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.

A nice triple conjunction

After the crazy weather we’ve been having , it was a treat to see Venus, Jupiter and Mercury crammed together into a neat triangle after sunset.   Mercury can be hard to find in the twilight, and it sure makes it easier to have Venus or Jupiter as a marker.  Tonight we have both!  Mercury is the faintest of the three, at the top of the triangle.

Venus, Jupiter and Mercury form a nice triangle May 26.  Canon 60Da 135mm lens, 1/60 at 5.6.

Venus, Jupiter and Mercury form a nice triangle May 26. Canon 60Da 135mm lens, 1/30 second  at f/5.6.  Click for larger.

Kentland Impact Structure Field Trip

Last year I discovered that the Geological Society of America (GSA) has annual regional meetings with really great field trips to local geological locations of interest.  So I joined up, and last year paid a visit to the Serpent Mound Disturbance, a fairly ancient meteor impact site in southeastern Ohio.

This year a trip was offered to the Kentland, Indiana impact site.  The trip was ably led by Dr John C. Weber,  Professor of Geology at Grand Valley State University, Allendale, Michigan.

The site is located in the flat Indiana farm land typical of the north western part of the state, and the only clue about the area’s unusual geologic history is a limestone quarry, now called the Newton County Stone Quarry, operated by the Rogers Group.  The surrounding landscape is covered by Pleistocene glacial deposits to considerable depth, which is the source of the rich soil that makes this such productive farm land.

 What the undisturbed strata should look like. Adapted from John C Weber field guide. Click for larger

What the undisturbed strata should look like. Adapted from John C Weber field guide. Click for larger.

Beneath the soil and glacial till, I’m told, are tidy, virtually horizontal layers of Middle-Lower Paleozoic bedrock that slope very gently from the Kankakee-Cincinnati Arch southwest to the Illinois basin.

Highwall of the center east pit, glacial debris at top, Maquoketa shale, then Galena and Platteville formations.  Stata tilts sharplt eastward. Click for larger size.

Highwall of the center east pit, glacial debris at top, Maquoketa shale, then Galena and Platteville formations. Looking east, the strata tilts sharply eastward. Location 1 (see Google Earth map below). Click for larger size.

Apparently there was a limestone outcrop that was obvious to local residents early on; the site has been a quarry since the 1880’s.

Strata in the impact area are not well-behaved, and require explanation.  Graphic adapted from Indiana Geological Survey. Click for larger.

Strata in the impact area are not well-behaved, and require explanation. Graphic adapted from Indiana Geological Survey. Click for larger.

Geologists recognized that explanation was required both for the raised bedrock, and for the very un-tidy, not-horizontal placement of the strata within the formation.

Why is Kentland important?  The impact site currently has no surface signs of a crater.  However the impact uplifted the strata at the center of the site, providing a handy outcrop of limestone for local use. The resulting quarry is exactly why the impact effects are so accessible; the site is a laboratory for studying impact-deformed strata.  Geologist love roadcuts because they expose strata that are normally covered by earth or vegetation.  The quarry is like a continually expanding roadcut that regularly reveals  new windows on the tortured layers of the site.

R.S. Dietz, one of the early proponents of impact geology, studied Kentland’s impact structures in place, especially shatter cones, and found the orientation of the cones were invariably normal (perpendicular) to the bedding:

“The orientation of the shattercones suggests that, assuming that the beds were essentially horizontal prior to deformation, the shock force resulted from some type of explosion directly above the beds rather than from a crypto-volcanic explosion below the beds.” (Science 10 January 1947: 42-43.)

Kentland shattercone in Silurian carbonate.  Click for larger.

Kentland shattercone in Silurian carbonate. Click for larger.

Along with Meteor Crater in Arizona, Kentland provided the essential clues to put “crypto-volcanic” theories to rest.

The site was carefully described and mapped by R.C. Gutshick from the 1960’s to late 1980s.  He showed that the quarry is at the apex of a structural dome, the central uplift area of a complex crater.

John C. Weber, field trip leader makes introductory remarks.  In background is original RC Gutschick quarry map.

John C. Weber, field trip leader ,makes introductory remarks. In background is original RC Gutschick quarry map.

The crater itself has long since eroded away (hence, “impact structure”), along with evidence of exactly when the impact occurred, and how large the crater was.  The glacial till that covers the neighborhood is about 50,000 years old; the upper layers of bedrock are of Silurian age, about 300 million years old. At some time in this 300 million year gap, an object made a sudden stop in Indiana – from maybe 20 km/sec to 0 in less than a second- and created a 6-13 km (3.7 to 8 miles) diameter crater. The center of the impact was raised by 600 meters by the rebound, and created a chaos of the formerly tidy  Silurian and Ordovician layer cake. Then all evidence of the crater, the outer rim and  glassy melts were eroded away, both here and over the surrounding region. Much later,  glaciers covered the area, leaving behind a layer of debris that has become home to corn and soybeans.

