Astrophotography Highlight – March 2018
Astrophotography Highlight – March 2018

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

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

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!