Sunday, February 17, 2013

Imaging Messier Marathon: Combining Targets in One Frame

So many objects, so little time. If only there were fewer objects!

Well, in a way there are. Some of the Ms are close enough together that one shot can encompass two or more objects, thus saving us time. Let's see what we can find in the way of grouped Messiers.

I'm going to list the Messier objects in the order given by Don Machholz in his book The Observing Guide to the Messier Marathon--A Handbook and Atlas. This book is available from AmazonBarnes and Noble and other sellers. Frugal? Look to used book stores. I paid $25 for my copy at Half Price Books.

Here are some combined fields for two different focal lengths. If I missed some, please let me know so  that I can add to the list.

These lists depend your go-to running with at least get-it-in-the-finder accuracy. In the lists I'm leaving out all the single-target fields. I'll add a master list of all 110 objects soon.


700 mm Focal Length Combined Fields


Eleven fields saved, five go-to ra/dec actions, four camera orientation checks.


Go-To target is indicated by bold. Tight fits may require camera rotation

M31+32+110:  Check Camera Orientation

M42+43

M95+96: Target RA 10:45:16, DEC +11:45:54

M65+66

M81+82: Target RA 9:55:39, DEC +69:23:38

M97+108: Target RA11:13:11, DEC +55:20:23 Check Camera Orientation

M84+86

M59+60

M17+18: Target RA 18:20:15, DEC -16:38:38 Check Camera Orientation

M21+20:: Target RA 18:03:23, DEC -23:07:31 Check Camera Orientation


432 mm Focal Length Combined Fields

Fourteen fields saved, four go-to ra/dec actions, five camera orientation checks.

Go-To target is indicated by bold. Tight fits may require camera rotation

M31+32+110

M42+43

M95+96+105 Check Camera Orientation

M65+66

M81+82

M97+108: Target RA11:13:11, DEC +55:20:23

M84+86+87: Target RA 12:27:51, DEC +12:38:53 Check Camera Orientation

M58+59+60: Target RA 12:40:25, DEC +11:42:19 Check Camera Orientation

M17+18: Target RA 18:20:15, DEC -16:38:38 Check Camera Orientation

M21+20 Check Camera Orientation


Your choice of imaging focal length(s) may well differ from mine. Focal lengths longer than 700 mm will find that some of the combinations flagged for an orientation check will not work. If your focal length is between 400 and 700mm you're safe if you follow the recommendations for 700mm.

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