How do you figure out the size of  a crater that has long since eroded away?  The Earth Impact Database  gives a diameter of 13 km probably based on Gutschick’s mapping.  However Gutshick also measured the uplifted Ordovician Shakopee dolomite to be  about 600 meters above its un-deformed counterparts.  Applying impact models developed by HJ Melosh, GS Collins, and RA Marcus (http://impact.ese.ic.ac.uk/ImpactEffects/effects.pdf), a 13 km crater should show a central uplift of 1 to 1.3 km.  A crater of 6 to 7 km would have a central uplift that more closely matches Gutschick’s measurement. You can play with the various impact parameters with the online  Impact Effects Program at http://impact.ese.ic.ac.uk/ImpactEffects/

Google Earth view of Kentland site from 18-odd miles.  6 km circle represents plausible crater diameter.  Click for larger size.

Google Earth view of Kentland site from 18-odd miles. 6 km circle represents plausible crater diameter. Click for larger size.

For me, the highlights of seeing this place first hand, were the incredible, and obvious distortions of the rock layers; the numerous shattercones, now considered an icon of impact geology; and the impact breccia, another hallmark of impacts, but not at all unlike volcanic breccia to my eyes.

 

 

Overview of quarry from Google Earth.  Numbers refer to approximate locations of pictures.  Click for larger.

Overview of quarry from Google Earth. Numbers refer to approximate locations of pictures. Click for larger.

I think I expected to get some understanding of a “system” that would describe the disturbed strata.  Nope. I liked Weber’s description  from his field guide: “It is a steeply dipping, bedding sub-parallel, folded fault that juxtaposes the St Peter Sandstone with the Middle Ordovician Platteville Group”  But I must admit this doesn’t seem to do the chaos justice.  Here’s a St Peter sandstone  –  Platteville sequence that is turned on its side, and then repeats. The St Peter sandstone is the distinctive white layer.  At its base, it’s pulverized to a flour consistency, which is characteristic of other impact sites.  I don’t know if that accounts for this occurrence, or if it has just weathered.

Panoramic view of highwall with alternating St Peter sandstone and Platteville carbonates.  Looking southeast. Click for larger.

Panoramic view of highwall with alternating St Peter sandstone and Platteville carbonates. Looking southeast, location 2. Click for larger.

Here’s a detail of a section with Platteville and St Peter sandstone.  There are shatter features, breccia dikes with hefty clasts, and a general sense of craziness.

Platteville, St Peter SS.  Looking aprox west.  Click for larger.

Platteville, St Peter SS. Looking approx west, location 2. Click for larger.

Similarly, Maquoketa shale  and Galena Platteville.  The Ordovician black Maquoketa shale is, I believe, a  member of the Richmond formation.  It’s another distinctive marker bed, and quickly weathers into  talus slopes.

Maquoketa shale alternates with Galena formation.  Click for larger.

Maquoketa shale alternates with Galena formation. Looking east, location 3.  Click for larger.

More Maquoketa shale  and Galena showing the MFS (Marine Flooding Surface):

Maquoketa shale, Marine Flooding Layer, and Galena carbonates. Looking west.  Click for larger.

Maquoketa shale, Marine Flooding Surface, and Galena carbonates. Looking west, location 4. Click for larger.

The north-east pit is working Silurian carbonates.  I don’t believe it’s been mapped;  I don’t which Silurian formations are presented.

    Massive highwall of Silurian carbonates. Looking north. Click for larger.

Massive highwall of Silurian carbonates. Looking north, location 5. Click for larger.

Some really big clasts thrown into Maquoketa shale:

Maquoketa shale with Galena clast(?).  Click for larger.

Maquoketa shale with Galena clast. Looking east, location 6.  Click for larger.

Shakopee dolomite is the oldest exposed layer.

Shakopee dolomite with breccia dike.  Looking east.  Click for larger.

Shakopee dolomite with breccia dike. Looking north, location 7. Click for larger.

One of the definitive, but not exclusive, indicators of impact are breccias.  At Kentland there are dikes filled with polymict breccias that were apparently forced into fissures and voids opened by the rearrangement of massive blocks by the impact.

Polymict impact breccia.

Polymict impact breccia. Location 4.

Inside, the breccias have a fairly fine grained matrix with clasts that are familiar  from the neighborhood:  St Peter Sandstone and various carbonate chunks, with conspicuous voids.

