Our server costs ~$56 per month to run. Please consider donating or becoming a Patron to help keep the site running. Help us gain new members by following us on Twitter and liking our page on Facebook!
Current time: March 28, 2024, 6:00 am

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
New astrophoto of the day
#1
New astrophoto of the day
I started a new thread because the old one was buried so far back.

[Image: m101-1.jpg]

Messier 101, in Ursa Major

From http://seds.org/messier/m/m101.html

Messier 101 (M101, NGC 5457) was discovered by Pierre Méchain on March 27, 1781, and added as one of the last entries in Charles Messier's catalog. It was one of the first "spiral nebula" identified as such, in 1851 by William Parsons, the third Earl of Rosse.

Although extended 22 arc minutes on photos and quite bright, only the central region of this galaxy is visible in smaller telescopes, best at low powers. Suggestions of the spiral arms can be glimpsed in telescopes starting from 4 inch as nebulous patches. Several of these patches (i.e., spiral arm fragments) were assigned their own catalog numbers by William Herschel and later observers; according to the NGC and Burnham, there are 9 such numbers, 3 of which go back to Herschel who has found them on April 14, 1789, while the RNGC states that five of the others don't exist (ne); it mentions however that deVaucouleurs has them as knots: NGC 5447 (H III.787), 5449 (ne), 5450 (ne), 5451 (ne), 5453 (ne), 5455, 5458 (ne), 5461 (H III.788), 5462 (H III.789), and 5471.

On photographs, however, the Pinwheel Galaxy M101 is revealed as one of the most prominent Grand Design spirals in the sky. While quite symmetric visually and in very short exposures which show only the central region, it is of remarkable unsymmetry, its core being considerably displaced from the center of the disk. Halton Arp has included M101 as No. 26 in his Catalogue of Peculiar Galaxies as a "Spiral with One Heavy Arm".

M101 is the brightest of a group of at least 9 galaxies, called the M101 Group. The brightest companions are NGC 5474 (type Sc, 10.85 mag vis) to the SSE and NGC 5585 (Sa, 11.49 mag; Glyn Jones and Burnham misprinted this as 5485) to the NE. Other probable group members are NGC 5204 (Ir, 11.26), NGC 5238 (SB(d)m, 13.35p), NGC 5477 (Ir+, 13.8), UGC 8508 (Ir+, 14.5 p), Holmberg IV (UGC 8837, Ir+, 13.1 p), and UGC 9405.

The distance of M101 has been determined by the measurement of Cepheid variables with the Hubble Space Telescope in 1994/95 to be about 24 +/- 2 million light years, by the HST H0 Key Project Team (paper III, 1996). Kenneth Glyn Jones mentions earlier Earth-bound attempts of 1986, when two Cepheids were claimed to have been detected (yielding distance estimates between 20 and 26 million light years). It is also in good agreement with a distance determined from the Planetary Nebula Luminosity function, by Feldmeier, Ciardullo and Jacoby (1996) which is 25.1 +/- 1.6 million light years. According to the recent recalibration of the Cepheid distance scale, the "true" distance of M101 should be closer to a 10 percent higher value (27 million light years).

At the new distance from the HST and Hipparcos, it has a linear diameter of over 170,000 light years and is thus among the biggest disk galaxies, and its total apparent visual brightness of 7.9 mag corresponds to an absolute brightness of -21.6 magnitudes, or a luminosity of about 30 billion (3*10^10) times that of our sun.

Three supernovae have been discovered in M101: The first one, SN 1909A, appeared on January 26, 1909 and was discovered by Max Wolf; it was of peculiar type and reached mag 12.1 (Glyn Jones reports that the discovery took place in February, and the SN reached only mag 13.5). The second supernova 1951H was of type II, occurred in September 1951 and reached mag 17.5, while the third, SN 1970G, also type II, was discovered on July 30, 1970 by Michael Lovas, and reached mag 11.5. The remnant of Supernova 1970G was later detected in X-ray light and e.g. observed with the Chandra X-ray Observatory (CXO) satellite.
__________________________

Image:
14x4 minutes for a total of 56 minutes at ISO 800
Stacked in DeepSkyStacker, Dark Subtracted
Processed in Adobe Photoshop CS3 Extended
Taken on February 11, 2010 at the Louisville Astronomical Society James Baker Observatory, in Curby, Indiana

Equipment:
Hutech Canon T1i DSLR
200 mm f5 Konus Newtonian with a Baader coma corrector and a UV/IR cut filter
Losmandy G11 Gemini GOTO mount on Heavy Duty Tripod
Orion Shorty Autoguide Scope with Starshooter autoguider
[Image: m3-1-1.jpg]

I only got 10 minutes of data on this one because I wanted to move on to M101. This was more of a test to see what I needed to adjust before I imaged M101. The focus was softer than I wanted, so I adjusted it a bit for the galaxy.

From http://seds.org/messier/m/m003.html

Discovered 1764 by Charles Messier.

