Strathspey 20x90 Binoculars Part 1 First Light

[Polar Bear]

Why Binoculars ?

It is generally accepted that binoculars are the best introduction to observing the night skies.

Most people start off with inexpensive 10x50's or have a pair as a quick 'grab and go' option to complement their scope. This was the direction I originally took but over time I have become more aware of the benefits of binoculars over scopes for visual use and have now gone over to solely using binoculars for night time observations.

I already use an excellent pair of Tasco 9x63 roof prism binoculars so I was looking for a pair of binoculars that would give me greater magnification and light gathering ability without compromising exit pupil size so that I could see 'deeper'

Thanks to the forum these Strathspey 20x90's were available second hand complete with a hard case.

The new price is £211.00 so a considerable amount was saved by buying second hand (thanks Tim)

When you consider these binoculars are 2 x 90mm 'fast' scopes the full retail price is reasonable.

Construction

These are typical mass production Chinese offerings with standard prism assemblies and a mix of metal and plastic with soft rubber coverings to most parts.

They feature a substantial adjustable centre pivot bar with an integral tripod bush for mounting.

IPD adjustment is smooth and stays in position, the central focussing adjuster is smooth as is the individual right eyepiece adjustment.

Fold down rubber eye-cups accommodate use with spectacles.

Overall they are very well made and function as they should with no sloppiness in the mechanisms.

Specification

Magnification 20x

Object lenses 90mm

FOV 3 degrees

Fully broadband level IV multi-coated

Bak-4 Prisms

Exit Pupil 4.5mm (measured)

Length 38cm

Weight 3.2kg

At this price you would expect nothing less than broadband coatings and Bak-4 prisms

Usage

At 3.3kg these are heavy binoculars and must be mounted on a sturdy tripod. I use a Miranda Titan 808 for my 9x63's but it is barely adequate for these binoculars.

The cost of a good mount must be taken into account if considering buying binoculars of this size and weight. I would recommend a parallelogram mount (which I will be making soon) for these, however the tripod was sufficient for this test.

Balancing the binoculars was easily achieved with the adjustable centre bar pivot mount and within minutes I was star gazing.

Performance

I went out at around 10.00pm under my usual light polluted skies and looked to the East and North East for the first test.

Focusing the binoculars was easy for my -2.5 and -2.25 eyes and the stars literally 'popped' into view. The 3 degree field enables you to see enough 'signpost' stars to be able to navigate without taking your eyes away from the binoculars.

First up was the Star cluster around Mirphak in Perseus. Stars over approx 80% of the view were rendered as pin points with no ghosting, no coma or any other aberrations. Next up was the Double Cluster under Cassiopeia with the 3 degree view enabling the whole to be taken in. Next up was my 'standard' test for any binoculars or scopes, M31 The Great Galaxy in Andromeda. Normally (from my viewing site) with 10x50's and even my 9x63's this object shows as a faint smudge that requires averted viewing to get the best from it. When it came into view I actually let out an "oh my god". Easily visible and showing shape with a brightening towards the core. Previously I have tried 15x70's on M31 and been disappointed , but the extra light gathering ability of these 90mm objectives makes all the difference.

To finish this quick test I had a look at Jupiter. Normally not the best of objects for binoculars due to its brightness but these binoculars coped very well with it. The moons were point sources of light and Jupiter itself produced a slight glare but was clearly visible as a perfect round disk. I am sure with correct filtering it may even be possible to discern some banding.

So overall very impressive. Next up will be some magnitude tests over the next few nights to see just how 'deep' these binoculars will go.

Also with the Moon back with us I will see how they handle chromatic aberration.

Paul

Size comparison with my Tasco 9x63's

[Syntarsus]

Interesting. I'm currently contemplating my first scope but as I really like my 8x40 bins I've thought about getting a bigger pair instead. Your description of M31 is exactly how I see it so most relevant to me.

I'll be interested to hear the rest of your testing and what you can and cannot see.

[JamesM]

Congratulations Paul on your latest acquisition and many thanks for the review. This size of binos seem to be proving very popular but I agree, suitable mounting is essential to get the best out of them. Look forward to reading up on the rest or your analysis.

James

[Polar Bear]

We had 100% cloud cover in Lancashire last night and I now have 2 night shifts so hopefully I will have more to report by the weekend.

Paul

[inspectapart]

Well I think I would go with the celestron 15x70s firstly because of the price and also many good reviews, however I`m a bit concerned about not being able to try befor I buy, as there isn`t an outlet near to me. All of my equipment so far purchased has been of high quality and I have been a firm believer in you get what you pay for.

But at around £70 it may be worth a punt.

Many thanks for all the input,

Bob

[Polar Bear]

Well I think I would go with the celestron 15x70s firstly because of the price and also many good reviews, however I`m a bit concerned about not being able to try befor I buy, as there isn`t an outlet near to me. All of my equipment so far purchased has been of high quality and I have been a firm believer in you get what you pay for.

But at around £70 it may be worth a punt.

Many thanks for all the input,

Bob

Hi Bob

the Celestron 15x70's are capable binoculars and I owned a pair for quite a while at the beginning of my star gazing about 3 years ago.

One reason the price is low on them is their success in sales which brings the advantages of lower production costs. As you say you get what you pay for with optical equipment but the Celestrons do punch above their weight for the cost and are probably the best value for money binoculars out there.

I am sure if you order from FLO or SBTC (Sockport Binocular and Telescope Centre) you will have no problems.

Paul

[West End Wendy]

Good to hear you're getting on with the bins Paul.

