Most Difficult Messier Object

[jrkirkham]

I just read that, at Mag. 10.1, M76 is the faintest of the Messier objects, but not the most difficult to see. What is the most difficult to see, and what equipment have other members used that gave a satisfying view?

[AustinPSD]

This becomes kind of a subjective set of answers...

Messier objects with high magnitude numbers, say 10 and above combined with other factors like azimuth at a particular time of year, and either very small, or very large angular sizes can be problematic for anyone.

It depends on your observing location, seeing conditions, the instrument in use relative to its aperture, FOV in any particular configuration, along with the magnitude, angular size and azimuth.

At present, a couple of good examples for me, from my observing location include M103 and M105. In the case of M103, at transit it is only 1.4-degrees above the horizon, and even though it is relatively bright at magnitude 7.00, its large angular size (13') combined with its low altitude make it difficult to see, even through a relatively large 11" SCT...

For M105, at transit it is about 36-degrees above the horizon, dim at magnitude 11.0, and small to moderate in angular size (about 5').

The object type can also be a factor - for some, a galaxy will resolve better than a cluster. The underlying issues can be optics, eyesight, and seeing conditions.

[powerwindows1985]

I don't find M76 that difficult. It is very small, but I found it easily. For me M72 and M73in Aquarius were particularly difficult. M97 and M108 were difficult until I got to a darker site then they were quite easy (and very cool). Of course I have yet to try to navigate the Coma/Virgo Custer.

[MarkM]

To date, I have found M97 the hardest--but it yields readily now in the 15". M101 was a close second.

M1 and M33 are no piece of cake. And if the moon is out, the usually bright M4 downright vanishes.

There was a time when I really could not see M110 either.

[Sarge]

I am using Astrobyte as my planner for observing all 110 Messier objects and I have so far logged 22 objects. Bearing in mind Astobyte is a northern hemisphere software program and Aust is in the south, it can be frustrating trying to locate some objects. This month includes M72 and M73. They are both in the western sky late evening in Aust. I found M72 once earlier in the month, but have not been able to locate it since. Have never found M73, which is right next to M72. That's one of the fun things about astonomy, even when you found one object is is still fun (if not sometimes frustrating) to find it again.

Rod

[EricFD]

I have to agree with AustinPSD about this becoming kind of a subjective set of answers. There are many variables to consider.

But, if I had to pick one, I would have to say M73. I think the reason is because of all the Messier objects, M73 is the only asterism of the bunch. It has very little or no nebulosity and is parallel in declination to the globular cluster M72 in the same constellation. It is a trio of 10th magnitude stars that simply don't stand out very well against the backdrop of surrounding stars. To date, I can't confirm that I have actually seen M73 through my 8" Dob, even though I have tried to find it.

Eric

[WWPierre]

Cruising Stellarium in reference to this thread, I found an unusual asterism that has to be an object, or else the cosmic coincidence to end all cosmic coincidences. It is a perfectly straight line of about 30 13th-14th magnitude stars at RA 23h 48' DE 11deg 33' 49" Very close to Juno's present position under Uranus. It is not labled in Stellarium.

[EricFD]

Originally Posted by WWPierre

Cruising Stellarium in reference to this thread, I found an unusual asterism that has to be an object, or else the cosmic coincidence to end all cosmic coincidences. It is a perfectly straight line of about 30 13th-14th magnitude stars at RA 23h 48' DE 11deg 33' 49" Very close to Juno's present position under Uranus. It is not labled in Stellarium.

Hi Pierre,

If you're referring to M73 in Aquarius, it's coordinates are RA 20h 56m.4 Dec. -12° 50'. Three of the stars in the asterism form a triangle and a fourth star in the triangle is 12th magnitude star.

Now SEDS has slightly different celestial coordinates for M73 which you can view here: [Registered users can see links. ].

But the asterism is triangular in shape and not a straight line. So I guess what you found is one of the biggest cosmic coincidences of all times after all, but not M73.

Eric

[WWPierre]

Nope. After checking out M73, I wandered over to see where Juno was, and noticed this little slash. I thought it was an artifact in Stellarium, but it seemed to be stars. I can't find it in CDC.

Here is a Stellarium screenshot.

[EricFD]

Originally Posted by WWPierre

Nope. After checking out M73, I wandered over to see where Juno was, and noticed this little slash. I thought it was an artifact in Stellarium, but it seemed to be stars. I can't find it in CDC.

Oh, I see, Pierre. My mistake. I'll have to check out what you're talking about on Stellarium. Now you've got my curiosity up!

Eric