RBA Premium Astrophotography

Photos: Galaxies

Archipelago of Galaxies

Posted: June 15th, 2017



With a total of about 128 hours of exposure, this is a rather deep image of a huge are of the sky, mostly void of colorful nebulas, but packed with literally hundreds of galaxies in sight, many of them appearing so small they can be easily confused with stars. You can find most of the galaxies in the top 1/3 of the image , including what's known as the Markarian's Chain, a stretch of galaxies part of the Virgo Cluster. Still, tiny galaxies spread all over the image.

Remember, each of those fuzzy dots is home to billions of stars and who knows what else.

In the lower 1/3 of the image, to the left we can see the Blackeye Galaxy (M64) right under a stream of galactic cirrus clouds never imaged before like this until the image of this area I published a few months ago. At the bottom-right corner, globular cluster M53, right under the blue giant star Diadem, wants to be in the picture.



Clouds Of Andromeda

Posted: January 1st, 2017


"Ionized gas in the Milky Way is ubiquitous, with a pervasive
yet faint background detectable in nearly every direction in the northern sky."

~ The Wisconsin H-Alpha Mapper Northern Sky Survey, Haffner et al.


Image: Clouds of Andromeda
(click on the image for a larger version)

Image: Clouds of Andromeda II
(click on the image for a larger version)



WHAT IS "CLOUDS OF ANDROMEDA"?

Clouds of Andromeda is a rather unique - yet 100% based on real data- view of the Andromeda galaxy, also known as M31. It is, to my knowledge, the first known image of M31 that also shows at high resolution, depth and full color several of the cloud formations from our own Milky Way that happen to be in this very same field of view - but much closer to us than M31.

If you're familiar with views of Andromeda, the clearly visible reddish nebula in the image might surprise you. Being one of the most photographed objects in the night sky, if not the most, you might even be skeptical at first. How could everyone miss it and all of a sudden it's here, clear and obvious? Well, we all did... until now. Or at least, most of us did! If you came here out of curiosity or looking for answers, be reassured that the data is real and the clouds really are there. Just keep reading.

UPDATE 6/2018: Clouds of Andromeda II is a newer version of the image, with more data added, specifically from an image of Andromeda I captured in 2014 and a new processed layer of the same H-Alpha signal used to create "COA I". The image was released on June 28, 2018.


HOW THIS GOT STARTED?

On September 9, 2016, Sean Walker from "Sky & Telescope" shared with me a heavily stretched image he had captured - 1 hour total exposure - of the area surrounding the Andromeda Galaxy in the very narrow Hα spectral band, where he had noticed some extremely faint but visible structures. I had been capturing this area with broadband filters in the past, and I knew there's certainly some very faint dusty structures detectable in visible light around the vicinity of M31's field of view that Sean also used to compare his own findings. I had no idea however that there would also be such well-defined clouds glowing in Hα, though. Sean's own curiosity is what really sparked the flame to get this image, and for that I thank him, and please, do thank him too if you run into him online or anywhere else.

If you're familiar with my work, you know I've always been attracted to capturing the dust high galactic cirrus clouds that are so faint they rarely appear in most astroimages. I talk about this extensively in my book Deep Sky Colors, by the way. It is no surprise then, that I was incredibly interested in these faint clouds Sean just noticed.


THE DATA

After accumulating several hours of Hα exposure over the area per pane (the image is a cropped three panes mosaic: A:15h, B:15h, C:7.25h), I was able to bring out - in some cases nearly from the noise floor - a number of extremely well defined structures accompanied by even fainter clouds. I then captured a few hours of LRGB - nothing deep - that I merged with existing broadband data I already had, and then I combined both, the Hα and LRGB data the best way I could, bringing out as much as the Hα signal as possible while trying not to introduce artifacts or false data and of course, while keeping the noise to a minimum.


WHAT ARE THESE CLOUDS? WHAT ARE THEY MADE OF?