Polymict breccia from dike in Shakopee dolomite. Click for larger.

Polymict breccia from dike in Shakopee dolomite. From location 7.  Click for larger.

Polymict breccia sample.  Click for larger.

Polymict breccia sample. From location 7.  Click for larger.

I haven’t gone into the studies of microscopic features of this site.  Weber authored an interesting study (“Kentland Impact Carater, Indiana:  An Apatite Fission-Track Age Determination Attempt” ; Weber, et al) using fission tracks in apatite grains in the St Peter SS to attempt to find an impact date.  The fission tracks would show a thermal reset, possibly at the time of impact.  Unfortunately, the reset seems to occur regionally, so presumably local evidence has eroded away.  There are several GSA Field Guides available from http://fieldguides.gsapubs.org/ (by subscription).

A look at M99

I intended to get a good hour in for LRGB on this, but as it turned out the guiding was intermittent and I really only got 4 each good RGB frames for 20 minute total exposure.  So the image is not deep.

M99

M99, exposed 4-13-2013; RGB each 4 x 300 seconds. 12″ LX-200 at f/10 with SBIG ST-10XME, resolution .47 arc-seconds/pixel. Click image for larger size.

I’ve started using CCDStack and, when calibrating the frames, was getting a “negative ADU” alert when applying the flats.  This was quite mystifying.  It turns out I was not making flats with enough exposure. I resolved it by re-exposing the flats with the 40 watt bulb (instead of 15 watts), increasing the exposure so I was getting about 60% full well capacity.  That satisfied CCDStack, and should make a better flat. I’m still seeing irregularities in the background areas, which were repaired in Photoshop with Astronomy Tools from ProDigital Software.

M99 is a “grand design” spiral, except for its crazy arm which has presumably been distorted by a close encounter.  Because it presents itself so well, it’s been the subject of a lot of research, mainly concerned with the distortion of the spiral. This gets interesting because HI (neutral hydrogen) mapping from Areceibo showed a massive (about 100 million solar masses) rotating accumulation of neutral hydrogen fairly nearby, dubbed VirgoHI21.

Wikisky screenshot of M99 vicinity

Wikisky screenshot of M99 vicinity

There’s nothing to see of Virgo HI21, it seems to be mass without stars, which only shows up in radio survey.  From its mass, it should be a 12th mag galaxy.  The discovery of VirgoHI21 was greeted with great excitement, because it was thought to be the first candidate for a dark matter galaxy, which maybe it is.  Would that be cool!  But it seems that dark matter refuses to reveal itself that easily. Evidence is mounting that the VirgoHI21 is a tidal tail, probably from M99, the result of nearby NGC 4262 gliding thru the neighborhood 280 million years ago. This is all gleaned from the detail page on M99 from WikiSky.

NGC 4298 and 4302 are a lovely pair that I will image soon, if it ever clears up.

Orion and New Moon

We’ve had a rainy week and 5 or 6 inches of rain, but it cleared up nicely.  I planned a run on M99, which I had botched a few weeks before.  i unparked the scope, fired up the camera & coolers, opened the roof and aimed at Denebola to check the aim.  That accomplished, I headed inside to do the rest from the living room.

I stepped out of the Hut into a lovely twilight and had to just stop to take in the Big Picture, which is so often lost when futzing with gear.

The Hut in a lovely twilight. Canon 60Da, 38mm; 4 seconds and 1/60 sec exposures combined in Photoshop.  Our local ugly green gradient was cheerfully removed with the Astronomy Tools Soft Gradient removal action.

The Hut in a lovely twilight with Orion and our moon. Canon 60Da, 38mm; 4 seconds and 1/60 sec exposures combined in Photoshop. Our local ugly green gradient was cheerfully removed with the Astronomy Tools Soft Gradient removal action. The red wash was added by my headlamp. Click image for full size.

I heard peepers chorusing across the field and the  redwings calling in the bamboo patch. Then coyotes had a brief earnest discussion.  I haven’t processed the M99 frames yet.  Will put them up soon.

Supernova 2013am in Leo

In my continuing, ongoing shakedown, I set up a full LRGB series of M65 (NGC 3623) on the clear, moonless night of April 3. The forecast was good, so I set things running and went to bed. Somewhere in the green series, things murked up a bit, and the tracking crapped out for some of the greens and all of the blue.

M65 on April 3, 2013. 10-5 minute luminance exposures with LX200 12" at f/10 with ST10XME.

M65 on April 3, 2013. 10-5 minute luminance exposures with LX200 12″ at f/10 with ST10XME.

