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.

First look at Pan-STARRS C/2011 L4

It’s been a fairly blue day and I had hopes of glimpsing Pan-STARRS.  I went out after sunset, and between the crescent moon and the sun is a beautifully textured but mostly opaque mass of cirrus.  Quite a lovely evening but not a glimpse of the comet through the binoculars.  I was helped by Callie the cat who thought it helpful to rub on the binoculars while sitting on my chest.  I pretty much gave up and went inside to warm up and hope I’d get another chance if the clouds moved off.

image of comet panstarrs

Comet Pan-STARRS C/2011 L4. Canon 60Da; 135 mm; ASA 1000; 4 sec at 5.6.  20130314.

In fact, when I went back out, a fairly bright spot was emerging from the low side of the clouds, followed by a distinct tail, easy in the binoculars.

Cropped detail of comet PANSTARRS C2011 L4.

Cropped detail of comet Pan-STARRS C2011 L4.  20130314.

I ran in to grab the camera, which I had already set up on a tripod.  I made a few exposures at 4 seconds f/5.6,  but only one was steady enough to use.  The comet was visible but not obvious with the naked eye.

Time repairs

Periodically there’s a thread on the AstroPhysics forum on why the scope isn’t exactly on target, and sometimes a lot off target, after start up and un-parking.  There are lots of mechanical reasons for this:  if the optics of the scope are not parallel to the scope’s axis (“unorthogonality”); flexure of the scope in relation to the mount; and “mirror flop” (bane of the schmidt-cass); as well as atmospheric refraction (if the target is at low altitude).

If the error is mostly East-West,  it’s probable that the mount’s time is a bit off.  In permanent installations, the time is grabbed from the controlling PC.  The PC, if it’s connected to the internet, syncs time to a time server via the Windows Time Service.  As it turns out, the PC time syncs to a reference only once per week, usually on Sunday night.  It’s typical for a PC to be off by several minutes. How does that translate into centering your target?

Each second of time is 15 arc-seconds on the sky; a minute of time is 15 arc-minutes on the sky.

With my setup, a Meade 12 inch schmidt-cass, with an SBIG ST-10XME, I get a field that is 17×11.5 arc-minutes.  If I’m more than a minute off in my time settings, the target is off the chip.

image of ngc 90

NGC 90 (center), part of a busy field in Andromeda. Exposed on 20130107, 20 minutes total exposure.

How can you update your PC time more frequently than once a week?  The NIST (National Institute of Standards and Technology) is probably the last word in time accuracy and is probably the source your PC is syncing to.  There are a bunch of applications that can set your PC time; NIST has a list at http://www.nist.gov/pml/div688/grp40/softwarelist.cfm.  Most amateur astronomers mention Dimension 4 (free) from Thinking Man Software.  It makes it easy to setup  time sync on a regular schedule. Dimension 4 panel

In Windows, you can you can force an immediate synchronization by clicking the Update Now button on the Internet Time tab in Date and Time in Control Panel.   Windows Date and Time Properties

Presumably this is calling the Windows Time Service application, w32tm.exe, located in c:\windows\system32.  You can also run this from the command line as w32tm.  Or, you can set it to run as a scheduled task using Task Scheduler in Administrative Tools.

If you use a workflow with Maxim or TheSky, you can use their plate-solving utility to sync the mount to its actual position, then slew to the target.  Here’s my start-up procedure:

  1. Power up mount, dew heaters, camera, and focuser
  2. Start FocusMax; this connects to focuser, starts Maxim, connects Maxim to ST10 camera and guide camera.
  3. Start TheSky; link the mount (telescope); this launches the ASCOM V2 control panel.  Unpark the scope from the ASCOM panel.
  4. In Maxim, connect to telescope (mount)
  5. In TheSky, slew to a target
  6. In Maxim take focus frame. Here’s where you think, “that doesn’t look like NGC 7007!”
  7. If the target is off center, you can right click it in Maxim and select “Point telescope here”.
  8. If the target is nowhere in sight, select Pinpoint astrometry from the Analyze menu. Click Process.  The software will hum and purr for a while and hopefully stop with a solution.  Assuming a solution,
  9. Open the Observatory panel in Maxim, select the Telescope tab, and click “Sync”.  The mount now thinks it’s pointed where it is, in fact pointed.
  10. Go to TheSky and slew to your target again, and it will be, god willing, in the center of your frame.  Any time-based errors have been resolved from the source — the position of the stars.

 

 

NGC 2775

On a rare clear night, I wanted to improve the auto-focus routine, and spent some time getting it pretty close,  Then I picked a promising object somewhat at random, which turned out surprisingly well.

NGC 2775, 10 x 300 seconds; LX200 12" at f/10 and SBIG ST10-XME

NGC 2775, 10 x 300 seconds; LX200 12″ at f/10 and SBIG ST10-XME

NGC 2775 has a very tight spiral structure with very fine detail that reminds me of M63, the “sunflower” galaxy, but a bit more face on.  It’s also about a third of the angular size and almost twice as far, about 55 million light years.  The image showed a pretty bland disk:

Raw integration with only some levels and curves applied

Raw integration with only some levels and curves applied

until processed with Maxim’s DDP and wavelet filter.  The processing reveals the curdled knots in the disk, and a dust lane at top.  I’m also interested in the little clump of presumably background galaxies to the left of the galaxy.  They certainly look like they are associated with each other, but don’t seem to be part of a named group.  They do have catalog numbers from the USNOA2 catalog (two of them are USNOA2 0900-06308497 and 0900-06308509)