M87
 

No apologies for posting this one I took in the wee hours of this morning. I think it is pretty.

Deep in the heart of M87 is a particularly super-massive black hole, the first image of which was released earlier this year. The BH itself is far to small to be imaged at optical wavelengths from the ground. It produces jets of highly relativistic particles which emit light over distances of many kiloparsecs. The jet pointing generally towards us is visible in relatively small telescopes. The false-colour image here shows the region close to the center of the galaxy and clearly shows the jet.

M87 is the 87-th Mersenne number: 2^87-1, its factorization is 7 · 233 · 1103 · 2089 · 4177 · 9857737155463 :cmd::cmd::cmd:

[QUOTE=sweety439;520126]M87 is the 87-th Mersenne number: 2^87-1, its factorization is 7 · 233 · 1103 · 2089 · 4177 · 9857737155463 :cmd::cmd::cmd:[/QUOTE]:tu: You chose exactly the most appropriate smiley

Very nice one; you must be getting some good skies there. What sort of exposure time are we looking at?

M87 is also the far future 87th known Mersenne Prime.

Calculating approximate value in the best case scenario using our last 13 lucky primes:

M87 = 82589933 * ((82589933/6972593)[SUP]1/13[/SUP])[SUP]38[/SUP] ~ 113.5 B


Using the "standard" factor of 1.47576:

M87 = 82589933 * 1.47576[SUP]38[/SUP] ~ 218537 B

[QUOTE=ATH;520136]M87 is also the far future 87th known Mersenne Prime.

Calculating approximate value in the best case scenario using our last 13 lucky primes:

M87 = 82589933 * ((82589933/6972593)[SUP]1/13[/SUP])[SUP]38[/SUP] ~ 113.5 B


Using the "standard" factor of 1.47576:

M87 = 82589933 * 1.47576[SUP]38[/SUP] ~ 218537 B[/QUOTE]

Is this number "lucky prime" ([URL="https://oeis.org/A031157"]OEIS A031157[/URL] = 3, 7, 13, 31, 37, 43, 67, 73, 79, 127, 151, 163, 193, 211, 223, 241, 283, 307, 331, 349, 367, 409, 421, 433, 463, 487, 541, 577, 601, 613, 619, 631, 643, 673, 727, 739, 769, 787, 823, 883, 937, 991, 997, ...)? :crazy::crazy:

[QUOTE=ATH;520136]M87 is also the far future 87th known Mersenne Prime.

Calculating approximate value in the best case scenario using our last 13 lucky primes:

M87 = 82589933 * ((82589933/6972593)[SUP]1/13[/SUP])[SUP]38[/SUP] ~ 113.5 B


Using the "standard" factor of 1.47576:

M87 = 82589933 * 1.47576[SUP]38[/SUP] ~ 218537 B[/QUOTE]Where does "38" come from?

M(82589933) is the 51st. So 87-51=36. Maybe you meant 36?

Yeah I meant 36, for some reason I did 89-51.

M87 = 82589933 * ((82589933/6972593)[SUP]1/13[/SUP])[SUP]36[/SUP] ~ 77.6 B

M87 = 82589933 * 1.47576[SUP]36[/SUP] ~ 100344 B

[QUOTE=xilman;520129]:tu: You chose exactly the most appropriate smiley[/QUOTE]Come to think about it, where is cmd these days? Not seen horseshit around for ages.

Remarkable, the progress in imaging that's being made. And this is the information age, so...

I'm not an astronomer, but even I've heard of [url=http://www.seasky.org/astronomy/astronomy-messier.html]The Messier Catalog of Deep Sky Objects[/url]:
[quote]The Messier Catalog, sometimes known as the Messier Album or list of Messier objects, is one of the most useful tools in the astronomy hobby. In the middle of the 18th century, the return of Halley's comet helped to prove the Newtonian theory, and helped to spark a new interest in astronomy. During this time, a French astronomer named Charles Messier began a life-long search for comets. He would eventually discover 15 of them. On August 28, 1758, while searching for comets, Messier found a small cloudy object in the constellation Taurus. He began keeping a journal of these nebulous (cloudy) objects so that they would not be confused with comets. This journal is known today as the Messier Catalog, or Messier Album. The deep sky objects in this catalog are commonly referred to as Messier objects.

