Whenever I see other people observing or imaging and ask them what they have their scope pointed towards, it is almost always some single object or a pair of objects. It might be a nebula, galaxy, or they may be splitting double stars, but few of them think of the Virgo Supercluster.
The Virgo Supercluster is a group of approximately 47,000 galaxies situated just outside the constellation Virgo. Although there are a lot of superclusters in the universe, this is probably the most studied and certainly is the most amazing to view.
I am not really sure why I never paid much attention to it, and I admit it never even occurred to me until I ran across a description of it in a book I was reading. It sounded pretty interesting so I took a quick look and was amazed. Then I imaged it, oh wow!
The part of the Virgo Supercluster that was the most interesting was an area called Markarian’s Chain. This was a little section that all fits into one low power eyepiece or a single image and contains such prominent members as Messier 84 and 86 in the lower left of the following image.
This is one of those targets that can just make you stare for hours picking out little details one right after another. Find a fuzzy spot, open your star chart and see what it is. Another galaxy!
The name Markarian’s Chain comes from the American Astrophysicist Benjamin Markarian who in 1960 noticed that several of the galaxies in the chain seemed to move together, as if connected.
Many members of the chain were discovered well before 1960 such as the two Messier objects being discovered by Charles Messier in 1871 and many others being noted in 1888 by John Louis Emil Dreyer in his New General Catalog.
While the primary members of the chain are M84 (NGC4374), M86 (NGC4406), NGC4477, NGC4473, NGC4461, NGC4458, NGC4438 and NGC4435, there are many others as you can see in the image above.
Both of the Messier galaxies and most of the NGCs can be seen in a small telescope from a reasonably dark site while the IC and PGC galaxies require a little bigger telescope to see as anything more than maybe a speck of light.
Opening up Stellarium and pointing it to the Virgo Supercluster we see a lot of objects. I have surrounded the area of Markarian’s Chain with a yellow box in the image above so you get an idea of how large the area is, and how many objects are in it. Even what is shown here by Stellarium is not the full area of the Virgo Supercluster, but is the majority of it.
Note that in the above image only Messier, NGC, and PGC objects are shown, IC and other catalogs are not.
To find the Virgo Supercluster, look north of Virgo between Virgo, Coma Berenices, and Leo. Trust me, once you get close with your telescope it will be hard to miss!
Hopefully you will see that the entire area of the sky around the Virgo Supercluster, and Markarian’s Chain in particular, are worthy of some of your observing and/or imaging time.
So you have decided to move up from a DSLR or other regular photography camera to a CCD but not face the question of which variety to get. You have heard about CCDs that are just like a DSLR in that they shoot a color image, while you have heard others shoot in monochrome and require color filters to get a color image. What to do?
Start by understanding that every camera records in monochrome, yes, even your DSLR and one shot color CCDs, and yes, even a film camera!
Above you see a representation of a Bayer matrix used in many one shot color CCDs. The gray squares are the actual sensors in the camera called photosites, each colored square (marked with a R for red, G for green and B for blue) is a filter on top of the photosite (note that all photosites are covered by colored filters, they are removed in this image for demonstration purposes). These are combined to form a single color in the camera so the output you see is in full color. Every four-pixel square (one red, one blue and two green because the human eye is most sensitive to green in normal daylight) is combined using a complex math formula to create one colored area with four pixels of detail.
You can manually do the exact same thing with a monochrome camera and three colored filters:
The four images above are the three color channels and then the final combined image. This is how monochrome imagers create color images, and of course, how your camera works. This is called RGB (easy!).
You do not necessarily have to shoot red, blue and green filters to use this function. This is also how people shoot “narrowband” using Ha, SII and OIII filters, among others. They use a monochrome camera (or in my hard headed case, a DSLR) and shoot one set using the Ha, one set using the SII and another set using the OIII filter and then combine them on the green, red and blue channels respectively (for “Hubble pallet” images). You can mix and match colors, shoot one through a regular colored filter, another through a narrowband filter, and a third through no filter at all, then combine them. You can even combine MORE than three colors by adding new channels! While there are no rules, I suggest you start with standard RGB and/or Hubble pallet narrowband to get a feel for things and then move on.