Messier 3 (M3, NGC 5272) is one of the most outstanding globular clusters, containing an estimated half million stars. It is famous for the large number of variable stars discovered in it.

This cluster was the first 'original' discovery by Charles Messier when he logged it on May 3rd, 1764. At that time it was the 76th deep sky object ever observed by human eyes (and apparatus), although at that time, it was only the 55th known nebulous object, while 21 objects had been forgotten again, according to the sources and current knowledge of the present author (see the Deep Sky Object Discovery Table). Perhaps the discovery of this object eventually caused Charles Messier to start a systematical search for these comet resembling objects, and not just catalog chance findings as in the previous cases, M1 and M2. Alternatively, Messier may have started this endeavor due to other reasons, and it was just his first discovery - anyway, the search which started with M3 lead him to catalog the objects up to M40 during this year 1764.

When the final object of the catalog, M107, a globular cluster in Ophiuchus, was discovered by Messier's friend Pierre Méchain 18 years later, in 1782, a total of at least 143 objects were known, more than double the number, and 110 of them described by Messier (who discovered 42 or 43) and Méchain (27 or 28) -- the doubty counting being a result of the dubious circumstances concerning the discovery of M102.

M3 was first resolved into stars and recognized as cluster by William Herschel around 1784.

At a distance of about 33,900 light years, M3 is further away than the center of our Galaxy, the Milky Way, but still shines at magnitude 6.2, as its absolute magnitude is about -8.93, corresponding to a luminosity of about 300,000 times that of our sun. M3 is thus visible to the naked eye under very good conditions - and a superb object with the slightest optical aid. Its apparent diameter of 18.0 arc minutes corresponds to a linear extension of about 180 light years; Kenneth Glyn Jones mentions an estimate of even 20 arc minutes from deep photographic plates, corresponding to about 200 light years linear diameter. It appears somewhat smaller in amateur instruments, perhaps about 10 minutes of arc. But its tidal radius, beyond which member stars would be torn away by the tidal gravitational force of the Milky Way Galaxy, is even larger: About 38.19 minutes of arc. Thus, this cluster gravitationally dominates a shperical volume 760 light years in diameter.

On the other hand, M3 has a compressed, dense core measuring 1.1' in diameter, or linearly, 11 light years, comparatively large for a globular. Its half-mass radius is 1.12', or about 11.2 light years, so that half of this clusters mass is contained in a volume of only 22 light years in diameter.

The cluster's brightest stars are of mag 12.7, while the so-called Horizontal Branch giants are of mag 15.7, and the 25 brightest stars have an average brightness of 14.23 mag. The age of globular cluster M3 has been estimated from its color-magnitude diagram on various occasions; historically, early values have been given at 5 billion years (Baade), 11.4 billion years (Woolf), 20 billion years (Arp) and 26 billion years (Sandage). Sandage (1954) counted 44,500 stars brighter than mag 22.5 within a radius of 8 arc min; the total mass has been estimated at 245,000 solar masses (Sandage and Johnson). Helen Sawyer Hogg has given M3's overall spectral type as F2, and a color index -0.05, rather blue for a globular, while the Sky Catalogue 2000.0 gives its spectral type at F7, and W.E. Harris lists it as F6. Its color index was determined as B-V=0.69. This stellar swarm is approaching us at 147.6 km/sec.

Situated in the Galactic halo, out about 40,000 light-years from the Galactic Center, M3 is moving on a box-type orbit of approximate excentricity 0.55, which takes it out up to 66,000 light-years apogalactic distance and up to 49,000 light-years above and below the Galactic plane (currently it is about 33,000 light-years above - i.e., north of - that plane). On the other hand, its perigalactic distance is only 22,000 light-years - at that distance, the tidal radius of M3 will go down to below 200 light-years, so that the outermost stars may easily escape from this globular cluster.

Globular cluster M3 is extremely rich in variable stars: According to B. Madore (in Hanes/Madore, Globular Clusters, 1978), 212 variables have been found, 186 periods determined, more than in every other globular cluster in our Milky Way galaxy (and thus the most ever observed); at least 170 RR Lyrae variables (sometimes called "cluster variables") were discovered. These stars have served as "standard candles" to determine the cluster's distance. The first variable star was discovered by E.C. Pickering in 1889, the next 87 were found by S.I. Bailey in 1895 (see Pickering and Bailey 1895).

M3 contains a relatively large number of so-called Blue Stragglers, blue main-sequence stars which appear to be rather young, much younger than the rest of the globular's stellar population would suggest. These were first discovered by Alan Sandage (1953) on photographic plates taken with the 200-inch Hale telescope on Mt. Palomar. A mystery for a long time, these stars are now thought to have undergone dramatic changes in stellar interactions, getting their cooler outer layers stripped away in close encounters, which occasionally occur when stars are passing through the dense central regions of globular clusters.

