itelescope/TELESCOPES.md

iTelescope.net telescope review

A review of every telescope on the iTelescope.net network, grouped by observatory. Compiled 2026-07-17 from the network's own sources:

• Support article (observatory summaries, minimum elevations): https://support.itelescope.net/support/solutions/articles/247371
• Maintained specs Google Sheet (snapshotted in data/itelescope-telescopes.csv): https://docs.google.com/spreadsheets/d/1jZWkkjewOuyNC9YzQ8y2d0pO1e4T7EBeysmQMPBVSOk/
• The launchpad (https://go.itelescope.net/) is login-only and holds no public specs.

Note on coverage: the Google Sheet is the maintained source and is what this review follows. The older support article additionally lists T9, T19, T31 and T69, which no longer appear in the sheet (retired or rebuilt); T74 appears in the sheet with no specs, presumably in commissioning.

The network at a glance

Observatory	MPC code	Hemisphere	Telescopes
Utah Desert Remote Observatory, USA	U94	North	T2, T5, T11, T14, T20, T21, T25, T26, T68
Sierra Remote Observatory, California, USA	U69	North	T24
Siding Spring Observatory, Australia	Q62	South	T8, T17, T30, T32, T33, T59
Deep Sky Chile	X07	South	T70, T71, T72, T73, T74, T75
AstroCamp Observatory, Spain	I89	North	T18
Entre Encinas y Estrellas (e-EyE), Spain	(none listed)	North	T80

Two systems are free to use (30 minutes per day): T68 (Utah, fast colour widefield) and T33 (Siding Spring, narrow deep field).

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Utah Desert Remote Observatory (MPC U94)

Dark Great Basin desert site; the largest cluster on the network and the main northern-hemisphere hub.

T2: Takahashi TOA-150 + QHY268C (one-shot colour)

• 150 mm f/7.3 apochromatic refractor, 1105 mm focal length
• QHY268C colour CMOS (Sony IMX571, APS-C), 0.69"/px, 72.6 x 48.6 arcmin
• Paramount GTS, off-axis guided, no filters; minimum elevation 25 degrees

Review: the premium one-shot-colour option. Superb refractor optics and a modern back-illuminated sensor at a well-sampled 0.69"/px make it the easiest route to a finished colour image of medium-sized targets (galaxy groups, planetary nebulae, globulars) with no filter runs to plan. No narrowband, so emission nebulae under moonlight are off the menu. Files are large (26 MP 16-bit FITS).

T5: Takahashi Epsilon 250 + SBIG ST-10XME

• 250 mm f/3.4 hyperbolic flat-field astrograph, 850 mm focal length
• ST-10XME CCD (NABG), 1.66"/px, 60.6 x 40.8 arcmin
• Paramount PME, external guiding; RGB, Ha/SII/OIII, and Johnson-Cousins B, V, I

Review: a fast classic. The f/3.4 Epsilon gathers light quickly for its class and the photometric filter set makes it one of the few scopes that does both pretty pictures and science. The small, old NABG CCD is the weak point: only 3.2 MP, and bright stars bloom on long exposures, so keep subs short around bright fields.

T11: Planewave CDK20 + FLI ProLine PL11002M

• 510 mm (20") f/4.5 corrected Dall-Kirkham with 0.66x reducer, 2280 mm
• PL11002M CCD (full frame), 0.81"/px, 54.3 x 36.2 arcmin
• Ascension 200HR; LRGB, 3 nm narrowband, and U, B, V, R, I; minimum elevation 20 degrees

Review: big aperture at a fast reduced focal ratio with a generous field: a strong general-purpose deep-space scope for nebulae and larger galaxies, plus full UBVRI for photometry. The sensor's 51% peak QE is dated, so it needs more integration time than the CMOS scopes for the same depth, and it is noted as sensitive to stray-light gradients near full moon.

