For wide-field imaging the JSO LS-12D, a (nominally) 125/475 mm Wright Väisälä Camera often referred to as a Wright-Newtonian telescope. This rather exotic catadioptric telescope is designed as an astrocamera with an ellipsoidal primary mirror, an aspherical front plate to correct for the resulting optical errors, and a flat secondary mirror to achieve a Newtonian-like focus on the side of the tube. It was manufactured by Japan Special Optics Co, a company that ceased to exist in 1996. I obtained my specimen used from a long chain of predecessors. With a measured focal length of 469 mm and a focal ratio of f/3.8, it is very good for imaging large nebulae and Milky Way structures, the results often having Schmidt camera-like quality. Its drawbacks are an inadequate drawtube and slight off-axis astigmatism. However, the latter can be used for precise focal plane adjustment. The front glass plate is prone to dew formation (or ice in cold conditions), so I use a dew cap in front of it, in the photo you can also see a dust shroud covering the front end during daylight.

For medium-to-wide field imaging the TS-Optics GSO Photon 6" F4 Newtonian with metal tube which I have fitted with a primary mirror baffle to improve its star images. I actually like the 0.5 mm thin stainless steel spider which provides good stability to the secondary mirror, although it causes large spikes. Due to the aperture ratio of f/4, this Newtonian is quite fast, but requires a coma corrector to work with photographically. Most often I use the TS-Optics Newtonian Coma Corrector 0.95x Maxfield, which reduces the focal length to 578 mm. The front end of the GSO Newtonian is covered by a dust cap in the photo.

For medium focal length imaging a 9.5" Newtonian with a nominal aperture/focal length of 250/1200 mm; actually measured as 242/1180 mm at an optical bench. Its optics were purchased from Orion Optics UK via Teleskop-Service, while the shiny aluminium tube assembly was custom-made by a mechatronics expert. The secondary mirror has a small diameter of 3.5". Its drawback are a reduced serviceablity of the main mirror because it can't be removed from the rear end of the tube (instead it needs to be removed from the front) and some faults in the main mirror coating which formed over time. I use two different coma correctors with this telescope:

• A Tele Vue Photographic Paracorr, which boosts the focal ratio of this scope to f/5.6 and to an effective focal length of 1345 mm;
• A TS-Optics Newtonian Coma Corrector 0.95x Maxfield, which reduces the focal ratio of this scope to f/4.7 and to an effective focal length of 1130 mm.

The cardboard disk fitted to the rear end of the tube which can be seen in ths photo prevents light from entering from the rear while still maintaining a gap open for air flow.

Mainly to capture the colors of the stars, but sometimes for [OIII] narrowband imaging, I use a small TS-Optics Doublet SD Apo 72 mm f/6 refractor with Lanthanum glass objective. It uses a FPL53 glass element from Ohara (Japan). I use it in combination with an 1x field flattener which does not change the focal length. The focuser is a 2.5" dual-speed rack-and-pinion type. Since the small refractor is usually mounted on top of other telescopes, most often the 6" GSO Newtonian featured above, I use ajustable guidescope rings to hold the refractor in place. This way I can adjust the pointing of the refractor. The front end is ususally surrounded by a dew cap to prevent dew from forming on the front glass surface, as can be seen in the photo.

For visual observation, and sometimes also for astrophotography, the TMB 105 which is a 105/650 mm triplet apochromatic refractor with optics designed by Thomas M. Back (USA), manifactured by LZOS (Russia) and originally sold in Europe by APM Telescopes in Germany. My version of this refractor has a heavy German-made tube. For astrophotography, a flatfield corrector is mandatory, I use the flatfield corrector which was optionally sold with this telescope. It is designed for medium film format, so I use a custom-made adapter for my CCD and digital cameras. I have measured the refractor's effective focal length with flatfield corrector as 699 mm at a focal ratio of f/6.7, which I find a bit slow for astrophotography. Also, the focuser has no gear reduction for fine focusing. However, I used the TMB refractor successfully for lunar eclipse phototgraphy as can be seen here (YouTube link).

Since 2022 I use a Skywatcher EQ6-R Pro SynScan mount for astrophotography. It has a total weight of 16 kg and is rated for loads up to 20 kg. It has GoTo capability with over 42.000 stored objects in its SynScan hand controller - however, for astrophotography, I exclusively control it via Notebook per USB cable. It is belt driven, resulting in minimal backlash. Telescopes van be mounted both via 3" Losmandy and 2" Vixen rails. It has a built-in Polar Alignment Scope, which is good enough for my applications. GoTo almost always lands me right next to the object I want to photograph. However, the 9.5" Newtonian plus finder-guidescope, camera, autoguider and other accessories push the EQ6-R mount to its limits. I would not load it with much more than that. The Skywatcher EQ6-R is a good standard mount used by many astrophotographers.

