Telescope Accessories

Introduction | LED Red + White Flashlight (Adjustable Brightness) | Crosshair eyepiece, 12.5 mm focal length, illuminated | 12V / 7 Ah Rechargeable Power Tank | SkyWire Serial Accessory | Telrad Finder | Baader Laser-Colli Mark III (Laser Collimator) | Variable Polarizing Filter (Gray Filter) | Sun Filter | Focal Extender (Tele Extender) | Focal Reducer | Amici Prism | Diagonal Mirror | Digiklemme 1 | Focusing Aids | Links

On this page, I present an overview of my telescope accessories.

 

Introduction

As with all hobbies, you are not done with astronomy when you buy a telescope with perhaps two kit eyepieces. Unfortunately, this is only the beginning of a series of further investments. These do not only apply to larger and larger telescopes, but also to better eyepieces, which can be even more expensive than beginners' telescopes, as well as a wide range of accessories that improve the observation experience or make it possible at all.

Note: One might list the Atik Infinity Colour camera as an accessory here as well, but I present it in a section of its own. Here is the information page for the camera.

In the following I present the most important accessories (except eyepieces), which I acquired over time. This includes things such as devices that

 

LED Red + White Flashlight (Adjustable Brightness)

Flashlight with box, side view

Side view: You can see three screws that need to be loosened to open the case for changing the 9 V battery

White light

Flashlight with box, top view

Top view: On the top you can see the red-white switch (left) and the control for setting brightness and turning the light on or off (center)

Red light

I use this lamp (from Sky-Watcher) to read star charts and astronomy books or do other things at the telescope without losing my dark adaptation. Unfortunately, the red light illuminates everything rather unevenly. Annoying is also that you have to unscrew the lamp for changing the battery (9V block battery; I am curious how long this will work...).

Link

 

Crosshair eyepiece, 12.5 mm focal length, illuminated

Package content, batteries already installed in the illumination device

Above: Illumination device with batteries and brightness control / on/off switch screwed in

Middle right: double cross hairs, not illuminated

Bottom right: double cross hairs, illuminated

I bought the crosshair eyepiece (12.5 mm focal length; by Seben) for two purposes:

However, I have the impression that the focal length of the eyepiece is a bit short (or the magnification is too high...) for the second purpose. After experiencing some difficulties, I once again returned to the 32mm eyepiece for the alignment...

I am curious, how long the two small batteries will last...

Links

 

12V / 7 Ah Rechargeable Power Tank

The 12 V cable for charging via car battery and for supplying the GoTo mount is stored in a timber (with caption); initially, I thought it would be missing (in the instructions it is listed, but not where it is ...)

I bought the Sky-Watcher 12V / 7Ah Power Tank with red / white light and a rechargeable lead acid battery, because the 8 AA batteries, with which I had initially supplied the Star Discovery mount, had been used up very quickly. So I hoped that with this device power will last longer. However, I read that even the Power Tank is drained in only one night. In my eyes, this is not a problem, because you can recharge the Power Tank over night (if you do not forget this*...). At the moment, I can only tell that the power did not exhaust in one session. This was, however, before I also used an Atik Infinity camera with the mount. I have no idea up to now, how the camera impacts battery drain...

*) You should recharge the Power Tank after each observation session before you stow it away, because fully charged battery cells are more robust against damage than partially charged cells (did I read in a forum).

Main technical data:

Link

 

SkyWire Serial Accessory

Originally, I intended to use the Star Discovery GoTo mount only with the SynScan hand box, even though I knew that controlling the telescope using astronomy software applications such as Stellarium is possible with the Star Discovery mount. However, an RS232 to USB adapter is required to connect the hand box to the computer, but it is not guaranteed that such an adapter will work on the Apple Macintosh. So I did my first attempts on using GoTo with the SynScan hand box. This succeeded fairly well, but I'm not a friend of this kind of interaction and find hand boxes rather counter-intuitive - quite in contrast to controlling telescopes using astronomy apps.

Southern Stars SkyWire Serial Accessory

Ditto connected to iPad and hand box

Ditto

Ditto, detail

Ditto

Ditto

I accidentally came across SouthernStars' SkyFi WiFi device (built for Simulation Curriculum, the developers of the Starry Night and SkySafari astronomy applications), which seemed too expensive for me. But then I discovered that there is also a wired solution for the iPad from SouthernStars, the considerably cheaper SkyWire (unfortunately it does not work with the MacBook ...). This device is available in two versions, a cheaper one for the old 30-pin connector and a slightly more expensive one for the Lightning connector. Since my iPad sports a Lightning connection, I would have needed an adapter for the cheaper version. But this combination would be priced similarly to the Lightning version - and would include a potentially wobbly adapter. So I finally decided to buy the Lightning version of the SkyWire device, because I was curious to learn how controlling a telescope using an astronomy app does work.

