Day of Rest

I need to do some painting.  Not the creative kind, but the Hut is showing wear, and the Scope Shed is still wearing its original brown.   This occurred to me at maybe 4:30 am after getting up to pee, and before falling back to sleep.  So it made sense to get the painting stuff laid out this morning.  Thinking about painting reminded me I have a window to replace in the barn, which has been boarded up since winter, and I should really paint the window before replacing it.  It would be best to lay it out on the picnic table.  IMG_1056The picnic table is currently loaded up with a pretty cool, very heavy cast iron sink that until we re-did the kitchen last year was, in fact, our kitchen sink, since probably about 1924.  It’s something that is actually desirable for a person wanting a funky antique update to a modern kitchen, but whatever, it’s a cragslist thing as far as I’m concerned.  And it’s tying up the picnic table.  So I’m going to hook up the trailer to our Craftsman garden tractor and move the sink to the barn with other flea market stuff.  The trailer is pretty old, and the tires don’t hold air.  IMG_1057I have some Green Slime — you know Green Slime?   It’s an eponymous product that you pump into iffy tires and it generally plugs up slow leaks.IMG_1069 I pump slime into the trailer tires, and pump them up.  The tiller also has a leaker tire, so I slimed it as well. I get the sink loaded; it’s about 120 pounds of cast iron, but I can horse it around and get it loaded.  Ollie, the labrador interrupts, demanding a Frisbee  break.  IMG_1059 The sink accumulated a lot of debris sitting there for months, so I run it over to the hydrant, and see the tire looks low, but the sink cleans up okay, and I run it to the comoressor and put some more air in.  Meanwhile the male alpacas are mowing the back yard, and Express, who seems to have more testosterone than he strictly needs, is running down Ferb, biting and generally harassing him.  Ferb is making an alarming noise that is unequivocably a scream.  You can’t really separate them when they’re doing this; you just end up chasing them around uselessly.  But they react well to being hosed down.  It distracts them, cools them off, and they forget they’re mad.  In fact they love being hosed down. They’re like city kids on a hot day; cracking a hydrant does wonders for everybody’s attitude.  I got pretty hot too, and take a break for a dip. IMG_1064

IMG_1068

This can’t be good.

It looks like the tires are holding air, and the sink is put away.  I’m ready to put the tractor away, but it doesn’t start, it makes an alarming grinding noise but doesn’t turn over.  The solenoid?  I am constantly struggling with the various  small motors that run things around here.  I get the cover off the engine; need to replace the air filter, how does this poor thing breathe?  And, um, it’s way overdue for an oil change….

Once I get it opened up, there’s an obviously broken bendix gear, at least I think it’s a bendix….  Bendix? Nope, I think it’s broke-ixs.  So now I’m inside surfing for parts.  PartsTree is my friend.  But I have to go back out to get the model number off the engine.  I get the number, but it doesn’t come up!

Part Number 501!

Part Number 501!

I dig thru the yellowed pages of the tractor manual, and get an entirely different model number, which does come up in PartsTree, and I will be trying to install this thing in 3 to 5 business days.

Meantime I need to put the dead tractor away. It’s 3:30 now.   I rig a tow strap to the zero turn mower, and drag its ass to the barn .  On the way, I see some mulberries coming on. IMG_1063They’re not quite there yet, but actually mulberries are best when they’re almost but not quite ripe.  In the barn, I lay out the covers and bolts so they’re ready to go when I get the parts.

It’s time to get a brief dip in before the afternoon thunder storm arrives.

I need to do some painting.

Visit to Sleeping Bear Dunes

On a lovely but chilly May morning I arrived at Sleeping Bear Dunes National Lakeshore and saw this marvelous mountain of sand that begged to be climbed.

The Dune Climb

The Dune Climb

I was glad it was chilly because the Dune Climb is steep, and, well, sand is a bitch to walk thru.  Once at the top, there is a dune trail is marked by posts and levels out somewhat.

