TMB 105 (4.1" f/6.2 APO) - My current wide-field imaging instrument. With the optional 3" flat-field corrector, this telescope is designed for medium-format photography, however I use it up to date only with small format. With the corrector, it delivers pinpoint stars out to the edges of 35mm format without any vignetting. It also proved to be a good CCD platform, there is an increasing number of CCD images in my Gallery of Astrophotography taken with the TMB APO. It is also an excellent instrument for visual observations, see the First-Light Report (April 2001, written in German). In the star test at high power the instrument shows stars free of any secondary color at focus, a slight trace of sperical undercorrection but no other aberrations. The internal baffling works well. About the only drawback is the heavy weight of the tube - approx. 8 kg (18 lb) for tube and optics without flatfield corrector. This telescope is designed by Thomas M. Back (TMB Optics USA), produced in Russia and sold in Europe by APM Telescopes, Germany.

Meade LX100 8" f/10 SCT - This telescope I owned from 1993 to 2011, it was my first "big" telescope and I had many of my first-time views of astronomical objects with it. It was also my first photo scope. Currently I use it mounted on the Vixen GP-DX for prime-focus and piggy-back astrophotography with a Lumicon Cassegrain Easy-Guider. For that task, it works well, but is a bit slow with its focus ratio of f/10.8. I still sometimes use it for visual observing, although the image suffers from about 1/3 lambda spherical aberration, image contrast therefore diminishes below an exit pupil of 1 mm or above 200 power. This model is no longer produced, but has many successors in the 8" LX50, LX200 and other models produced by Meade.

Starsplitter II 18" f/4.5 Dob - Howdii's big and excellent light-bucket. In this article (written in German, April 1999) he describes life and observation with this "monster". A good overview for those interested in what 18" telescopes are able to do and for those who intend to buy such a monster. The telescope was made by Starsplitter, the optics by Pegasus. Yes, that's Howdii standing beside the scope... :-)

Ceravolo HD145 (5.7" f/6 Maksutov-Newton) - an excellent telescope owned by Howdii. The optical performance of this instrument, which was made by Peter Ceravolo, never fails to astonish me, as this is an very good rich-field telescope, in fact the best I have seen yet, which as well delivers superb high-power views of planets. Howdii wrote an article about it, which has been updated in October 2003 (in German).

APM 4" f/8 APO - a Russian-made apochromatic fluorite refractor in a Vixen tube, another telescope owned by Howdii. I have taken some astrophotos and CCD images with this instrument which are excellent. It is color-free and has very good optics. Click here to read the First Light report (in German, December 1998) written by Howdii. This telescope is sold by APM Telescopes Markus Ludes in Germany. The picture shows it in astrophotographic use at the Ebenwaldhöhe in Lower Austria. As guiding scope served my old Zeiss Telementor 63/840 and the mount is my Vixen GP-DX. Yes, the guy beside the scope, that's me... :-)

APM 4" f/6.5 APO - This telescope I did own from April 1999 until May 2001. I used it for taking wide-field astrophotos with success. Click here to read a photographic evaluation of this telescope (April 1999, updated in February 2000). Field curvature is noticeable at the edges of a 35mm negative, otherwise my pictures taken with it were quite good. It is also a fine instrument for visual observations, as you can read in the First Light report, written in German (also April 1999); it shows only a barely noticeable trace of purple around bright stars and slight undercorrection when viewed at high power. This telescope was sold by APM Telescopes Markus Ludes in Germany and features Russian optics contained in a Vixen tube. The picture at left shows it mounted on my trusty Vixen GP-DX.

TASCO 4.5" f/8.2 Newton - This is a typical low-price reflector available at department stores. It comes with mount and tripod, 0.965" focuser, two Huygens eyepieces, a barlow lens and a tiny finderscope. Mount, tripod and finderscope are undersized and limit the usefulness of the scope.
This was Howdii's first "big" telescope. It had good optics, but suffered all the other problems mentioned above. To overcome these, Howdii built a solid tripod and bought better eyepieces before selling it. Read his retrospections about the TASCO Newton (in German, November 2000).

