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:	3,000.0mm
Aperture:	150.0mm
Focal Ratio:	20.0
Include 2-inch data:	True
Table corrected for Paracorr:	False
List only DIOPTRX eyepieces:	False
Max recommended mag. for aperture:	350x

d:150mm, f:3000mm, 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"	54.5	2.8	0.88	210	46.0	--	109.1	--	--	218.2	--
Panoptic	41	68	27	2"	73.2	2.1	0.88	210	46.0	--	146.3	--	--	292.7	--
Plössl	40	43	28	1¼"	75.0	2.0	0.52	123	27.0	150.0	150.0	187.5	225.0	300.0	375.0†
Panoptic	35	68	24	2"	85.7	1.8	0.74	177	38.7	--	171.4	--	--	342.9	--
Plössl	32	50	22	1¼"	93.8	1.6	0.52	123	27.0	187.5	187.5	234.4	281.3	375.0†	468.8†
Nagler 5	31	82	19	2"	96.8	1.6	0.80	192	42.0	--	193.5	--	--	387.1†	--
Panoptic	27	68	19	2"	111.1	1.4	0.58	139	30.5	--	222.2	--	--	444.4†	--
Plössl (disc)	26	50	18	1¼"	115.4	1.3	0.42	101	22.1	230.8	230.8	288.5	346.2	461.5†	576.9†
Plössl	25	50	17	1¼"	120.0	1.3	0.40	97	21.2	240.0	240.0	300.0	360.0†	480.0†	600.0†
Panoptic	24	68	15	1¼"	125.0	1.2	0.52	123	27.0	250.0	250.0	312.5	375.0†	500.0†	625.0†
Nagler 4	22	82	19	2"	136.4	1.1	0.59	142	31.1	--	272.7	--	--	545.5†	--
Panoptic (disc)	22	68	15	2" & 1¼"	136.4	1.1	0.48	114	25.0	272.7	272.7	340.9	409.1†	545.5†	681.8†
Ethos	21	100	15	2"	142.9	1.1	0.69	165	36.2	--	285.7	--	--	571.4†	--
Plössl (disc)	21	50	14	1¼"	142.9	1.1	0.35	83	18.1	285.7	285.7	357.1†	428.6†	571.4†	714.3†
Plössl	20	50	14	1¼"	150.0	1.0	0.33	78	17.1	300.0	300.0	375.0†	450.0†	600.0†	750.0†
Panoptic	19	68	13	1¼"	157.9	0.95	0.41	97	21.3	315.8	315.8	394.7†	473.7†	631.6†	789.5†
DeLite	18.2	62	20	1¼"	164.8	0.91	0.36	87	19.1	329.7	329.7	412.1†	494.5†	659.3†	824.2†
Radian (disc)	18	60	20	1¼"	166.7	0.90	0.35	84	18.3	333.3	333.3	416.7†	500.0†	666.7†	833.3†
Delos	17.3	72	20	1¼"	173.4	0.87	0.40	97	21.2	346.8	346.8	433.5†	520.2†	693.6†	867.1†
Ethos	17	100	15	2"	176.5	0.85	0.57	135	29.6	--	352.9†	--	--	705.9†	--
Plössl (disc)	17	50	12	1¼"	176.5	0.85	0.27	65	14.3	352.9†	352.9†	441.2†	529.4†	705.9†	882.4†
Nagler 5	16	82	10	1¼"	187.5	0.80	0.42	101	22.1	375.0†	375.0†	468.8†	562.5†	750.0†	937.5†
Panoptic (disc)	15	68	10	1¼"	200.0	0.75	0.33	78	17.1	400.0†	400.0†	500.0†	600.0†	800.0†	1,000.0†