There's mainly two types of clouds/nebulae in our Universe: emission and reflection nebula (there's other types, just trying to keep it simple!). Emission clouds emit light on their own and are usually made of ionized gas. The most popular and abundant type of gas clouds are made of Hydrogen, glowing bright in the H-Alpha wavelengths (deep in the red), so astrophotographers often use an Hα filter to capture them. Reflection nebula, on the contrary, is usually made of dust that doesn't produce any light, but we can see it because it reflects light from nearby stars and it usually shines nicely in visible light.

Along with all the bright emission and reflection nebula we usually see in photographs, our night sky is filled with a much fainter type of clouds that goes by different names: High Galactic Cirrus, Integrated Flux Nebula (IFN), Translucent Clouds, High Latitude Clouds and so on...  (Low et al., 1984)

IFN is usually visible in infrared, and can also be - barely - captured under dark skies in "visible light" because it's mostly dust (not gas) that manages to reflect the light of our own galaxy as a whole. It, however, can also emit some light in the Extended Red Emission or ERE (Witt et al. 2008), a wide spectral range that covers all red visible light all the way to the near infrared. This is one reason IFN usually appears brownish in color when captured with broadband filters: it's a mix of reflected blue light and some emitted ERE (red) light.

This, however, means that capturing dust cirrus with an Hα filter, which, unlike visible light, ERE or infrared, covers a minuscule spectral range (see image below) where ionized Hydrogen (a gas) glows, makes absolutely no sense. Or... does it?

The following chart illustrates the classification of the electromagnetic spectrum as we know it, also indicating the different spectral ranges we're discussing: H-Alpha, visible light, infrared and ERE.



About 99% of the times, if not 100%, astrophotographers like myself use Hα filters with the sole purpose of capturing the many clouds of ionizing gas shinning strong at this band pass that abound in our night sky, and it's amazing the amount of signal we get. Likewise, some of us try our luck capturing the IFN by shooting with broadband filters (visible light).

In this case, however, what I captured by using an Hα filter is cirrus dust that happens to glow at precisely this very narrow spectral range - that's the consensus from the professional astronomers I've contacted prior to releasing this image. Of course, the conundrum here is that we're talking about dust that glows because of ionizing gas, but I'll leave it at that. If you want to learn more about this topic, there's plenty of information out there - look for scholar papers, thesis, scientific journals and the like.

As a long time astrophotographer chasing the faint galactic dust that can be detected - but rarely seen - in nearly every direction in the sky, being able to reveal just self-glowing "IFN" for the first time in an outreach-type image is short of amazing. Being accurate, these clouds aren't quite Integrated Flux Nebula or IFN, as the name IFN derives from dust reflecting light from our whole galaxy, while these clouds of dust fluoresce in the deep red instead, so they're more like Dust Fluorescent Nebula or DFN :-) (I just made that up, not an official name!).


PROCESSING CRITERIA


The relative brightness between M31 and the faint clouds in "Clouds of Andromeda" is not depicted in the image. The galaxy is actually much, MUCH brighter than the glowing clouds! Please, see below the half-cooked negative of one of the panes, where a more relative brightness can be seen, with M31 completely saturated in order to get a glimpse at some of these clouds.



That said, the relative brightness of the glowing clouds has been preserved as much as possible in the final image, so clouds that appear brighter than others, really are brighter.

Integrating Hα and LRGB data was not done via a copy/paste/crop composite or a typical HDR. Instead, I registered both sets (broadband and narrowband data), then went onto process them and integrate them, bringing out the signal from the extremely faint clouds while containing the brightness of M31. Processing was done with PixInsight for all of the initial work on each data set, then all integrated via several layers in Photoshop, where I applied further enhancements and final adjustments. My goal was to produce a nice representation of  the best of what both data sets could offer, and present the image in a typical "true-color" LRGB+Hα composition.


CONFIDENCE

I am 100% confident on the results, at least the 5-7 brightest structures - identified in the image below. These are no artifacts. AN-6 would be the only labeled structure for which I'm still not 100% certain, not because my data was doubtful but because of no match with existing survey data (see the "Comparison" section below). As for the faintest yet reddish smudges across the image, being pulled nearly from the noise floor, I would still assign them some level of confidence, although not as much as the obvious brightest structures.



