Overview of My Current Telescopes

Introduction | Omegon Photography Scope 72/432 OTA | Celestron C8 OTA | Unistellar eVscope | TS-Optics Photoline 102/714 | Celestron C5 OTA | Vaonis Vespera | Unistellar eVscope 2 | Links | Appendix: Data of My Current Telescopes

On this page, I present some information about my current telescopes. Further below you will find a tabular overview of the basic data for the telescopes.

Note: Here you will find an overview of all telescopes that I own and owned. And here is my own little astronomy history.

 

Introduction

In the course of time, I have already tried a couple of telescopes and extended my "collection"several times, but also reduced again it at times. The reasons for the changes were of a different nature, and often the criteria "large aperture" and "weight/transportability" conflicted with each other. At the moment, my collection consists of the following devices:

The following overview lists the various options offered by the individual telescopes:

Telescope Omegon Photography Scope 72/432 OTA Celestron C5 OTA Vaonis Vespera Pro
Type Refractor tube (doublet), also usable as a spotting scope and camera lens Schmidt-Cassegrain scope for travel and fast observing Refractor scope (quadruplet) with sensor chip, fully automated

Data
Aperture, Focal Length, Focal Ratio 72 mm, 432 mm, f/6 125/127 mm, 1250 mm, f/10 (9.84) 50 mm, 250 mm, f/5
Light Gathering Power, Limiting Visual Stellar Magnitude, Resolving Power 105.8, 11.1 mag, 1.61" 329, 13 mag, 0.91"/0.93" 51.0, 16 mag, 2.32"
Maximum Magnification approx. 144 x 250/254 x approx. 40 x???, > ??? x digitally
Magnification with 32 mm / 4 mm Eyepiece 13.5 x / 108 x 39 x / 312.5 (too high) => 250 x (5 mm) ---

Use
Used as... Telescope for travel and home use; telescope for a "quick look"; for moon, planets, and brighter deep sky objects; rich-field telescope; can be used as a spotting scope Moon and planets telescope; travel scope; telescope for a "quick look"; best suited to moon, sun, and planets, but also suited to brighter deep sky objects; not quite, but nearly a rich-field telescope; can be used as a spotting scope Telescope for EEA / "video astronomy" (rich-field telescope)
Usable with My Sky Discovery GoTo Mount? yes yes (but the finder is located poorly...) no, has its own GoTo mount
Usable with My AZ Pronto Mount? yes yes no, has its own AZ mount
Usable with My AZ-GTi GoTo Mount? yes yes (but the finder is located poorly...) no, has its own AZ mount

Observation
Sun yes (with solar filter size 4 - I do not own one) yes (with solar filter size 6 that I own) yes (with solar filter)
Moon yes (I own a gray filter for the moon) yes (I own a gray filter for the moon) no (but not well suited to observing the moon)
Planets yes-and-no (planets are rather small...) yes, but the maximum usable magnification is about 250 x no, tiny...
Deep Sky Objects yes (the brighter ones; low magnification - rich-field observations) yes (the brighter ones) yes
Terrestrial Observations yes, with an Amici prism yes, with an Amici prism (is sold as a spotting scope) no

Further down, you will find a table with additional technical data for the telescopes.

 

Omegon Photography Scope 72/432 (September 2018)

Side view on AZ Pronto mount with extension tube

Ditto (detail)

Other side, on AZ Pronto mount with extension tube

Ditto (detail)

Purchased in September 2018 at the AME2018 astronomy fair and delivered soon after. The Omegon Apochromatic Refractor Pro APO AP Photography Scope 72/432 ED OTA is a refractor tube, which is useful for observing the sun, the moon, and maybe the planets, but also for wide-field DSO observations. It can also be used as a spotting scope (with an Amici prism) and as a camera lens. Most of the time, I use the tube on the Sky-Watcher AZ Pronto mount. I wanted to use it on the Sky-Watcher Star Discovery AZ GoTo mount as well, but this did practically not happen. Later, I used it on the Sky-Watcher AZ-GTi GoTo mount head together with the tripod taken from the AZ Pronto mount.

For details see page Omegon Photography Scope 72/432 ED OTA Information (2.8" Refractor). For technical data see below.

 

Celestron C5 OTA (December 2020)

C5 - side view on the AZ Pronto mount with the original finder and as a spotting scope

C5 tube, oblique front view

C5 tube from the rear

The Celestron C5 is a Schmidt-Cassegrain telescope which, like Maksutov-Cassegrains, is a reflector with a "folded" light path and therefore very compact for its large aperture. Accordingly, it has a long focal length, which makes it particularly suitable to observing the moon and the planets. However, the C5 is also suitable as a "universal telescope" for DSO, especially when using the f/6.3 reducer/corrector. However, this tube is marketed by Celestron as a spotting scope... Nevertheless, I call it here "OTA" and not "spotting scope". I bought the C5 in December 2020 in order to have a lighter and more flexible travel and "fast" telescope than the Skymax-127. I use(d) the C5 on my Sky-Watcher AZ Pronto mount and (as long as I owned it) on my Sky-Watcher AZ-GTi AZ GoTo mount (the bigger mounts are possible as well...)..

For details see page Celestron C5 OTA Information (5" Schmidt-Cassegrain). For technical data see below.

 

Vaonis Vespera Pro (May 2024)

         

Photo: My Vaonis Vespera Pro (May 8, 2024)

Vespera Pro is an update of the telescope Vespera by the French company Vaonis. It could be preordered* since mid-June 2023 on the Vaonis Website. Delivery of the telescope was scheduled for May 2024; I received mine on May 8, 2024. Like the original Vespera, it is a refractor. The lens again is a quadruplet with 50 mm aperture (like binoculars), but with a focal length of 250 mm (aperture ratio f/5) and with a specially designed "pro" field corrector.
*) Since I already owned a high tripod, I decided to go for the simple package without an additional high tripod (2000 EUR instead of 2500 EUR).

