Messier 110

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Graeme
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Messier 110

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A satellite galaxy of the Andromeda galaxy.

M110 Autosave-s.jpg

I tried capturing a 4 panel mosaic to show a chunk of the Andromeda galaxy to give perspective and be arty but that didn't come together! So this is just M110 on it's own. It looks like an image gradient on the bottom right but that is the outer edge of M110's big sister!

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Graeme
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HansV
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Re: Messier 110

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Wow! Great picture, very detailed!
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Rudi
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Re: Messier 110

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I may have missed your technique, but are you sticking your cellphone's camera up against the eyepiece of a heavy duty backyard telescope? :tongue:
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Re: Messier 110

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Graeme wrote:
28 Oct 2020, 07:37
I tried capturing a 4 panel mosaic to show a chunk of the Andromeda galaxy to give perspective and be arty but that didn't come together! So this is just M110 on it's own. It looks like an image gradient on the bottom right but that is the outer edge of M110's big sister!
Hi Graeme.
Wikipedia shows an image of Andromeda with M110 to the bottom right.
I understand that you were trying for a shot than included part of Andromeda, but settled instead for M110 alone.

Please and thank you: what do you mean by " an image gradient on the bottom right "?

I stare at your image and can't see anything out of the ordinary (to my uneducated stare).
I see a galaxy and a background of stars of various apparent strengths.

Please and thank you: Is that white dot in the centre of M110 the bright centre of the galaxy, or a star from our galaxy that just happened to be aligned with M110?


Thanks
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stuck
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Re: Messier 110

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Rudi wrote:
28 Oct 2020, 09:23
..are you sticking your cellphone's camera up against the eyepiece of a heavy duty backyard telescope?
Not exactly. Graeme will give full detail but he has a dedicated 'astro camera' mounted on a good telescope, which is fitted with a gizmo that makes it track the stars as the earth rotates. That means he can capture multiple images that all all align and so can be stacked on top of each other, which in turn gives a composite image with a high signal to noise ratio.

Ken

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Re: Messier 110

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HansV wrote:
28 Oct 2020, 08:40
Wow! Great picture, very detailed!

Thanks
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Re: Messier 110

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Rudi wrote:
28 Oct 2020, 09:23
I may have missed your technique, but are you sticking your cellphone's camera up against the eyepiece of a heavy duty backyard telescope? :tongue:

No, I'm sticking an astro camera on the back of a Schmitt Cassegrain Telescope in place of an eye piece.

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Re: Messier 110

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Great, great image, Graeme.

I'm envious of your great equipment and your clear, dark skies.

Please, continue to share your work.
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Re: Messier 110

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ChrisGreaves wrote:
28 Oct 2020, 12:34
Hi Graeme.
Wikipedia shows an image of Andromeda with M110 to the bottom right.
I understand that you were trying for a shot than included part of Andromeda, but settled instead for M110 alone.

Please and thank you: what do you mean by " an image gradient on the bottom right "?

I stare at your image and can't see anything out of the ordinary (to my uneducated stare).
I see a galaxy and a background of stars of various apparent strengths.

The version of the image I posted is quite a low resolution. Light pollution causes an astro image to be lighter on the side nearest the horizon in a gradual gradient as a function of the level of light pollution and the elevation of the target. It can be processed out in Photoshop. This image, in the full resolution version, shows a similar effect slightly but it's not light pollution, it's the outer edge of the mighty Andromeda galaxy.

Here's a screen dump from the excellent Stellerium, the darker bit at the bottom is Amdromeda:

Capture.JPG
ChrisGreaves wrote:
28 Oct 2020, 12:34
Please and thank you: Is that white dot in the centre of M110 the bright centre of the galaxy, or a star from our galaxy that just happened to be aligned with M110?

Good one! It's the core of the galaxy that's been slightly over processed. Big sis has two magnitude 8 stars as you describe. M110 just has one magnitude 14 Milky Way star off centre from the line of sight of the core. M110 is an elliptical galaxy with no black hole at the centre, unusual on both counts for a satellite galaxy.
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Re: Messier 110

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stuck wrote:
28 Oct 2020, 14:08
Rudi wrote:
28 Oct 2020, 09:23
..are you sticking your cellphone's camera up against the eyepiece of a heavy duty backyard telescope?
Not exactly. Graeme will give full detail but he has a dedicated 'astro camera' mounted on a good telescope, which is fitted with a gizmo that makes it track the stars as the earth rotates. That means he can capture multiple images that all all align and so can be stacked on top of each other, which in turn gives a composite image with a high signal to noise ratio.

Ken

Thanks Ken

The mount that sits between the tripod and the telescope is aligned with the earth's rotation and slews in right ascension at the same rate. With a field of view of arc minutes it's not possible to align accuratly enough to stay on target for a long duration camera exposure so in addition there is a guide scope on top of the telescope with another camera on the end of it. An excellent (and free) piece of software called PHD2 locks onto a star, any star and keeps the telescope on target by gently nudging when it drifts off course.

This image is just 5 x 180 second exposures because I spent a lot of time trying to set up the futile four panel mosaic and it was a school night! Then you have to take dark frames, identical to the image frames with the lens cap on. This data is subtracted in the stacking process to remove sensor noise. Then there's flat frames and dark flat frames but I'm starting to ramble now! :smile:
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Re: Messier 110

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BobH wrote:
28 Oct 2020, 18:20
Great, great image, Graeme.

I'm envious of your great equipment and your clear, dark skies.

Please, continue to share your work.