One advantage of the SkyWire compared to the SkyFi is that it does not need any power supply. Its drawback is that it is connected to the iPad via cable. This means that the device can not be positioned at will, and in the dark the cable is also a potential stumbling block.

So far, I made only had a few experiences with SkyWire, but I can already report that the setup is hassle-free, and controlling the telescope works well. Furthermore, if the deviations from the target are not too large, the position can be corrected so that the observed object is actually approached and not a point in its vicinity. Sometimes, however, the deviation was too large for a correction. Then, however, I mostly managed to step-by-step approach the target while updating the position in the SkySafari app (command "Align").

Note: The SkyFi and SkyWire telescope control accessories are now owned and supported by Simulation Curriculum Corporation. Contact Simulation Curriculum for technical support on these products (from: www.southernstars.com/products/index.html).

Links

 

Telrad Finder

Base from above and already mounted on the telescope tube

Finder (without base) from the side. You can see the little feet for mounting the finder to the base as well as the main switch (left).

Finder (without base) seen more from above

Rear view of the finder; you can see the three collimation screws at the back and the main switch on the side (also regulates brightness of the LED/rings)

 

Telrad finder with LED switched on; regrettably, the rings on the mirror are blurred

Telrad finder opened; battery holder on the right (2 AA cells)

I purchased the Telrad finder for my GSD 680 telescope, because I prefer a red dot finder to a (magnifying) viewfinder. The Telrad finder projects three rings (corresponding to a visual angle of 0.5°, 2°, and 4°) on a mirror, which serve to target celestial objects. However, I have not yet resolved the assembly of the viewfinder at the GSO 680 telescope satisfyingly.

In February 2017, I bought a 5 cm riser base and a dew cap with 90° mirror for the Telrad finder:

Riser base (5 cm)

Telrad with riser base and dew cap+

Mirror in "use" position...

Note: In April 2017, I sold the Telrad finder including its accessories, because the Telrad finder was too large for my Sky-Watcher 6" Explorer 150PDS tube and I had given my 8" Dobsonian telescope to a dealer for selling it. I am therefore regrettably unable to report any further experiences with the Telrad finder on this site.

Links

 

Baader Laser-Colli Mark III (Laser Collimator)

To adjust misaligned telescopes correctly, a collimator is used. A collimator using a laser beam is also referred to as a laser collimator. In the case of a Newtonian reflecting telescope, the primary and the secondary mirror must be adjusted so that they are mutually centered as well as centered on their optical axes. Since I was not satisfied with the performance of my telescopes, I decided to buy a laser collimator to improve the adjustment of my telescopes.

The Laser-Colli Mark III with package and instructions

Laser-Colli Mark III in "off" state

Laser-Colli Mark III in "on" state: Laser beam made visible

Baader Planetarium offers a laser collimator, called Laser-Colli Mark III, which differs from other collimators by having a vertically mounted transparent disc with a central hole and a grid of crosses to show the position of the the laser dot. Thus, one can observe the adjustment process when adjusting the primary mirror. Moreover, the device has a particularly large cut-out, which also reduces its weight.

Since this collimator was selected in a comparative test by the magazine Night at Sky in 2010 as the winner, I decided for it. It is a little more expensive (85 EUR) than other devices (but there are also much more expensive devices ...), but Baader is considered to be a renowned manufacturer of astronomical products, and therefore, I hope that the device was adjusted properly at the factory (you can re-adjust it).

Links

 

Variable Polarizing Filter (Gray Filter)

Package

The variable polarizing filter (a bit dirty) from above...

...consists of two filters that can be turned to adjust the brightness

Filter taken our of the package

Filter at eyepiece

Ditto, more oblique view

The moon, as well as the planets, can be very bright - sometimes too bright - so that it is advisable to dampen the light. In addition, details of the moon or of planets can be overshadowed by areas that are too bright. Remedy is provided by gray filters of different densities or by variable polarization filters, which allow to adjust the brightness within certain limits (the filters are screwed into the eyepiece). I decided for the latter, even though damping the light is sometimes a bit "fiddly".

