TS-Optics CF-APO 90 mm f/6 FPL55 Triplet APO Refractor with Certificate

TS CF-APO 90/540 mm FPL55 Triplet Apochromat

The 90 mm apo is pure in colour and bright in light and is equally suitable for visual observation and astrophotography. Thanks to the FPL55 APO element (comparable to FPL53) the image is first-class and in practice cannot be distinguished from the world-famous LZOS lenses from Russia.

The compact apo is only slightly larger than apos with 80 mm aperture, but offers a much better performance in the sky. This refractor is an ideal traveling telescope due to the retractable dew cap and a transport length of a good 400 mm.

The objective of the 90 mm apo:

The triplet lens with 90 mm aperture and 540 mm focal length fulfils the criteria of a full apo. Even at magnifications of 300x, the image is free of annoying chromatic aberrations. Even bright stars are shown on astrophotos without disturbing blue fringes.

The APO element consists of FPL55. A further special glass supports chromatic correction. The air-spaced triplet objective is fully adjustable. Each optical glass-air surface is multi-coated. The objective is in a temperature compensated, adjustable cell.

The photographic 2.5" rack&pinion focuser:

The 2.5" CNC focuser is optimized for photography and can handle a load of up to 6 kg. The adjustment of the draw tube is done by gear drive. We also offer motorized focusing for the focuser. An M63x1 internal thread is available for screwed adaptations. The focuser also offers 360° rotation for selecting the correct image section.

Astrophotography with the apochromat

To achieve the optimal imaging in the field, a corrector is needed. The corrector is screwed directly to the M63 thread of the apo. We recommend two correctors, both are suitable for cameras up to full format. The working distance from the M48 thread to the sensor is 55 mm.

TSCFRED90 - 0.8x corrector: The corrector is specially calculated for this apo. It reduces the focal length to 432 mm and improves the focal ratio to f/4.8.

TSFLAT25del - 1.0x corrector: The corrector provides maximum illumination. It does not change the focal length and focal ratio. The working distance from the M48 thread to the sensor is 55 mm.

Video

TS has made a video about the CF Apos:

Astrophotographic results obtained with this telescope on Astrobin

Here you can find some astrophotographs made with this telescope model: Link to Astrobin

Technical Information

Teleskop-Service has collected a lot of helpful information about refractors and provided it in English as a PDF file: refractors.pdf

Astrophotographic results obtained with this telescope on Astrobin

Here you can find some astrophotographs made with this telescope model: Link to Astrobin

Customer photo without corrector

Our customer Harley Grady (AstroPhotoBooth at Instagram) from Texas (USA) mounted his astro camera to the telescope, took a series of images through a dual band filter and then combined them. You can notice the influence of the field curvature, but nevertheless the nebula has been photographed very appealingly:

Object: Rosette Nebula (NGC 2237-2239)
Photographer: Harley Grady from Texas, USA (Bortle 5)
Imaging optics: TS CF-APO 90 mm (TSCFAPO90)
Filter: Optolong L-eXtreme
Imaging camera: ZWO ASI2600MC Pro
Exposure time: 126 x 300 sec (126 x 5 min, shot over three nights)
Guiding scope: TS-Optics 50 mm guiding scope TSL501
Guiding camera: ZWO ASI120MM Mini
Mount: Skywatcher AZ-EQ5
Image processing: Pixinsight, Topaz AI, Topaz DeNoise, Photoshop

Many thanks to our customer Harley Grady from Texas (USA) for the great photograph of the Rosette Nebula.

Customer photo with corrector

Our customer Mario Barrera from Chile also took a series of images through a dual band filter and then combined them. The use of a corrector specially designed for this telescope provides a very good image:

Object: Dolphin Head Nebula (Sh2-308)
Photographer: Mario Barrera from Chile (Bortle 5)
Imaging optics: TS CF-APO 90 mm (TSCFAPO90)
Field corrector: TS-Optics 0.8x Corrector for TS 90 mm f/6 CF-Apo (TSCFRED90)
Motor focus: ZWO EAF (ZWO-5V-EAF-A)
Filter: Optolong L-Ultimate (L-ULTIMATE2)
Imaging camera: ZWO ASI2600MC Pro (ASI2600MC-P)
Exposure: 23 x 300 sec (23 x 5 min), additionally Flat + DFlat + Bias + Dark
Guiding scope: William Optics Guidestar 61 (alternative: TSMPT60)
Guiding camera: ZWO ASI290MM Mini (ASI290MINI)
Mount: ZWO AM5 (ZWO-AM5)
Imaging processing: Pixinsight, Photoshop

Many thanks also to our customer Mario Barrera from Chile for this great photograph.

Here is a picture of Mario Barrera´s gear:

This brings color into life ...

Equipment as above, i.e.

Guiding scope: William Optics Guidestar 61 (alternative: TSMPT60)
  Guiding camera: ZWO ASI290MM Mini (ASI290MINI)
Telescope: TS CF-APO 90 mm (TSCFAPO90)
  Motor focus: ZWO EAF (ZWO-5V-EAF-A)
  Field corrector: TS-Optics 0.8x Corrector for TS 90 mm f/6 CF-Apo (TSCFRED90)
  Filter: Optolong L-Ultimate (L-ULTIMATE2, not visible)
  Imaging camera: ZWO ASI2600MC Pro (ASI2600MC-P)
Mount: ZWO AM5 (ZWO-AM5)
Black half pier
Purple pier, inside
  Control: ZWO AsiAir Plus (ASIAIRPLUS)

Question:
Does the EAF motor focus fit to the CF Apos from Teleskop-Service?

Answer from Teleskop-Service:
The EAF fits directly without additional adapter to the focusers of the CF Apos.