by using colour filters. Optimize all that you can then be patient because good seeing comes and goes.

Is there a difference between the EQ4 and EQ5 mount?

There are small differences in mechanical designs of the two mounts. The functions and performances of the two, however, are the same.

What is the difference between the EQ3 and EQ3-2 mount?

The EQ3 and EQ3-2 are identical. EQ3 is the former model name for the EQ3-2 mount.

My new Sky-Watcher telescope only came with an assembly instruction, shouldn't I get a complete manual?

We sincerely apologize for this. We are currently working on more complete telescope operation manuals. In the meantime, you can download a temporary manual for your telescope from the Support page of our Web site. The instruction manuals on the Web site are constantly being updated. New instructions will be announced in the New to the Web site section of the What's new page.

I clicked on the link to download the manual but all I see is page 1 out of 9 pages, and it is incomplete. What is wrong?

Some of the instructions may take a while to download, especially for people who are on a dial-up modem. Adobe Acrobat Reader allows you to view the file while downloading. If an incomplete page shows up in the browser, the chances are that it is still downloading the rest of the file. You should be able to view all the pages after it is done downloading.

How do I collimate my Sky-Watcher reflector?

In order for your reflecting telescope to produce proper images, the primary (objective) mirror must reflect light directly back up the tube to the secondary mirror which directs the beam at 90?to the eyepiece.
Download the detailed information on collimating your reflecting telescope. (You will need Adobe Acrobat Reader to open the file.)

How do I collimate my Sky-Watcher refractor with the adjustable objective-lens cell?

Download the instruction.

How do I find out the model number for my Sky-Watcher telescope?

To find out which model your Sky-Watcher telescope is, you will need to know the Diameter and Focal Length of your telescope, and the model of your mount. Near the focus tube you should see a sticker with technical information of the telescope. For example, if you see “D=130mm F=1000mm", the diameter of your telescope is 130mm and the focal length is 1000mm. You should be able to find the name of your mount on the assembly manual that comes with your telescope. The instruction manual will be titled “Reflector/EQ2 MOUNT", if your mount is EQ2 mount. In this particular case, the model number of the telescope is 1301EQ2. 

How do I adjust the secondary mirror of my 10" Dobsonian?

You will need a 2mm Allen wrench.

I cannot open the manual I downloaded.

You will need either the Adobe Acrobat Reader or Adobe Acrobat to open the instruction files. If you do not already have one installed in your computer, you can download the Adobe Acrobat Reader for free from the Adobe Web site.

How do I choose my eyepiece?

For standard eyepieces with a 50 degree apparent field of view, Plössl eyepieces are a good choice if your telescope's focal ratio is f7 or less. For longer focal ratio instruments, simpler eyepieces such as Kellners will be sufficient. Choose eyepiece focal lengths that won't give you a duplicate magnification when a Barlow lens is used. For example, don't get 10mm and 20mm eyepieces with a 2x Barlow. 

Why are some eyepiece more expensive than others?

When you pay more for an eyepiece you are usually paying for: Field of view: Eyepieces that have many lenses to correct for the five major aberration (these aberrations give increasingly worse, the lower the focal ratio of the telescope) have obviously higher costs in lenses and coatings. Eye relief: Using larger, more expensive elements in eyepieces allows for a greater distance between the eyes and eyepiece. Coatings: 2-layer multicoatings on both faces of all lenses will typically add 25% to the cost of an eyepiece, but this is absolutely necessary to preserve the contrast of the image when the light has to go through 7-9 lenses. Advertising: Those ads aren't free.

Why is the image better at the center of the field?

All commercial eyepieces are made with spherical elements, as these are the only type that are easily mass produced. These naturally produce aberrations, which become much worse in highly convergent light beams. There is no way to avoid all aberrations when using spherical elements. Clever eyepiece designer can, however, minimize the objectionable ones and cause others to manifest themselves in an acceptable form.

What is the black spot I see in a low powered eyepiece in my reflector during daylight?

A low powered eyepiece in a reflector produces a large exit pupil with a large image of the secondary mirror obstruction. During the day, when the pupil of the eye is small, if the size of the secondary obstruction image approaches the size of the pupil, it will appear as a darkened region in the center of the field. At night, when the pupil of the eye is large, the darkened region is not noticed.