The luminance looked pretty good, except for the usual annoying, slightly oval star images.  But wow, quite by accident, the image shows Supernova 2013am, discovered on

Supernove 2013am

Supernova 2013am, UT 03:50 April 4. .47 arc-seconds/pixel

March 30 by M. Sugano (Japan).  I’m probably the only one who didn’t know this was now playing in one of Leo’s Kodak Photo Spots.  Still, hitting it by accident means I could have discovered it!  Well, if I had actually noticed it!  I found out about the supernova via a casual mention on a mailing list, and thought, “didn’t I just image that?”

Control System Prefs with AppleScript

I use TeamViewer to control the PC in the Hut, because it’s free, and it often works quite well.  The thing that drives me most nuts about it is how to right-click remotely.  I’m working from a Mac Book Pro with a trackpad.  I suppose I could actually use a two button mouse, but I haven’t used a mouse with a MBP forever.  I’m not even sure I have a two-button mouse… The solution is to go to the System Prefs Trackpad panel and set the Secondary Click checkbox for two-finger click.  trackpad-panel

That actually works great for TeamViewer remote sessions.  But it drives me nuts in MacLand, because I seem to use two hands on the trackpad and am constantly getting unwanted context menus.  So I wanted a handy way to turn on or off the two finger click trick programatically, which is to say, with AppleScript.

So how do you get your hooks into the Systems Preferences elements?

The key is to use System Events to get and set the window’s UI elements.  Here’s a simple script that collects the UI elements for the frontmost window of the application you want to peek at, in this case System Preferences:

tell application "System Preferences"
    --bring System Prefs to front
    activate
end tell

tell application "System Events"
    tell process "System Preferences"
        set windowsProperties to entire contents of front window
    end tell
end tell

return windowsProperties

The results window displays a lengthy list of elements that you’ll have to noodle over to figure out what you want.  In this case, I had opened System Preferences and clicked  to open the Trackpad panel, as in the image at top.  Here’s what the ScriptDebugger window looked like:  results of ui inspector

 

Here’s the pasted value (pasted into ScriptDebugger) from the results for “checkbox 2 of tab group 1 of window “Trackpad” of application process “System Preferences”:

tell application "System Events.app"
    tell application process "System Preferences"
        tell window "Trackpad"
            tell tab group 1
                tell checkbox 2
                    -- your code goes here
                end tell
            end tell
        end tell
    end tell
end tell

This nested tell set is clunky, but lets you easily understand exactly what’s going on, and you can just paste it into a script to get or set a value to a particular UI element.  I had to horse around to check or un-check the  secondary click checkbox.  “Normal” checkboxes have a value of “0” for unchecked and “1” for checked.  The script would let me get the value, “0” or “1”, but not let me set the value.  However, it did let me treat the checkbox like a button, and “click” it.  Go figure. That would be a problem if I really needed to set a particular value, but in this case, I’m happy to let it toggle:

--toggles "2 finger click" for secondary click on or off via trackpad pane of system Prefs
--needs "does trackpad panel exist?" 
--JJ McClintock 20130411

tell application "System Preferences"
    activate
end tell
tell application "System Events"
    tell application process "System Preferences"
        tell window "System Preferences"
            tell scroll area 1
                --hopefully this will catch issues if no trackpad panel exists
                try
                    click button "Trackpad"
                    tell application "System Events"
                        tell application process "System Preferences"
                            tell window "Trackpad"
                                tell tab group 1
                                    ----set value doesn't seem to work
                                    --set value of checkbox 2 to 1
                                    ----get works fine
                                    --get value of checkbox 2
                                    --click works as toggle
                                    click checkbox 2
                                end tell
                            end tell
                        end tell
                    end tell
                end try
            end tell
        end tell
    end tell
end tell
--we want to quit System Prefs when we're done
tell application "System Preferences"
    quit
end tell

I saved the “toggle 2 finger secondary click” script as an application bundle and placed it in my script menu folder. Now I can turn on 2 finger click when I begin a TeamViewer session and turn it off the same way when I’m done.

Second look at The Eyes

I had a few hours before moonrise, and wanted another stab at NGC 4435 & 4438.  I  thought I had good focus, and was getting about 5.5 FWHM on the focus run, but it looks like the focus drifted quite a bit during the run. NGC 4435 and 4438; 5 x 300 with 12" LX-200 at f/10 and ST-10.

NGC 4435 and 4438; 5 x 300 with 12″ LX-200 at f/10 and ST-10.

