Tele Vue Optics: Calculator

Calculator

Eyepiece Calculator

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Input Box

Follow the steps below to see the eyepiece table.

(1) Enter any 2 of the 3 parameters for your telescope

Focal Length

Aperture

Focal Ratio (f/#)

... or Recall a Stored Run

(2a) Choose telescope eyepiece preferences

Does your telescope accept 2" eyepieces?

Are you using a Tele Vue Paracorr?

Limit to eyepieces that accept DIOPTRX astigmatism correctors?

(2b) Limit to these eyepieces

Current: Ethos Nagler Delos Panoptic DeLite Plössl
Discontinued: Nagler (+zoom) Panoptic Wide Field Radian Plössl Click Stop Zoom Apollo

(3) Enter optional run name and select table presentation order

Run Name

Sort

True Field: Listed from wide to narrow. Eps with same field sort higher mag first.
Magnification: Listed from low to high. Eps with same mag sort wider field first.
Design: Listed from narrow to wide field designs and zooms last.
Note: Zooms sort based on low-power specification.

(4) Calculate Results

Initial Conditions

Focal Length:	4,800.0mm
Aperture:	150.0mm
Focal Ratio:	32.0
Include 2-inch data:	True
Table corrected for Paracorr:	False
List only DIOPTRX eyepieces:	False
Max recommended mag. for aperture:	350x

