Shoot for the Moon!

For the April 2018 Astrophotography Highlight I’m going to go for some low hanging fruit and talk about shooting the moon!  If I had a dollar for every time I’ve heard a fellow astrophotographer lament that the moon was up… well, I could probably buy the moon! The moon was my first love and is to me one of the most amazing targets in the sky that you can shoot; it is also the easiest. No matter what kind of camera, optics, or mount… and this includes TRIPODS, you can get great images of the moon you can be proud of!

The moon doesn’t know any seasons, it’s available all year long!

The moon was the gateway drug that got me started in astrophotography as a whole taking photographs of the moon through my telescope as if it were nothing but a very long telephoto lens. It is a great (possibly the best) way to get started in astrophotography because you can get results you will be happy with your very first night out. The moon is available all year long, it shines through the worst light pollution any city can muster, and it’s a fascinating world that changes nightly! You can even with some success photograph the moon through very thin clouds or haze.

Plato’s hook shown here as a jagged shadow inside the lower lip of the crater Plato is not visible every month.

You could spend a lifetime exploring the moon (photographically or visually). Once I watched the same crater for several hours one night, and you could see the changes over the course of as little as an hour. Because of libration (the monthly “swivel” of the Moon) you’ll see different features along the limb each month, and even features not near the limb (edges) can cast different shadows that can only be seen every few months.

There are many great ways to get started in lunar imaging. Let’s go quickly over a few of them.

Use a Cell Phone
The most common way people take photographs today is with their cell phone cameras, and just about everybody has one. You can literally hold your cellphone up to a telescopes eyepiece and take a photo. It takes some practice, but I’ve seen teenagers do it on their very first try at outreach events. One trick is to rest the phone on the eyepiece cup to keep it flat and steady. You’ll find quickly that moving to the left actually moves the image to the right, etc. but after a few minutes you’ll get the hang of it. Often when there is a group of people, it becomes almost a game to see who can get the better shot. There are also many brackets on the market designed to hold your cell phone steady so you can take a photo directly.

Using a cellphone on a telescope. This bracket is made by iOptron.

DSLR or Point and Shoot
The most economical entry point for any serious photographer is the so-called “Point and shoot” camera with a fixed lens system (the front lens cannot be removed and is not interchangeable). Put this camera on a tripod, and with an optical zoom, you will easily get full images of the Moon showing craters, Maria, and ray systems in great detail. You can also try holding this in front of an eyepiece, or purchase some commercially made brackets that will hold your camera in front of the eyepiece for you. The same applies to a DSLR with a long lens, except this is more difficult to mount in front of an eyepiece. I’ve shot many lunar eclipses this way, and you can make interesting nightscape images by framing up a large moon with some distant landmark.

It’s quite easy to mount a DSLR on a telescope.

DSLR on a Telescope
You can also find very inexpensive adapters that will mount your DSLR directly to a telescope. The lens comes off the camera, and the adapter connects to your camera just like a lens would, but then slides into your telescopes draw tube. Essentially, the telescope becomes a large telephoto lens.

If you don’t have a remote release cable, turn on mirror lock, and set an exposure delay. Typically I will set the camera for a 10 second delay with mirror lock enabled. Then when I fire the camera, the mirror comes up, and there is a delay before the image is taken. This delay gives everything a few seconds to stop shaking/vibrating and you’ll get steadier images. If your camera does not have mirror lock, you can achieve much the same thing by using live view. Live view however tends to warm up the imaging sensor, introducing more thermal noise so I tend to stick to the previous technique.

CCD image of the moon taken through an SII narrowband filter.

CCD Cameras
Yes, you can shoot the moon with a CCD camera too, although now you need a computer to control the camera! Some CCD’s are so sensitive compared to a DSLR that you can’t get a good image without over saturating. Sometimes this is due to the fact that the shutters on these cameras were designed for long exposure purposes and you simply cannot get the exposure short enough. There are two solutions to this; the first is simply to stop down the aperture of your telescope with a mask at the front. The second is my favorite… use a red or narrowband filter! A red filter (if you have a monochrome camera with filters) will reduce the light considerably, and might improve sharpness of your monochrome image because the red wavelengths are less affected by seeing conditions than the blue and green. If you have a hydrogen alpha, or sulfur filter, use those! They cut down on the light even more, and also have that advantage of helping to mitigate the seeing due to their long wavelengths.

So called “lucky imaging” techniques make use of video cameras to capture fleeting moments of stability in the atmosphere.

