问个小技术问题

	登录/注册后可看大图 PowerSeeker 114 EQ 21045	登录/注册后可看大图 AstroMaster 114EQ 31042
OPTICAL DESIGN	Newtonian Reflector	Reflector
WEIGHT	19 lb (8.62 kg)	17 lb (7.71 kg)
CD ROM	"The Sky®" Level 1	The Sky L1
ACCESSORY TRAY	No-Tool Tray with Eyepiece holder	N/A
TRIPOD	Aluminum	1.25" steel tube legs
MOUNT	German Equatorial	CG-2 Equatorial
FINDERSCOPE	5x24	Built-on StarPointer
BARLOW LENS	3 x	N/A
MAGNIFICATION 2	225 x	100 x
EYEPIECE 2	4 mm (0.16 in)	10 mm (0.39 in)
MAGNIFICATION 1	45 x	50 x
EYEPIECE 1	20 mm (0.79 in)	20 mm (0.79 in)
FOCAL RATIO	7.89	8.77
FOCAL LENGTH	900 mm (35.43 in)	1000 mm (39.37 in)
APERTURE	114 mm (4.49 in)	114 mm (4.49 in)
LIMITING STELLAR MAGNITUDE	12.8	12.8
RESOLUTION (RAYLEIGH)	1.22 arcsec	1.22 arcsec
RESOLUTION (DAWES)	1.02 arcsec	1.02 arcsec
PHOTOGRAPHIC RESOLUTION	253 line/mm	N/A
LIGHT GATHERING POWER	265 x	265 x
ANGULAR FIELD OF VIEW	0.9 °	1 °
LINEAR FIELD OF VIEW (@1000 YDS)	48 ft (14.63 m)	53 ft (16.15 m)
OPTICAL COATINGS	Aluminum	Aluminum
SECONDARY MIRROR OBSTRUCTION	1 in (25.4 mm)	N/A
SECONDARY MIRROR OBSTRUCTION BY AREA	5 %	N/A
SECONDARY MIRROR OBSTRUCTION BY DIAMETER	22.3 %	N/A
OPTICAL TUBE LENGTH	34 in (863.6 mm)	20 in (508 mm)
TUBE ATTACHMENT	N/A	Dovetail Bar
STAR DIAGONAL	N/A
HIGHEST USEFUL MAGNIFICATION	N/A	269 x

这里的SECONDARY MIRROR OBSTRUCTION是不是指副镜遮挡.
副镜在牛反中是指啥,
为啥astroMaster 114EQ 没副镜,我以为两个结构类似
菜鸟菜问

PowerSeeker 难道是马牛？加改正镜是修正像差的。反射系统加不加改正镜全有中心遮挡。
没正经使用过反射...详细的不知道。

不同系列的产品我还真没注意过，我以为差别不是很大