RCC I, Rowe Coma Corrector

Description

• The RCC I (Rowe Coma Corrector) is a Coma Corrector from Dave Rowe with Triplet Lense design for f/4 Newtons
• The RCC works from f/3.5 to f/6- it is perfect on f/4
• Coma Corrector with backfocus 91,5mm
• reproduction scale is 1:1- in contrast to many other coma correctors, the RCC is no Barlow lens which rely on a magnification to make the larger back-focus to the sensor possible
• The RCC is the only coma corrector which gives you enough back-focus for filter wheels or other accessories without changing the focal ratio

The Baader Planetarium RCC-I (Rowe Coma Corrector) is designed specifically to correct Coma in fast Newtonian imaging systems. The RCC is the ideal match for today's Digital SLRs and CCD Cameras.

• Long Back Focus: The RCC-I triplet optical design has been optimized to work at a large 91.5mm back-focus distance, enabling the use of Off-Axis Guiders, Adaptive Optics, and Filter Wheels. The RCC even allows users of DSLRs to incorporate off-axis guiding with the Baader RCC Off-Axis Guider.
• No magnification increase: Unlike most other coma correctors, the RCC-I does not impart a barlow effect- it works at 1:1, with no loss in imaging speed or reduction in field size.
• Fast Imaging Speeds: The RCC-I has been optimized for Newtonians with focal ratios from f/3.5 to f/6 (nominally designed for f/4).
• Ease of Focus: Addition of the RCC-I into the optical train extends the focal point slightly (approximately 5mm, in an f/4 system). This important attribute ensures that your system will be able to reach focus without needing to shift the primary mirror or increase the size of the secondary mirror (* IMPORTANT; this assumes your system will already reach focus without the RCC).

The RCC-I inserts into 2" focusers and has external T-threads on the camera side for attachment to any other T-threaded accessory. The RCC-I also includes a removable stop flange. Removal of this flange allows the RCC to be fully inserted into 2" focusers. The RCC is also threaded for standard 2"/48mm filters.

The RCC is designed for a nominal 91.5mm distance from the mounting flange to the image plane (55mm is the standard dimension for all SLRs, measured from the front of their T-adapter to their image plane). The 91.5mm distance needs to be held to within +/-3mm for best image quality. We sell a range of adapters and extension tubes that can be used to configure practically any imaging system to meet the 91.5mm requirement (see Astro T-2 System). In particular, we recommend the Baader VariLock Variable Extension Tubes.

Users of DSLRs will find the Baader RCC Off-Axis Guider to be the perfect compliment to the RCC-I. It is designed to have the proper spacing needed to meet the 91.5mm requirement, and offers precise axial and radial adjustments for ease of locating guidestars.

* Back Focus Example: assume that you have a DSLR and the matching Baader RCC off-axis guider. That combination of equipment has a combined path length of 91.5mm (which is intentionally the back-focus spec of the RCC). If you attach a plain 2€ nosepiece to the front of the Off Axis Guider + DSLR and then insert them into the 2€ focuser of a Newtonian, your scope would need at least 91.5mm of back focus in order to reach focus on the chip of the DSLR. Now, remove the 2€ nosepiece and replace it with the RCC-I. Re-insert the assembly fully into the focuser until the off axis guider seats against the focuser (the RCC inserts fully into the focuser since it is 2€ OD), focus the camera, and you should find that the focuser would be racked out about 5mm farther than it was with just that plain 2€ nosepiece.

The weight of the RCC by itself is 142gm (5oz).

Technical Data- Overview

• Reproduction scale: 1:1
• Recommended focal ratios: f/3.5- f/6 (optimised for f/4)
• Focal position (perfect distance to the sensor): 91.5 mm measured from the T-2 thread / 94.5 mm from the M48 thread
• Inner connection (lens side): 2" nosepiece with M48_i filter thread for 2" eyepiece filters
• Outer connection (telescope side): T2 (M 42 x 0.75_a; without the stop ring M 48_a)
• Longest overall depth: 73 mm / without the stop ring 75 mm / without the stop ring and RCC Off Axis Guider 84mm
• Diameter of the housing: 50.8mm/2"

Specifications