T14: Takahashi FSQ-106 Fluorite + SBIG STX-16803

• 106 mm f/5.0 Petzval refractor, 530 mm focal length
• STX-16803 CCD, 3.5"/px, 238.8 x 238.8 arcmin (4 x 4 degrees)
• Paramount ME, unguided; LRGB, 5 nm Ha/SII/OIII, V; minimum elevation 25 degrees

Review: the classic mono widefield workhorse. Four square degrees on the square 16803 sensor suits large nebula complexes (North America, Veil, Rho Ophiuchi) and mosaics. CCD rather than CMOS, so integration is slower than modern rivals, and dithering is recommended. Pick it for framed mono narrowband over T20's colour.

T20: Takahashi FSQ-106ED + ZWO ASI2400C (one-shot colour)

• 106 mm f/5.0 Petzval refractor, 530 mm focal length
• ASI2400C colour CMOS (Sony IMX410, full frame, 14-bit), 2.31"/px, 233.7 x 155.8 arcmin
• Paramount ME, unguided; Optolong L-Pro and L-Ultimate (3 nm dual-band), Astrodon narrowband
• Field rotated 90 degrees relative to T14 for alternative framing

Review: the colour twin of T14 with a modern full-frame CMOS. The L-Ultimate dual-band filter is the clever bit: one-shot-colour narrowband on emission nebulae, even with the moon up. Sensor is 14-bit, so dynamic range trails the mono 16-bit scopes. The best low-effort widefield choice on the network.

T21: Planewave CDK17 + FLI PL6303E

• 431 mm (17") f/4.5 corrected Dall-Kirkham with 0.66x reducer, 1940 mm
• PL6303E CCD (NABG), 0.96"/px, 49.2 x 32.8 arcmin
• Ascension 200HR; Astrodon LRGB, 5 nm narrowband, and UBVRI; minimum elevation 20 degrees

Review: billed as a combined photometry and imaging system, and that is its niche: the sensitive NABG chip plus a full Johnson-Cousins set makes it a proper science scope. The same NABG sensitivity means blooming on bright subjects, so it rewards careful target and exposure choice rather than casual use.

T25: Planewave CDK20 + Player One Zeus 455M PRO

• 508 mm (20") f/6.8 corrected Dall-Kirkham at native focal length, 3454 mm
• Zeus 455M mono CMOS (Sony IMX455, full frame), 0.23"/px, 36.2 x 24.2 arcmin, 61 MP
• Planewave L-500; Astrodon LRGB and 3 nm narrowband

Review: the resolution monster. At 0.23"/px it is oversampled for almost any seeing, which means you can bin or drizzle as you please and still resolve fine structure in small galaxies and planetary nebulae. The cost is enormous files (61 MP per sub) and a narrow field. Choose it when the target is small and detail is the point.

T26: Planewave Delta Rho 500 + ZWO ASI6200MM Pro

• 508 mm (20") f/3.0 corrected astrograph, 1537 mm focal length
• ASI6200MM mono CMOS (IMX455, full frame, Bin2 only), 1.01"/px, 80.4 x 54.0 arcmin
• Planewave L-550 on equatorial wedge; Chroma LRGB and 3 nm narrowband
• Recommended subs: LRGB 30-180 s, narrowband 180-300 s (900 s available)

Review: arguably the best imaging system on the network: half a metre of aperture at f/3.0 with a modern 91% QE sensor is a light bucket that reaches faint extended nebulosity (integrated flux nebulae, faint Ha shells) in a fraction of the usual integration time, over a 1.3-degree field. Bin2-only is a software limitation, not an optical one, and barely matters at this image scale.

T68: Celestron RASA 11 + ZWO ASI2600C (free, one-shot colour)

• 279 mm (11") f/2.2 Rowe-Ackermann Schmidt astrograph, 620 mm focal length
• ASI2600C colour CMOS (IMX571, APS-C), 1.25"/px, 130.2 x 87.0 arcmin
• Paramount ME II, mount-guided, no filters; 30 minutes free per day

Review: the free taster scope, and genuinely good: f/2.2 means even short free sessions produce satisfying colour images of bright nebulae and comets over a 2-degree field. No filters and modest QE cap its ceiling. Ideal for trying the network, time-lapse of transients, or quick-look framing before booking a paid scope.

