MundiScope equipment review
BRESSER Messier NT-150S/750 + HRCC
A 150 mm Newtonian with a coma corrector for tighter views of galaxies, clusters and compact nebulae.
By MundiScope · Updated · Specifications and calculated framing
In plain English
This configuration combines a parabolic Newtonian mirror with the Explore Scientific HR coma corrector. The corrector reduces the stretched appearance that stars can have near the edges of a Newtonian image. Its 1.06× factor changes the native 750 mm focal length to 795 mm. This gives the tightest field of our four configurations with the same camera. Its larger aperture gathers more light, but atmospheric steadiness and tracking determine how much fine detail an exposure records.
A good choice for
Smaller deep-sky targets that would look tiny in a wide-field refractor, when tracking and sky conditions support the finer image scale.
What to keep in mind
The narrow field needs more careful framing. Mirror alignment, focus and corrector spacing matter; the secondary mirror also blocks part of the incoming light.
How much sky fits in an image?
With the ZWO ASI533MC Pro camera, this configuration covers approximately 0.82° × 0.82°. That is about 1.6 full-Moon widths across the frame, using half a degree as a familiar reference.
Each pixel samples about 0.98 arcseconds of sky. These are calculations from focal length and sensor geometry, not measured image quality. Cropping, atmosphere, focus and tracking affect what your final image shows.
Compare fields of view →Detailed specifications, explained
Start with the overview, then open the technical details when you want to understand the camera and optics.
Optics, camera, tracking and image scale
- Aperture
- 150 mm
The diameter of the main lens or mirror. A larger aperture collects more light and can resolve finer detail under suitable conditions.
- Focal length
- 795 mm
With the same camera, a longer focal length gives a closer view of a smaller area of sky.
- Focal ratio
- f/5.3
Focal length divided by aperture. A lower number generally records extended objects more quickly with the same camera and comparable transmission.
- Optical design
- Parabolic Newtonian with external four-element HR coma corrector
Refractors use lenses; a Newtonian uses mirrors. Field correction helps keep stars better shaped away from the centre.
- Central obstruction
- 36.7% of aperture diameter
The secondary mirror blocks some light in a reflector. This percentage is a diameter ratio, not a percentage of light lost.
- Corrected image circle
- 30 mm
The image area the optics are designed to cover. It is different from the field of sky captured by the fitted sensor.
- Focuser
- Hexafoc
Focus brings stars to their smallest size. Remote adjustment depends on the equipment fitted at the site.
- Camera
- ZWO ASI533MC Pro
A colour astronomy camera. The figures below describe its native sensor, not a guaranteed download format or processed image size.
- Sensor
- Sony IMX533CQK-C · 11.31 × 11.31 mm
Sensor size and telescope focal length together determine how much sky fits in one frame.
- Native resolution
- 3008 × 3008 pixels
The camera's native pixel grid. Cropping, binning or processing may change a delivered image's dimensions.
- Pixel size
- 3.76 μm
The physical size of one sensor pixel. Together with focal length, it determines the angular sampling below.
- Calculated field of view
- 0.82° × 0.82°
Approximate uncropped field with this camera and optical configuration. It describes the frame, not which targets are currently visible.
- Calculated image scale
- 0.98 arcsec/pixel
How much sky each pixel samples. A smaller number does not guarantee sharper detail if the atmosphere or tracking blurs the image.
- Sensor readout
- 14-bit ADC · 50,000 e− nominal full well
Readout precision and charge capacity describe the sensor. Effective dynamic range varies with the gain setting.
- Read noise
- 1–3.8 e− (manufacturer range)
Electronic noise added during readout. The value depends on the operating gain; this is not a measurement of a specific session.
- Peak quantum efficiency
- >80%
The manufacturer's peak light-to-charge conversion figure. Sensitivity varies with wavelength; it is not total system transmission.
- Mount
- ZWO AM3 · equatorial configuration
Tracks the apparent motion of the sky. Guiding, alignment and conditions affect the result of longer exposures.
- Filters & rotation
- Check the session's available controls
A filter thread or manual rotator on an optical tube does not mean a motorised filter wheel or remote rotation is installed.
- Optical transmission
- Not specified
Total light throughput has not been established here. No exposure-time guarantee is inferred from aperture alone.
This is a guide based on published specifications and calculated framing, rather than a scored laboratory test. Session controls and equipment availability are shown when you connect. Sensor specifications do not guarantee a particular capture format or output resolution.