One reason all this is important is resolution. If you take a look back at the first figure this post you will notice that each photosite, or pixel, records one color. To make a real color image we just learned that you need three colors, red, blue and green. So how does that relate to resolution in the camera?
A color camera, CCD/DSLR/Point & Shoot all work the exact same way. The camera takes a square, one red pixel, one blue pixel and two green pixels and creates one color pixel from these. Basically this takes your 10MP camera and turns it into a 2.5MP camera (10 divided by 4) when it comes to colors, yet it retains the 10MP luminosity. Stripping away the techno-babble this means that your image has the black and white resolution of 10MP (luminosity) but the color resolution of 2.5MP. Said another way, it takes a 2.5MP color image and overlays that color (not the detail, just the colors) on top of a 10MP image.
I know this is a hard concept to visualize so let’s do one more analogy. Take two images, one 2.5MP in size and one 10MP in size. Convert the 10MP to grayscale (sometimes called black and white, but actually has all the gray shades as well) and print them out the same size, the 2.5MP on tracing paper in full color, the 10MP on regular paper in monochrome. Now overlay the 10MP with the 2.5MP and see the results. Note that the edges on the 2.5MP image will be very jagged compared to the 10MP so the color will not line up just right with all the edges. This will cause some blurring on the edges and your objects will not be nearly as sharp and well defined.
Enough with analogies, let’s see what that looks like:
The image on the left is a 300 pixel wide crop of image NGC2244 in monochrome, the image on the right is a 75 pixel color crop stretched over the 300 pixel monochrome image with an opacity of 50%.
This fairly accurately simulates the difference between two cameras, one monochrome and one color, with the same megapixel sensor. Notice how much sharper and clearer the monochrome image is.
So what the heck does this mean? Simply stated this means that a monochrome camera will always have better detail than a color camera if they are both rated at the same number of pixels or resolution.
If it sounds like all the advantages are with the monochrome, you would not be far from the truth. You will always be able to get better images with a monochrome CCD, period. The advantage of a one shot color camera, and it is a big one, is time.
With a monochrome CCD if you want to capture a color image and you need about one hour of capture time, that means you need at least three and preferably four (red, blue, green, and luminance). This means four hours of capturing. If you want to do the same thing with a one shot color, one hour is all you need assuming it has the same sensitivity. For four hours that may not be that big of a deal, but some images I have are made up of twenty or more hours using a one shot color!
Now you can add to your shooting time, processing time. Images from a one shot color are generally faster to process because they are already combined into a color image. Monochrome images require you to combine and calibrate the images to create a color image you can then work with, the one shot color takes all of this work out of the equation.
So it basically comes down to this; if you are short on time or want an easier time of it, get a one shot color CCD, if you have plenty of time and don’t mind working harder to get a superior image, go for the monochrome CCD.
Astrophotography image captures can add up quickly. They also tend to not be very small. Once you add in darks, bias and flats, you can have quite a mess on your hands.
The fist problem is figuring out how to store the files so that it makes sense and you can get the files you need in a hurry. I started off with just a folder where I threw everything in and thought my naming convention would keep my astrophotography image collection organized enough. I was very very wrong.
What I recommend now is a different method, and I suggest you take a look at this one and then make changes to get a system that works for you. Organization is not just so you can go back and find stuff, which you will want to do, but also to make processing and backups easier.
If you tend to shoot multiple targets in one night and rarely if ever shoot the same target over multiple nights and combine them, the method I recommend for your astrophotography image folders is something like this:
This was the first astrophotography image organization system I used. In this case, you start off with a folder called Astrophotography, then make a folder inside of that for each year, then one in that for each session, then one inside that for each target. Lastly, you have folders inside each target folder for each of the image types you are storing. If you are shooting monochrome CCD, then inside the Lights folder you could have folders for Red, Green, Blue and Luminance. Or you might have folders for Ha, S and O3 if you are shooting narrowband.