d:150mm, f:4800mm, w/2in

Design	Focal Length (mm)	Apparent Field (°)	Eye Rel. (mm)	Barrel Size	Mag. (x)	Exit Pupil (mm)	True Field (°)	Star Drift Time (sec)	True Field @ 1000 yards (feet)	Mag. w/2x Barlow (2x)	Mag. w/2x Big Barlow or Power- mate (2x)	Mag. w/2.5x Power- mate (2.5x)	Mag. w/3x Barlow (3x)	Mag. w/4x Power- mate (4x)	Mag. w/5x Power- mate (5x)
Plössl	55	50	38	2"	87.3	1.7	0.55	131	28.8	--	174.5	--	--	349.1	--
Panoptic	41	68	27	2"	117.1	1.3	0.55	131	28.8	--	234.1	--	--	468.3†	--
Plössl	40	43	28	1¼"	120.0	1.3	0.32	77	16.9	240.0	240.0	300.0	360.0†	480.0†	600.0†
Panoptic	35	68	24	2"	137.1	1.1	0.46	111	24.2	--	274.3	--	--	548.6†	--
Plössl	32	50	22	1¼"	150.0	1.0	0.32	77	16.9	300.0	300.0	375.0†	450.0†	600.0†	750.0†
Nagler 5	31	82	19	2"	154.8	0.97	0.50	120	26.3	--	309.7	--	--	619.4†	--
Panoptic	27	68	19	2"	177.8	0.84	0.36	87	19.1	--	355.6†	--	--	711.1†	--
Plössl (disc)	26	50	18	1¼"	184.6	0.81	0.26	63	13.8	369.2†	369.2†	461.5†	553.8†	738.5†	923.1†
Plössl	25	50	17	1¼"	192.0	0.78	0.25	61	13.3	384.0†	384.0†	480.0†	576.0†	768.0†	960.0†
Panoptic	24	68	15	1¼"	200.0	0.75	0.32	77	16.9	400.0†	400.0†	500.0†	600.0†	800.0†	1,000.0†
Nagler 4	22	82	19	2"	218.2	0.69	0.37	89	19.4	--	436.4†	--	--	872.7†	--
Panoptic (disc)	22	68	15	2" & 1¼"	218.2	0.69	0.30	71	15.6	436.4†	436.4†	545.5†	654.5†	872.7†	1,090.9†
Ethos	21	100	15	2"	228.6	0.66	0.43	103	22.6	--	457.1†	--	--	914.3†	--
Plössl (disc)	21	50	14	1¼"	228.6	0.66	0.22	52	11.3	457.1†	457.1†	571.4†	685.7†	914.3†	1,142.9†
Plössl	20	50	14	1¼"	240.0	0.63	0.20	49	10.7	480.0†	480.0†	600.0†	720.0†	960.0†	1,200.0†
Panoptic	19	68	13	1¼"	252.6	0.59	0.25	61	13.3	505.3†	505.3†	631.6†	757.9†	1,010.5†	1,263.2†
DeLite	18.2	62	20	1¼"	263.7	0.57	0.23	55	11.9	527.5†	527.5†	659.3†	791.2†	1,054.9†	1,318.7†
Radian (disc)	18	60	20	1¼"	266.7	0.56	0.22	52	11.4	533.3†	533.3†	666.7†	800.0†	1,066.7†	1,333.3†
Delos	17.3	72	20	1¼"	277.5	0.54	0.25	61	13.3	554.9†	554.9†	693.6†	832.4†	1,109.8†	1,387.3†
Ethos	17	100	15	2"	282.4	0.53	0.35	85	18.5	--	564.7†	--	--	1,129.4†	--
Plössl (disc)	17	50	12	1¼"	282.4	0.53	0.17	41	8.9	564.7†	564.7†	705.9†	847.1†	1,129.4†	1,411.8†
Nagler 5	16	82	10	1¼"	300.0	0.50	0.26	63	13.8	600.0†	600.0†	750.0†	900.0†	1,200.0†	1,500.0†
Panoptic (disc)	15	68	10	1¼"	320.0	0.47	0.20	49	10.7	640.0†	640.0†	800.0†	960.0†	1,280.0†	1,600.0†
DeLite	15	62	20	1¼"	320.0	0.47	0.19	46	10.0	640.0†	640.0†	800.0†	960.0†	1,280.0†	1,600.0†
Plössl	15	50	10	1¼"	320.0	0.47	0.15	36	7.9	640.0†	640.0†	800.0†	960.0†	1,280.0†	1,600.0†
Delos	14	72	20	1¼"	342.9	0.44	0.21	49	10.8	685.7†	685.7†	857.1†	1,028.6†	1,371.4†	1,714.3†
Radian (disc)	14	60	20	1¼"	342.9	0.44	0.17	41	9.0	685.7†	685.7†	857.1†	1,028.6†	1,371.4†	1,714.3†
Ethos	13	100	15	2" & 1¼"	369.2†	0.41	0.27	64	13.9	738.5†	738.5†	923.1†	1,107.7†	1,476.9†	1,846.2†
Nagler 6	13	82	12	1¼"	369.2†	0.41	0.21	50	11.0	738.5†	738.5†	923.1†	1,107.7†	1,476.9†	1,846.2†
DeLite	13	62	20	1¼"	369.2†	0.41	0.16	39	8.6	738.5†	738.5†	923.1†	1,107.7†	1,476.9†	1,846.2†
Plössl (disc)	13	50	9	1¼"	369.2†	0.41	0.13	31	6.8	738.5†	738.5†	923.1†	1,107.7†	1,476.9†	1,846.2†
Delos	12	72	20	1¼"	400.0†	0.38*	0.18	43	9.4	800.0†	800.0†	1,000.0†	1,200.0†	1,600.0†	2,000.0†
Radian (disc)	12	60	20	1¼"	400.0†	0.38*	0.15	36	7.9	800.0†	800.0†	1,000.0†	1,200.0†	1,600.0†	2,000.0†
Apollo (disc)	11	85	18	2" & 1¼"	436.4†	0.34*	0.19	46	10.1	872.7†	872.7†	1,090.9†	1,309.1†	1,745.5†	2,181.8†
DeLite	11	62	20	1¼"	436.4†	0.34*	0.14	33	7.3	872.7†	872.7†	1,090.9†	1,309.1†	1,745.5†	2,181.8†
Plössl	11	50	8	1¼"	436.4†	0.34*	0.11	26	5.7	872.7†	872.7†	1,090.9†	1,309.1†	1,745.5†	2,181.8†
Plössl (disc)	10.5	50	7	1¼"	457.1†	0.33*	0.10	25	5.4	914.3†	914.3†	1,142.9†	1,371.4†	1,828.6†	2,285.7†
