A Messier Marathon alternative

hi everyone,

we've all heard of the "Messier Marathon" -- where around the Spring equinox it is possible to glimpse all the deep-sky objects in Charles Messier's catalogue in a single night. From Ireland though, about 100 of the 110 is the best you'll do due to low altitude of some and twilight interfering for others.

however, it's an event that is quite popular though a good knowledge of some parts of the sky is a prerequisite ("GoTo" scopes excepted!)

many observers may feel that such an achievement is beyond them either through lack of equipment, knowledge, or motivation. To correct this, I've devised what I call The Springtime Sixty -- a tour of celestial showpieces that can be completed WITH JUST A PAIR OF BINOCULARS on "Messier Marathon" night. All these objects can be seen in a pair of 10x50mm binoculars with some also naked eye.

a few challenging objects are to be found in the list while you'll find some parts of the night where you will have to hurry a little to complete your observations due to the object getting low or morning twilight encroaching.

the list is split into 2-hour time slices with 12 objects for each period -- that's 10 minutes per object. Some are doubled-up too where they lie in the same binocular field while the Auriga star clusters I've counted as a "trio".

the sequence has been carefully selected so that it highlights the optimum time when you should be searching for, or viewing, an object before you need to move on to the next. If you find you are spending too much time at a point in the list, move on to the next object as you may have time towards the end of that section to return to search again.

many of the objects are familiar while others are new for most where you may never have seen them before. There is a broad selection of classes of object too with clusters, nebulae, double stars, and asterisms. Many of Messier's objects are listed as his catalog is really a showcase of the best deep-sky objects in it's own right.

although the list is specifically devised as an alternative to the Messier Marathon, you can also spend weeks tracking down the objects within -- the main aim is to encourage people out to observe so take as much time as you want.

we'll devise a "marathon" certificate though to award to those who complete the list in the one night but will also award a certificate of completion no matter how long you take to do so. Send your reports, comments, certificate claims or calls for help to my e-mail address -- skynotes at eircom dot net

the objects are all in the Collins GEM book "Stars" which costs about eight euro or any other star atlas will do. Also, a planisphere is a must (or a series of "all sky" charts for the course of the night).

ideally, use tripod-mounted binoculars as you will need to keep your hands free to juggle the charts, red torch, etc. Wrap up well too and have somewhere you can take rest breaks -- some sections will be easy to complete if you have prepared well so you will have some free time on occasions.

the list is in the OBSERVING sub-directory of the FILES section of the board and is an Ms-Excel 95 document -- I'll convert it later to a pdf for those without Ms-Excel. Click on www.irishastronomy.org/user_resources/fi...9016569-spring60.xls

not everyone might agree with my selection and I'm open to debate or correction! Let the Springtime 60 marathon begin!!!

John Flannery,
SDAS

Excellent resource, John - thanks a lot! :mrgreen: Can't wait for a chance to get out and give the Spring 60 a go.

A dumb question: what's the difference between visual and photographic magnitude?

hi Paul,

many thanks for the comments on the list . . . I've uploaded a slightly modified version (mostly cosmetic changes) and will probably tweak a little over the next few days to amend the descriptive notes for each object. I've an idea to do a "Wicklow 200" as well of 200 objects for binoculars but that's a little more planning!

not a silly question at all on Visual v. Photographic magnitude . . . I gleaned this short description of photographic magnitude off a website;

" The magnitude of a celestial object as measured on a photograph may be considerably different than that measured by the eye. This happens because most film emulsions react more strongly to red light than does the human eye, which tends to be more sensitive to blue light. An object that is redder in color will tend to have a brighter photographic magnitude than visual magnitude. "

I guess that means that the magnitude of nebulae are slightly over stated because they tend to be reddish objects anyway. That said, most are extended objects so the surface magnitude (brightness per square arcsecond) is lower and a large diffuse deep-sky thingie appears dim (e.g. M33 galaxy). The magnitude for clusters would be an averaged brightness for all the member stars if summed into one point source (it's a little more complex than that as to how it's derived though -- generally, it's based on the cluster's position on a luminosity graph).

best,

John,
SDAS

Excellent work John, well done. I assume you're going to place a copy of the list in Arcturus. It certainly deserves to be widely read.