The lowest area of confidence would be the entire area being covered by M31 and its very immediate halo - still brighter than the sky background. In other words, the pitch-black area over the glowing M31 in the negative image above. The galaxy is so bright that any signal from any faint clouds in front of it simply can't be detected. This results in no visibility of clouds right over M31 or its immediate halo. That's the reason you don't see red clouds right in front of M31, perhaps giving the impression that the clouds are behind the galaxy, when they're not.

If the above wasn't too clear, the animation below hopefully helps. The candle is assumed to be in front of the bright light, not behind. We can see the candle light only as long as it's NOT right in front of the bright light. When it is, the fainter candle light is simply overwhelmed by the bright light behind, so we can't tell there's a candle light in front. In this case, the bright light is Andromeda and the candle light represents our very faint red clouds. Since we can't detect these faint clouds right in front of M31, it makes sense you don't see any in the image, and see M31 instead.




COMPARISON


Although my data seemed reliable, once the final image was completed,  I compared it to existing surveys, to see whether there was a match or not.

Some people will find interesting to know that infrared sky surveys revealed no spatial correlation with my image nor with Hα surveys, neither did microwave surveys, meaning these clouds are invisible at infrared - odd for high galactic cirrus clouds - and microwave wavelengths.

Visible light surveys simply don't show any clouds whatsoever, which isn't surprising, as these clouds are extremely faint. The two Hα surveys I checked (WHAM and VTSS), however confirmed the structures are there. It makes sense, as that's the wavelength I used to capture them. Here's an animation blinking between my image and the VTSS survey, confirming the presence of the 5-7 brightest structures in my image. A mismatch in the fainter areas does not mean my representation is necessarily wrong, but a lower degree of confidence in those areas.



Please note that the survey image has been aggressively softened to remove noise, and globally adjusted to offer better contrast.


ACQUISITION

To capture the data I used two Takahashi FSQ106-EDX refractor telescopes (4" telescopes) and two SBIG STL11000 CCD cameras, in tandem, all on top of my trusted Takahashi EM-400 mount. Being a nomadic imager (I don't have an observatory of my own), I actually captured the data from three different locations: DARC, Henry Coe State Park and Montebello OSP, all in California. Data was acquired between October and December, 2016. Here's a black and white picture of my rig during my last session for this project in Montebello on December 21, 2016, in company of some good old astro-friends (who got the premier right that night! ;-) and pointing, of course, at M31.




DISCOVERY?

As the above blinking sequence comparing both Hα surveys indicate, the presence of clouds emitting light in the Hα wavelength around the field of view of M31 is not unknown. I could not however find any "decent" image (resolution and/or depth) of these clouds, other than very low resolution public data from the sky surveys I've mentioned, that didn't say much about these clouds other than they're there. Discovery? I don't know and it's not something I'm after. Besides, Sean Walker would definitely deserve the credit, since he's the one who noticed and brought it to my attention. That said, there is something definitely special about this image, discovery or not.

The Andromeda galaxy is the most photographed object in our night sky, along with Orion's Nebula and the Pleiades - and one of the oldest ever been photographed as well. There's literally thousands of images of M31, and many more being taken every year, from professional observatories to some hobbyist attaching a camera to a telescope for the first time.  It is also the most studied galaxy (other than our own Milky Way), being so close to us and providing us with the largest view of a whole galaxy that we have. The fact I was able to produce such unexpectedly gorgeous view of M31 "surrounded" by real clouds based on actual data, in a first-of-its-kind photograph is both, humbling and tremendously exciting.

Clear skies!
Rogelio Bernal Andreo


ACKNOWLEDGEMENTS
  • The blinking VTSS Survey image was obtained from Sky-Map.org, based on the Finkbeiner H-Alpha All-Sky map which, for this region is based on the Virginia Tech Spectral-Line Survey (VTSS), which is supported by the National Science Foundation.