My other mount and old workhorse for astrophotography is an OTE-150 (2002 version), which is a mid-weight German Equatorial Mount produced in Germany. It may not look attractive, but it is rigid, and its drives run quite smoothly with a built-in mechanical (!) periodic error correction. I have been using it for 20 years for taking my images. This mount handles most telescopes well, even under windy conditions, but is a bit on the heavy and unwieldy side.

The first serious mount I bought second-hand for astrophotography was a Vixen GP-DX. I still use it, but almost exclusively as secondary mount for visual observations, often with the TMB refractor. On rare occasions, the GP-DX serves as rotating base for time-lapse videos of the night sky.

My primary monochrome camera as of 2023 is a ToupTek ATR3CMOS26000KMA which features an APS-C sized Sony IMX571 CMOS sensor. With a size of 23,5 mm x 15,7 mm it has the largest sensor of the astro-cameras in my arsenal, equal only to the OMEGON veTec 571 C (see below). At the same time it has the smallest pixels of all my cameras with a pixel size of 3.76μm x 3.76μm, the ADC has a bit depth of 16 bit, and it features 6224 × 4168 effective pixels. It cools down to a maximum of 40 degrees below ambient temperature, the chip temperature is regulated. I set it to minimum gain (100) to use the camera's entire dynamic range and full-well capacity. "High gain" and "Ultra" modes are active, the latter noticably reduces the camera's readout noise.

The secondary monochrome camera is the ZWO ASI1600MM Pro which features a MN34230 CMOS sensor with 4656 × 3520 pixels (16.3 megapixels). The pixel size is 3.8μm × 3.8μm It (slowly) cools down to a maximum of 45 degrees below ambient temperature. The ASI1600 is used for taking deep luminance frames in the field, and in combination with narrow-band filters in my backyard (see below). I use gain 30 with this camera, as anything less results in noticable horizontal banding.

My primary single-shot color camera is a OMEGON veTec 571 C. This is basically the same camera as the ToupTek ATR3CMOS26000KMA described above, but it has a sensor with RGGB filter matrix. The Omegon color cameras are also equipped with an infrared-blocking filter. I use the same "minumum gain" setting as with the ToupTek camera.

My secondary single-shot color camera is a ZWO ASI294MC Pro. It is equipped with the Sony IMX294CJK CMOS sensor which has 4188 × 2822 pixels (11.8 Megapixels). The pixel size is 4.63μm × 4.63μm and the bit depth 14 bit. The ZWO ASI also has a RGGB bayer matrix on the sensor. It can be cooled down to -35 degrees below ambient temperature. With the ASI294MC, I use gain 0 as standard setting.

My primary DSLR camera is an astromodified Nikon D5600 comes in Nikon DX (APS-C) format and features a sensor with 6000 × 4000 pixels (24 megapixels). The pixel size is 3.9μm × 3.9μm, the bit depth 14 bit. To overcome the camera's weak Hα sensitivity, the IR-cut filter has been replaced by the shop. The camera is otherwise unmodified and thus not cooled. For astrophotography, I mainly use it with a Samyang 135mm F2 ED UMC lens, which is a fast aspherical telephoto manual focus lens well-suited for astrophotography.

When astro-imaging with the Nikon 5600, I use a sensitivity of ISO 400. 5-minute exposures will yield a nice Signal-to-Noise (S/N) ratio and a sky background level somewhere between 10% and 30% of saturation level, and this ISO setting turned out to yield the best S/N for faint object detail when astro-imaging at a dark site.

For time-lapse videos of the night sky, I use my old Nikon D7000. It has not been modified. I couple Nikon lenses to it, most often the Nikon 18-200mm VR lens locked down to 18mm for wide-angle expsures. Usually, the ISO is set to 6400 for the indivual exposures which I later combine to a time-lapse video. The flexible band around the lens which can be seen in the photo is a heater against dew.

Since 2012 I am guiding my astrophotos with a Lacerta MGEN-2 stand-alone autoguider. This is another one of these good devices which worked perfectly right from the start and never gave me any troubles. The MGEN is placed in the primary focus of a TS-Optics 8x50 Finder for most telescopes. My prefered guide settings are: Mode 2, 0.3 pixel tolerance for both axis, and an aggressiveness of 30%-120% depending on the mount, local seeing and wind speed (if any). The MGEN is attached to the guidescope of the TMB 105 refractor via 2x Barlow lens in this image.