The "supermoon" is BS

A supermoon is not visually, nor geophysically significant. Even the full size version of the image below is a very large magnification. To get the real effect of its significance, look at this thumbnail below from at least 15 feet away.

Average sized moon vs. "supermoon"
Click to enlarge

Any pictures you see this weekend or during any subsequent "supermoon" event (which are still beautiful and magnificant sights, don't get me wrong) will be nothing more than uninformed misinterpretations of the Moon illusion: where objects close to the horizon appear larger than it does further into the sky.

• Check out a Google Image search of "Moon on horizon"

Check out @NeilTyson on Twitter

I'm glad people are interested in the world and universe around them, but it's being portrayed in an unacceptable, unscientific manor.

Custom Scuba Diving Logs

Near the end of my first diving log book (≈100 dives), I started looking for for a new set of logs that would be a bit more advanced and provide enough space for the detailed descriptions of dives like I wanted to write.  Unfortunately I could only find log books that were unnecessarily complex (individual check boxes for wetsuit gloves, a full suit, shortie, jacket, how much weight was used, etc. - overkill)  I can see how that level of detail could be useful if you end  up only doing 10 dives in a lifetime, or for your first dozen dives, but that was ridiculous.

I ended up making my own and used them through cavern training with a lot of enjoyment, however I ended up losing the whole pack of logs (from dive #1 to Dive #154) due to some unknown event (likely slid off the top of my car or something terrible), so this is my second shot at creating advanced (enough) custom scuba diving logs.

Download: PNG (single) / PDF (print on 8.5" x 11" paper) / DOC (template to edit)

Updates:
Over time I will update the template to be the most clear, concise, and easy to use.  Here's a list of previous versions and their changes:

Date	Downloads	Description
August 1, 2012	PNG / PDF / DOC	Added space for Equivalent Air Depth (EAD) and Dive-turn time
May 13, 2012	PNG / PDF / DOC	Highly updated draft uploaded. Print formatting applied and formatted for advanced diving. Space is provided on each page for 2-sided printing, which leaves enough room for binding
July 19, 2011	PNG	Original basic dive log template

Overview: 

• Printing: The PDF & DOC templates are setup for printing on standard 8.5" x 11" paper, which will give you 4 log spaces per sheet of paper (using a 2-sided printing option). A small margin has been set in case you choose to bind the logs at any point.  I recommend taking a stack of written logs to Office Depot, etc. to be bound with a coil binding.  Be sure to punch holes in a test page so your logs are not ruined. Add a clear plastic cover and a colored back to protect it.

Finished log: 25 pages bound with a ¼" coil binding

25 sheets of paper (100 entries) fit very well into a ¼" coil binding, and at least twice as many fit into a ½" binding.  Since binding is so cheap ($5 to bind 25 pages with a clear front cover and a black rear cover), it may be worth binding smaller groups of logs and combining them as volumes later.  One could even replace the smaller coil with a larger one when additional groups o flogs are completed

• Editing: Download the .DOC file, which was created using Microsoft Word 2003 & 2007. Much of the formatting includes tables with invisible borders.  It may help to select an area and apply borders to better understand how things are set up.  Additionally, custom cell padding is attained by adding blank lines of text with very small pixel values (1-4 pixels) above or below lines of text.  Use the Show Paragraph & Formatting Marks tool in Microsoft Word, etc. for further assistance.
  
  Finally, I suggest editing only the first of the four tables in the document.  Delete the remaining three tables from the document. Copy the updated table and paste it below (now 2 identical log entries will be present on one page) and align it to the bottom of the page.  Now copy the contents of the first page and past it onto page 2 (four log entries will be present on 2 pages).  Select one table at a time on page 2 and adjust the alignment to the left side of the page, leaving room for a binding on the correct side of the page; when these 2 pages are printed on a single sheet of paper, the borders should align if you gaze through the paper when help up to a light.

•  Chronology: Write the dive number in increasing order for every new dive so it's easy to see how many dives have been completed.  The date follows.  I have two methods of recording how much time a diver has spent underwater: the first is the accrual of dive time in total hours/minutes, then again in days/hours/minutes (i.e. 25 hours 1 minute (25:01), or 1 day 0 hours 1 minute (1:00:01).  It's fun/interesting to track blocks of hours as milestones (dozens, hundreds of hours, etc.) while being able to quickly see each "day underwater" pass, as well as each block of hours pass.  Additionally, it serves as error checking - if a dive was miscalculated, simply calculate between hours and days until you find where they two figures no longer disagree

•  Location: Enough room is provided to describe the location/sub location (i.e. Orange Grove Sink @ Peacock Springs State Park), along with a lat/long coordinate if a GPS is available

•  Purpose: Self explanatory, check boxes

• Dive type conditions: More simple check boxes are available to describe the dive, however there are now multiple opportunities to circle parameters of a given condition.  For instance, there was some flow during this Intro-level cave dive.  Otherwise, if this were an open water drift dive, "drift" would be circled instead.
  An Emergency option is also available.  I've logged this a few times where there was a situation that needed to be responded to (signs of a near-panicking diver, a diver that was caught in a slight rip current, divers were very low on gas at depth, etc.).  This is interesting to note, even if the "emergency" situation does not escalate into a serious event.
  Additionally, a user can track how many dives have been completed at various levels of overhead training: including Wreck penetration / Cavern / Intro Cave / Apprentice Cave / Full Cave.  This was my 19th cave dive, but I could also use the number that corresponds to another type of overhead diving (i.e. 7 Wreck penetrations, or 43 Cavern dives).
  Further, I have been jotting a small note about how much current (slight/med/strong) was present on a dive in the blank space

Conditions, with multiple types of overhead diving, including:
Wreck penetration / Cavern / Intro cave / Apprentice cave / Full Cave

• Weather conditions: There is space to jot down the weather (hot/warm/chilly/windy/air temperature), water temperature (with space for two temperatures in case a thermocline is present), and visibility under water (here I put 40' to unlimited/infinite).
  Weather.gov is a good tool to use to find a 3 day history of temperatures and weather data for anywhere in the country.  For an example at Little River, use this link and look for the "3 Day History" link in the "Current Conditions" box. Pan around using the embedded Google map and click on an area of interest to update the forecast location.  Once you are centered over an area of interest, click on the "3 day history" link for that area to find your data.