To find M3, either prolong the line from Gamma Comae Berenices near the Comae Berenices Cluster over Beta Comae by about 2/3 and look slightly north to have M3 in the low-power field: it is about 6 degrees north-northeast of Beta Comae.

While M3 is visible to the naked eye only under very good conditions and stays just below the limit of visibility under more average conditions, it can be easily seen with the smallest instrument. In binoculars, it appears just like a hazy, nebulous patch. A 4-inch shows its bright compact core within a round and mottled, grainy glow, which fades slowly and uniformly to the outer edges; it doesn't resolve the cluster, but shows just some of the brightest stars under good conditions. A 6-inch resolves the about outer two thirds into faint stars on a background glow formed by the unresolved fainter member stars of the cluster. An 8-inch shows stars throughout the cluster but in the very core, which is resolved into stars by larger telescopes (about 12-inch).

Image:
10x1 minutes for a total of 56 minutes at ISO 800
Stacked in DeepSkyStacker, Dark Subtracted
Processed in Adobe Photoshop CS3 Extended
Taken on February 11, 2010 at the Louisville Astronomical Society James Baker Observatory, in Curby, Indiana

Equipment:
Hutech Canon T1i DSLR
200 mm f5 Konus Newtonian with a Baader coma corrector and a UV/IR cut filter
Losmandy G11 Gemini GOTO mount on Heavy Duty Tripod
Orion Shorty Autoguide Scope with Starshooter autoguider

Location of M3 relative to the sun:

[Image: locationofm3-1.jpg]
'The difference between a Miracle and a Fact is exactly the difference between a mermaid and seal. It could not be expressed better.'
-- Samuel "Mark Twain" Clemens

"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".

- Galileo Galilei (1564-1642)

"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "

- Dr. Donald Prothero
Reply
#2
RE: New astrophoto of the day
Thanks for the4 kudos, Leo.
'The difference between a Miracle and a Fact is exactly the difference between a mermaid and seal. It could not be expressed better.'
-- Samuel "Mark Twain" Clemens

"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".

- Galileo Galilei (1564-1642)

"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "

- Dr. Donald Prothero
Reply
#3
RE: New astrophoto of the day
In a galaxy, far, far, far, far, far away.........

I was wondering what happened to you the other day.
Reply
#4
RE: New astrophoto of the day
(March 18, 2011 at 6:59 am)orogenicman Wrote: Thanks for the4 kudos, Leo.

Specially the first one of Messier 101 is brilliant.
Best regards,
Leo van Miert
Horsepower is how hard you hit the wall --Torque is how far you take the wall with you
Pastafarian
Reply
#5
RE: New astrophoto of the day
(March 18, 2011 at 7:04 am)ib.me.ub Wrote: In a galaxy, far, far, far, far, far away.........

I was wondering what happened to you the other day.

What do you mean?
'The difference between a Miracle and a Fact is exactly the difference between a mermaid and seal. It could not be expressed better.'
-- Samuel "Mark Twain" Clemens

"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".

- Galileo Galilei (1564-1642)

"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "

- Dr. Donald Prothero
Reply
#6
RE: New astrophoto of the day
What do I mean?

That galaxy is far, far, far away from us!

&

The other day I was wondering why you hadn't post any photos lately!
Reply
#7
RE: New astrophoto of the day
(March 19, 2011 at 1:26 am)ib.me.ub Wrote: What do I mean?

That galaxy is far, far, far away from us!

&

The other day I was wondering why you hadn't post any photos lately!

Okay. The main reason is that we've had really lousy weather here since the above images were taken. The only thing Ive been able to do since then astronomically has been to do some maintenance on the club's large scope inside the observatory. And that's about it. Hopefully, next month will be better, weatherwise.
'The difference between a Miracle and a Fact is exactly the difference between a mermaid and seal. It could not be expressed better.'
-- Samuel "Mark Twain" Clemens

"I think that in the discussion of natural problems we ought to begin not with the scriptures, but with experiments, demonstrations, and observations".

- Galileo Galilei (1564-1642)

"In short, Meyer has shown that his first disastrous book was not a fluke: he is capable of going into any field in which he has no training or research experience and botching it just as badly as he did molecular biology. As I've written before, if you are a complete amateur and don't understand a subject, don't demonstrate the Dunning-Kruger effect by writing a book about it and proving your ignorance to everyone else! "

- Dr. Donald Prothero
Reply



Possibly Related Threads...
Thread Author Replies Views Last Post
  My Latest astrophoto attempt at Messier 42 orogenicman 14 4951 February 21, 2012 at 11:10 am
Last Post: MarkOfEnglandshire
  New Astrophoto orogenicman 8 3031 February 15, 2012 at 12:14 am
Last Post: Modular Moog V
  My New Astro Photos Of The Day orogenicman 9 2312 October 20, 2011 at 6:19 pm
Last Post: orogenicman



Users browsing this thread: 1 Guest(s)