Ethos	10	100	15	2" & 1¼"	480.0†	0.31*	0.21	51	11.1	960.0†	960.0†	1,200.0†	1,440.0†	1,920.0†	2,400.0†
Delos	10	72	20	1¼"	480.0†	0.31*	0.15	36	7.9	960.0†	960.0†	1,200.0†	1,440.0†	1,920.0†	2,400.0†
Radian (disc)	10	60	20	1¼"	480.0†	0.31*	0.13	30	6.6	960.0†	960.0†	1,200.0†	1,440.0†	1,920.0†	2,400.0†
Nagler 6	9	82	12	1¼"	533.3†	0.28*	0.15	35	7.8	1,066.7†	1,066.7†	1,333.3†	1,600.0†	2,133.3†	2,666.7†
DeLite	9	62	20	1¼"	533.3†	0.28*	0.11	27	6.0	1,066.7†	1,066.7†	1,333.3†	1,600.0†	2,133.3†	2,666.7†
Ethos	8	100	15	2" & 1¼"	600.0†	0.25*	0.17	40	8.7	1,200.0†	1,200.0†	1,500.0†	1,800.0†	2,400.0†	3,000.0†
Delos	8	72	20	1¼"	600.0†	0.25*	0.12	28	6.2	1,200.0†	1,200.0†	1,500.0†	1,800.0†	2,400.0†	3,000.0†
Radian (disc)	8	60	20	1¼"	600.0†	0.25*	0.10	24	5.2	1,200.0†	1,200.0†	1,500.0†	1,800.0†	2,400.0†	3,000.0†
Plössl	8	50	6	1¼"	600.0†	0.25*	0.08	19	4.1	1,200.0†	1,200.0†	1,500.0†	1,800.0†	2,400.0†	3,000.0†
Plössl (disc)	7.4	50	5	1¼"	648.6†	0.23*	0.07	18	3.9	1,297.3†	1,297.3†	1,621.6†	1,945.9†	2,594.6†	3,243.2†
Nagler 6	7	82	12	1¼"	685.7†	0.22*	0.12	28	6.1	1,371.4†	1,371.4†	1,714.3†	2,057.1†	2,742.9†	3,428.6†
DeLite	7	62	20	1¼"	685.7†	0.22*	0.09	21	4.7	1,371.4†	1,371.4†	1,714.3†	2,057.1†	2,742.9†	3,428.6†
Ethos	6	100	15	2" & 1¼"	800.0†	0.19*	0.12	30	6.5	1,600.0†	1,600.0†	2,000.0†	2,400.0†	3,200.0†	4,000.0†
Delos	6	72	20	1¼"	800.0†	0.19*	0.09	22	4.8	1,600.0†	1,600.0†	2,000.0†	2,400.0†	3,200.0†	4,000.0†
Radian (disc)	6	60	20	1¼"	800.0†	0.19*	0.08	18	3.9	1,600.0†	1,600.0†	2,000.0†	2,400.0†	3,200.0†	4,000.0†
Nagler Zoom	6 - 3	50	10	1¼"	800.0† - 1,600.0†	0.19* - 0.09*	0.06 - 0.03	15 - 7	3.2 - 1.6	1,600.0† - 3,200.0†	1,600.0† - 3,200.0†	2,000.0† - 4,000.0†	2,400.0† - 4,800.0†	3,200.0† - 6,400.0†	4,000.0† - 8,000.0†
Nagler 6	5	82	12	1¼"	960.0†	0.16*	0.08	20	4.4	1,920.0†	1,920.0†	2,400.0†	2,880.0†	3,840.0†	4,800.0†
DeLite	5	62	20	1¼"	960.0†	0.16*	0.06	15	3.3	1,920.0†	1,920.0†	2,400.0†	2,880.0†	3,840.0†	4,800.0†
Radian (disc)	5	60	20	1¼"	960.0†	0.16*	0.06	15	3.3	1,920.0†	1,920.0†	2,400.0†	2,880.0†	3,840.0†	4,800.0†
Ethos SX	4.7	110	15	2" & 1¼"	1,021.3†	0.15*	0.11	26	5.6	2,042.6†	2,042.6†	2,553.2†	3,063.8†	4,085.1†	5,106.4†
Delos	4.5	72	20	1¼"	1,066.7†	0.14*	0.07	16	3.5	2,133.3†	2,133.3†	2,666.7†	3,200.0†	4,266.7†	5,333.3†
DeLite	4	62	20	1¼"	1,200.0†	0.13*	0.05	12	2.7	2,400.0†	2,400.0†	3,000.0†	3,600.0†	4,800.0†	6,000.0†
Radian (disc)	4	60	20	1¼"	1,200.0†	0.13*	0.05	12	2.6	2,400.0†	2,400.0†	3,000.0†	3,600.0†	4,800.0†	6,000.0†
Ethos SX	3.7	110	15	2" & 1¼"	1,297.3†	0.12*	0.08	20	4.4	2,594.6†	2,594.6†	3,243.2†	3,891.9†	5,189.2†	6,486.5†
Nagler 6	3.5	82	12	1¼"	1,371.4†	0.11*	0.06	14	3.0	2,742.9†	2,742.9†	3,428.6†	4,114.3†	5,485.7†	6,857.1†
Delos	3.5	72	20	1¼"	1,371.4†	0.11*	0.05	13	2.8	2,742.9†	2,742.9†	3,428.6†	4,114.3†	5,485.7†	6,857.1†
Radian (disc)	3	60	20	1¼"	1,600.0†	0.09*	0.04	9	2.1	3,200.0†	3,200.0†	4,000.0†	4,800.0†	6,400.0†	8,000.0†
DeLite	3	62	20	1¼"	1,600.0†	0.09*	0.04	9	2.0	3,200.0†	3,200.0†	4,000.0†	4,800.0†	6,400.0†	8,000.0†
Design	Focal Length (mm)	Apparent Field (°)	Eye Rel. (mm)	Barrel Size	Mag. (x)	Exit Pupil (mm)	True Field (°)	Star Drift Time (sec)	True Field @ 1000 yards (feet)	Mag. w/2x Barlow (2x)	Mag. w/2x Big Barlow or Power- mate (2x)	Mag. w/2.5x Power- mate (2.5x)	Mag. w/3x Barlow (3x)	Mag. w/4x Power- mate (4x)	Mag. w/5x Power- mate (5x)

Table Notes

For further reading, see Eyepieces Advice.

†Tele Vue recommends maximum magnification of 60x / inch (2.5x / mm) of telescope aperture and 350x maximum regardless of aperture.

*An exit pupil greater than 7.5-mm may be too big for a telescope with central obstruction (most reflectors). Conversely, small exit pupils may reveal eyesight defects such as floaters. Consider binocular viewing to diminish the effect of an eye having floaters.