Salvatore Iovene / Mostly astrophotography and code

A proficuous Autumn has gifted Samuel and me of many clear nights, so I am able to share once again a deep image of two nice galaxies with background wisps of Integrated Flux Nebula.

NGC 2633 (mag 12) and 2634 (mag 11.8) are two galaxies in the constellation of Camelopardalis (also known as the Giraffe), each about 2’ across in apparent size.

The entire field is permeated by the Integrated Flux Nebula, which is well visible in a structure of two definite wisps. Samuel’s version of this image shows a larger field and a greater extension of the filaments.

This image was acquired in Nerpio, Spain, as detailed below:

• Luminance: 86x1200”, GSO RC10, Atik 4000, Paramount MX
• RGB: 83x600”, GSO RC8, Moravian Instruments G2-1600, 10Micron GM2000

I have found traces of the IFN on other images of this fields, but this is the one where they are the most obvious.

The image is also available on AstroBin: NGC2633-34 and wisps of IFN on AstroBin.

Across the end of November and the beginning of December 2013, Samuel and I have collaborated on another nice project. I’m really taking a liking for galaxies with nearby dust, whether it be the Integrated Flux Nebula in our Milky Way, or some extragalctic residual of gravitational interaction.

This image is the result of 23.2 hours worth of data, structured as follows:

• Luminance: 40x1200”, GSO RC10, Atik 4000, Paramount MX
• RGB: 59x600”, GSO RC8, Moravian Instruments G2-1600, 10Micron GM2000

The image can be seen on AstroBin as well: NGC 7496 and dust on AstroBin.

At the end of November 2013, Samuel and I have turned our telescopes towards the Abell 426 galaxy cluster in Perseus.

This image is the result of 43.5 hours worth of data, structured as follows:

• Luminance: 30x1200”, GSO RC10, Atik 4000, Paramount MX
• Hα: 15x3600”, GSO RC8, Moravian Instuments G2-1600, 10Micron GM2000
• RGB: 222x300” bin2, GSO RC8, Moravian Instruments G2-1600, 10Micron GM2000

The image can be seen on AstroBin as well: Abell 426 on AstroBin.

From Wikipedia: The Perseus Cluster (Abell 426) is a cluster of galaxies in the constellation Perseus. It has a recession speed of 5,366 km/s and a diameter of 863’. It is one of the most massive objects in the universe, containing thousands of galaxies immersed in a vast cloud of multimillion degree gas.

Having been outrageously busy with AstroBin from mid September up to the time of writing, I literally had no time to process the most recent batches of subframes I’d been collecting. At some point I didn’t even have the time to acquire any subs at all, because due to the change to DST, my mount went out of alignment somehow.

Anyway, I can finally enjoy some respite, so let me present the most recent images I’ve taken.

NGC 7129

NGC 7129 is a reflection nebula located 3,300 light years away in the constellation Cepheus. A young open cluster is responsible for illuminating the surrounding nebula. A recent survey indicates the cluster contains more than 130 stars less than 1 million years old. NGC 7129 is located just half a degree from nearby cluster NGC 7142. The nebula is rosebud-shaped; the young stars have blown a large, oddly shaped bubble in the molecular cloud that once surrounded them at their birth. The rosy pink color comes from glowing dust grains on the surface of the bubble being heated by the intense light from the young stars within. The ultra-violet and visible light produced by the young stars is absorbed by the surrounding dust grains. They are heated by this process and release the energy at longer infrared wavelengths as photographed by the Spitzer Space Telescope. The reddish colors in the false-colour infrared image suggest the distribution of hydrocarbon rich molecular material. The much cooler molecular cloud outside the bubble is mostly invisible to Spitzer. However, three very young stars near the center of the nebula are sending jets of supersonic gas into the cloud. The collision of these jets heats carbon monoxide molecules in the nebula. This produces the complex nebulosity that appears like a stem of a rosebud.

(Source: Wikipedia)

SH-2 188

The image is of Sharpless 2-188, an unusual planetary nebula located in the constellation Cassiopeia. The expanding gas from the planetary nebula is colliding with ambient gas in the interstellar medium. The nebula is nearly circular in shape but is much brighter to the southeast (lower left) because the central star is moving rapidly in that direction. Faint wisps of gas can also be seen in the opposite direction.

(Source: NOAO)

NGC 7217

NGC 7217 is a gas-poor system whose main features are the presence of several rings of stars concentric to its nucleus: three main ones -being the outermost one the most prominent and the one that features most of the gas and star formation of this galaxy-, plus several others inside the innermost one discovered with the help of the Hubble Space Telescope, a feature that suggests NGC 7217’s central regions have suffered several starbursts, and a very large and massive spheroid that extends beyond its disk. Other noteworthy features this galaxy has are the presence of a number of stars rotating in the opposite direction around the galaxy’s center to most of them and two distinct stellar populations: one of intermediate age on its innermost regions and a younger, metal-poor on its outermost ones. It has been suggested these features were caused by a merger with another galaxy and, in fact, computer simulations show that NGC 7217 could have been a large lenticular galaxy that merged with one or two smaller gas-rich ones of late Hubble type becoming the spiral galaxy we see today; however right now this galaxy is isolated in space, with no nearby major companions.