Link

 

Solar Filter

EMC Solar Filter SF 100, Order Number 600-105

In order to be able to observe the Mercury transit in May 2016, I acquired a euro EMC solar filter for my Sky-Watcher Heritage 100P Dobsonian telescope, namely the type SF 100 filter (order no. 600-105, size 5: for tubes with a diameter from 103 to 131 mm, aperture = 96 mm). These filters utilize the Baader Planetarium Astro Solar film of density 5 (ND5), which is suitable for both visual observation and projection photography.

    

Packaging of the filter size 5 from above

 

Ditto from below and with included Allen wrench

 

Filter from below

 

Filter from above

EMC Solar Filter SF 100, Order Number 600-106

In order to be able to also observe the sun, I acquired a euro EMC solar filter for my Sky-Watcher Skymax-127 OTA, namely the type SF 100 filter (order no. 600-106, size 6: for tubes with a diameter from 129 to 157 mm, aperture = 120 mm). These filters utilize the Baader Planetarium Astro Solar film of density 5 (ND5), which is suitable for both visual observation and projection photography.

    

Packaging of the filter from above

 

Ditto from below

 

Filter from below

 

Filter from above

EMC Solar Filter SF 100, Order Number 600-107

In order to be able to also observe the sun, I acquired a euro EMC solar filter for my Sky-Watcher Explorer 150PSD Newton tube, namely the type SF 100 filter (order no. 600-107, size 7: for tubes with a diameter from 155 to 202 mm, aperture = 146 mm). These filters utilize the Baader Planetarium Astro Solar film of density 5 (ND5), which is suitable for both visual observation and projection photography.

    

Packaging of the filter size 5 from above

 

Ditto from below and with included Allen wrench

 

Filter from below

 

Filter from above

EMC Solar Filter SF 100, Order Number 600-109

Initially, I had purchased a solar filter from the same series for my GSO GSD 680 8" Dobsonian telescope (order no. 600-109, size 9: for tubes with a diameter from 219 to 283 mm, aperture = 207 mm).

   

Packaging of the filter from above

 

Ditto from below

 

Filter from below - note the 4 additional slots (from size 9 on)

 

Filter from above - note the 4 additional slots (from size 9 on)

But I had to order also the smaller filter, because, due to a surgery, I was no longer able to carry the heavy 8" telescope. So I had to resort to my smallest telescope, the Heritage 100P, for the observation of the Mercury transit in May 2016.

Note: In April 2017, I sold the EMC Sun Filter SF 100, order number 600-109 (size 9), because I sold my GSO GSD 680 8" Dobsonian telescope (it was too heavy for me). I am therefore regrettably unable to report any further experiences with the filter size 9 on this site.

Links

 

Focal Extender (Tele Extender)

Extenders such as Barlow lenses or telecentric extenders (Focal Extender or Tele Extender) prolong the focal length of telescopes, so that you can virtually double or triple the number of your eyepieces if you use one or two of them. In May 2017, I first bought a 2 x focal extender from Explore Scientific and shortly afterwards a 3 x version of it.

Like Barlow lenses, focal extenders move the focus point outward. This can be relevant in the case that a camera does not come into focus, which is often the case with telescope tubes that are primarily designed for visual observation.

Explore Scientific Focal Extender 2 x with caps

Explore Scientific Focal Extender 2 x top view

Explore Scientific Focal Extender 2 x rear view

Explore Scientific Fokal Extender 2 x alone

Ditto with TeleVue 24 mm eyepiece

Ditto with TS Optics 4mm UWA eyepiece

Explore Scientific Focal Extender 3 x with caps

Explore Scientific Focal Extender 3 x top view

Explore Scientific Focal Extender 3 x rear view

Explore Scientific Fokal Extender 3 x alone

Ditto with TeleVue 24 mm eyepiece

Ditto with TS Optics 4mm UWA eyepiece

Links

 

Focal Reducer

Focal reducers, as the name implies, shorten the focal length of a telescope. Using them actually doubles the number of eyepieces (or triples them for two reducers), but usually and in contrast to Barlow lenses and focal externders, this is not the reason why they are being used. In December 2017, I purchased a simple 2 x focal reducer from TS Optics (1.25"), plus a 1.25" extension sleeve (2.5 cm long) that transforms it into a 3x reducer (the exact values depend on the distances from).

Focal reducers are primarily used in astrophotography to increase the field of view. According to their factor, they also increase the the aperture ratio of the telescope.