And for some reason Maxim refused to connect to the mount, so the exposures are unguided.  I got 5 sort of acceptable 300 second frames.  NGC 4438 is one abused galaxy.  It seems likely but not certain that NGC 4435 is responsible.  From ESO (http://www.eso.org/public/news/eso1131/) :

“NGC 4435 could be the culprit. Some astronomers believe that the damage caused to NGC 4438 resulted from an approach between the two galaxies to within about 16 000 light-years that happened some 100 million years ago. But while the larger galaxy was damaged, the smaller one was significantly more affected by the collision. Gravitational tides from this clash are probably responsible for ripping away the contents of NGC 4438, and for reducing NGC 4435’s mass and removing most of its gas and dust.”

The dark patches on 4438 are enormous clouds of visually opaque dust.  I believe the fuzzy patch just to the right of 4438 is a small companion galaxy.

Sucker hole

For amateur astronomers, a “sucker hole” is when it looks clear enough to set up, but as soon as you’re ready to get started, it clouds up again, and you feel like a dope.  We’ve been waiting for Spring to get started for what seems like forever.  I first heard spring peepers March 9, and knew spring was at least a possibility.  But that was followed by weeks of mostly wintry weather  and several days of serious snowfall.  So for our little tree frogs, a day warm enough to chorus and mate might turn out to be just a “sucker hole”, and I’ve often wondered if the following cold snap is a nuisance or a disaster for them.  On March 26, I heard the peepers again; it was 31 degrees, and blizzarding giant flakes of snow.

Tonight, we had a few clouds around sunset, but it cleared up very nicely, so I opened the hut and hoped to get a few pictures before the moon came up.  I framed NGC 4435 and 4438 in Virgo (“The Eyes”) and set up a series of 300 second exposures.  I went inside and saw that the results were crap;  I went back out, and sure enough, alto-cumulus had moved in.  partly_cloudy_IMG_4598-2I collected 3 frames and processed them just to see what results you could actually get under really, really poor transparency, with strong moonlight illuminating the cloud cover.  The remarkable thing to me is that the galaxies are easily identifiable, including a suggestion of the distorted chaos of 4438 on the right.  4435-003L_c_crop

The image combines 3 – 300 second integrations, without very good registration.  The actual exposure is probably much less, with the clouds acting as a shutter.

Two of the Leo Trio

After I got a glimpse of Pan-STARRS, it looked like it would be clear enough to open the Hut.  I wanted to run some more v-curves (calibration runs) in FocusMax, but apparently I had the steps set too small and the center focus position set too far off.  So the run took forever and didn’t give a good curve.  Meanwhile I went inside and was working remotely and the network was uncharacteristically slow, in fact excruciating, so I went back out to the hut and worked from there.  TeamViewer was running at 90% CPU, which is not normal.  Anyway to salvage the evening, I chose an easy target that was far enough from the meridian to avoid mirror flop issues.  The “Leo Trio” consists of M 105, NGC 3384 and NGC 3389, a pretty tight grouping of obvious galaxies.  My camera field at 17 x 11.5 arc-minutes is a bit tight for all three, so I framed  3384 and 3389 and set up for 10 – 300 second exposures.

Two of the Leo Trio, NGC 3371 and NGC 3389.  8 x 300 seconds.

Two of the Leo Trio, NGC 3384 (left) and NGC 3389 (right). 8 x 300 seconds.

The stars in the subs are a bit oval in the  East-West direction, so something is not optimal with guiding, will work on that later.  I didn’t shoot RGB because the sky started murking up, and ended up with 8 ok luminance frames to work with.

After processing the image, mainly with Maxim’s DDP (“digital development”) utility, you can see what looks like the remnant of a central bar or disk not exactly perpendicular to the axis of the ellipse.  I was expecting an elliptical galaxy, but it looks like NGC 3384 hasn’t evolved quite that far yet.  NGC 3384Elliptical galaxies are considered to be the end state of possibly numerous galaxy mergers and are mostly found in crowded galactic neighborhoods, in this case the M96 group.  When I selected NGC 3384 from TheSky, it was identified as NGC 3371, and guess what, it’s both!  NGC 3371 was discovered Mar 11, 1784 by William Herschel and eventually listed as NGC 3384, then recorded Mar 23, 1830 by John Herschel and listed as NGC 3371. Apparently this is one of the ways that errors cropped up in the NGC catalog; the accepted name seems to now be 3384.  Depending on the source, it’s identified as an E07 elliptical, or occasionally as an SB0 (which is to say a lenticular galaxy with no apparent spiral structure but with a bar), which looks to be more accurate.  NGC 3389 looks like a beat-up spiral that has been distorted by a close encounter, and would be fun to add some RGB data.  It’s blue and has active star formation going on; from it’s motion and distance, it’s not considered to be part of the the M96 Group.