(Source: Wikipedia)

NGC 925

NGC 925 is a barred spiral galaxy located about 30 million light-years away in the constellation Triangulum. The morphological classification of this galaxy is SB(s)d, which indicates that this has a bar structure and loosely wound spiral arms with no ring. The spiral arm to the south is stronger than the northern arm, with the latter appearing flocculent and less coherent. The bar is offset from the center of the galaxy and is the site of star formation all along its length. Both of these morphological traits — a dominant spiral arm and the offset bars — are typically characteristics of a Magellanic spiral galaxy. The galaxy is inclined at an angle of 55` to the line of sight along a position angle of 102`. This galaxy is a member of the NGC 1023 Group, a nearby, gravitationally-bound group of galaxies associated with NGC 1023. However, the nearest member lies at least 650 kly (200 kpc) distant from NGC 925. There is a 10 million solar mass cloud of neutral hydrogen attached to NGC 925 by a streamer. It is uncertain whether this is a satellite dwarf galaxy, the remnant of a past tidal interaction, or a cloud of primordial gas.

(Source: Wikipedia)

NGC 1977

This image was acquired in conjunction with Samuel Dќaz.

NGC 1973/5/7 is a reflection nebula 1/2 degree northeast of the Orion Nebula. The three NGC objects are divided by darker regions. It is also called The Running Man Nebula and Sharpless Catalog 279. This object was named ‘The Running Man Nebula’ by Texas Astronomical Society member Jason Ware. Approximately 20 years ago his downstairs neighbor looked at the object and said it looked like a running man. He brought this up a TAS club meeting and the name stuck. Now widely accepted as ‘The Running Man’.

(Source: Wikipedia)

I’m just looking at my git-log, and I’m dumbfounded to realize that I’ve been hard at work on the latest and greatest AstroBin update for six weeks.

I must have had a wonderfully good time, because these weeks of late night working to improve AstroBin have really been flying.

Looking at the difference between the current master branch and my 1.10 development branch is even more astounding:

 434 files changed, 69324 insertions(+), 71068 deletions(-)

Now, not all these insertions and deletions are actually my code, of course: I’ve upgraded several large JavaScript libraries, for instance, and that’s a lot of pluses and minuses. If you look closely, you will see that the net amount of lines of code has actually gone down. That’s fantastic because I’ve added a lot of new features, and there were plenty new auto-generated files, like database schema and data migrations, and they can be large.

Overall, this new version of AstroBin is the largest incremental change I’ve had since launch! So let’s see what’s new.

Visible improvements

5-star rating system replaced by “Like” button

Many of you have seen this coming. There have been many discussions all over the place. In the end I’ve decided that a 5* rating system is just not ideal for astronomical images. Nobody needs “negative” votes like a 1 and a 2. I’ve implemented a Like button to replace the 5 stars. Old votes of 4 and 5 will be converted to a Like.

Because of this, a Favorite (heart) button doesn’t make sense anymore, so I’ve renamed it with “Bookmark”, and it works the same way.

New activity streams with more detail

The activity stream has become the central part of the front page experience. The activities are more detailed (for instance with the content of the comment, for comment actions) and thumbnails. It’s gonna be better to see what’s happening on AstroBin! Furthermore, there is a global stream with all activities, and a personal stream with activities from people you follow, and on their images.

Easier way to manage people you follow

A lot of focus has been placed on the follower/followee interactions. You get to see your follower numbers, and a list of people you follow / who follow you.

Smart thumbnail

AstroBin will try to find the most interesting area of the image, to generate the thumbnail. So if you have a picture with the moon in a corner, and the sky completely black, AstroBin should be able to generate a small thumbnail that has the moon in it, and not just a black square!

Revisions are solved too

This one has been in my todo-list for a while… now Revisions are first class citizens too! The will get plate-solved independently from the main image upload :)

Sky plot

Solved images have a small star chart next to them! How cool is that?

Behind the scenes

Complete refactoring of thumbnail generation

Instead of generating thumbnails by manually running PIL code after each upload, I’ve taken Django east-thumbnails into use. This allows me to generate whatever thumbnail size on the fly upon request.

This change simplified a lot of AstroBin’s code, and unifies the displaying of images everywhere, be them small thumbnails or full size ones.

Such unification allows me to cache the entirety of an image’s HMTL code, for faster performance and less strain on AstroBin’s database server.

In addition, generating thumbnails only when they are needed will help me lower the hosting costs. We are approaching half a terabyte.

Finally, I was able to completely remove the use of celery for the processing of images: they’re not run in the background anymore, but, as I was saying, they are now being generated on the fly.

For the reason that thumbnails generated for the first time won’t be cached, nor will they actually exist as physical files, displaying of all images on AstroBin now happens asynchronously.

Complete refactoring of uploads processing

Handling uploaded images was pretty much the first thing I did when I started AstroBin back in 2010 (has it been already three years?!?) and I wasn’t very experienced with web development back then, so it’s obvious that I made some mistakes.