Video Cameras
A live view of the moon is also a compelling outreach tool. You don’t even have to be scope side to slew around the surface and show off the moon to a room full of people. Video captured at long focal lengths can also be processed to create stunning high-resolution images using a technique call “lucky imaging”. This is perhaps extreme lunar photography in that it does require a good bit of work using special software to pick out just the sharp frames from the video file and combine them. Never-the-less, it’s still a lot less work to process than the typical deep sky photo!

Any of these methods are within reach of even the most inexperienced beginning astrophotographer. It’s also a great way to get your feet wet processing images just by tweaking levels, curves, and sharpness. I’ll talk about each of these different approaches to lunar photography in turn in future blogs here, or in my Sky & Telescope blog on imaging foundations.

Clear skies!

 

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Astrophotography Highlight – March 2018

Messier Poster

My rather sparse attempt at bagging all the Messier objects!

March brings the beginning of Spring for us in the Northern Hemisphere (at exactly 12:15 p.m. Eastern on March 20th if you must know). March is also Messier Season! With careful planning, you can observe all 110 Messier objects in a single evening, and many clubs and organizations will host marathons the weekend of new moon this month (March 17th). Here is a good link for info about this. There is even “An App for That!” on Apples App Store! (I could not find a corresponding Android app, sorry).

Charles Messier’s list of objects was at first intended to be a carefully cataloged list of bright objects that he did not want anyone to accidentally misidentify as a comet (searching for comets being all the rage in those heady days). A good many showcase nebula, galaxies, and globular clusters have made this list and I can see how these could easily be seen as smudges and thought to perhaps be a comet. However, even given the state of telescopes in the 1700’s, it’s hard to believe some of these open clusters could be mistaken for a comet! Most likely, they just made the list because they were interesting and noteworthy.

Messier 13, one of my favorite objects in the eyepiece or with the camera!

How great it must have been to live in a time where with a telescope and eyepiece, you could identify an interesting group of stars, add them to your own catalog, and actually be one of the first people to see them! Today, we take this for granted and just type in M13 into our GOTO telescopes to slew on over to the Hercules globular cluster, a gorgeous jewel of the night sky and my favorite globular.

I’ve started my own poster project (shown above) with the goal of eventually getting a high quality image of each of the Messier objects. As you can see, it’s rather sparse at this point. Some of the images are hours of exposure time and my intent is to have a complete collection of high quality images of the entire catalog. This is still a long term goal, but I have another one for this month.

Photographing all 110 objects in a single night has been attempted and successfully completed by a few very careful astrophotographers. A good resource with a list of objects in the order that they can be observed/photographed is listed here. An all night Messier

M44

The Beehive cluster (M44). Interesting, pretty… but a fuzzy comet?

imaging marathon has long been on my bucket list, but so far, I have not had a clear night at an opportune time to attempt it! I plan to try again this year using the list above as the main basis of the order of objects in which to progress through the evening. Ideally, you will want to use some sort of automation package unless you want to watch… which I actually think is kind of fun. I’ll make some tweaks to Don Machholz’s list linked above as it seems M31 and friends are the lowest to the horizon at twilight and I want to grab them first before they get any lower.

So, a new poster project would be a collection of all 110 Messier objects taken in a single night! A photographic Messier Marathon if you will. For an all night photographic messier marathon we have no such luxury as long multi hour exposures, and in some cases there is only going to be a few minutes that you can spend on any given object. For this reason I plan to use a one shot color camera. I will be the first to tell you that you’ll get better data if

ShrinkMe

Shrinking even the noisiest images improves them!

you shoot monochrome, and a single short exposure through red, green, and blue filters will give you less noise than a single color exposure of their combined lengths (good topic for a future blog!). Never-the-less… tradeoffs! A filter wheel is one more moving part that can fail in the night, and shooting 110 objects in a single night is going to be challenge enough! Further, there are workflow issues. In my (hopeful) chart/poster, the images are not going to be very large. One of my favorite astrophotography tips is that making images smaller always improves them! So, small images will be very forgiving of noise, and images with all three color channels already aligned are going to be MUCH easier to process… times 110! I’m estimating that the tradeoff I’m making will be fine given these considerations. Next year I may change my mind on this… as they used to say in the aerospace industry, a single test is worth a thousand expert opinions!

The size of the various objects in this catalog vary from the very small Ring Nebula (M57), which is hardly 3 arc minutes across, to the enormous Andromeda Galaxy (M31) which can stretch 6 full moons width across at about 3 degrees! An issue to come to grips with in planning this is what focal length and camera chip do you use? You don’t want the smaller objects to be tiny blips in the middle of a large field, and in order to do this you are going to have to select a field of view that compromises the rather large Andromeda galaxy. Bear in mind too that many times you will be able to capture more than one of these targets in a single field of view!