• Time: Include a time to assist with repetitive dive planning

• Gear: Use check boxes and circle any gear or equipment that is used on a dive.
  I placed a check box to the RIGHT of the Reels item because I had two safety reels on me, however I did not run line and I did not run any lost line/lost buddy drills in the cave so I placed a check beside the item, indicating that they were present but not used.
  Additionally, a blank space is provided for unlisted items.  For instance I usually dive with a hood/beanie cap when I dive my wetsuit so I wouldn't bother noting that, though I rarely dive with gloves unless I'm on a deep wreck with an up-line, so I would likely include that in the blank space.

• Tec parameters & O2 exposure: There is optional space to note a diver's Surface Air Consumption (SAC rate), Oxygen to Central Nervous System Exposure percentage, and Oxygen Tolerance Units (OTU) & Unit Pulmonary Toxic Dose (UPTD) units for advanced planning and decompression diving.  These information are usually reserved for decompression or repetitive dives with significant exposure to high concentrations of oxygen.

• Repetitive dive profile: This is a slightly updated version of a basic repetitive dive profile diagram.  A diver can denote whether the profile will be a generally square dive strictly using tables, a multi-level dive, or a dive with a decompression stop.  Since a majority of the time was spent traveling to or from 93' (a true "bottom time" of 22 minutes, recorded in the Turn time) this single cave dive (with no Surface Interval Time calculated on either upper side of the profile) is treated as a multi-level dive and a repetitive group will not be calculated (in the circles at the top of the profile).
  Additionally for Nitrox divers, spaces are available for recording the Equivalent Air Depth (EAD) and the maximum partial pressure of oxygen (PO₂) reached on the dive.

• Gas Supplies: Breathing gas and cylinder information have been placed together, which just makes more sense from a data management standpoint.  The back gas, or primary gas source, has the option of reporting single or double cylinders, cylinder material, type/rated volume (reported in this example is a low pressure steel cylinder rated to 95 cubic feet (LP95), gas mix, and starting/ending pressures.
  
  Additionally, a decompression cylinder or a stage cylinder can be recorded.  There is blank space directly below these for additional cylinders that are used on a dive.

• Comments / Diagrams: The remaining blank space is reserved for a description of the dive and other important details and information.  The grid is available to help sketch maps or illustrations of fish or other objects observed during the dive.  Often I'll just use the space for text if an illustration is not necessary.

Example:
Here is an example of a completed log for this example above (using the original template).

Click to enlarge

Impossible Khan Academy Question

KhanAcademy.org is very cool.  This Web site offers lessons and exercises on a wide variety of mathematics, science, and other subjects.  I am going through and playing with some exercises in hopes of honing my advanced statistics, trig, and calculus skills.

I came across this scuba diving example that uses simple arithmetic to solve.  The math is correct, but the situation is virtually impossible:

Daniel was scuba diving 28 meters below sea level when he spotted a beautiful fish below. To see the fish up close, Daniel dove 29 meters until he was level with the fish, staring into its eyes.

Where was the fish relative to sea level?

Answer: -57 meters

57 METERS DEEP!? Really? That's 187 feet!  Let's convert this situation to imperial units and interpret what is more likely ocurring:

Some BS open water diver isn't prepared for a deep dive and heads down to 92 feet on a ledge somewhere amazing for far too long time and gets narced out of his mind since he's breathing air instead of Nitrox.  In a hallucination he sees something and decides to dive another 95 deeper and immediately dies from running out of breathing gas.
How deep was Derpo when he died?

Answer: Derpo died at -187 feet

The follow is my nerdy response when I reported a problem for this question:

---

Greetings,

Although the math is correct, there is a problem with the unrealistic units of depth that are chosen in this example.

A basic recreational scuba diver - who would be interested in observing and following fish rather than performing industrial or scientific work - is generally limited to diving within 100 feet from the surface (≈30.5 meters).  Beyond this depth a number of physiological factors limit a dive without having highly technical training and gear; including nitrogen narcosis, oxygen toxicity, and an elevated risk of decompression illness.

The question states that a diver finds a fish at 28 meters below the surface (92 feet), and descends another 29 meters (95 feet) below this, giving a maximum dive depth of 187 feet.  This diver will surely suffer narcotic effects from the high partial pressure of nitrogen unless he or she were to switch to an anoxic breathing gas that is a specific mixture of oxygen, nitrogen, and helium (referred to as "heliox" or "trimix") which cannot otherwise sustain life at the surface.

Beyond physiological limitations, it is technically plausible however unlikely that a diver will encounter conditions where visibility beyond 80-90 feet of vertical visibility.  In the case that a diver could view an object that lies an additional 95 feet below in the water column with any definition, it is unlikely that the object will appear to be anything more than a dark shadow, as water quickly absorbs much of the visible light spectrum.

Without significant and expert dive planning in perfect conditions, this description of a scuba dive is virtually impossible.  Simply switching the units of depth from meters to feet would make this a far more plausible, and realistic example.

Best regards,
 - Derpington