Explore Scientific 8x50 Non-Illuminated Straight-Through Finder Scope with Bracket

Product Overview

The Explore Scientific VF0850S is an 8x50 straight-through finder scope with a standard crosshair reticle, supplied with its quick-release bracket. Explore Scientific publishes a 6° field of view, a 55.5 mm body diameter and a weight of 1.35 lb (0.61 kg) for the optic.

The job of a finder is to bridge the gap between what you can see with your eye and the narrow slice of sky a telescope eyepiece shows. At 8x with a 50mm objective, the exit pupil works out to 6.25 mm — close to the diameter of a dark-adapted eye pupil, which is why a 50mm finder shows stars several magnitudes fainter than the naked eye at the same time as showing 6° of sky. For scale, the full Moon spans about half a degree, so the field holds roughly twelve Moon diameters end to end. That is enough sky to recognise a naked-eye star pattern and enough magnification to pick out the faint stars a chart uses as stepping stones.

The image is straight-through and non-erect, which means it is inverted in the same way a Newtonian or a refractor with a star diagonal inverts. Astronomical charts and planetarium software handle that without difficulty; terrestrial use is where a non-erect image becomes awkward.

Who It's For

• Star-hoppers: a 6° crosshair field is the classic tool for walking from a bright naked-eye star to a faint target one chart step at a time.
• Owners replacing a red-dot finder: a red dot shows you where the tube is pointing but adds no light grasp. A 50mm objective adds several magnitudes, which changes what is findable from a light-polluted yard.
• Anyone whose finder bracket has an Explore Scientific footprint: the same optic serves both the Hybrid Finder Scope base and the original Explore Scientific finder bases.
• Observers who prefer a passive finder: with no illuminator there is no battery to go flat halfway through a session and nothing to switch on in the cold.

Key Features & Design

• 8x magnification with a 50mm objective: a 6.25 mm exit pupil, which sits well within the range a dark-adapted eye can use.
• 6° true field of view: about twelve full-Moon diameters across, wide enough to keep a recognisable star pattern in frame.
• Standard crosshair reticle: a simple cross that marks the centre of the field for precise centring, with nothing in the view to distract from faint stars.
• Straight-through, non-erect image: the observer sights along the same axis as the telescope tube.
• 55.5 mm body diameter: the published figure across the tube body.
• 1.35 lb (0.61 kg) published weight: light enough that adding it rarely upsets a balanced tube by much, though it does shift the balance point.
• Quick-release bracket included: the optic and its mounting bracket ship together, so the only compatibility question is the base on your telescope.
• Multi-base compatibility: works with the Hybrid Finder Scope base as well as Explore Scientific's earlier finder base pattern.

Recommended Uses

• Locating and centring deep-sky targets by star-hopping from naked-eye anchor stars.
• Aligning a telescope on a bright star before starting a goto or setting-circle routine.
• Recentring a target that has drifted on an undriven mount, without hunting through a narrow eyepiece field.
• Replacing a lost, damaged or under-specified finder on an existing tube that carries an Explore Scientific base.
• Public outreach sessions, where getting from object to object quickly keeps a queue moving.

Compatibility and Accessory Notes

• Bases: the supplied bracket fits the Hybrid Finder Scope base and the original Explore Scientific finder base. If your telescope carries a different shoe pattern, send us a photograph of the base and we will tell you whether this bracket seats in it.
• Field of view arithmetic: the 6° field is a true field, not an apparent one, so it can be laid straight onto a star chart at the chart's own scale.
• Balance: at 1.35 lb the finder sits at the front of the tube on most instruments, so rebalancing after fitting is usually a small adjustment on the dovetail or the counterweight shaft.
• Alignment: the bracket's adjustment screws set the finder parallel to the main tube. That alignment is done once in daylight on a distant landmark and touched up on a bright star.
• Reticle illumination: this model is the non-illuminated version. On very dark nights the crosshair can be hard to see against the sky, and observers who want the wire lit choose an illuminated finder instead — we stock those if that turns out to be the deciding factor.

Good to Know Before You Order

• The image is non-erect. That is normal for a straight-through astronomical finder and matches what most star charts and planetarium apps can be set to display, but it does rule the finder out as a spotting scope for daytime use. A correct-image right-angle finder is the alternative if terrestrial use matters, and we carry those.
• The reticle is unilluminated. Under a genuinely dark sky the crosshair reads as a silhouette against the sky glow, which works well on most nights and less well when the background is very dark. A dim red light held near the objective for a moment is the usual field workaround.
• The optic sights along the tube axis. On a telescope pointed near the zenith, a straight-through finder puts the observer in an awkward position, which is why some observers eventually add a right-angle unit alongside it.
• Explore Scientific does not publish the optical coating specification or the eye relief for this finder, so those rows read as unpublished rather than carrying an estimate. If either figure is important to your decision, we can put the question to our Explore Scientific rep.

Frequently Asked Questions

Is it difficult to set up?

No. The bracket slides into the finder base on the telescope and locks, and the finder is then aligned to the main tube using the adjustment screws — a five-minute job done once on a distant daytime landmark and fine-tuned on a bright star that night. There is nothing to assemble and no power to connect.

How much sky does 6° actually cover?

Roughly twelve full-Moon diameters across the field. In practical terms, most of the bowl of the Little Dipper would sit inside it.

Will it fit my telescope?

It fits telescopes carrying the Hybrid Finder Scope base or the original Explore Scientific finder base. For anything else, a photograph of your base is enough for us to give you a straight answer before you order.

Is the view upside down?

The image is non-erect, so it is rotated relative to the naked-eye view. That matches the orientation most astronomical charting software can display, and it becomes second nature quickly.

Does it need batteries?

No. This is the non-illuminated version, so there is no electronics and nothing to charge.

How much better is it than a red-dot finder?

A red dot projects a reticle onto the sky at 1x and adds no light-gathering at all. A 50mm objective at 8x shows stars several magnitudes fainter, which is the difference between pointing at a patch of empty-looking sky and actually seeing the stepping-stone stars a chart is asking you to follow.

Bottom Line

In short: an 8x50 straight-through finder with a crosshair reticle, a 6° field, a 55.5 mm body and a published weight of 1.35 lb, supplied with its quick-release bracket for Explore Scientific Hybrid and original finder bases. If you are unsure whether the base on your telescope matches, send us a photo of it and we will check the fit for you.