Eyepiece Calculator
Scope Name
:
Focal Ratio of Scope
(f)
:
4
4.5
4.8
5
5.6
6
6.3
6.7
7
7.9
8
8.8
9.2
9.8
10
11.1
11.3
11.4
11.7
12
13.3
15
Size of Primary Mirror (in):
1
2
3
4
4.5
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Maximum Useful Magnification :
x
Eyepiece Value
(mm)
:
2.5
3.6
4
4.7
5.2
6
6.3
6.4
6.7
7
7.5
8
8.8
9
9.5
9.7
10
10.5
11
12
12.4
12.5
13
13.8
14
15
16
17
18
19
20
21
22
24.5
25
26
27
28
30
32
35
40
55
56
2.5
3.6
4
4.7
5.2
6
6.3
6.4
6.7
7
7.5
8
8.8
9
9.5
9.7
10
10.5
11
12
12.4
12.5
13
13.8
14
15
16
17
18
19
20
21
22
24.5
25
26
27
28
30
32
35
40
55
56
2.5
3.6
4
4.7
5.2
6
6.3
6.4
6.7
7
7.5
8
8.8
9
9.5
9.7
10
10.5
11
12
12.4
12.5
13
13.8
14
15
16
17
18
19
20
21
22
24.5
25
26
27
28
30
32
35
40
55
56
2.5
3.6
4
4.7
5.2
6
6.3
6.4
6.7
7
7.5
8
8.8
9
9.5
9.7
10
10.5
11
12
12.4
12.5
13
13.8
14
15
16
17
18
19
20
21
22
24.5
25
26
27
28
30
32
35
40
55
56
2.5
3.6
4
4.7
5.2
6
6.3
6.4
6.7
7
7.5
8
8.8
9
9.5
9.7
10
10.5
11
12
12.4
12.5
13
13.8
14
15
16
17
18
19
20
21
22
24.5
25
26
27
28
30
32
35
40
55
56
Magnification :
x
x
x
x
x
Barlow @ 2x::
x
x
x
x
x
NJ Night Sky