Which works better? An eyepiece or a Barlow+eyepiece giving the same magnification?

The only time the eyepiece alone may perform as well, is on-axis, in a high-contrast application, as the extra optics of the barlow may cause a slight depreciation. Optically, for all other sues, the eyepice+barlow outperforms the eyepiece working alone. The reason? Most of the aberrations caused by positive spherical lenses (Coma, Astigmatism, Curvature of Field and Spherical Aberration) can be reduced and sometimes almost eliminated by introducing a negative system (barlow) which has the same aberrations in negative quantities! Spherical aberration of the system is reduced as the positive spherical aberration of the eyepiece is cancelled by the negative spherical aberration of the barlow. The other aberrations cancel in a similar way! This is one of the eyepiece designer's most powerful weapons, and it is used in most of the shorter focal length ultra-wide designs. Another great benefit of this idea is that the longer eye relief of the longer f.l. eyepiece used with the barlow is retained.

How important it is to get a parfocal series of eyepiece?

Parfocal eyepiece sets reduce the amount of refocusing when changing powers, but it is rare when no refocusing is required. Parfocallizing of eyepiece sets is a non-performance factor when choosing oculars.

Do anti-reflection coatings improve light transmission?

Yes. Conventional thought seems to be that all the light not reflected is transmited through to the next medium. This is critial to the performance of high-element wide angle designs with many refractive surfaces.

When I'm observing a bright object like a planet, I see an opposing ghost image. What causes that?

The ghost image, and it's evil twin, the out-of-focus ghost is caused by internal reflections inside the eyepiece. The only way to eliminate these is to eliminate air-spaces in the eyepieces, as the ghost is caused by a double bounce between two lenses in close proximity. While the ghost is an annoyance, the out of focus ghost is more of an enemy, as it reduces overall contrast of the image, which determines how much detail you'll be able to see. The treatment, if not eh cure, is di-electric multicoating of the lens-facing surfaces inside the eyepiece.

How many eyepieces should I have?

Eyepieces are the most critical factor concerning the performance of your telescope, excepting a dark sky. Eyepieces create the image your eye will see, and the right ones will give you the experience that makes amateur astronomy so rewarding. Even the best instrument will never perform to it's potential visually with poor oculars. Since most manufacturers sell their telescopes with inexpensive ones, and since most people selling a telescope keep their good eyepieces, the aftermarket is your best source. Borrow as many as you can and try them out; for every object there will be an eyepiece that works best with your particular telescope. You'll probably be satisfied with 5-8 good eyepieces; and you'll use your telescope much more often with good ones.

How do I choose the alignment stars for Three Star Alignment?

The first alignment star should be an object close to the meridian line. For the other alignment stars, choose any two objects from the list of the recommended star provided by SkyScan.

What is the appropriate magnification for alignment?

High magnification is recommended for any type of alignment procedure. It increases the measurement precision. For Star Alignment, choose an eyepiece that produces a true field of view no more than 30 arc min.  See "Which Eyepiece Should I Choose?" in Eyepiece FAQs for details on how to calculate the true field of view. 

What is Cone Error and how do I correct it?

"Cone" error is a common inaccuracy found on all German equatorial mount. It is a result from the optical axis not being aligned to the R.A. axis of the mount. The calibration procedure should be performed before the initial use of the telescope and periodically thereafter to ensure the accuracy. See Manual Mount Calibration.

I don't see a Date Circle Pointer on my EQ6 mount. What do I do?

It is easy to make an indicator that you can use as a pointer for our date scale. Start by putting your mount in the home position. That is, with the OTA pointing in line with the polar scope and with the counterweights hanging strait down. Now, put a piece of masking tape over the top of the mount at the back, just above the polar scope (See Figure below). You only need an inch or two. Try to centre it above the polar scope. Take a piece of string about 12 - 18 inches long. Hold one end of it on the centre of the RA Setting Indicator. Pull the string taught and down over the centre of the eyepiece for the polar scope. Note where the string crosses your masking tape and mark the position. The mark you just made is your Date Scale Indicator/pointer.
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**Information provided by KW Telescope and Nature