Grasses colonize the sand wherever it holds still long enough.

Grasses colonize the sand wherever it holds still long enough.

It’s about 3 miles to the lake, and I believe I went about a mile and a half before thinking I didn’t want to be too tired to get back.

A Google Earth view of the area.  1 is the parking area, 2 is an area of outcrops.

A Google Earth viewshowing the Dune Trail.   1 is the parking area, 2 is an area of weathered sand dunes that expose cross bedding “in action”.

I found the traverses down and back up the dunes to be brutal.  And not knowing what I was getting into, I hadn’t brought any water (always take water!).  But what a place!

Grass and the invention of the circle.

The invention of geometry.

Grasses, especially beachgrass, grab any opportunity to thrive; they slow the wind, making deeper sand downwind.  The increased sand load can then bury neighboring plants.  But in windy corridors (or along trails), plants can’t get established, and the sand and wind express themselves in complex ripples.

Differential drying adds to the complexity of ripple development.

Differential drying adds to the complexity of ripple development.

Here’s how I understand the formation of the dunes at Sleeping Bear.  The last ice age delivered vast moraines of sand and gravel to Michigan.  The glaciers were pretty much gone by 8,000 years ago, and as the ice load came off, the land rose (“isostatic rebound”), and blocked the North Bay drainage pathway to the east through what is now Lake Huron.  The new drainage pattern created the Lake Nipissing Great lakes, with a proto-Lake Michigan.  With lots of sand, and wildly fluctuating water levels, prevailing winds from the West began building the dunes we see today.  These are called  “perched dunes”; old, high dunes made of sand deposited on top of glacial moraine. The highest elevation of the dunes, Sleeping Bear dune itself, is about 450 feet above Lake Michigan, but the sand is not that thick.  The park also has plenty of lake-level beach dunes

The sand itself comes from glacial deposits near the lake shore, or that have washed into the lake from inland deposits.  Then during periods of relative low water, the sand is blown on shore by prevailing winds.

About a mile from the parking lot there’s a notch between the dunes.

Google Earth view of location of sand outcrop. Click for larger.

Google Earth view of location of sand outcrop. This is location 2 on the overview aerial.  Click for larger.

The formation is probably encouraged or created by by trail erosion,  but it has beautifully exposed layers of sand showing bedding and cross bedding structures.

Crossbed formations.

Cross bed formations.  Image from #2 on the map.

I found this area oddly exciting, like seeing sandstone come alive in these delicately patterned layers of sand.  The structures are fragile.

Bedding and cross bedding.

Bedding,  cross bedding and ripples. Image from #2 on the overview.

What preserves the distinction between layers?  The sand is pretty thoroughly unconsolidated, but apparently there is already enough structural variation between layers for them to erode at different rates.  Presumably layers represent episodes of various wind

Cross bedding.  Rusty beer can for scale.

Cross bedding. Rusty beer can for scale. Image from #2 on the overview.  Click for larger size.

conditions; the cross bedding occurs on the lee side of the dune with the maximum slope corresponding to the wind direction. This was bothering me, so I consulted Arthur L. Bloom’s Geomorphology – Systematic Analysis of Cenozoic Landforms, which has a really good discussion of aeolian processes.  The threshold velocity for erosion is related to grain size, so the layering  reflects sorting during deposition.

Cross bedding.  Image from #2 on the map.

Cross bedding. Image from #2 on the map. Click for larger.

The gravel is “lag” gravel, and is left behind as sand blows away.  Still a bit curious that there’s so much of it this high, about 300 feet above the lake, and pretty much local high ground.

Lag gravel.

Lag gravel.

The Sleeping Bear Dunes Website  has a website at http://www.nps.gov/slbe/index.htm and good geology field notes at http://www.nature.nps.gov/geology/parks/slbe/; there’s also a good explanation of ancient shorelines of the Great Lakes at http://www.nps.gov/piro/naturescience/upload/August_2009_PIRO_Resource_Report_Blewett.pdf Also, I’ve learned much from Raymond Siever’s Sand, a Scientific American Library mongraph that is about a lot more than just sand.