The Vespera Pro uses a Sony IMX676 Starvis 2 sensor with a resolution of 3536 x 3536 pixels (12.5 MP). This delivers a field of view of 1.6° x 1.6° (3,2° x 3,2° in mosaic mode = 50 MP), which makes also the Vespera Pro a small rich field telescope. Its image scale or sampling rate is 1.65"/pixel, which is much better than that for the original Vespera (2.99"/pixel). With a weight of 5 kg and a height of 40 cm, the Vespera Pro has remained light and compact, making it an ideal travel telescope. The internal battery lasts for 11 hours, which is quite a long time.

For details see page Vaonis Vespera Pro - Information. For technical data see here.

 

Links

 

Appendix: Data

Technical Data of My Current Telescopes

Telescope Omegon Celestron Vaonis
PS 72/432 C5 Vespera Pro
Optical Design Refractor (Doublet) Schmidt-Cassegrain Refractor (Quadruplet)
Primary Mirror Diameter 72 mm (2.8") 125/127 mm (5") 50 mm (2")
Focal Length, Focal Ratio 432 mm
f/6 		1250 mm
f/10 (9.84)		 250 mm
f/5
Resolving Power (arc secs) 1.61" ** 0.91"/0.93" 2.32"
Limiting Visual Stellar Magnitude 11.1 mag ** 13 mag 16 mag
Light Gathering Power 105.8 ** 329 51.0
Maximum Practical Visual Power 144 x 250/254 x 40 x???, ??? digitally
Optical Tube Dimensions
(diam. x length)		 10 cm x 39.4 cm 15 cm* x 28/33 cm 48 x 20 x 9 cm (HxWxD)
Net Weight Basis --- --- ---
Net Weight Optical Tube 2.06 kg 2.72 kg 5 kg (everything)

*) My own measurement; **) corrected values

Observation-Relevant Data

Telescope

Focal
Length
(mm)

Aperture
(mm)
Focal
Ratio
Light
Gathering
Power
Maximum+
Minimum*
Maximum*
Minimum+
Usable Magnification
Usable Focal Length
of Eyepiece (mm)
Factor/Exit Pupil (mm) >
Manuf.
1.5
2
6.5
7
6.5
7
1.5
2
PS 72 (Refractor, Doublet)
432
72
6
106
144
108
144
11.08
10.29
39.0
42.0
4.0
3.0
Celestron C5 (Schmidt-Cassegrain)
1250
127
10
329
295
190
254
 19.69 18.29
65.0
70.0
6.7
5.0
Celestron C5R (Schmidt-Cassegrain)
787.5
127
6.3
329
295
190
254
 19.69 18.29
41.0
44.1
4.2
3.2

*) Calculated for an exit pupil of 6.5 mm and 7 mm
+) Factor 1.5 or 2 for Dobsonian telescopes; in general, the lower value of 1.5 is used for Newtonian telescopes; if the manufacturer specified a different magnification, it is also listed (some manufacturer provide considerably higher numbers...).

Visual Power (Magnification), True Field of View, and Exit Pupil for Different Focal Lengths of Eyepieces

Blue: borrowed eyepieces; italic 2" eyepiece; gray: sold

Telescope
Further Data
Focal Length of Eyepiece (mm)
Magnification
 
Focal Length of
Telescope (mm)
4
7
10
16
18
24
26
28
32
32
35
38
40
56
PS 72/432
432
108.00
61.71
43.20
27.00
24.00
18.00
16.62
15.43
13.50
13.50
12.34
11.37
10.80
7.71
C5
1250
312.50
178.57
125.00
78.13
---
52.08
---
---
39.06
---
---
---
---
---
C5 (Red.)
787.5
196.88
112.50
78.75
49.22
---
32.81
---
---
24.61
---
---
---
---
---
 
True Field of View (°)
Apparent Field of View (°) >
82
82
72
82
82
65
70
56
52
70
69
70
68
52
 
Focal Length of
Telescope (mm)
4
7
10
16
18
24
26
28
32
32
35
38
40
56
PS 72/432
432
0.76
1.33
1.67
3.04
3.42
3.61
4.21
3.63
3.85
5.19
5.59
6.16
6.30
6.74
C5
1250
0.26
0.46
0.58
1.05
---
1.25
---
---
1.33
---
---
---
---
---
C5 (Red.)
787.5
0.42
0.73
0.91
1.67
---
1.98
---
---
2.11
---
---
---
---
---
 
Exit Pupil (mm)
 
Focal Ratio
4
7
10
16
18
24
26
28
32
32
35
38
40
56
PS 72/432
6
0.67
1.17
1.67
2.67
3.00
4.00
4.33
4.67
5.33
5.33
5.83
6.33
6.67
9.33
C5
10
0.41
0.71
1.02
1.63
---
2.44
---
---
3.25
---
---
---
---
---
C5 (Red.)
6.3
0.65
1.13
1.61
2.58
---
3.87
---
---
5.16
---
---
---
---
---

Magnification: Yellow: low (30-50 x); magenta: medium (80-100 x); violet: high (150-200 x - and more); red: beyond maximum usable magnification.

Field of View: Allows to predict whether an extended object can be fully captured or whether adjacent objects can be observed together.

Exit pupil: Values in magenta cells are either too small (< 1 mm) or too large (> 6.4/7 mm); yellow background: best for galaxies (about 2-3 mm).

 

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17.11.2024