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Sierra Remote Observatory, California (MPC U69)

High Sierra site with steady seeing; hosts the network's largest northern aperture.

T24: Planewave CDK24 + Player One Zeus 455M PRO

• 610 mm (24") f/6.5 corrected Dall-Kirkham, 3962 mm focal length
• Zeus 455M mono CMOS, 0.395"/px (Bin2), 31.6 x 21.1 arcmin
• Ascension 200HR, external guiding beyond 300 s; Astrodon LRGB, 3 nm narrowband, V and Ic
• Match subs to calibration set (60/120/180/300/600/900 s); minimum elevation 25 degrees

Review: the northern flagship. The biggest glass in the northern half of the network on a steady-seeing site, with a modern high-QE sensor: first choice for small galaxies, quasar fields and faint photometry (V and Ic fitted). The operational notes (RBI flush, fixed exposure ladder, dithering) show it is run seriously for calibrated science data. Narrow field, so not for showpiece nebulae.

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Siding Spring Observatory, Australia (MPC Q62)

The network's southern-hemisphere anchor, on the AAO site. The only access most users have to Magellanic Cloud and far-southern targets at serious aperture. Roof geometry limits northern views (horizon limits 35-75 degrees depending on scope).

T8: Takahashi FSQ-106ED + FLI Microline 16803

• 106 mm f/5.0 Petzval refractor, 530 mm focal length
• ML16803 CCD, 3.5"/px, 238.8 x 238.8 arcmin (4 x 4 degrees)
• Paramount PME, external guiding; Astrodon LRGB, EXO, narrowband, NIR luminance
• North horizon limit 75 degrees; dithering recommended (occasional dark columns)

Review: the southern widefield essential: four square degrees on the LMC, SMC, Eta Carinae or the Gum Nebula is something no northern scope can offer. Same era of CCD as T14 with the same patience requirement, and its known dark-column quirk makes dithering effectively mandatory. Book it for large southern showpieces.

T17: Planewave CDK17 + ZWO ASI6200MM Pro

• 432 mm (17") f/6.8 corrected Dall-Kirkham, 2939 mm focal length
• ASI6200MM mono CMOS (Bin2 only), 0.53"/px, 42.4 x 28.3 arcmin
• Paramount PME, unguided; Astrodon LRGB and 5 nm narrowband; minimum elevation 35 degrees

Review: a modern deep-field machine pointed at the southern sky: 91% QE at half an arcsecond per pixel is a potent combination for southern galaxies (NGC 1365, Centaurus A) and planetary nebulae. The tight 35-degree elevation floor means plan targets near culmination.

T30: Planewave CDK20 + FLI PL6303E

• 508 mm (20") f/4.4 corrected Dall-Kirkham with 0.66x reducer, 2262 mm
• PL6303E CCD (NABG), 0.81"/px, 41.6 x 27.8 arcmin
• Ascension 200HR; Astrodon LRGB, 5 nm narrowband, and full Johnson-Cousins UBVRcIc

Review: the southern science scope: big aperture, fast reduced optics and the full photometric filter set. Same NABG blooming caveat as its northern siblings, and the CCD needs more integration than T17's CMOS for imaging, so treat it as photometry-first, imaging-second.

T32: Planewave CDK17 + ZWO ASI6200MM Pro

• 431 mm (17") f/6.8 corrected Dall-Kirkham, 2912 mm focal length
• ASI6200MM mono CMOS (Bin2 only), 0.53"/px, 42.4 x 28.3 arcmin
• Ascension 200HR; Astrodon LRGB, 5 nm narrowband, plus V and Ic; minimum elevation 30 degrees

Review: effectively T17's twin with a slightly friendlier elevation limit and V/Ic photometric filters added. If T17 is booked, this is the same capability; if you need magnitudes as well as pictures, prefer T32 of the pair.