DeLite	15	62	20	1¼"	200.0	0.75	0.31	73	16.0	400.0†	400.0†	500.0†	600.0†	800.0†	1,000.0†
Plössl	15	50	10	1¼"	200.0	0.75	0.24	58	12.6	400.0†	400.0†	500.0†	600.0†	800.0†	1,000.0†
Delos	14	72	20	1¼"	214.3	0.70	0.33	79	17.3	428.6†	428.6†	535.7†	642.9†	857.1†	1,071.4†
Radian (disc)	14	60	20	1¼"	214.3	0.70	0.28	66	14.4	428.6†	428.6†	535.7†	642.9†	857.1†	1,071.4†
Ethos	13	100	15	2" & 1¼"	230.8	0.65	0.43	102	22.3	461.5†	461.5†	576.9†	692.3†	923.1†	1,153.8†
Nagler 6	13	82	12	1¼"	230.8	0.65	0.34	80	17.6	461.5†	461.5†	576.9†	692.3†	923.1†	1,153.8†
DeLite	13	62	20	1¼"	230.8	0.65	0.26	63	13.8	461.5†	461.5†	576.9†	692.3†	923.1†	1,153.8†
Plössl (disc)	13	50	9	1¼"	230.8	0.65	0.21	50	10.9	461.5†	461.5†	576.9†	692.3†	923.1†	1,153.8†
Delos	12	72	20	1¼"	250.0	0.60	0.29	69	15.0	500.0†	500.0†	625.0†	750.0†	1,000.0†	1,250.0†
Radian (disc)	12	60	20	1¼"	250.0	0.60	0.24	58	12.6	500.0†	500.0†	625.0†	750.0†	1,000.0†	1,250.0†
Apollo (disc)	11	85	18	2" & 1¼"	272.7	0.55	0.31	74	16.2	545.5†	545.5†	681.8†	818.2†	1,090.9†	1,363.6†
DeLite	11	62	20	1¼"	272.7	0.55	0.22	53	11.7	545.5†	545.5†	681.8†	818.2†	1,090.9†	1,363.6†
Plössl	11	50	8	1¼"	272.7	0.55	0.17	42	9.1	545.5†	545.5†	681.8†	818.2†	1,090.9†	1,363.6†
Plössl (disc)	10.5	50	7	1¼"	285.7	0.53	0.17	40	8.7	571.4†	571.4†	714.3†	857.1†	1,142.9†	1,428.6†
Ethos	10	100	15	2" & 1¼"	300.0	0.50	0.34	81	17.7	600.0†	600.0†	750.0†	900.0†	1,200.0†	1,500.0†
Delos	10	72	20	1¼"	300.0	0.50	0.24	58	12.7	600.0†	600.0†	750.0†	900.0†	1,200.0†	1,500.0†
Radian (disc)	10	60	20	1¼"	300.0	0.50	0.20	48	10.5	600.0†	600.0†	750.0†	900.0†	1,200.0†	1,500.0†
Nagler 6	9	82	12	1¼"	333.3	0.45	0.24	57	12.4	666.7†	666.7†	833.3†	1,000.0†	1,333.3†	1,666.7†
DeLite	9	62	20	1¼"	333.3	0.45	0.18	44	9.6	666.7†	666.7†	833.3†	1,000.0†	1,333.3†	1,666.7†
Ethos	8	100	15	2" & 1¼"	375.0†	0.40	0.27	64	13.9	750.0†	750.0†	937.5†	1,125.0†	1,500.0†	1,875.0†
Delos	8	72	20	1¼"	375.0†	0.40	0.19	45	9.9	750.0†	750.0†	937.5†	1,125.0†	1,500.0†	1,875.0†
Radian (disc)	8	60	20	1¼"	375.0†	0.40	0.16	38	8.3	750.0†	750.0†	937.5†	1,125.0†	1,500.0†	1,875.0†
Plössl	8	50	6	1¼"	375.0†	0.40	0.12	30	6.5	750.0†	750.0†	937.5†	1,125.0†	1,500.0†	1,875.0†
