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Advanced Telescope Use
Advice From an Expert!

The Sky Plus owner Todd Rosenfeld has over 20 years experience in astronomy education!

Computerized and Go-to-Telescopes

[Nexstar 130 SLT by Celestron]
Nexstar 130 SLT by Celestron

The first introduction of computers into the telescope family has made the purists in Astronomy uneasy. However, computers in telescopes have quickly become the industry's standard. A computerized telescope will locate many more objects in a single night than you could find on your own. You do not have to be highly technical, since most telescope computers are user-friendly and relatively simple to operate. A computerized telescope is also highly recommended for observing under badly light polluted skies, when manual navigation with the use of star charts is more difficult. Lastly, a computer on a telescope can make an excellent teacher for a motivated beginner. With the help of a computer, you can spend your valuable observing time viewing objects instead of hunting for them. Still, many advanced astronomers regard this manual navigation to be one of the most enjoyable aspects of astronomy. Celestron's computer controlled go-to telescopes are extremely accurate and make locating cataloged, hard to find objects as easy as a push of a button. The user-friendly display panel gives the observer instructions for manually moving the telescope to get the object in view.
[CPC 1100 GPS by Celestron]
CPC 1100 GPS by Celestron

The go to system makes finding the guidestars for aligning the telescope an easy task at the beginning of the observing session. They allow the observer to sit back and move the telescope via operating a remote control in order to point it to the desired objects. Beware, however, of go-to telescopes with high focal ratios and small apertures that have as many as 14,000 objects in the database. Because most of these objects are very dim, it is almost impossible to see them with a small aperture telescope.


Any type of telescope can be used for astrophotography as long as it has a solid mount and a clock drive. Astrophotography, however, can be rather challenging, but many astronomers become motivated to try themselves at this skillful art. A great picture makes any effort worthwhile. A number of accessories is required for successful astrophotography. However, it does not have to be a very expensive hobby as you can purchase them one at a time while familiarizing yourself with the sky and your telescope. The following are just a few suggested accessories for astrophotography. Be sure to ask your representative from The Sky Plus which accessories are appropriate for your telescope. Orion Nebula

Camera and Tripod
You will need a camera with the ability to take time exposures and a sturdy tripod on which to mount it. You can achieve nice wide-field shots of constellations and Milky Way star clouds if you are using high-speed film ( ISO 400 or higher) and exposures up to 30 seconds. If you would like to capture star "trails', longer exposures will be needed.
With an Equatorial mount, equipped with a motor drive, you can "piggyback" the camera on the optical tube of the telescope and the motor drive "tracks" the motion of the sky.
Prime Focus
If you couple up your camera body with the telescope in place of the eyepiece, you can get close-up shots of deep sky objects, like the ones you see in the magazines. This type of an arrangement is known as "prime focus". The telescope is now acting as the giant telephoto lens. During the exposure, as you make slight adjustments in the right ascention and declination, you carefully follow a reference star in an off-axis guider or guide scope.
Eyepiece Projection
When capturing close-up images of the Moon and planets, you will need even more power than that provided by the prime focus. Using eyepiece projection, you use a telescope and an eyepiece to project and image onto the film.
Camera Adapters
To attach 35 mm SLR camera securely to the telescope, you need the proper adapters. Piggyback Camera Adapters: The adapter attaches to the telescope's optical tube , allowing you to take advantage of the telescope's equatorial mount and clock drive.
T-Rings: Can be used for both prime-focus and eyepiece projection photography since they convert the lens mount on a camera body to a standard T-thread.
T-Adapters: This type of adapter is generally used for prime-focus photography with Schmidt-Cassegrain and maksutov-cassegrain telescopes. During photography, the adapters replace the visual backs on these telescopes. At the other end of the adapter is a T-thread, which allows attachment of a camera body with a T-ring.
Universal Camera Adapters: Used for reflecting or refracting telescopes. At the telescope end, these adapters slide into the focuser like an eyepiece. At the camera end, they thread into a T-ring on the camera.
Tele-Extenders:These adapters are necessary accessories for eyepiece-projection photography with Schmidt-Cassegrain telescopes. The telescope end of the adapter threads over the visual back of the telescope with the eyepiece installed, and the camera end couples to the T-ring on your camera. The tele-extenders allow higher-magnification projections than those possible with a regular T-adapter.
CCD Imaging
CCD imaging is taking a digital picture of an object using a CCD camera and projecting it onto a computer monitor. Meade CCD imagers and accessories are helping astronomers around the world capture spectacular images of celestial objects. Check our links section to find sites containing breath taking images and helpful information on the exciting art of CCD imaging.

Filtering for Planets and Deep Sky Objects

The most popular filters can be classified into four categories: color filters, moon filters, solar filters and nebula filters. Color filters allow you to resolve different details on planets, reduce glare, increase contrast through selective filtration, and lesson eye fatigue. Moon filters cut down on the glare of the moon and preserve the night vision of the observer. Solar filters allow viewing the sun safely. Nebula filters allow higher details and better views of various nebula by increasing the contrast between the nebula and background sky.

MercuryGlobular Cluster NGC 6093
# 25 Red will make the planet's disk stand out against the blue sky in the twilight or daytime. After the sunset, it is best to use #21 Orange with high magnification to see the planet's phases.
Because of Venus' excessive brightness, the twinkling makes it difficult to observing its changing phases. A #47 Violet filter or stacked # 58 Green and #80 A Medium Blue filters help reduce the twinkling.
# 25 Red and # 21 Orange help enhance the detail, and #15 Deep Yellow or # 80A Medium Blue expose the polar caps while # 58 Green help examine the melt lines.
# 15 Deep Yellow improves globular details. # 25, #12, #58, #80A help produce images of the rings of different brightness. When photographing Saturn, it is good to use #15 filter.
#12 Yellow, # 80A, #58 and #25 Red are great for revealing the cloud bands and Red Spot.
Besides a lunar filter, try using #80A Medium Blue and # 15 to enhance the contrast of shades in the craters.
LP-3 (Oxygen III)-Great all around nebula filter. Gives excellent images of many nebula ranging for the Orion Nebula to the Veil nebula.

LP-4 (H-Beta) -Primarily used for the Horse Head Nebula

Please remember to review our advice on selecting a telescope!

Please check our Frequently Asked Questions for more information!

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Celestron is a copyright held by Celestron International
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