I participated in one of these for the first time last night with the local astronomy group here. It was their 11th annual Messier Marathon. A welcome break from the intensity of imaging. Sometimes we forget what got us into this hobby! Anyway this is a very interesting and enjoyable activity which many amateur groups participate in. There is no grand prize or anything in our group for finding all 110 in the same night but a great time with like-minded colleagues engaging in the “thrill of the cosmic hunt”. We had a pot luck dinner an hour before sunset, set up the coffee thermoses, then several group members set up their various refractors and dobs. I assisted with operation of the club’s observatory scope which is a 16″ Meade and piggybacked 100mm Williams Optics refractor with Mallincam Extreme attached, housed in a roll-off roof structure. We use the equipment mainly for outreach events here at the Leasburg National Park, about half hour north of town.
I never really knew much about how this Marathon worked practically speaking but there is a lot written about it. To find all 110 Messier objects in 1 night you do have to do your homework. There is only a small window of days where this can actually be done! It turns out that between lattitude 20 and 40 you can only realistically accomplish this at the end of March. There is a well-known sequence of objects which Marathoner’s know about which enables you to see all 110. For example we started with M77 and M74 low in the west, then went over to M31 and M33 before making our way east. Of course we did have the goto capabilities of the main observatory scope but ran into glitches such as the roof obscuring a few of them and having to work around preset slew limits! At any rate I learned a lot about the layout of the Messier Objects and we got some great views of many of the classics and some I never really knew much about. M46 for example has this really cool planetary nebula embedded right in the middle! All in all a great experience and a lot of fun.
For more on Charles Messier and his catalog of 110 objects, see http://messier.seds.org/
What is true color in Space? We know violets are blue and roses are red, but what does M1 or M101 really look like? Here on Earth there are so many variables due to the thick atmosphere that undoubtedly alter the color by the time it gets to the camera. I think this is the most difficult aspect of imaging, especially with many hours of data. Now the “Hubble Palette” really confuses everything. I never could get into narrow band imaging for the reason that I just can NOT get used to the color green in Space.
Several methods exist to try to get as close as we can to the “true” color. That’s not the main subject today though. After finishing close to 40 hours of imaging for M1 I went through the processing and came up with these 2 drastically different results! Interestingly the color calibration is exactly the same for both. The difference was in the first run I was trying in my mind to create a result that I THOUGHT was the most accurate. Certainly the resolution and detail is fine, but there is very little color except the Ha on the fringes of the nebula. That is because I basically processed it out. I THOUGHT it should look a certain way. When we create these images most of us look at previous ones. Maybe there was an APOD of your image so you want it to look like that. I think this is a path that leads to nowhere. For M1 I was not able to find more than 1 deep image that was not narrow band so I didn’t have much to go on. I thought to myself “we really need to push the Ha detail because that’s what everyone else did”. In doing that I created an image that was washed out, overprocessed and unnatural. I went back and redid everything. I made sure my background gradients were eliminated before combining the RGB with Luminance. I did little if any stretching of the image and I just let the data speak for itself. If you think about it, I had close to 30 hours of binned color, plus the Ha! It had to go somewhere! And of course somewhere it did go, which was the second image. At first I did not believe the color, but I checked several calibration methods and they all came out the same. I asked a couple of the local astronomers here and they said that this was in fact consistent. The deep blue is expected from the high energy synchrotron radiation caused by rapidly moving electrons in an intense magnetic field created by the neutron star we know is at the core! So there you have it. I discovered something above and beyond taking a picture! Trust your processing methods if carefully done and the colors they produce even if you haven’t seen them ever before! Discoveries are still out there for astroimagers!
This was the first run of M1. Nice detail is seen but the core is pale and washed out. The edges of the nebula are overstretched and unnatural looking.
Quite a difference here with rich color both in the core and even the outer portion of the nebula where there are some heavier elements in addition to hydrogen producing some hints of green (did I say “green”?)