T33: 12.5" RCOS Ritchey-Chretien + Apogee Alta U16 (free)

• 320 mm (12.5") f/9.0 Ritchey-Chretien, 2885 mm focal length
• Alta U16 CCD (NABG), 0.54"/px, 37 x 37 arcmin
• Paramount ME, external guiding; Astrodon LRGB and narrowband
• 30 minutes free per day; north horizon limit 45 degrees
• Recommended: LRGB 300 s; narrowband 300 s Bin2 or 600 s Bin1 on calm nights

Review: the free southern scope, and a much more serious instrument than "free" suggests: a proper RC with narrowband filters at 0.54"/px. The NABG CCD blooms on bright stars and f/9 is slow, so free 30-minute slots are best spent on compact, reasonably bright targets, or accumulated across nights.

T59: Planewave CDK20 + FLI ProLine 16803

• 510 mm (20") f/6.8 corrected Dall-Kirkham, 3411 mm focal length
• ProLine 16803 CCD, 0.54"/px, 37.2 x 37.2 arcmin
• Ascension 200HR; Astrodon LRGB, 5 nm narrowband, Ic and Z; capable of 15-minute subs

Review: deep and square: the 16803's square field at half-arcsecond sampling with an ABG chip rated for very long exposures. The scope to book for faint southern targets that need 900-second narrowband subs without blooming worries. QE is dated (60%), so it trades sensor efficiency for exposure headroom.

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Deep Sky Chile (MPC X07)

Newest site, Atacama-quality southern skies; a modern all-CMOS lineup built around astrophotography.

T70: Samyang 135 mm f/3.5 + ZWO ASI2600MM Pro

• 65 mm camera lens at f/3.5, 129 mm focal length
• ASI2600MM mono CMOS (IMX571, APS-C), 4.51"/px, 469.8 x 355.2 arcmin (7.8 x 5.9 degrees)
• Paramount ME, guided; Astrodon LRGB and narrowband; minimum elevation 0 degrees

Review: an eight-degree mono narrowband field under Atacama skies, down to the horizon. Made for constellation-scale mosaics, the Gum Nebula, and the Milky Way core. It is a camera lens, so expect corner coma and halos on bright stars; that is the stated trade for the field of view.

T71: Takahashi Epsilon 180ED + ZWO ASI2600MM Pro

• 180 mm f/2.8 hyperbolic Newtonian astrograph, 500 mm focal length
• ASI2600MM mono CMOS, 1.55"/px, 161.4 x 108.0 arcmin
• Paramount MyT, guided; Astrodon LRGB and 5 nm narrowband
• Electronic shutter: no user darks; calibrated data supplied for standard sub lengths

Review: the best fast-widefield system on the network: f/2.8 optics, a modern sensor and Chilean skies. A 2.7 x 1.8 degree field at 1.55"/px suits nearly every showpiece southern nebula. Subs are constrained to the standard calibration ladder (10-600 s) since you cannot take your own darks, and files are large (101 MiB).

T72: Planewave CDK20 + FLI ML-16200

• 510 mm (20") f/6.8 corrected Dall-Kirkham, 3411 mm focal length
• ML-16200 CCD, 0.359"/px, 26.9 x 21.5 arcmin
• Planewave L-500; LRGB, narrowband, and U, B, V, R, I
• Precision-scaled raw calibration frames published at data.itelescope.net (0-900 s)

Review: the Chilean science workhorse: full UBVRI photometry, very fine sampling, and a published high-precision calibration pipeline aimed squarely at photometric work. The 39Ke full well is modest, so watch saturation on bright comparison stars. For pretty pictures the CMOS scopes on site are faster; for southern photometry this is the one.

T73: Planewave CDK14 + ZWO ASI2600MM Pro

• 356 mm (14") f/7.2 corrected Dall-Kirkham, 2563 mm focal length
• ASI2600MM mono CMOS, 0.31"/px, 31.8 x 21.0 arcmin
• Paramount ME II, guided; Chroma LRGB and 3 nm narrowband

Review: a fine-detail southern imager: 0.31"/px oversampling with a near-zero dark current sensor (darks essentially redundant) and tight 3 nm Chroma narrowband. The pick for small southern galaxies and planetaries when T25-style resolution is wanted below the celestial equator. Short 240 s max recommended subs keep runs simple.