TS focal reducer 2 x (right) and extension tube (left) Ditto Ditto
TS focal reducer 2 x (right) and extension tube (left) TS focal reducer 2 x (left) and extension tube (right) Ditto
Both fitted together Ditto Ditto

Links

 

Amici Prism

An Amici prism serves for achieving a correct and upright image. I purchased the Baader Amici Prisma BA2956150 for 1.25" eyepiece mount and with 45° angle for terrestrial observations. The reason for buying this specific Amici prism was Baader's claim that this prism has a large opening (24 mm instead of 19 mm), larger than most others prisms. In addition, the glass surfaces multi-coated.

Baader 45° Amici Prism

Ditto

Ditto

Baader 45° Amici Prism in use

Ditto

Ditto

2'' to 1.25'' Amici Prism

I purchased the Omegon 45°, 2'' to 1.25'' Amici prism for terrestrial observations with the Omegon PS72/432 refractor, which allows to use 2" equipment. This Amici prism is recommended for the telescope.

Omegon 45°, 2'' to 1.25'' Amici prism

Ditto

Ditto

Ditto

Omegon 45°, 2'' to 1.25'' Amici prism in use

Ditto, closer view

Links

 

Diagonal Mirror

When you observe sky objects that are located close to the zenith using a refractor or a Maksutov-Cassegrain telescope, this can turn into acrobatics because you have to creep "under" the telescope to be able to look through the eyepiece. Diagonal mirrors offer a remedy because they redirect the light by 90°. A diagonal mirror was included with my Sky-Watcher Maksutov Cassegrain telescopes, but this mirror is of lower quality (91% transmission). When I purchased a used Sky-Watcher Skymax 127 tube, I also got a better diagonal mirror (Lacerta, 99% transmission) because the previous owner had bought one additionally. However, right away I do not see much difference between the two mirrors...

Sky-Watcher diagonal mirror
Ditto
Ditto
Ditto
Ditto, at the Skymax-102
Lacerta diagonal mirror
Better diagonal mirror (Lacerta) bought by the previous owner of my Skymax-127
Lacerta diagonal mirror in use

Better diagonal mirror (Lacerta) bought by the previous owner of my Skymax-127
Lacerta diagonal mirror in use

2" Diagonal Mirror

I purchased the Omegon star diagonal with 99% reflection, 2" with dielectric coating for my Omegon PS 72/432 refractor, because this telescope can utilize 2" accessories and because the 2" to 1.25" adapter from Sky-Watcher, which I wanted to use, did not fit securely in the eyepiece holder.

Omegon star diagonal with 99% reflection, 2" (dielectric coating) with 2" to 1.25" adapter
Ditto
Omegon star diagonal in use with 1.25" eyepiece

Ditto, closer view
Ditto with 2" eyepiece
Ditto, closer view

Links

 

Digiklemme 1

I often use the 1:50 method to take photos of the moon, but holding the camera (one with or without a filter thread ...) to the eyepiece is a wobbly affair, and I often have trouble getting a view without vignetting. The Digiklemme 1 from Teleskop-Express announces itself as the solution to this problem: "The Digiklemme offers an easy to use adaptation that works with most compact digital cameras and most eyepieces for telescopes, spotting scopes, microscopes etc. Each compact digital camera has the 1/4" camera thread needed for this adaptation." But already on the Website the Digiklemme 1 looks more like a "handicraft solution." Nevertheless, I ordered one for myself (the price had dropped a little...) to try it out. I soon found out that I cannot use my better wide angle eyepieces together with Digiklemme 1 because the maximum allowed eyepiece diameter is 40 mm... I describe my experiences on page Digiklemme 1.

Digiklemme 1, all parts

Ditto

Ditto

Figure of Digiklemme 1 on its box

Digiklemme 1 at the telescope, no camera

Digiklemme1 with Ricoh GR camera at the telescope

Links

 

Focusing Aids

Bahtinov Mask and "easy-sharp" Focusing Mask

Both with my Atik Infinity camera and when photographing with the projection method, I have problems with focusing the telescope reliably. I therefore bought two focusing aids on the AME2018 astronomy fair in Villingen-Schwennigen, Germany: a Bahtinov mask from Lacerta and an "Easy-sharp" focusing mask from noctutec. I will report my experiences as soon as there are any..

Bahtinov mask (Lacerta, for 150 mm aperture), delivered with 3 clamps

"easy-sharp" mask (noctutec, for 150 mm aperture)

Links

 

Links

 

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made by walodesign on a mac!
11.10.2018