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An excel formula for the SOLO R/T?

Posted: Sat Jul 13, 2019 12:40 am
by John Harvey
So I've been using the SOLO R/T monocular for a while now and I was wondering if anyone had a formula worked up on Excel for it. For instance at a distance of 13.5 yards, 50 reticle or hash marks comes out to 2 feet. Using basic math you can come up with any estimate just based on that. At 27 yards away, 50 would be 4 feet across for instance...and on and on. I just think it would be much easier to have it worked into a formula on Excel where you could punch in the distance in yards, the amount of reticles, and have an instant width pop up. I've been doing a math problem every time I take a measurement which is fine but I wouldn't know the first thing about making something possible on Excel.

Thanks!

Re: An excel formula for the SOLO R/T?

Posted: Sat Jul 13, 2019 9:15 am
by Erik Danielsen
You would just need two input columns, and then a third column with a simple formula that incorporates the reticle factor and the inputs from the first two columns (just the same math problem you do on paper now). Then a fourth column dividing the results from the third column by three, if you're inputting yards and want to end up with feet. Should be a pretty simple one to set up, as far as spreadsheet math goes.

Re: An excel formula for the SOLO R/T?

Posted: Sat Jul 13, 2019 11:14 am
by dbhguru
John,

Alas, Excel formulas abound. I guess that we have so much material on the BBS that searching for an answer to a specific question can be daunting.

Here are some relevant BBS posts on the reticle:

Measurement & Dendromorphometry: Reticle Testing – Mon Oct 23, 2017, latest post Feb 18, 2018.

Measurement & Dendromorphometry: Use of reticle for measuring limb length – Feb 6, 2018, latest post Feb 7, 2018

On the www.championtreescertificationcadre.org forum there are the following reticle posts under Measuring methods development:

1. Reticle and Bosch GLR825
2. Reticle Methods Test
3. Comparison of Reticle Formulas
4. Simple and Advanced Reticle Methods
5. A Final Reticle Measurement Method
6. More Reticle Methods
7. Meet Gizmo


You are still listed as a member in the Forum. So, the above materials should be available if you sign in. Admittedly, there's a lot of repetition in this material, but its coverage is soup to nuts.

Let me know if you don’t find what you need in the above posts.

Bob

Re: An excel formula for the SOLO R/T?

Posted: Sat Jul 13, 2019 11:35 am
by John Harvey
Bob, Eric,

Thank you for the replies. Bob, I will look through the posts. I was thinking to myself that there must be a ton of data on my very question. I will log in to the cadre site as well. I've since changed emails and need to update that in the system,

Thanks!

Re: An excel formula for the SOLO R/T?

Posted: Sun Jul 14, 2019 6:49 am
by dbhguru
John,

If you are measuring tree trunk diameters that are reasonably circular, you can get by with a single formula.

W = MD/(F-0.5M)

where M = reticle reading, D = distance to middle of trunk, and F = reticle factor, which should be 1000 for the Solo RT 8x36. The bigger the tree, the more important the 0.5M factor is.

Bob