T74: (in commissioning)

Listed in the network sheet with no published specs yet.

T75: ASA N250 + ZWO ASI6200MM Pro

• 250 mm f/3.8 Newtonian astrograph, 950 mm focal length
• ASI6200MM mono CMOS (Bin2 only), 1.72"/px, 137.4 x 91.8 arcmin
• Paramount MyT, guided; Chroma LRGB and 3 nm narrowband

Review: the middle option at Deep Sky Chile: faster and wider than the CDKs, deeper than the Epsilon. A 2.3 x 1.5 degree field at f/3.8 with 91% QE makes quick work of medium-large southern nebulae. Bin2-only sampling is coarse but well matched to the focal length.

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AstroCamp Observatory, Spain (MPC I89)

High-altitude site in the Spanish mountains; fills the European longitude gap so northern targets can be followed when America is in daylight.

T18: Planewave CDK12 + QHY600M

• 318 mm (12.5") f/5.3 corrected Dall-Kirkham, 1683 mm focal length
• QHY600M mono CMOS (IMX455, full frame, Bin2 only), 0.92"/px, 73.6 x 49.1 arcmin
• Paramount PME, externally guided; Astrodon LRGB, 5 nm narrowband, photometric V and Ic
• Minimum elevation 40 degrees

Review: a well-balanced all-rounder: enough aperture for galaxies, a wide enough field (1.2 degrees) for most nebulae, modern sensor, and V/Ic for photometry. Its real value is longitude coverage for time-critical work (exoplanet transits, variable stars, GRB follow-up) from Europe. The 40-degree elevation floor is the strictest on the network, so target selection matters.

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Entre Encinas y Estrellas (e-EyE), Spain

Hosting site in Extremadura; currently one iTelescope system.

T80: Samyang 135 mm f/3.5 + ZWO ASI2600MM Pro

• 65 mm camera lens at f/3.5, 129 mm focal length
• ASI2600MM mono CMOS, 5.98"/px, 622.2 x 415.8 arcmin (10.4 x 6.9 degrees)
• Paramount MyT, guided; Astrodon LRGB and narrowband

Review: T70's northern sibling: a ten-degree mono field for constellation-scale imaging (whole of Orion's belt and sword in one frame, big Ha mosaics of Cygnus). Same camera-lens caveats on corner stars. Between this and T70 the entire sky is covered at super-wide field.

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Choosing a telescope

Use case	First choice	Alternatives
Widefield narrowband, north	T14 (mono), T20 (colour dual-band)	T68 (free colour)
Widefield narrowband, south	T71	T8, T75
Constellation-scale mosaics	T80 (north), T70 (south)
Faint extended nebulosity	T26	T75, T71
Small galaxies / fine detail, north	T24	T25
Small galaxies / fine detail, south	T73	T17, T32, T59
Photometry / science, north	T21, T24	T5, T11, T18
Photometry / science, south	T72	T30, T32
One-shot colour, minimum effort	T20	T2, T68
Long (15 min) narrowband subs, south	T59
European longitude / transit timing	T18
Free / trying the network	T68 (north), T33 (south)

General observations

• The network is mid-migration from legacy CCDs (16803, PL6303E, ST-10XME) to modern back-illuminated CMOS (IMX455, IMX571): the CMOS scopes reach the same depth in roughly half the integration time thanks to 85-91% peak QE, and several of the CCD systems (NABG chips especially) carry blooming caveats the CMOS ones do not.
• Several CMOS systems are Bin2-only due to software limitations (T17, T18, T26, T32, T75). At their focal lengths this costs little real resolution.
• Minimum elevation limits vary widely (0 degrees at T70 up to 40 degrees at T18) and are a real planning constraint, especially at Siding Spring where the roof blocks much of the northern sky.
• Calibration is handled network-side on several scopes (T71's electronic shutter disallows user darks; T72 publishes precision-scaled calibration frames; T24 wants subs matched to its calibration ladder). Check the per-scope notes before planning exposures.