The first of the Messier objects to be observed by Messier was the remnant of a supernova explosion known as the Crab Nebula (M1). Over the next few years, Messier and his colleagues would catalog a total of 110 nebulae, galaxies, and star clusters. Today, the Messier Catalog is a valuable tool for amateur astronomers. In fact, the "Messier Marathon" is somewhat of a rite of passage for those who are new to the hobby. Astronomy enthusiasts have been known to stay up all night in an attempt to observe all 110 Messier objects before the Sun rises the next morning.[/quote]

In particular. looking at

[url=http://www.seasky.org/astronomy/astronomy-messier-81to90.html]Messier Catalog: M81 - M90[/url] we find
[quote][b]M87[/b] Galaxy in Virgo
Common Names: Virgo A
NGC Number: 4486
Visual Magnitude: 8.6
ra: 12h 30.8m
dec: +12° 24'

The constellation Virgo is the site of an elliptical galaxy known as M87. This galaxy is also a member of the famous Virgo cluster of galaxies. It is located about 60 million light-years from Earth and has a diameter of around 120,000 light-years. M87 lies within the heart of the Virgo cluster. It is well known for huge system of globular clusters that can be easily seen on long exposure photographs. This galaxy also features an unusual jet of gaseous material that extends out thousands of light-years. A supernova explosion occurred in this galaxy in 1919 but was not discovered until 1922 when it discovered on photographs of the galaxy.[/quote]

[QUOTE=Dr Sardonicus;520175]It is well known for huge system of globular clusters that can be easily seen on long exposure photographs.[/QUOTE]Patience, caterpillar ...

[QUOTE=sweety439;520138]Is this number "lucky prime" [/QUOTE]

By 13 lucky primes I meant the last 13 Mersenne Primes above 10M, because only ~6 are expected on average between p and 10*p, for example 10M-100M, but so far we found 13 between 10M and 100M.

[QUOTE=xilman;520187][quote=Dr Sardonicus;520175]
It is well known for huge system of globular clusters that can be easily seen on long exposure photographs.[/quote]Patience, caterpillar ...[/QUOTE]
Yeah, well, I was just quoting from the web page. But the admonition is apt notwithstanding, because (if I read things right) the jets show up well on [i]short[/i] exposures, while the globular clusters reqire [i]long[/i] exposures.

Years ago, I tried a few photos of night sky objects with a film camera on a tripod. One of them was a multiple exposure of the moon coming into and out of eclipse. I had to use daylight exposure so the moon wouldn't "burn out" on the film. It came out pretty well.

Another one was of the comet Hale-Bopp. I let in as much light as possible to limit the exposure time, because I didn't have a tracking drive and wanted to limit the motion blurring. A 30-second exposure worked reasonably well -- the motion blurring wasn't too bad, and both tails of the comet were clearly visible on the film.

I noted that, with the lens I was using, the moon's disk was almost exactly the same size as the little circle in the middle of the viewfinder. This provided an easy way to check that the "moon illusion" was just that -- an illusion. Even though the moon looks [i]way[/i] bigger on the horizon than when it's high in the sky, when I pointed my camera at it and got it centered in the viewfinder, it always filled that little circle just the same, no matter where it was in the sky.

[QUOTE=Spherical Cow;520133]Very nice one; you must be getting some good skies there. What sort of exposure time are we looking at?[/QUOTE]Apologies for the very late answer. I've been diverted. That image was taken only a couple of hours or so before the camera caught a severe attack of death. First light on its replacement was ~36 hours ago.