M64’s unusual dust feature

We had a really clear night June 3rd, following a cold front, so I set up an imaging run on M64, the descriptively named “Black Eye” galaxy.  I got a good hour of luminance data, but only about 15 minutes each of RGB.  I haven’t made anything acceptable with the color data yet, but the luminance is ok.  M64 (aka NGC 4826) is a crowd-pleaser  for amateurs because it shows visible structure in modest scopes due to its startlingly obvious dust lane.

M^$

M64 (NGC 4826), exposed 6-3-2013; luminance 12 x 300 seconds. 12″ LX-200 at f/10 with SBIG ST-10XME, resolution .47 arc-seconds/pixel. Click image for larger size.

But the dust lane wants an explanation.  It’s located at the inner third of of a broad disk, and is obvious even at the fairly broad angle at which the galaxy presents itself.  The outer disk has suggestions of spiral structure, but the details have apparently softened over time.  The explanation is probably related to the observation that the outer part of the galaxy includes a gas disk rotating in the opposite direction of the stars and gas in the inner disk, presumably from accretion or collision at some time in the distant past.  From  a paper by Corsini, E. M.; Bertola, F,  “The Phenomenon of Counterrotation in Galaxies” (http://adsabs.harvard.edu/abs/1998JKPS…33S.574C):

This galaxy contains two nested counter-rotating gaseous disks.  Radio and optical observations revealed an inner disk of about 1 kpc radius containing ~107 solar masses in HI and  ~108 solar masses in H2 and a counter-rotating outer gas disk extending from 1.5 to 11 kpc and containing ~108 solar masses in HI.

 

They are coplanar to the stellar  disk. Stars co-rotate with the inner gas  but beyond the dust lane less than 5% of them (~108M ) co-rotate with the outer gas.  The kinematical features of NGC4826 are interpreted considering an original gas-poor galaxy with prograde gas which slowly acquires a comparable mass of external retrograde gas.  The new counterrotating gas settles in the outer parts of the stellar disk,leaving undisturbed the galaxy morphology.

The galaxy is now relatively isolated, so there is no obvious smoking gun.  The culprit may have been a counter-rotating dwarf galaxy in orbit around M64, which has now completely lost its identity, and is suggested only by the Black Eye.

 

 

Find files by month ignoring the year, with AppleScript

I find that I take a lot of pictures of seasonal stuff, and  I wondered how to find images taken at the same time of year but in different years.  As it turns out, there’s no obvious way to do that.  Computers keep time by counting the number of ticks or seconds since an arbitrary start date, and calculate a particular date and time  from the number of ticks.  So most date functions treat time in its relation to the arbitrary start date.  Mac OSX gives the current date as “Saturday, June 8, 2013 9:33:35 AM”, but when you search by date from iPhoto or Aperture,

Date search in Aperture

Date search in Aperture

you can only search for time periods relative to a given time.  It might be handy to add a “contains” to the list, eg, “Date contains May”, but alas.

Nevertheless,  AppleScript can easily parse a file’s creation date to let us search for files by “month of creation date”,  which might return “June” or a day of the week with “weekday of creation date”, which might return “Saturday”.