That's a far more rigorous test of their capabilities than I ever gave them and a very interesting read - a bit like finding out what someone else thinks of an old friend.

Cheers,

Tim

[mdstuart]

The sound like my 20 x 80's...but better. I love looking at clusters etc with them. Try some binocular doubles as mine bring out the colours well with the extra aperture. Try Albeiro!

Mark

[Polar Bear]

Good to hear you're getting on with the bins Paul.

That's a far more rigorous test of their capabilities than I ever gave them and a very interesting read - a bit like finding out what someone else thinks of an old friend.

Cheers,

Tim

Hi Tim, they are an excellent piece of kit, thanks for making them available.

The sound like my 20 x 80's...but better. I love looking at clusters etc with them. Try some binocular doubles as mine bring out the colours well with the extra aperture. Try Albeiro!

Mark

Hi Mark, one of the reasons I decided to go down the large binocular route was to observe star clusters and the 3 degree field of these combined with the 90mm objectives produces some awesome sights. I have noticed good colour rendition with these binoculars and as you suggest will try some doubles in my next report.

Paul

[Polar Bear]

What a miserable week and weekend so far.

I just managed to get about 30 minutes on the Moon last night before the 100% cloud cover that we get here so often moved in.

Even at these binoculars 20x magnification the Moon is not large in the eyepieces but it is large enough to study

the main regions and craters (theoretically and with excellent viewing down to approx 5 miles across)

The real benefit this view delivers over a scope is the 'floating in space' feel you get with using two eyes.

With the Moon central in the view and with careful eye placement I could detect no chromatic aberrations.

However it was easy to induce them by moving ones eyes about or by letting the Moon drift out of the centre of the field.

Even so it was well controlled considering that these binoculars are approx F4.0 and was certainly not intrusive.

I took a quick hand held grab shot with my Nokia N8 to try and demonstrate the CA at its worst. You will notice a little yellow and violet fringing.

Overall I was very impressed with how the 20x90's performed on the Moon.

Paul

[JamesM]

Thanks for the update Paul and look forward to the magnitude assessment in due course - if the clouds are willing to oblige!

Many thanks

James

[Polar Bear]

Sorry for the lack of an update but we have not seen the Sun or any Stars here in Lancashire since Saturday !!!

[Polar Bear]

This evening the clouds are nowhere to be seen for the first time in a week.

With an almost full moon tonight the contrast in the sky is drastically reduced along with the usual light pollution here.

The actual transparency is very good with little air turbulence.

Double Star Test

First object to find was the old favourite Albireo (beta Cyg HIP 95947-A) in Cygnus.

Easy to find being the bright yellow star at the bottom of the cross.

Accompanying the yellow giant is a slightly fainter blue/green star.

The 20x90's showed them as 2 points of light with a distinct size and magnitude difference although its smaller fainter neighbour appeared to lack colour.

A harder test next with a star double in Aries (Lambda Ari HIP 9153)

This can be found by extending a line from Hamal (Alpha Ari) to the south and is the second star along in a line of 3.

Separation on this double is only 38" but the 20x90's showed clear sky between them with good colour and a distinct difference in size and magnitude.

Limiting Magnitude.

With the Moon so bright I decided to test in the same direction to push the performance of these binoculars and chose the Pleiades.

Amongst the myriad of stars in this cluster is a line of them that appears like a tail running down under Alcyone with diminishing magnitudes.

Even tonight with the bold Moon I was able to see the Mag 10 star just to the right of HIP 17776.

A Surprising Jupiter

With the transparency so good tonight I had to have a quick look at Jupiter and was literally gob-smacked with the view.

Viewed dead centre of the optics the moons were pin sharp and Jupiter itself had no coma or CA.

The surprise came with being able to see 2 distinct bands.

I would not of thought it possible through binoculars of this magnification and price, but I saw it tonight with my own eyes

Conclusion

Simply put these are excellent performers for the price, especially good in the centre of the field.

I have found they are excellent to use (for me at -2.5 dioptre) with glasses, which for some reason gives a better 'floating 3D' perceived image.

They are too heavy and powerful without a tripod for astronomical use but I would advocate a support even for 10x50's.

They are not without flaws and the biggest disappointment is not having individual focus on the eyepieces.

Additionally on this pair I have to adjust the right EP to almost its maximum value to have both eyes focused even though my eyes are very similar at -2.5 / -2.25.

This may be a mechanical issue with the eyepiece crossbar.

Other that that I would recommend them but suggest trying them out first if possible in a suppliers shop.

Paul

[JamesM]

Thanks for the write up Paul and for you your recommendations - made very interesting reading.

James

[Syntarsus]

Yes, thanks for the review.

[LukeSkywatcher]

I was selling mine a few weeks ago but quickly removed them from sale due to me over pricing them. I'm glad i didn't sell them now.

[Phil4130]

A little tip. On the central bar, the knurled aluminium knob which clamps them into postion. On my 25x100s I drilled through this knob dead centre and cut an m4 thread. I then fitted the base of my rigel quickfinder to this by packing it out with some washers. I then centred the quikfinder. I know have a super accurate pair of large binoculars. I have managed to pick out many dso's with ease and speed as oppose to just sky scanning before.

[Merlin]

I use a laser-pen finder on my 20X60 bins with rubber bands to hold the pen in place. A problem with all of my laser pens is that they are temperature sensitive and don't work below about 5C.

Are there any UK suppliers of non-temperature sensitive laser pens? I dare say they'll be quite expensive.