Plössl (disc)	7.4	50	5	1¼"	405.4†	0.37*	0.12	28	6.2	810.8†	810.8†	1,013.5†	1,216.2†	1,621.6†	2,027.0†
Nagler 6	7	82	12	1¼"	428.6†	0.35*	0.19	44	9.7	857.1†	857.1†	1,071.4†	1,285.7†	1,714.3†	2,142.9†
DeLite	7	62	20	1¼"	428.6†	0.35*	0.14	34	7.5	857.1†	857.1†	1,071.4†	1,285.7†	1,714.3†	2,142.9†
Ethos	6	100	15	2" & 1¼"	500.0†	0.30*	0.20	48	10.4	1,000.0†	1,000.0†	1,250.0†	1,500.0†	2,000.0†	2,500.0†
Delos	6	72	20	1¼"	500.0†	0.30*	0.15	35	7.6	1,000.0†	1,000.0†	1,250.0†	1,500.0†	2,000.0†	2,500.0†
Radian (disc)	6	60	20	1¼"	500.0†	0.30*	0.12	29	6.3	1,000.0†	1,000.0†	1,250.0†	1,500.0†	2,000.0†	2,500.0†
Nagler Zoom	6 - 3	50	10	1¼"	500.0† - 1,000.0†	0.30* - 0.15*	0.10 - 0.05	23 - 12	5.1 - 2.6	1,000.0† - 2,000.0†	1,000.0† - 2,000.0†	1,250.0† - 2,500.0†	1,500.0† - 3,000.0†	2,000.0† - 4,000.0†	2,500.0† - 5,000.0†
Nagler 6	5	82	12	1¼"	600.0†	0.25*	0.13	32	7.0	1,200.0†	1,200.0†	1,500.0†	1,800.0†	2,400.0†	3,000.0†
DeLite	5	62	20	1¼"	600.0†	0.25*	0.10	24	5.3	1,200.0†	1,200.0†	1,500.0†	1,800.0†	2,400.0†	3,000.0†
Radian (disc)	5	60	20	1¼"	600.0†	0.25*	0.10	24	5.3	1,200.0†	1,200.0†	1,500.0†	1,800.0†	2,400.0†	3,000.0†
Ethos SX	4.7	110	15	2" & 1¼"	638.3†	0.24*	0.17	41	8.9	1,276.6†	1,276.6†	1,595.7†	1,914.9†	2,553.2†	3,191.5†
Delos	4.5	72	20	1¼"	666.7†	0.23*	0.11	26	5.6	1,333.3†	1,333.3†	1,666.7†	2,000.0†	2,666.7†	3,333.3†
DeLite	4	62	20	1¼"	750.0†	0.20*	0.08	20	4.3	1,500.0†	1,500.0†	1,875.0†	2,250.0†	3,000.0†	3,750.0†
Radian (disc)	4	60	20	1¼"	750.0†	0.20*	0.08	19	4.2	1,500.0†	1,500.0†	1,875.0†	2,250.0†	3,000.0†	3,750.0†
Ethos SX	3.7	110	15	2" & 1¼"	810.8†	0.19*	0.13	32	7.0	1,621.6†	1,621.6†	2,027.0†	2,432.4†	3,243.2†	4,054.1†
Nagler 6	3.5	82	12	1¼"	857.1†	0.18*	0.09	22	4.8	1,714.3†	1,714.3†	2,142.9†	2,571.4†	3,428.6†	4,285.7†
Delos	3.5	72	20	1¼"	857.1†	0.18*	0.08	20	4.4	1,714.3†	1,714.3†	2,142.9†	2,571.4†	3,428.6†	4,285.7†
Radian (disc)	3	60	20	1¼"	1,000.0†	0.15*	0.06	15	3.3	2,000.0†	2,000.0†	2,500.0†	3,000.0†	4,000.0†	5,000.0†
DeLite	3	62	20	1¼"	1,000.0†	0.15*	0.06	15	3.2	2,000.0†	2,000.0†	2,500.0†	3,000.0†	4,000.0†	5,000.0†
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.