Here’s a simple script which has you choose a folder, then uses the Finder’s label index property to label all files with “May” in their creation date.  The script will find all files in the folder made in the chosen month, label them with one of 8 indices (0 thru 7; 0 is no label).  It sorts the finder window by label, so all your labels are grouped; then it selects the labeled files.  From the Finder, you can run QuickLook by touching your  spacebar.  You can then browse all the files from May no matter what year.  We’re hard-coding the label index (5) and month (May) for now.

set the_folder to choose folder with prompt "Select a folder:"
set the_label_index to 5
--label index:
-- 0=none
-- 1=orange
-- 2=red
-- 3=yellow
-- 4=blue
-- 5=purple
-- 6=green
-- 7-grey

tell application "Finder"
    activate
    set the_files to every file of the_folder
    repeat with current_file in the_files
        set the_creation_date to creation date of current_file
        set the_month to month of the_creation_date
        --we're hard coding the month now but will assign a variable in the next version
        if the_month is May then
            set the label index of current_file to the_label_index
        end if
    end repeat
    sort the_folder by label index
    select (every document file of the_folder whose label index is the_label_index)
end tell

It would make it easier for the user to select the month from a list, especially since month names vary by OSX language preferences.  Also, who knows what label index goes with what color?  We can use AppleScript’s choose from list method  to make those selections easier:

set the_month to choose from list {January, February, March, April, May, June, July, August, September, October, November, December} with prompt "Choose a month"
if the_month is false then error -128 --handles cancel button
--the chosen month is an item of a list, so we need to get it from the list
set chosen_month to item 1 of the_month

set the_label to choose from list {0, 1, 2, 3, 4, 5, 6, 7} with prompt "Choose a label; 0 is none, 1 orange, 2 red, 3 yellow, 4 blue, 5 purple, 6 nauseous green, 7 grey"
if the_label is false then error -128 --handles cancel button
set the_label_index to item 1 of the_label

Also, you may want to have the script navigate folders recursively.  For that, we turn the script into a subroutine.  The script calls the subroutine, then call it again for each sub-folder.   Here’s a script that does that:

--Label files by month
--recursively gets month of creation date and sets label for chosen month
--jjmcclintock 20130606

set the_folder to (choose folder)
set the_month to choose from list {January, February, March, April, May, June, July, August, September, October, November, December} with prompt "Choose a month"
--need to handle error if user cancels
if the_month is false then error -128
--the chosen month is an item of a list, so we need to get it from the list
set chosen_month to item 1 of the_month
--it would be nice to call the labels by color name and let the script convert your choice to index numbers, but
--putting that in the prompt is as far as I'm likely to go with it.
set the_label to choose from list {0, 1, 2, 3, 4, 5, 6, 7} with prompt "Choose a label; 0 is none, 1 orange, 2 red, 3 yellow, 4 blue, 5 purple, 6 nauseous green, 7 grey"
if the_label is false then error -128
set the_label_index to item 1 of the_label

--call the subroutine, passing the chosen parameters
label_for_month(the_folder, chosen_month, the_label_index)

--the subroutine:
on label_for_month(the_folder, chosen_month, the_label_index)
    tell application "Finder"
        --Check each of the  files in this folder
        set the_files to every file of the_folder
        repeat with current_file in the_files
            set the_creation_date to creation date of current_file
            set the_month to month of the_creation_date
            if the_month is chosen_month then
                set the label index of current_file to the_label_index
            end if
        end repeat
        sort the_files by label index
        --now each sub-folder
        set sub_folders_list to folders of the_folder
        repeat with the_sub_folder_ref in sub_folders_list
            my label_for_month(the_sub_folder_ref, chosen_month, the_label_index)
        end repeat
        sort the_files by label index
    end tell
end label_for_month

The script sorts the files by label, so you should see big blocks of similarly colored file labels. The script can’t select files across folders, but you can select them manually and run QuickLook (spacebar).  While the script is non-destructive, you may want to use it with care with folders that have many sub-folders; it can take a long time to run.  If you use labels for other purposes, this will! make a mess.

It should be fairly easy to modify this script to move or copy selected files if you want them for, for example, a calendar project. The choose from list method also supports multiple selections (“multiple selections allowed“) but you would have to futz with the the_label_index variable to make it work right.  It seems like overkill. But  for getting Saturday ball game snapshots from years past, or April invoices, or Christmas movies, this should do the trick.