One of them was not taking advantage of Django’s ImageField and the wonderful django-storages, by pretty much doing everything manually with boto. Now, that part is done properly and a result is much leaner and more robust.

Much faster, always blind, plate-solving

Pate-solving won’t happen on AstroBin’s server anymore, but using the API provided by nova.astrometry.net. This means that AstroBin’s server will suffer less strain, and be faster overall. Astrometry.net have a massive server, so plate-solving will be super fast! Usually 10-60 seconds, in my experience, for reasonably solver-friendly images. The plate-solving happens on the fly the first time a deep-sky image is displayed by a user and you get real time status updates.

Those were the main features. There have been other smaller improvements and bug fixes, plus some care for the IE and mobile browsers. I’m really excited about this new release of AstroBin and I hope it will strengthen the community and make the users even happier!

During some moonless hours, this August, I aimed my telescope to NGC 7129, a beautiful reflection nebula in Cepheus.

Young suns still lie within dusty NGC 7129, some 3,000 light-years away toward the royal constellation Cepheus. While these stars are at a relatively tender age, only a few million years old, it is likely that our own Sun formed in a similar stellar nursery some five billion years ago. Most noticeable in the sharp image are the lovely bluish dust clouds that reflect the youthful starlight. But the compact, deep red crescent shapes are also markers of energetic, young stellar objects. Known as Herbig-Haro objects, their shape and color is characteristic of glowing hydrogen gas shocked by jets streaming away from newborn stars. Paler, extended filaments of reddish emission mingling with the bluish clouds are caused by dust grains effectively converting the invisible ultraviolet starlight to visible red light through photoluminesence. Ultimately the natal gas and dust in the region will be dispersed, the stars drifting apart as the loose cluster orbits the center of the Galaxy. (APOD)

I collected 14.8 hours in LRGB over the course of five nights.

The image can be seen on AstroBin as well.

This new moon I decided to try a galaxy. NGC 6503 is not a commonly imaged target: there are only seven instances on AstroBin.

It’s a dwarf spiral galaxy located in the Local Void, 17 million light-years away in the constellation of Draco.

The Local Void is a vast, empty region of space, lying adjacent to our own Local Group. Discovered by Brent Tully and Rick Fisher in 1987, the Local Void is now known to be composed of three separate sectors, separated by bridges of “wispy filaments”. The precise extent of the void is unknown, but it is at least 150 million light years across and may have a long dimension of up to 70 Mpc (230 million light years). The Local Void also appears to have significantly fewer galaxies than expected from standard cosmology. (Wikipedia)

For this image, I let my equipment run for ten hours and twenty minutes.

The image can be seen on AstroBin as well.

This time, taking advantage of the New Moon nights, I went for a relatively easy and widely popular target: the Bubble Nebula, NGC 7635.

Here’s a quote from Wikipedia:

NGC 7635, also called the Bubble Nebula, Sharpless 162, or Caldwell 11, is a H II region emission nebula in the constellation Cassiopeia. It lies close to the direction of the open cluster Messier 52. The “bubble” is created by the stellar wind from a massive hot, 8.7 magnitude young central star, the 15 a 5 MЂЂЂ SAO 20575 (BD+60 2522). The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by William Herschel. The star SAO 20575 or BD+602522 is thought to have a mass of 10-40 Solar masses.

And this is what APOD has to say about it:

Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. Although it looks delicate, the 10 light-year diameter bubble offers evidence of violent processes at work. Above and right of the Bubble’s center is a hot, O star, several hundred thousand times more luminous and around 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The intriguing Bubble Nebula lies a mere 11,000 light-years away toward the boastful constellation Cassiopeia.

For my interpretation, I used L, Ha, and RGB filters, for a total integration time of 19 hours.

The image can be seen on AstroBin as well.

Here’s my latest astrophotography work, the beautiful reflection nebula NGC 6914, in Cygnus.

Dipped in a sea of red, this blue haven is thusly described by the folks at APOD:

The complex of nebulae lies some 6,000 light-years away, toward the high-flying northern constellation Cygnus and the plane of our Milky Way Galaxy. With foreground dust clouds in silhouette, both reddish hydrogen emission nebulae and dusty blue reflection nebulae fill the 1/2 degree wide field. [..] Ultraviolet radiation from the massive, hot, young stars of the extensive Cygnus OB2 association ionize the region’s atomic hydrogen gas, producing the characteristic red glow as protons and electrons recombine. Embedded Cygnus OB2 stars also provide the blue starlight strongly reflected by the dusty clouds.

My rendition took a lot of integration time, possibly more than it was, necessary, but the result is very nice and noise free.

I ended up totalling a whopping 67 hours, 41 of which in Ha. The Ha subs were all collected when the Moon was up though, but they didn’t seem to suffer terribly from it.

The equipment used was the usual: GSO RC8 with APCCDT67, Moravian Instruments G2-1600FW, Astronomik LRGB and Ha 6nm filters, and a 10Micron GM2000 mount.

The image can be seen on AstroBin as well.