Downtown Milky Way

Posted: October 21st, 2016



Here's my deep-sky project for the months of June to October, 2016. It's a 108-panes (approx) mosaic of a fun area in the Milky Way and roughly about 130 hours of exposure.

The original is over 40,000 pix wide (in landscape orientation), possibly the highest resolution artistic photograph of this whole area to date. That produces a monster JPEG, so here we're sharing a small vertical view - click to see it bigger at about 10% of the original size, which is still pretty big. Technically one could do a 133" long print (3.3 meter) at 300dpi with zero rescaling.


Andromeda Galaxy

Posted: August 25th, 2014



The last time I took an image of M31 was five years ago, in 2009. On wednesday and friday night last week I felt it was time to take another shot and here it is. The image adds about 17 hours of exposure time. It was also a warm up session after not having used my deep-sky gear since April.



M31 and PanSTARRS (C/2011 L4)

Posted: April 2nd, 2013



Click here for a larger version

The image above shows Comet PanSTARRS (C/2011 L4) passing next to M31, the Andromeda galaxy - "next" from our vantage point, of course. In reality, they're more than a couple of million of light-years away.

The image is actually a composite of data from two different sessions. One session, the one that captured the entire field, including both the comet and the galaxy, is a two pane mosaic of only RGB data. This is the FOV presented in the image (well, the original is a bit bigger). In addition to that, I also used data from a previous session, at a time M31 is much easier to photograph (not so low in the horizon), which added a bit of punch to the entire field and much more manageable data for bringing out the details inM31. 



Virgo Cluster Deep Widefield

Posted: March 18th, 2011




GOALS
AND PRESENTATION

It would be easy to produce a "standard looking" image with this data. Truly minimal processing would be required, but in this case and at this time, for me that wouldn't be nearly as fun neither challenging.

The goals when producing this image were very precise. Just a glance at the image should reveal what these goals are, and I am somewhat satisfied with the results - meaning the goals were achieved to an extent. Clearly the main goal was to reveal any subtle and faint data - the data that typically sits right above the noise. A secondary goal was to do this while containing galaxy brightness and at the same time, being able to bring out small scale details in such galaxies.
 
To enhance details in the galaxies, a dynamic range compression process was applied to reduce brightness in the larger galaxies, as well as wavelets-based HDR enhancements. Preserving background illumination was accomplished by very careful gradient reduction and further non-selective histogram adjustments.

There may be some people who find all the "dust" in the background distracting, or the small details in the galaxies somewhat the result of processing and not a "natural" depiction of the field, but ...In order to appreciate this image you need to understand the goals set for it, then conclude whether those goals were met or not, rather than whether you would have aimed for different goals.

DETAILS IN THE DUST

In order to better see the "dusty background" I have also prepared a monochrome image that you can see here:

Click on the image for a larger version.

It may be surprising to see an image with all this dusty appearance in this direction, out of the galactic plane.  To be honest, that is not for me to judge, but this is what came out of my data, and the processing involved was as careful as possible. Data capture wasn't perfect but all the data was taken from the same location, during the same hours on three different nights, and on nights I was very discriminative as to whether  I should capture data for this project or not: all nights displayed an SQM reading of magnitude 21.7 or higher at the zenith at some point during the session, and were all consistently above 21.5 at any time.

Although most of the dust above the background you see in this image is likely from our own galaxy, if you look closely, on top of NGC 4435 (the "eyes"), you may see a thick faint tail moving towards 10-11 o'clock, and that is most likely pulled from that galaxy, not a foreground cloud. The "1" arrow in the image below points to this area. There's also some even fainter strikes visible (barely) going from M86 towards NGC 4435. The lines to the right of the "2" in the image show where these strikes are happening. You will need to go back to the larger version of the above image to better discern them (the green lines in the image below are covering the most visible strikes).

There's also some intergalactic "fluff" - though very diffuse in the image - from M87 to NGC 4461 and NGC 4473. And of course, the well-known interaction between IC 3481 and IC 3483 is clearly visible towards the bottom of the image:

Other than that, I personally cannot tell whether other faint signal is intergalactic, it belongs to our Milky Way or, suffice to say, might be an enhanced artifact during capture or processing.

