Meade LX200 Series & LX400-ACF telescopes may be operated in the altazimuth mode (i.e., without polar alignment) for all visual applications and for photographic or CCD imaging exposures of up to about five minutes' duration. Most owners use their telescope in the altazimuth mode the great majority of the time. During longer photo or CCD exposures in the altazimuth mode, however, an effect called field rotation becomes evident.
Meade #1220 Field Derotator
Simply put, even if the telescope is perfectly guided on a central star during a long exposure, stars at the edge of the field appear to rotate about the field center during the exposure. As a result, stars away from the field center appear as small concentric arcs on the film, rather than starpoints. This effect, which in no way relates to the accuracy of the telescope's computer or internal alignment, occurs on all altazimuth-mounted telescopes, whether large observatory telescope, LX400-ACF or LX200R, and is caused by the telescope not being polar aligned.
Field rotation with an LX-200 or LX400-ACF telescope can be cured with the simple addition of an equatorial wedge; the wedge enables precise polar alignment, negating all field rotation. Alternately, the optional Meade #1220 Field De-rotater may be attached to the rear cell of any 7", 8", 10", or 12" Meade LX200-ACF or 10" or 12" LX400-ACF model, simplifying field operation of the telescope, since no wedge is required.
With the Meade #1220 De-rotater attached to the telescope's rear cell, other accessories (T-Adapter, Off-Axis Guider, etc.) can in turn be threaded to the #1220 unit.
The #1220 is easy to use! Just align the telescope as usual, using the GPS alignment procedure or one of six other available alignment procedures, and, automatically, signals are fed through one of the RS-232 ports on the telescope's control panel to the Field De-rotater, causing it to rotate at the correct speed and precisely counter the effects of altazimuth-induced field rotation. The Meade #1220 Field De-rotater is powered through connection with the RS-232 serial port.
Meade Product Number: 07456
- Additional Information
SKU ME-07456 Manufacturer Meade Warranty 1 Year Warranty
- Included Items
- Meade #1220 Field Derotator
- One Year Manufacturer Warranty
- Questions & Answers
Product QuestionsDo you support to ship international (actually Japan in my case) ? And would like to know cost for that.Question by: Masakazu Kubo on Oct 26, 2016 9:59:00 AMDue to our agreements with our vendors we are limited to certain items that we can ship internationally. We always want to help in any way that we can. Please contact us at 1-800/4838-6287 or email us directly at email@example.com to discuss options for you.Answer by: Jonathan Cheek (Admin) on Oct 31, 2016 2:12:00 PMHi just wondering if The meade field derotator can be used on other telescopes like celestron cpc 800 xlt gps?
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