If on the other hand you tend to shoot the same target over multiple nights you might try something like this:
In this system, each target can be shot over multiple nights, even spanning years. Either way, you may need to adjust things based on the way you need your astrophotography image collection to work for you. You will probably adjust things over time to better suit you as you evolve.
You might also need folders for processing or storage depending on what your astrophotography software or astrophotography tools require. For example, Photoshop tends to need little more than a PSD file while other astrophotography post processing software such as PixInsight makes a ton of files as it steps through processing towards your final astrophotography image.
How much storage?
This can be a pretty complicated figure which depends heavily on what camera you shoot, and how many frames. Let’s take a look at one session of mine and then extrapolate from there.
On January 3rd, 2014, I imaged Caldwell 4 (among other targets). I took 25 lights, 25 darks, 2 bias and 2 flats along with 5 focusing shots of this target that evening. Each image from my Nikon D7000 is about 10MB in size. In total, there were 59 camera images coming to a total of 590MB of data I want to keep for that one target. That much imaging took about five hours, so let’s say that is about 120MB/hr.
If you are a prolific astrophotographer you might image two nights a month (new moon only) and that works out to about 16 hours a month for 12 months or 192 hours. Multiply that by the 120MB/hr figure we got earlier and you have 23GB of data. Now we need to figure for processing and my experience has been that either with PixInsight or Photoshop I tend to have a lot of image files for processing and output so let’s double our previous figure and say that is 46GB of astrophotography image data.
Of course if you are dealing with FITS files from a CCD the capture images may be smaller, but you will probably have more processing files.
And lest we forget video, if you plan on doing planetary or some high resolution lunar work, our video files might be pretty large as well. Let’s say our video runs about 125MB per minute of capture and a reasonable capture might be five minutes per capture, of which we have 20. That all comes out to about 12.5GB, doubled for processing makes 25GB added to our 46GB to make 71GB of data per year.
Keep in mind that this formula was meant to show you how you can calculate your own data consumption, not really to say you need 71GB of storage per year to put your astrophotography image collection on. Heck, if you get good and you have an astrophotography photos for sale you might want to keep multiple copies in different sizes.
Internal or External?
Now we need to decide on whether we want to keep our astrophotography image collection inside our computer, or externally such as on an external USB hard drive.
Having all our images on our internal hard drive will make finding and processing those image faster, it will also make it easier to fill up our hard drive (a very bad thing) and if something happens to our computer, we could potentially lose our images easier this way. If I was going to buy an internal hard drive for astrophotography image storage I would use this one:
Seagate Green 4TB SATA Internal Hard Drive
Putting the images on an external hard drive is moderately safer, and a little slower, although it also gives us portability so we can work on our images anywhere. If you want an external hard drive and will be processing the images while they are on this external hard drive, I would suggest this one:
Fantom Drives Gforce3 Pro 4TB 7200 RPM USB 3.0
If you just want one to store the images on, copy them to the computer for processing and then copy the finished product back to the external, then I would suggest this one:
Seagate Expansion 2TB Portable External Hard Drive USB 3.0
Personally I keep the images I may work on in the near future on my local computer drive and then keep a more “permanent” copy of all my images on a NAS (a big fancy external hard drive that connects through the network).
You know what is worse than your imaging session getting rained out? Getting awesome images and then losing them because a hard drive failed or you accidentally deleted the wrong folder. That is why you need a backup.
The only real backup solution I can recommend for astrophotography image backup is BackBlaze. Why them? Because for $95 a year, you can upload unlimited images (or any other data you want) and they will keep it all nice and safe. I should reword that because it sounds like you have to remember to upload your images and that is incorrect, all you have to do is install BackBlaze and tell it where your astrophotography image files are, then let it do its thing.