BACKGROUND MODELING

The hardest part in processing this image was the gradient removal process. It's not that the gradients were complicated or severe. In fact, they were very smooth and subtle, thanks to the dark skies of the DARC Observatory, and if I hadn't gone after the fainter signal, it would have been quite easy to deal with it, but there was a great mix of very light gradients from so many frames, and it took me a lot of trials and analysis until I was convinced I had built a background model that would mainly subtract gradient signal and nothing else (and nothing more). Although it's quite possible that not ALL of the faint but visible data is 100% accurate, I believe most of it is. Here's some of the data and processing involved to "flatten" the master luminance data.

Below you can see the master luminance after being cropped (to remove "bad" edges due to misalignment between frames) and with nothing else done to it but a non-linear stretch tailored to reveal the gradients in the image:

And here you can see a non-linear stretch version of the final background model applied to the image:

As you can see the background model is very smooth and gradual even after a strong stretch - obviously when the background model was subtracted, it was in linear form and visually it looked like a completely dark image.

PROCESSING

The processing of the data did not include at any time any curves transformation, DDP nor selective or masked histogram stretch. All data stretching was done by unmasked and non-selective non-linear histogram adjustments.

More specifically, after the gradient removal, a rather standard process was done to the luminance/lightness data, that mainly included:

  1. Slight deconvolution, with masks at three levels: local, global and external. The purpose of the local and global masks was to avoid the Gibbs effect, and the external (lightness-based) mask was used to avoid applying deconvolution to areas low in SNR, and increase the deconvolution effect as the SNR improved.
  2. A first non-linear unmasked histogram stretch.
  3. Masked ACDNR (noise reduction). The lightness-based mask here served the opposite effect of the external mask used for the deconvolution: applying the noise reduction only on areas low in SNR and gradually reduce the effect as the SNR improved.
  4. A second non-linear unmasked histogram stretch. This is because after the noise reduction, our histogram has been altered, and so it allows for a new adjustment.
  5. Masked HDRWT. This is the process that reduced brightness in the larger galaxies and also revealed some of the data and details in them. The lightness-based mask here is also helping avoid ringing.
  6. A third non-linear unmasked histogram stretch. Again, we readjust the histogram because after the HDRWT process we have a different scenario that allows a new adjustment.
  7. Slight masked sharpening using wavelets. The lightness-based mask here kept noise from being sharpened.
  8. Very light masked morphological transform. This process reduced overall presence of the largest stars, bringing them back to their form as they were prior to the last histogram adjustments. A star-based mask is necessary with every morphological transformation process, otherwise we would be applying the morphological changes to structures that shouldn't be affected by it.
  9. A last histogram adjustment.
  10. A last masked Laplacian sharpening.

In between some of these processes, I did integrate scaled before/after images via PixelMath at some stages during the processing, to apply a process only so slightly...



Andromeda (M31) versus Triangulum (M33)

Posted: September 17th, 2010



This large panorama (a 3x4 mosaic) presents an unusual view that confronts two of the largest galaxies (as seen from Earth) in the night sky: the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33).

The Andromeda Galaxy (top left corner) is a spiral galaxy approximately 2,500,000 light-years away, in the constellation of the same name. The Triangulum Galaxy (bottom right corner) is also a spiral galaxy, at approximately 3 million light years distance in the constellation Triangulum. The bright star in the middle is Mirach, a red giant star about 470 times as luminous as the sun and approximately 200 light years away.

Between them, and invading the entire scene, the often very elusive galactic cirrus clouds can be seen.

Because of the large field of view required to capture these two galaxies in one image, there aren't many images, if any, presenting these two galaxies in the same composition. For that reason, I find this image to be of unusual beauty as well as perhaps a bit thought provoking.