Selected chunks of the FITS headers answer your question and a few more besides.
[C]
SIMPLE = T / This is a FITS file
BITPIX = -32 /
NAXIS = 2 /
NAXIS1 = 900 / NUMBER OF ELEMENTS ALONG THIS AXIS
NAXIS2 = 666 / NUMBER OF ELEMENTS ALONG THIS AXIS
EXTEND = T / This file may contain FITS extensions
EQUINOX = 2000.00000000 / Mean equinox
MJD-OBS = 5.865900000000E+04 / Modified Julian date at start
RADESYS = 'ICRS ' / Astrometric system
CTYPE1 = 'RA---TAN' / WCS projection type for this axis
CUNIT1 = 'deg ' / Axis unit
CRVAL1 = 1.877035354096E+02 / World coordinate on this axis
CRPIX1 = 4.505000000000E+02 / Reference pixel on this axis
CD1_1 = -3.960297908634E-04 / Linear projection matrix
CD1_2 = 0.000000000000E+00 / Linear projection matrix
CTYPE2 = 'DEC--TAN' / WCS projection type for this axis
CUNIT2 = 'deg ' / Axis unit
CRVAL2 = 1.239356794190E+01 / World coordinate on this axis
CRPIX2 = 3.335000000000E+02 / Reference pixel on this axis
CD2_1 = 0.000000000000E+00 / Linear projection matrix
CD2_2 = 3.960297908634E-04 / Linear projection matrix
EXPTIME = 2.018000000000E+03 / Maximum equivalent exposure time (s)
FOCALLEN= 2614.0000000000000 /Focal length of telescope in mm
APTDIA = 400.00000000000000 /Aperture diameter of telescope in mm
APTAREA = 116502.82520771027 /Aperture area of telescope in mm^2
EGAIN = 2.6800000667572021 /Electronic gain in e-/ADU
OBJECT = 'M87 '
OBJCTRA = '12 30 52' / Nominal Right Ascension of center of image
OBJCTDEC= '+12 24 02' / Nominal Declination of center of image
OBJCTALT= ' 31.8082' / Nominal altitude of center of image
OBJCTAZ = '266.9463' / Nominal azimuth of center of image
OBJCTHA = ' 4.0192' / Nominal hour angle of center of image
SITELAT = '28 38 30' / Latitude of the imaging location
SITELONG= '-17 52 04' / Longitude of the imaging location
JD = 2458660.4782638890 /Julian Date at start of exposure
JD-HELIO= 2458660.4782602866 /Heliocentric Julian Date at exposure midpoint
AIRMASS = 1.8843917125197109 /Relative optical path length through atmosphere
TELESCOP= 'Dilworth Relay 0.4m f/6.5' /telescope used to acquire this image
INSTRUME= 'SBIG ST-8 Dual CCD Camera w/ AO'
OBSERVER= 'Paul Leyland, Tacande Observatory'[/C]

The EXPTIME is the sum of 69 subs, some of which were only 5 seconds but most were 30 seconds.

[QUOTE=Dr Sardonicus;520253]Yeah, well, I was just quoting from the web page. But the admonition is apt notwithstanding, because (if I read things right) the jets show up well on [i]short[/i] exposures, while the globular clusters reqire [i]long[/i] exposures.[/QUOTE]Once more I apologize for the lengthy delay.

Almost everything circular in this image is a globular cluster; very few are stars in our galaxy. AFAIK, everything else are Virgo cluster galaxies; five are obvious and you should be able to pick up more with careful examination. [url]http://aladin.u-strasbg.fr/AladinLite/[/url] may be helpful here.

The image is the result of a quick and dirty effort. Doubtless a much better one could be produced if more care were taken with the image processing

HVGC-1
 

[QUOTE=Dr Sardonicus;520253]Yeah, well, I was just quoting from the web page. But the admonition is apt notwithstanding, because (if I read things right) the jets show up well on [i]short[/i] exposures, while the globular clusters reqire [i]long[/i] exposures.[/QUOTE]This image was the last taken with the old camera. It consists 137 x 30 second subs, median co-added which comes to 4110 seconds total. No filter was used and the spectral response corresponds quite well to Gaia's g-band.

M87 is 16.4Mpc away, which corresponds to a distance modulus of 31.0. At that distance M13, which has an absolute magnitude of -8.5, would appear as a star of magnitude 22.5. The imaged globular cluster "Hyper-Velocity Globular Cluster 1" shines with a Gaia-g magnitude of 20.61. It would be an easy naked eye object at the distance of M13, comparable in brightness to ⍵ Centauri.

HVGC-1 is near to M87 but is technically not one of its globular clusters. It was ejected from the galaxy a long time ago, presumably by a gravitational sling shot from a black hole binary. It is now travelling at 1026 km/s towards us (i.e. it is blue shifted) and moving at a speed of 2200 km/s away from M87, faster than the escape velocity of the entire Virgo cluster of galaxies!

[QUOTE=xilman;524255]Apologies for the very late answer. I've been diverted. That image was taken only a couple of hours or so before the camera caught a severe attack of death. <snip>[/QUOTE]
My condolences on your loss.

The replacement's performance confirms the adage, "Patience is a virtue."

[QUOTE=Dr Sardonicus;524266]The replacement's performance confirms the adage, "Patience is a virtue."[/QUOTE]
Or as we Romanians say, any kick in the butt is a step ahead...

Waiting for more nicer photos...

[QUOTE=LaurV;524270]Or as we Romanians say, any kick in the butt is a step ahead... [/QUOTE]
Must add this to my repeartoire

[QUOTE=xilman;524255]
Selected chunks of the FITS headers answer your question and a few more besides.
[/QUOTE]

Excellent- thanks. I don't know why, but seeing the technology available to the non-professional astronomer is genuinely heart-warming. And your note about HVGC-1 is fascinating; have to read up on that.

Norm