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You define exactly the issue: Stratus inconsistencies. Yep, I don't have a scientifically accurate 'caliper'. AND the measurement MUST be at the LIP TOP... NOT down in the cylinder! That's the actual 'collector' diameter... anyway I can't claim your precision...

BUT:

see this attachment.

I wouldn't question your measurements at all. As for my "precision"... the Stratus cap measurement is difficult, but nowhere does it measure 4".

I think the measurements you've posted should prompt everyone to measure, to the extent they have the tools to do so, the various components of their Stratus gauges before telling anyone that they are accurate. ]]>

see this attachment.

OOPS: forgot to add THIS note from my draft, pertinent to this attachment:

Climalytic says that

That taper is computer/laser calibrated to imprint the gradual spacing of the measurement lines, and is done AFTER the fabrication.

Looking at my Tropo inners, I can begin to see the graduation adjustments at about "0.3".

And the math at various ‘marks’ indicates they follow the MV computations for those several marks I checked.

The STRATUS apparently DOES NOT taper,

Whatever...

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I have 3 Stratus outer cylinders. When I measure the inner diameter

When my inner cylinder (I only have one) indicates 1.0" of water using the score marks the weight (minus the inner cylinder dry weight of 91 g) is 202 g.

When I use the same (CoCoRaHS-approved) scale for the TROPO, 1.0" indicated in the inner cylinder equates to 206 g (minus the inner cylinder dry weight of 123 g).

Measuring the TROPO cap I find it's

There appears to be no bias in my TROPO inner cylinder paired with the cap. Whether the TROPO cap leads to splash out I cannot say.

I am not trying to say that there have not been Stratus manufacturing variances in the past that led to varying outer cylinder widths. But my 3 outer cylinders, which were all acquired from WeatherYourWay (CoCoRaHS official supplier) between approximately 2015 and 2020, are consistent in size.

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EDIT: The one Stratus cap I have does appear to be 3 31/32" across (1/32" short of 4"). It's harder to measure because it lacks score marks. When I deploy the Stratus, I don't use the cap since I don't use the inner cylinder.

EDIT 2: So if my cap is paired with my inner cylinder then the proper metric weight denominator should be 202.72 (rounds up to 203 g).

Here's my math using the cap as the capture radius (3.96875" = diameter):

volume (cu inch) = height (1") x pi (3.14159) x radius squared (diameter halved^2)

volume (cu inch) = 1 * 3.14159 * (3.96875/2)^2

12.3707 cu inch = 202.72 mL (1 cu inch = 16.387064 mL)

202.72 g (1 mL = 1 g)]]>

'

If we go with the reference '1' for density, then grams, milliliters, cm

4"cylinder, 1" deep, 4°C (39.2°F) pure H2O = 205.96MV

volume=

NOTE: An 8x1 cylinder MV should be EXACTLY 4 times the MV of a 4x1 cylinder. The radius of the 4” is doubled, so

Does

IF I ‘weigh’ my liquid, I MUST FOLLOW THE MATH for ‘cylinders’, and the density of water, related

QUERY: Variations in observations must be related to exact size of 'collecting' cylinders? And/or calibration of visual indicator 'magnifying' cylinders?

Now,

I made a wax cast of the lip...

BUT my Stratus

And if I use my 3.981± Stratus cap with ANY of those 4 inner cyls, at 1”it will drop 203.97MV, and...

Furthermore, if I was reporting using 'weight' method, AND if I were using 201gm/inch, I'd 'over-report', and if I were using '206gm/inch' I'd Under-Report!

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BUT 1” of rain = 205.93 (206) gm in a 3.956 cylinder is NOT valid.

ALL MY stratus outer cylinders are virtually (averaging) 3.956±. BUT ONE INCH ain’t 206gm!

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TROPO

I've 2 Tropos, one is production series, one is a field test version (differences are mostly cosmetic, dimensions are identical) BOTH the CAPS, INNER CYLINDERS, and OUTER cylinder dimensions match exactly between the 2 versions.

Those 'caps' are ±3.988± avg around the rim.

..the math says that a 3.99” diameter cylinder, one inch in depth, with water at 4°C or 39.2°F with a density of 1, will MV 204.9.

(Result depends on how you round the numbers)

For this, within miniscule decimals, the caps are identical... and other ‘constants’ are... ...constant..

In fact, BOTH my Tro...]]>