In addition, they keep multiple versions of your files which helps protect you from things like cryptoviruses and overwriting files you didn’t mean to. With versioning, you can get the previous version of the file instead of the current one, or the previous to the previous, etc. Click on one of the links for BackBlaze and get a month free trial, what are you waiting for?
Of course they back up not only your astrophotography image files, but all your other files too!
I hope you enjoyed my article on Astrophotography image storage and backup!
Since this is our first contest, hopefully of many to come, we decided to keep things simple. Sign up for our mailing list and get entered for a free Kindle version of any of the books by Allan Hall currently available. It’s that easy!
It is probably overdue but Allans Stuff is finally joining social media. To start off, we will work on getting our blog posts linked/posted to Facebook, Twitter, Instagram and Google+, in that order. This may take a while to get fully implemented so if you are primarily a Google+ user it may be a little while before you start seeing content. Of course we will be engaging with our fans on these platforms as well but that too may be a little slow to start with so please bear with us.
We already have a presence on YouTube at https://www.youtube.com/c/AllanHall with about 550 subscribers and over 100,000 video views, so be sure and drop by and subscribe to the channel. There are a lot of good videos already with more on the way.
Today I am proud to release a new book aimed squarely at beginning astrophotographers who want to know what astrophotography objects they can image with their equipment.
From the webpage:
Are you interested in astrophotography objects in the northern hemisphere?
Do you need good information on astrophotography objects that can help you as a starting point?
Taking images of astrophotography objects that are millions of miles from Earth is about as complicated as it sounds and when you start out you will find it hard to target the right ones.
Size, brightness and type are just a few of the more common considerations, but there are many more that relate to the type of equipment you have to hand and what the best tools for the job will be.
Now, with 50 Best Astrophotography Targets for Beginners, you have a handy information guide that will provide the starting place you seek, with information on:
How to get started
Tackling close astrophotography objects like the sun and moon
What the targets look like
The best time of the year to shoot them
How big the targets are
How to find them
What the images look like straight out of the camera
And much more…
Once you have mastered the techniques needed to take stunning photographs of these amazing beginner astrophotography targets you can move on to further reading on the subject, but making sure that you are taking quality images of some of these is the first step.
Designed with the novice in mind, 50 Best Astrophotography Targets for Beginners provides good, clear information in an easily understood format, allowing you to take the photographs you’ve always wanted to take. It even includes photographs that realistically shows you, as a beginner, what you can expect to achieve. There are no NASA or Hubble images in this book!
Aimed specifically at the beginning astrophotographer using a camera such as a DSLR in the Northern Hemisphere, this is the book you have been looking for.
Get a copy today and see how it will improve the way you take amazing shots of the heavens that will impress and delight friends and family alike!
The book is available today in both print and Kindle editions.
When I first started writing books I thought setting up a forum for support of the books would be a good idea. Unfortunately I never really kept up with it and soon it fell by the wayside. It soon broke to the point that new users could not even register. Sad.
Recently I have had some people ask me what happened to the forums and so I decided to put in some work and get them back up and running. After many upgrades, head pounding, and new additions, the new and improved astrophotography forum is ready for action.
While originally intended to support my books, since my books are primarily aimed at astrophotography, that theme will permeate the forums making them mostly an astrophotography forum. This should be pretty obvious with the big moon phase at the top right of the screen!
Of course there is a set of astronomy forums in there too. Even though most of my work has been with a DSLR, and most of my books cover that form of imaging, this is not just a DSLR astrophotography forum.
Since allans-stuff.com is one of the leading astrophotography websites today, it just made sense to have its own astrophotography forum where you can not only discuss the techniques presented in my books, but general imaging topics too.
So if you have any comments, suggestions, ideas or corrections about any of my books, or want to talk about astrophotography, astronomy, or any other subjects really, head on over to the forums. If you have any problems getting signed up, use the contact form here on allans-stuff.com to send me a message and I will get it straightened out for you.
Hop on over to the AS Forum and post up some astrophotography pics!