Howdii's test report about the GSO 8" f/8 Ritchey-Chrétien which he collimated and tested in November and December 2011. Read his Test Report (in German) about this telescope. This telescope comes with a 2" Monorail focuser that proved inadequate, so Howdii exchanged it for a 2,5" Moonlite focuser. He had some trouble with fine-tuning the collimation of the RC and was delayed by bad weather, so he had no time for photographic tests. The visual performance was quite good after all improvements, especially so when considering the high linear obstruction of 46%.

Howdii's report about the Boren-Simon 8" f/2,8 ED Astrograph which he collimated and tested both visually and with a CCD in November 2011. Read his Test Report (in German) about this telescope which is marketed as "PowerNewt Astrograph". The Boren-Simon is essentially an 8" f/4 GSO Newtonian fitted with carbon tube, Monorail focuser and ASA 0,73x corrector. The variant which Howdii tested sports a Baader Steeltrack focuser instead of the Monorail, a larger 75mm secondary mirror, and wooden tube rings. Howdii found some complaints about the on-tube mechanics and photographic performance, the most serious being the rather limited photographic field due to off-axis radial distorsion and light falloff. Also, this is a rather difficult scope to collimate.

Howdii bought a Skywatcher Equinox 120/900 ED APO and used it for a while for visual observations and a bit of CCD imaging. He tested it extensively and found a few optical and mechanical quirks. The lens is a doublet and is not, by strict definition, an apochromat (although advertised as such), "Semi-APO" would describe the chromatic performance better. Optically, its optics suffer from stray light, pinching and slight misalignment, although the overall performance is ok for a telescope of this price and class. Mechanically, it would need a better focuser to be usable for serious astrophotography. Read Howdii's Test Report for more information (in German, October 2011).

The Vixen Super Polaris 102 M is a classical 4" f/10 CF achromatic refractor produced from 1986 onwards, which was usually sold together with the Super Polaris mount. Howdii got this well-used sample for testing, mounted it on his venerable SP-DX, and did a through visual star test using color filters and even a 33% obstruction. Read his Test Report (in German, June 2011). He found acceptable optics and solid mechanics on this scope, typical for a Vixen telescope of this period, with only minor complaints.

Skywatcher NEQ6 Pro SynScan - Howdii got this mount for a customer and tested its performance. He subsequently wrote a Test Report (in German, May 2011) about this mount which started some years ago as inexpensive mount for visual use only and became a serious platform for astrophotographers in the meantime. Howdii found superb guiding performance on this sample, which he carefully documented, and generally attributes the NEQ6 good characteristics and handling. He also found a few minor design glitches. The NEQ6 is best mounted on a rigid hard-wood tripod.

Celestar 8" f/10 Schmidt-Cassegrain. The Celestar was produced from 1996 onward, and is in essence a downgraded successor of the Celestron C8+ of the early 1990's. Howdii got this sample for collimation and visual testing in May 2011 and subsequently wrote a Test Report (in German) about it. The optics of the telescope are actually quite good, it is free of zonal errors, and spherical aberration is well with the λ/4 criterion, maybe even as good as λ/8. However, Howdii detected signs of a rough optical surface finish, which reduces the visual contrast. The mechanics, i.e. "wedgepod" (wedge and tripod), fork-mount, etc. were made with cost reduction in mind, and are not rigid enough for a telescope of this size, thus reducing it to visual use only. It would deserve a good German Equatorial Mount for better performance.

Meade 2080 8" f/10 Schmidt-Cassegrain - The "upper-class" telescope of the beginning 1980's. Howdii got this telescope for collimation and visual tests in March 2011 and subsequently wrote a Test Report (in German) about it. The optics and mechanics are quite ok for a telescope of its time and class, the spherical aberration and off-axis coma being well within tolerance limits. Howdii, who is usually not known as SCT fan, actually likes this sample, because it delivers sharp and contrasty images on-axis, although they suffer a bit because of ghost images and some color (aberration).

DS Maksutov 152/1900 (6" f/12.5 Maksutov-Cassegrain) - a catadioptrics made in China and sold by Teleskop-Service for Central Europe. It can be bought for a very cheap price. Howdii got this telescope for collimation and visual tests in May 2006 and subsequently wrote a Test Report (in German) about it. While the on-tube mechanics were solid, the optics of the tested sample proved to suffer from severe spherical overcorrection, which rendered the telescope quite useless for astronomical purposes. This may, however, have been a singular problem of the test sample and need not be typical for this telescope series. Some other minor problems (pinching, long cool-down time) were also identified.

