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TV 32 Wide Field vs Garrett Optical SWA 32mm 72 deg FMC

Posted by John Fitzgerald   10/19/2008 01:50PM

Reviewer: John Fitzgerald
Location: NW Arkansas
Years experience:40 plus

Garrett Optical 2" SWA 32mm 72 deg FMC (GO 32 SWA) $80.47 shipped (new)
This eyepiece is the same as the Orion Q70 ($112.90 shipped)


TeleVue 2" Wide Field 32mm 65 deg -discontinued (TV 32 WF) $160 shipped (used)

Physical Likes:
relatively light in weight
rubber grip band around body
rubber eye cup
nice coatings

TV 32 WF
very well made, solid
smooth barrel, no retaining groove
nice coatings for its mfg date (mid 1980's)

deeply cut retaining groove
black barrel, harder to see when inserting (minor)

TV 32 WF
no eye cup
relatively heavy
no grip on body

Performance on sky:

Telescope used: 120mm f5 achro (a good sample that does not exhibit objectionable aberrations other than normal CA)
Both eyepieces give 19x

GO 32 SWA:
This eyepiece gives contrasty and sharp images in the center 60% of the field, but exhibits increasing astigmatism toward the edges. Very little field curvature is seen in the 72 deg AFOV. In the outer 5% astigmatism is very bad. Transmission and sharpness in the center of the field is very good, about the same as the TV 32 WF, but astigmatism limits visibility of the fainter stars in the outer 30% or so of the field.

TV 32 WF:
The field is a barely noticeable amount smaller than the GO 32 SWA, but considerably sharper at the edges. This eyepiece does not exhibit any noticeable astigmatism, but has a very small amount of field curvature. This curvature of field is only objectionable in the outer 10% of the field, and does not approach the distortion caused by the astigmatism in the GO 32 SWA. Transmission and contrast are excellent over most of the entire field.

The TV cost almost twice as much as the GO, so it should be better, but the GO with its 72 degree field in my opinion is a very good bargain. In all respects at distances of 60% or more from the center to edge, the TV wins. Toward the center, they are essentially the same. I could not tell any differences in sharpness, contrast, or transmission between them near the center of the field. At f-ratios of 7 or greater, the GO 32 SWA would likely perform much better near the edges of the field. I will put in an addendum when I get the chance to try these at f7 or greater.