Lumicon Coma Corrector/Field Flattener


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Brand and Model:Lumicon Coma Corrector/Field Flattener
Price ($USD):240
Type:Coma Corrector
Description:The Lumicon Coma Corrector/Field Flattener Lens dramatically reduces coma (flared star images) and flattens the field when used, in particular, with f/3.5 to f/6 Newtonian telescopes. It is excellent for photographic use with 35mm and medium-format film up to 6 x 6 cm.

The Lumicon Coma Corrector Lens is an afocal, or 'zero-power' air-spaced doublet lens system and is fully multi-coated on all 4 surfaces to eliminate ghost images. The aluminum cell’s, 48mm (2”) threads can be used on all 48mm threaded accessories.

Optimal performance of the Lumicon Coma Corrector is achieved when the center of the last optical element is 3.8” (96.52mm) from the film plane.

The Coma Corrector lens is automatically positioned correctly when threaded directly into the 2” barrel of the Lumicon 2” Newtonian Easy-GuiderTM.

Photographic Performance
By reducing coma and flattening the field, the Lumicon Coma Corrector makes off-axis star images are much smaller on your photographic and CCD star images. The Lumicon Coma Corrector also shrinks the size and improves the quality of off-axis guide stars, making guiding much easier. Because of the zero-power lens design, the Lumicon Coma Corrector has no color aberration and neither shrinks nor magnifies the image. There is no shift in focus after lens insertion.

Visual Performance

The Lumicon Coma Corrector Lens would have minimal performance gain at high visual magnifications with well-corrected, modern design eyepiece.However, the Lumicon Coma Corrector Lens will certainly benefit and improve medium and low power observing with any 20mm to 56mm eyepiece. Wide apparent field eyepieces like the TeleVue Naglers and Panoptics are recommended for use with the Lumicon Coma Corrector since they are designed for a flat field. You will need a 2” diameter, 3” long extension tube and/or a 2”-1.25” reducer bushing to use both 2” and 1.25” eyepieces.

Vote Highlights Vote
Lumicon Coma Corrector/Field Flattener
I just purchased a Lumicon Coma Corrector. Advantage over the Televue Paracorr is NO MAGNIFICATION. It's always bothered me that I pay a lot of money for Nagler eyepieces to get wide fields of view only to throw away 15% by magnifying it in the Paracorr.

I have used a Paracorr in my 13.1 f4.4 scope for several years. It does improve the sharpness of edge stars in my low to medium power eyepieces.

We recently compared the two and while both did very well on coma the unmagnified view in the Lumicon was preferable. Note too that the Lumicon has 1.8" aperture so there's no vignetting.

Keep in mind that the Lumicon will not work as a convienient accessory like the Televue. I unscrew the lens cell and mount it INSIDE MY FOCUSER to use it. If you slide the entire unit into your focuser the way it comes you'd need 2-3 inches of in-travel and you'll have to make sure the focal plane is 3.8" from the top lense of the corrector.

This is a nice way to deal with coma. if you position the corrector properly it will work for the 22mm and 31mm Naglers. For the other Naglers you need to pull the eyepieces out a little to get the proper seperaltion.

All in all the Lumicon get a 10 from me and the Paracorr gets an 8.

Overall Rating: 10
Performance:10 Value:9
Weight: 5 (Veritable Vote)
Date:
By: Roman
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=303057

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