Meade 6" f/8 Achromat (also known as Meade AR-6, LXD55 series) - a big achromatic refractor made by Meade. Howdii got this telescope for visual tests from Astro-Experts in April 2003 and subsequently wrote a Test Report (in German) about it. This refractor is usually sold on the LXD55 mount, which is a bit overpowered with this long and heavy tube. The telescope turned out to be an allrounder, with no distinctive strengths and weaknesses, although Howdii detected modest astigmatism and diffraction spikes originating at some screw which protrudes into the light path at the lens flange. The optics of this achromatic refractor are not diffraction-limited because of the chromatic error.

Meade SN-8 (8" f/4 Schmidt-Newton) - a fast catadioptric telescope made by Meade. I got this telescope for two photographic test shots on 35mm transparency film on loan from Astro-Experts in March 2003 and subsequently wrote a short Photographic Test Report about it. The images taken with this telescopes suffer from vignetting and distorted stars near the edges. If bright stars are present near or within the photographed field, multiple reflections and Schmidt ghosts also become a major hassle.

Guan Sheng Optical 8" f/4 Newton - a fast Newtonian reflector made in Taiwan which Howdii got for servicing and testing in April 2003. Read Black and White - the double-test report of this telescope and the Leitz 8" f/4.4 Newton. This sample featured very good optics, but some major assembly problems like a pinched primary and an unnecessarily obstructing support clamp for the secondary mirror which had to be corrected to get optimum performance. In Austria this telescope is sold by Astrostudio Kamera in Vienna.

Leitz 8" f/4.4 Newton - a fast Newtonian reflector made in China which Howdii got for servicing and testing in April 2003. Read Black and White - the double-test report of this telescope and the GSO 8" f/4 Newton. This sample had some constructions problems like incorrectly positioned screwholes for the secondary mirror's collimation screws and an annoying rivet in the focuser which made the use of 2" eyepieces impossible. Also, the optical performance was not satisfying, the sample suffered from spherical aberration which makes the optics just barly diffraction-limited. Slight astigmatism and a zonal error were also detected in the startest. In Austria this telescope is sold by Astrostudio Kamera in Vienna.

10" Skywatcher Dob (10" f/4.72 Newton) - These large and low-price reflectors made in China become increasingly popular in recent times. Howdii and I got a model for testing provided by Astro-Experts in Wolkersdorf/Lower Austria. Read Howdii's Test Report (in German, March 2003). It featured a well-designed mirror cell, tube and focuser, a well-considered tension ajustment in altitude; but arrived out of collimation and showed some astigmatism in the star-test due to a flaw with the secondary mirror. This telescope is recommended for beginners.

Konus Model 1765 (6.3" f/7.6 Newton) - This telescope was tested by Howdii. The tested unit suffered from severe astigmatism and was only usable below an exit pupil of 1 mm, quality control on these scopes seems to be sloppy. The mount was shaky, barely sufficient for visual work and unacceptable for photography/CCD. This is a telescope often found in conventional photo stores and sold for cheap prices. Click here to read the test report (in German, September 1998).

TAL-2 (= Siberia 150, Sovietski 6") 6" f/8 Newton - This Russian-made telescope comes as a complete set and features ok optics and a firm, heavy mount. The drive has, however, some backlash. The telescope is a good bargain for the beginner, but is a bit heavy to haul around. When tested, it had a non-standard 32mm focuser and 32mm eyepieces; meanwhile 1.25" focuser & eyepieces should be standard. This telescope is sold under different names by many telescope vendors and are manufactured by Novosibirsk. Click here to read the double-test report about this scope and the GAT 10" (in German, 1995).

GAT 10" (=Discovery 10") 10" f/6.5 Dob - This telescope has good optics and on-tube mechanics, but a shaky mount which doesn't move well, allowing no higher magnifications than 200x. Click here to read the double-test report about this scope and the TAL-2 (in German, 1995). This telescope is sold by Grab Astro Tech.

PENTAX 105 SDHF (4" f/7 Refractor) - This telescope tested by Howdii is designed as astrocamera, is well corrected and has a very flat focal plane, but it shows visually a conspicuous purple halo around bright stars. It is quite expensive. In Austria this telescope is sold by Astrostudio Kamera in Vienna. Click here to read the report (in German, 1994).