Object of the Week April 24th, 2022 M102 The Spindle Galaxy

[Dragan]

M102

NGC5866

UGC9723

Galaxy

Constellation: Draco

RA: 15 06 29.4
DEC: 55 45 48

Class: SA0+sp
Size: 6.4’x2.8’
Mag: 9.9

My choice for this week’s object came as a surprise when I realized that it had never been chosen as an OOTW! M102 is not just a delight in the eyepiece in a wide variety of instruments, but it comes with some mystery as well.

Per Seds.org, M102 was “probably” discovered by French astronomers Pierre Méchain and/or by Charles Messier in 1781. In short, Méchain recorded observing M102 (NGC5866) in late March or early April of 1781. Charles Messier included the observation by Méchain in his catalog but failed to include the coordinates, nor confirming the observation, leaving some to question exactly which object was observed by Méchain. None of this was out of the ordinary as Méchain and Messier collaborated on many of the objects that would eventually be listed in Messier’s catalog. In 1783, Méchain in a letter to then Astronomer Royal of Berlin Johann III Bernoulli, disavowed his observation of M102 stating that his observation was in fact a duplication of M101 as well as an error in his star chart.

Descriptors used at the time point to M102 not being a duplicate observation of M101. Méchain described M101 differently from M102. M101 was described as a Nebula without stars, very obscure and pretty large, between 6' and 7' in diameter, between the left hand of Bootes and the tail of Ursa Major. Difficult to distinguish when graticule lit whereas M102 was described as Nebula between the stars Omicron Bootis and Iota Draconis: it is very faint, near it is a star of 6th magnitude.

Star positions were also called into question. Whether it was Mechain’s own star designation or the possibility that there was a misprint in the star catalog he was using at the time is up for debate but the most likely scenario was the latter rather than the former.

To add more drama, Herschel “independently” discovered this object in 1788! So, who knows what’s going on?!

Most probable is that M102 is in fact NGC5866. Either way, the story continues and leaves for some interesting reading material for anyone interested in coming up with their own conclusions. If you look at this link, you’ll see many people have differing opinions on the matter! And please feel free to read up on the fascinating history of this object here. I’m sure Steve Gottlieb with his vastly more knowledge than myself can add even more to this interesting story.

Visually, who hasn’t seen M102?! It’s a beautifully stunning object in all sizes of telescopes – even showing itself in binoculars from dark sites. M102 reveals itself as a bright, elongated NW-SE nearly edge-on galaxy. Sometimes called “The Spindle Galaxy” with its spindle-like appearance, larger scopes will reveal a distinct dustlane that splits the galaxy’s central bulge right along its axis.

So, no matter how, when or who first laid eyes on this galaxy, just know that it’s worth a look by your own eyes. Next new moon, be sure to get out and give this object a once over. It’ll be worth the look.

And as always,

Give it a go and let us know!

Good luck and great viewing!

m102.jpg
© http://messier.obspm.fr/m/ngc5866.html


m102_hubble2.jpg
©HST


https://www.messier.seds.org/m/m102.html

https://www.messier.seds.org/m/m102d.html

[Raul Leon]

Hi, here's my observation from 4/8/2016: Ngc 5866 aka Messier 102 is a galaxy in Draco; magnitude: 9.8 ; size: 6.3' x 2.7' ; fairly bright and elongated; spindle shaped, central area not discernibly brighter towards the center. On a night of mediocre seeing , I couldn't make out the dust lane. I used a 8mm Ethos at 238x with my 14.5 Starstructure f/4.3Scan0490.jpg

[Don Pensack]

With my 8:
large, bright, oval with lrg.bright oval core, core lrg % of visible galaxy, nearby several *s, edges uneven, not smooth.

From the 12.5" several years later:
Large bright oval center with projections at either end, couple superimposed stars, faint low contrast dark lane runs lengthwise across the bright core.
large and bright galaxy. Without the projections, looks like an elliptical, but could be an edge-on S0 spiral. Impressive!

In fact, I was right. It is an S0 spiral.
A great example of the next class, SA is M104
But NGC5866 is a great galaxy. It's in my list of 500 beginner's objects for 4-5" scopes.
The pics make it look like a thick spool of thread around a long thin spindle.
Anyone know where the name "Fool's Gold Galaxy" came from?

[lamperti]

It may have been Stephen James O'Meara: " He therefore calls M102 the Fool's Gold Galaxy because, if you think you've found it when you're observing NGC 5866, the joke's on you." - from Astronomy.com podcast 2014.

[Uwe Glahn]

M 102 has an interesting but a somewhat curious body, perhaps because of its brighter extensions beside the thin dark lane. I often missed the lane with 16-inch when seeing was only average.

sketch: 20", 543x, NELM 6m0+
M102.jpg
home

[akarsh]

I have two traceable observations of M 102 where I actually logged something. One time was in 2019 July from the Warner Mountains with my 18", where I wrote "Can feel the dust lane". The other time was just a few months earlier on Jimi's 48" in May 2019, when I produced this representative sketch:

M102.jpg


There's also one entry for "Spindle Galaxy" on Jimi's 48" from 2015, but that's ambiguous because the name "Spindle Galaxy" is sometimes also ascribed to NGC 3115 in Sextans.

[cloudbuster]

Hi all, here's my contribution with a 16". My hopes were up for spotting the tiny dustlane that crosses the face of this fine looking galaxy. At lower magnification it did not present itself, but with the 5mm eyepiece at 370x I could definitely confirm it. With the 3.5mm at 518x it was even more easy to see it, but the overall view softened a bit too much. The first thing I always do when starting a sketch is plotting the star field and I was surprised to see a very dim star at the tip of the NW side of the galaxy (down in the sketch). On the opposite side (SE) near the core I may have spotted a slightly brighter patch. I added it to the sketch, but I’m not sure if it’s real or if it was merely an illusion. Sketched with the 16? Alkaid @259x. (best viewed when dark adapted)

M102-uitsnede.jpg

Martijn