M45 Barely fits!

My recommendation is about 600mm focal length and a mid-sized chip, such as an 8300 or APS-C sized DSLR or larger if you have it. My best cooled color chip is a Sony 694 in a Starlight Xpress Trius body. Very low noise and cooled. I do wish it was slightly larger, but I think it will do fine for most targets. M31 will be cropped, and if I’m careful with placement I can still fit the next largest Messier object, M45 (the Pleiades) into the field of view. My exact field of view is shown here, with my Esprit 100 refractor having a focal length of 550mm. F/5.5 is reasonably fast too and again that is going to help with the fact that I’m only going to have a few minutes on each target.

Another idea is of course to team up with someone, with one person shooting long focal length targets, and another shooting wider field. Teams are fine and all, but of course there’s nothing like being that one marathon runner crossing the finish line. Good luck this month runners!

Richard

 

 

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Astrophotography Highlight – February 2018

Horsehead

The famous horsehead nebula in Orion.
Richard S. Wright Jr.

Welcome to the first, of a new series of monthly blogs about astrophotography! I’m not going to focus on techniques or processing in depth, (see my Sky & Telescope Blog about that) but rather I want to talk about what targets or objects are out this time of year that might be worthy of your attention, with maybe a few high level tips about acquisition or processing.

Our first candidate for your consideration is the well known, and stunning target, the Horsehead Nebula (Barnard 33). The horsehead is an area of dust against a bright background of glowing hydrogen gas. This creates a silhouette if you will that is shaped like a horses head, or a knights chess piece. This area is quite bright photographically in both visible and narrowband wavelengths and a favorite target for expert imagers, but is also an excellent target for beginning astrophotographers.

Look to the left most star in Orions belt (for northern hemisphere viewers).

Currently, the horsehead region is perfectly placed right as it get’s dark, high up in the eastern sky and can be imaged until about midnight early this month before it gets too low in the West. It is also easy to find, as the bright nebula where this lies is hanging right off the left most star in Orions belt, Alnitak (or Zeta Orionis).

Horsehead and Flame

Wide field views of the Horsehead Nebula are very popular.
Richard S. Wright Jr.

This part of the sky is a wonderland for imagers, and almost any focal length optic and camera combination is capable of capturing stunning views. Perhaps the most iconic views of the area are wide field images spanning about one and a half degrees horizontally.

The star Alnitak is featured prominently on the left, just above another well known target, the Flame Nebula (NGC 2024). Very often you will see both the horsehead and flame captured together like this. This whole area is glowing brightly from ionized hydrogen gas, which creates a glorious backdrop to the shadowy puff of curling dust that looks like smoke rising from a hidden furnace. This area is so bright in fact, even an unmodified DSLR will pickup quite a bit of this red glow. Narrowband imagers with hydrogen alpha filters can capture amazing details in this shimmering curtain of light too, such as the image below which is only an a hours worth of total exposure time (Officina Stellare RH-200 600mm f/3, FLI Microline 16200 camera).

Horse head in Ha

The Horsehead region in Ha light is jaw dropping by anyones standards.
Richard S. Wright Jr.

The entire region spans about a degree and a half, and can be captured with moderate focal lengths and APS-C sized chips. A smaller chip and/or a longer focal length will allow you to focus in primarily on the horsehead itself with an image like the first one in this blog. That image by the way is only three hours of data, captured with a small sensor (Sony 694 on a Starlight Xpress camera), and bit of focal length, 1200mm (Sky-Watcher Quattro 12″ f/4 imaging newtonian).

200mm Image

A DSLR and 200mm camera lens is all that’s needed.
Richard S. Wright Jr

This is not a target that requires dozens of hours of integration time to capture all the details

Alnitak and friend

Don’t over do it, or you’ll miss it!
Richard S. Wright Jr.

available. A 600mm telescope with a DSLR (cropped or not) will capture the entire region very quickly, and many astrophotographers will use long DSLR lenses to capture large swaths of the Orion constellation, with the horsehead and great Orion nebula both featured.

There are a few hidden jewels too to look for too in this region. First, the star Alnitak is actually a double star with a small companion 50 Orionis. In my earliest attempts to shoot this area, I often stretched far too aggressively, and the bright star Alnitak would swell up quite large and swallow it’s companion. In your own images, or when looking at someone else’s, look for this tell tail sign of attention to detail in processing.