CAPTURING THE DATA

I had to go "at it" several times for several reasons, so in the end the image is a potpourri of data captured in Spain in August, at the DARC Observatory early September, and at the Central Nevada Star Party last weekend. Same scope and camera, but different skies, different exposure times, different amount of subframes, and in one case, even different binning! This mosaic has it all! (BTW I do NOT recommend messing up like that at all - there are "reasons" for all of this, it's just too long of a story :-)

The FOV can be captured - with the FSQ+reducer and the STL11k - as a mosaic of 3x4 (12 frames), but in reality I ended up shooting 26 different frames, each with its LRGBs... This is because once I was done with the data I captured while in Spain, I didn't like the final FOV, so I rotated it, and then I had to capture more frames to "fill up" the holes, then creating seamless frames became very difficult - first because I used different binning and timing, and second because adding frames to an already processed mosaic is often a VERY BAD IDEA. So anyway, I went again and captured more data at the CNSP last weekend to have frames that would match better when building the mosaic. Even with that, some differences can be obvious if you pay attention, but the only way out of it would be to retake the 3x4 frames that make up the FOV and process them all together at once (and I've rather move onto other projects).

GOALS / INTERPRETATION / FINAL FOV

I was hoping Mirach (the star in the center) didn't end up dominating the image so much. Knowing how bright it is and that it was going to end up in the middle of the image, this was wishful thinking, but in the end I think it balances the image somewhat ok - kind of like the mid pivot of a seesaw between the two galaxies. Not quite the effect I was hoping for, which was more the effect of "confronting" these two monster galaxies, with the added challenge that the galaxies are very far apart and the attention may get lost, not sure where to focus, and Mirach constantly becoming the safe harbor of our attention, but I think something can be made out of it. Or maybe I'm reading the image backwards!!

PROCESSING THE GALACTIC CIRRUS

The signal from the galactic cirrus is quite real, not artifacts, not gradients. As always, with very faint data, I cannot guarantee absolute precision in the light intensity differences, and only suggest that it's approximate. In any case, if we were to capture it deep enough, and in a perfect world, the cirrus should look a lot wispier than in this image. Instead, it looks more like a blur.

To see what I mean, if I do a heavy stretch on the raw data, I can tell the visible cirrus clouds are quite wispy. Look at this crop of one of the areas (top-middle, though the very top in this stretched image doesn't appear in the final image because it was cropped out):

(yes, in the above image you can clearly see one seam :-)

It would be amazing if this kind of detail could be brought to the final "pretty" image, but unfortunately it was very hard to do, for me at least (it's really dim stuff), so I settled with being able to bring the signal above the noise, but heavily blurred. Also I didn't have a lot of data, so I simply didn't have the know-how or the means of better bringing out this signal that was sitting right with the noise.

BTW the blur doesn't come from applying noise reduction but from separating large and small scale structures in the image. The " trous" wavelets tool in PixInsight however tends to produce this effect when you abuse it, and although perhaps there's a way to preserve some of this appearance by breaking and processing the image in more than 3 scales, I didn't experiment with that and instead went for what I already know how to do: breaking the image in just 2-3 scale layers (wavelet planes), operating on them separately and then adding them back, rescaling. 



Milky Way, east to west

Posted: September 18th, 2009


See Explanation. Moving the cursor over the image will bring up an image of the Milky Way the way it woud look to our eyes.Clicking on the image will bring up the highest resolution version available of the photo version.
Larger "visual" version
Larger "photo" version

The image you see above is a mosaic of 10 different frames, each of them was acquired with either 5x5 minutes (around the Milky Way) or 5x3-4 minutes for the rest of the sky. The horizons are superimposed from two 3x1' shots, but they match both what was there and the orientation.

It's interesting to note that when I started shooting at the Sagittarius area, the Pleiades weren't even above the horizon, but by the time I've got to that part of the sky, they were already all the way up there.

Now, for the fun part, if you mouse over the image, you will see a digitally altered image of what our eyes could see that night, more or less. If you move the mouse out of the image, you see what the camera could catch. The idea is for those who have never seen the Milky Way from a very dark site, to give them an idea of what it would look like - so maybe they get excited about visiting a dark site and enjoy the night sky!

