Celestron 93507 manual Periodic Error Correction PEC, Using Periodic Error Correction

Page 42

1.Polar align the telescope using an optional equatorial wedge. To polar align the NexStar you must select EQ North Align (or EO South Align) from the alignment options. For more information on polar aligning, see the Polar Alignment section earlier in the manual.

2.Remove all visual accessories.

3.Thread the Radial Guider onto your telescope.

4.Thread the T-Ring onto the Radial Guider.

5.Mount your camera body onto the T-Ring the same as you would any other lens.

6.Set the shutter speed to the "B" setting.

7.Focus the telescope on a star.

8.Center your subject in the field of your camera.

9.Find a suitable guide star in the telescope field. This can be the most time consuming process.

10.Open the shutter using a cable release.

11.Monitor your guide star for the duration of the exposure using the buttons on the hand controller to make the needed corrections.

12.Close the camera's shutter.

Periodic Error Correction (PEC)

PEC for short, is a system that improves the tracking accuracy of the drive by reducing the number of user corrections needed to keep a guide star centered in the eyepiece. PEC is designed to improve photographic quality by reducing the amplitude of the worm errors. Using the PEC function is a three-step process. First, the NexStar needs to know the current position of its worm gear so that it has a reference when playing back the recorded error. Next, you must guide for at least 8 minutes during which time the system records the correction you make. (It takes the worm gear 8 minutes to make one complete revolution, hence the need to guide for 8 minutes). This “teaches” the PEC chip the characteristics of the worm. The periodic error of the worm gear drive will be stored in the PEC chip and used to correct periodic error. The last step is to play back the corrections you made during the recording phase. Keep in mind, this feature is for advanced astrophotography and still requires careful guiding since all telescope drives have some periodic error.

Using Periodic Error Correction

Once the telescope has been polar aligned using the EQ North Align (or EQ South for southern hemisphere) method, select PEC from the Utilities menu and press ENTER to begin recording your periodic error. Here’s how to use the PEC function.

1.Find a bright star relatively close to the object you want to photograph.

2.Insert a high power eyepiece with illuminated cross hairs into your telescope. Orient the guiding eyepiece cross hairs so that one is parallel to the declination while the other is parallel to the R.A. axis.

3.Center the guide star on the illuminated cross hairs, focus the telescope, and study the periodic movement.

4.Before actually recording the periodic error, take a few minutes to practice guiding. Set the hand control slew rate to an appropriate guide rate (rate 1 = .5x, rate 2 = 1x) and practice centering the guide star in the cross hairs for several minutes. This will help you familiarize yourself with the periodic error of the drive and the operation of the hand control. Remember to ignore declination drift when programming the PEC.

42

Page 41 Page 43
Image 42
Page 41 Page 43
Contents Page Introduction Quick Setup Assembly Telescope Maintenance Appendix E Time Zone MAP SKY Maps Observational Data Sheet Page Center Leg Brace Tension KnobLeg Finderscope Alignment Star Control Panel Auxiliary PortSetting Up The Tripod Assembling the NexStarAdjusting the Tripod Height Attaching the NexStar to the TripodAttaching the Hand Control 3a Attaching the Hand Control for NexStar 8 GPSAdjusting the Clutches Star DiagonalEyepiece Finderscope Installation FinderscopePowering the NexStar Aligning the FinderscopeNexStar Hand Control Alignment Procedures Hand Control OperationFew Words on GPS GPS AlignmentAuto-Align HelpfulHint Two Star Alignment Quick-AlignHelpful Hint EQ North / EQ South Alignment NexStar Re-AlignmentSelecting an Object Object CatalogFinding Planets Slewing to an ObjectTour Mode Direction ButtonsRate Button EQ North Setup ProceduresAlt-Az EQ SouthScope Setup Features Utility Features MenuHelpful Hint NexStar GPS Menu Alignment ListImage Orientation Focusing Calculating MagnificationDetermining Field of View General Observing Hints Celestial Coordinate System Celestial sphere seen from the outside showing R.A. and DECMotion of the Stars Polar Alignment with optional Wedge Finding the North Celestial PoleWedge Align Declination Drift Method of Polar Alignment DefinitionPage Lunar Observing Hints Observing the MoonObserving the Planets Planetary Observing HintsSeeing Conditions Observing the SunObserving Deep Sky Objects TransparencySeeing Short Exposure Prime Focus Photography Lunar Phase ISO Crescent Quarter Eyepiece ProjectionFull Long Exposure Prime Focus Photography Planet ISO Moon Mercury Venus Mars Jupiter SaturnPeriodic Error Correction PEC Using Periodic Error CorrectionTerrestrial Photography CCD Imaging MeteringReducing Vibration Fastar Compatible Optical System Fastar F/2 Imaging With Reducer/CorrectorPin out diagram for Autoguider port Auto GuidingCare and Cleaning of the Optics CollimationCollimated telescope Should appear Super Modified Achromatic SMA Eyepieces 1 ¼ Page Page Mechanical Specifications Optical Specification NexStar 8 GPS NexStar 11 GPSElectronic Specifications Software SpecificationsAppendix B Glossary of Terms Page Page Appendix C Longitudes Latitudes Georgia Minnesota Rhode Island Canada Description PC Command Ascii Hand Control Response Communication ProtocolSend a Slow-Goto Command Through RS232 To The Hand Control Reset The Position Of Azm Or AltSend Any Track Rate Through RS232 To The Hand Control Appendix E Maps of Time Zones Page Page Page Page Page Page Page Observational Data Sheet Celestron TWO Year Warranty

93507 specifications

The Celestron 93507 is a powerful and versatile telescope designed for both amateur and seasoned astronomers. This model combines advanced technologies and practical features to deliver an enriching stargazing experience. One of the standout characteristics of the Celestron 93507 is its robust optical design. It features a 90mm aperture, allowing users to capture bright, detailed views of celestial objects, from the lunar surface to distant galaxies. The telescope employs a Maksutov-Cassegrain optical design, known for its compact form factor and high-quality images, free from chromatic aberration.

In terms of usability, the Celestron 93507 is designed with an easy setup in mind. It comes equipped with a solid mount that provides stability during observation. The mount also includes slow-motion controls, facilitating smooth panning across the night sky, allowing astronomers to track celestial objects effortlessly. This feature is particularly beneficial for viewing planets and other fast-moving astronomical phenomena.

Furthermore, the telescope comes with high-grade optics, including fully coated glass elements that enhance light transmission and ensure sharper images with higher contrast. It includes two eyepieces — a low-power 25mm and a high-power 10mm — that provide versatility in viewing options, whether you’re looking at wide expanses of the night sky or zooming in on close details of lunar craters.

Additionally, the Celestron 93507 is compatible with various Celestron accessories, including solar filters and advanced eyepieces, enabling users to expand their observational capabilities. The telescope's compact design makes it portable, perfect for amateur astronomers who enjoy taking their telescope for trips to dark-sky locations.

Another noteworthy feature of this telescope is its durability. Built to withstand the rigors of outdoor usage, the materials used in the Celestron 93507 are resistant to wear and tear, ensuring that users can enjoy stargazing for years.

Overall, the Celestron 93507 is a well-rounded instrument that combines advanced optical technology, user-friendly features, and portability, making it an excellent choice for anyone looking to explore the wonders of the universe. Whether you're interested in planetary observation, lunar details, or deep-sky wonders, this telescope offers the tools necessary to make your astronomical explorations rewarding.
Top Page Image Contents