Often overlooked or glossed over too is NGC 2023, a reflection nebula to the lower left of the bigger celebrity here. This bluish reflection area looks like a tunnel to another world to me. The very bright star

NGC 2023

NGC 2023, a beautiful blue reflection area to the lower left of the horsehead proper.
Richard S. Wright Jr.

HD 37903 powers this area and if I were superstitious, I’d swear I was looking down a tunnel into the next world (follow the light Carol Anne…). At longer focal lengths and smaller pixel scales (and good seeing!), there is a surprising amount of intricate and beautiful detail to be captured here too.

The winter sky is full of jewels like this. Catch the horsehead this month before it gallops away!

Richard

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Solar Eclipsed

My view of Totality

You can prepare all you want. You can practice until you can do it in your sleep. You can have the best equipment and gear, spend hundreds or thousands of dollars for travel. Everything can work perfectly, and you can have your best game on, but a bit of water vapor is all it takes to derail the whole affair. You cannot out maneuver mother nature!

I need a T-Shirt that says “All my friends got great corona shots, and all I got was this T-Shirt!”.

For the Great American Eclipse of 2017, my wife, oldest son and I traveled to Western North Carolina to the path of totality and we setup at The Pisgah Astronomical Research Institute (PARI for short). PARI has long been one of my favorite summer escapes from the Florida heat and humidity, but alas in this instance PARI was a better location for radio astronomy than visual. PARI was

All the best gear was ready to rock!

holding a big eclipse event of course, and notably, this was the first time that totality passed over a radio telescope installation, so of course there was also some excitement about this, and I look forward to hearing about the results of their observations to see if anything unexpected was recorded (radio telescopes don’t care about no clouds!).

We setup the previous day (I also worked the event as a volunteer), and the weather was great that day and all morning. I practiced and took some shots of the full solar disk earlier in the day, and there was a beautiful set of sunspots that rewarded both visual and imaging observers alike.

There was a pretty good sized group of people there naturally, and as an event I think it was the largest that PARI has ever seen. There were food trucks with some excellent Blue Smoke BBQ, Pizza, Beer, etc. It was like going to the fair as a kid except there were no death-trap rides to terrify your parents. A large number of orange shirted volunteers were peppered everywhere (I was one of them) too answering questions, manning telescopes, etc.

A beautiful and promising morning the day of the eclipse.

The weather could not have looked more perfect that morning. Before the event opened to the public, we had everything ready to go near the nature center were I was setup and the sky was as blue and clear as I could possibly have hoped for. About an hour before first contact though, a rather foreboding group of clouds was seen approaching from the north east. My smart phone radar app showed the most terrifying thing it could show that day… rain in the area. We were in a terrible spot to be caught if there was lightning, and any strikes nearby would mandate an evacuation down to the buildings at the bottom of the ridge.

Fortunately, the rain and lightning held off, but unfortunately the clouds did not. Scattered clouds arrived just minutes before first contact, and I did get a couple of shots literally between the clouds from time to time. You could tell when it was time to man the camera because suddenly there would be hooping and hollering as the partially eclipsed sun became visible. Over all, I got perhaps a half dozen exposures, some through hazy clouds (moody!), and of course only of the partial phases. One only minutes after totality, with a razor thin crescent… that’s still a pretty good catch.

One does what one can with what one has!

Was it worth the trip? Absolutely, and for two reasons. One is it actually was raining at home, so no I could not have gotten even some partial eclipse images had I stayed home, much less that very thin crescent shot shown above. Second is totality. Even under scattered clouds, totality was an experience you do not forget. No, I got no streaming corona, I saw no beads or diamond ring, but there was an otherworldly atmosphere none-the-less. It wasn’t totally overcast, and you could see the shadow approaching from west over the ridges in the distance. It is a misnomer that during totality it gets as dark as night, it’s more like twilight, and I knew this. However, it got darker than I expected; it was a deep twilight and on the horizon for 360 degrees where there were no clouds (one of the reasons for being on a high ridge for this), you could see the red glow of sunset or sunrise all around you. Again too, dark like well after sunset, and it came on so suddenly after being bright mid-day that it was unnerving somewhere deep in my subconscious. Unnerving… and exhilarating! And then… it was over.

Yes, I’m ruined now. I’d do it all again even if I knew it was going to be cloudy in advance. I’m not entirely sure I can wait the seven years for another total eclipse in the US. It’s about time to renew my passport I think…

Richard

 

 

 

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