Have you ever been to a very dark site? I'd like to hear what you think. Do you see the image of the "visual" Milky Way too bright compared to what you see at a very dark site? Too dark? Perhaps the image is too "glowy"? Not enough contrast? Please let me know in the comments below!

Get a poster, t-shirt, mug, mousepad... with this image!



Andromeda (M31)

Posted: August 15th, 2009


See Explanation.Moving the cursor over the image will bring up an alternate version.
Original Image

DATE
August 15 and 16, 2009

PHOTO
Exposure time:
L: 18x5' & 10x20'
RGB: 10x5' each channel
Total: 7.3 hours
Focal: 500mm, f/5

EQUIPMENT
Imaging scope: FSQ106 EDX
Camera: STL11000
Guiding camera: StarShoot Autoguider
Mount: Takahashi EM400

SITE & CONDITIONS
Henry Coe State Park, California
Seeing: Very good
Transparency: Poor

SOFTWARE
Stacking: DeepSkyStacker
Processing: PixInsight & Photoshop

COMMENTS
This is a "mouseover" image that allow us to compare the image I took of M31 with the images taken by the Ultraviolet/Optical Telescope aboard NASA's Swift spacecraft of the same object.

First you see the Swift image (not mine!) and if you move your mouse over the image, you can then see the image I took. Moving the mouse in and out of the image you can compare the two images.

I did this to see how the details in the core of my image matched those details - whenever visible - in the Ultraviolet image from the Swift spacecraft.



Andromeda (M31)

Posted: August 15th, 2009



Bigger size: 3050x2174

DATE
August 15 and 16, 2009

PHOTO
Exposure time:
L: 18x5' & 10x20'
RGB: 10x5' each channel
Total: 7.3 hours
Focal: 500mm, f/5

EQUIPMENT
Imaging scope: FSQ106 EDX
Camera: STL11000
Guiding camera: StarShoot Autoguider
Mount: Takahashi EM400

SITE & CONDITIONS
Henry Coe State Park, California
Seeing: Very good
Transparency: Poor

SOFTWARE
Stacking: DeepSkyStacker
Processing: PixInsight & Photoshop

COMMENTS
M31 or Andromeda is without a doubt one of the most imaged objects of the sky, and one I knew I had to come back and try to get an image that at least escaped mediocrity. For that reason I focused on capturing an image that would allow me to get as many details as possible from the bright core that otherwise it tends to be either oversaturated or simply too bright to discern any details. I'm very happy with the results - with a fairly modest equipment I was able to scrap details out of the core that other images taken with much more expensive telescopes simply do not show.

I "blinked" several images from other authors - sometimes after a bit of tweaking to reveal the details in the core in such images - to make sure the details I was obtaining were not processing artifacts, and also made this animation:

Please note:

  • The quality of the images used in this animation is not great. In particular the "slides" from Tony Hallas and Robert Gendler are at a much lower resolution than the original images from these two fine astrophotographers. The purpose of this animation is not to compare the QUALITY of the images, but only to verify whether the details in my image are real or artifacts - or both.
  • Just because a particular image does not show more details in the core than another does NOT mean the image is of a lesser quality, not at all. Different images will have different goals when imaging M31 (or any other target). Again, the only reason to post these images is verify if the details in mine are real, not a competition to see who revealed more or less details.
  • To me, the most revealing comparison is the one with the image from Mark Jenkins and Roland Christen, and that's why I placed their "slide" right after the visualization of my image.
  • While none of my images are subject to traditional copyright and instead use a Creative Commons License, because this animation uses images subject to copyright by their authors as indicated in the next bullet, copy or reproduction of this animation is not allowed.
  • Portion of M31 image from Tony Hallas is Copyright by Tony and Daphne Hallas
    Portion of M31 image from Robert Gendler is Copyright by Robert Gendler
    Portion of M31 image from Vicent Peris and JL Lamadrid is Copyright by Vicent Peris and JL Lamadrid
    Portion of M31 image from from Mark Jenkins and Roland Christen is Copyright by Mark Jenkins and Roland Christen
  •  



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