Thanks Bob

I'm quite pleased with the telescope too! I saved up for 40 years for it and bought it out of my company pension money!

Thanks everyone for the interest.

Regards

Graeme
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Re: Messier 110

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Graeme wrote:
28 Oct 2020, 18:43
ChrisGreaves wrote:
28 Oct 2020, 12:34
Please and thank you: Is that white dot in the centre of M110 the bright centre of the galaxy, or a star from our galaxy that just happened to be aligned with M110?
Good one! It's the core of the galaxy that's been slightly over processed. Big sis has two magnitude 8 stars as you describe. M110 just has one magnitude 14 Milky Way star off centre from the line of sight of the core. M110 is an elliptical galaxy with no black hole at the centre, unusual on both counts for a satellite galaxy.

Chris

I was just looking again. There does appear to be a line of sight star at the centre of M110 in my image. Stellarium displays stars down to a magnitude of 16. It it might be a 16.x or dimmer. I'll endeavour to find out.

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Re: Messier 110

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Graeme wrote:
28 Oct 2020, 18:43
The version of the image I posted is quite a low resolution. Light pollution causes an astro image to be lighter on the side nearest the horizon in a gradual gradient as a function of the level of light pollution and the elevation of the target. It can be processed out in Photoshop. This image, in the full resolution version, shows a similar effect slightly but it's not light pollution, it's the outer edge of the mighty Andromeda galaxy.
Thank you Graeme.
Two related questions:

(1) "Light pollution causes an astro image to be lighter on the side nearest the horizon in a gradual gradient as a function of the level of light pollution and the elevation of the target" means that we as earth-bound observers may detect light pollution at the lower edge from earthly pollution sources, such as a nearby city some 20 miles away, but just over the horizon. We may not detect that light pollution with the naked eye, but a time-exposure will accentuate whatever faint light there is. (And an experienced astronomer will recognize it, whereas someone like me will be focused on the galaxy in the centre of the image)

(2)"the outer edge of the mighty Andromeda galaxy." which is below and a bit to the right of the M110 image you posted originally. Then I might say "Andromeda" is off-stage, to the SSE of M110," or even "there is a detectable brightness running from NNW towards SSE across the entire image". In this case the off-stage Andromeda is behaving like my distant city in my first supposition.


ChrisGreaves wrote:
28 Oct 2020, 12:34
Good one! It's the core of the galaxy that's been slightly over processed. Big sis has two magnitude 8 stars as you describe. M110 just has one magnitude 14 Milky Way star off centre from the line of sight of the core. M110 is an elliptical galaxy with no black hole at the centre, unusual on both counts for a satellite galaxy.
Two more related questions:

(3) OK, so it's not really good, but close. I had not really expected to be able to "see" a single star at the centre of any galaxy. But what I am seeing is (a) a long-time-exposure of (b) perhaps a thousand stars which are roughly at the centre of the M110 galaxy. I'd see the same thing if I took a time-exposure of ten automobiles cresting a hill some ten miles away on the far side of the valley floor.

(4) "M110 just has one magnitude 14 Milky Way star off centre from the line of sight of the core" and again, since I do not expect to see a single star from Our Galaxy against the core of M110, the time exposure has bundled the light from that one star with the (tens of? thousands of stars at the core of M110 and my eyes see a single bright spot, which is my one plus a thousand light sources bundled into a single bright dot. Is that close to what is happening? That would be like my ten cars ten miles away being bundled with a single diesel locomotive two miles away, all eleven vehicles coaslescing into a single light source (as seen by the camera, and hence by us)?

I don't know now whether I wish I'd gone into astronomy instead of computers fifty years ago. I suspect that I could have done Astronomy and indulged in computers on the side! I used to write in FORTH.

OK, one more:
(5) For all of our sakes, is a "magnitude 14" star brighter (to our human eyes) than a "magnitude 8" star? And regardless of direction, is this an exponential or logarithmic scale, like decibels and earthquakes?


Graeme, thanks for your explanations.
I have pretty well used up my electron quota so I'll stop here (grin)
Chris
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Re: Messier 110

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Re: (5)

See Magnitude (astronomy). It's a logarithmic scale, and lower means brighter.
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Re: Messier 110

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HansV wrote:
28 Oct 2020, 19:41
Re: (5) See Magnitude (astronomy). It's a logarithmic scale, and lower means brighter.
"Stellar absolute magnitudes are usually designated with a capital M with a subscript to indicate the passband. For example, MV is the magnitude at 10 parsecs in the V passband. A bolometric magnitude (Mbol) is an absolute magnitude adjusted to take account of radiation across all wavelengths; "

Thanks Hans.
That answers my question about whether Computing was the right choice; it sounds much easier!

So Graeme's mag 14 star at the centre of M110 is much, much fainter than either of the two Mag 8s in Andromeda.

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Re: Messier 110

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Chris

1) It would be great to live in a place where light pollution is not detectable to the naked eye. That would be a Bortle 1 sky. I live in a Bortle 4/5 area. It's all around. I have London to my West!

2) In that case I have light pollution in the image!

3) Possibly a star that Stellerium is not displaying. See post 12 above.

4) Probably doable. A magnitude 16 star in front of a bunch of stars who's magnitude is reduced by the square of the distance at a distance of 2.5 million light years? I don't know much about cars.

5) Vega magnitude is about 0. Most stars are dimmer than that so a higher number. At a dark site we can see to magnitude 5 or 6. Sirius is 1.46. Venus gets up to 4 and a bit. Thankfully our eyes have logarithmic sensors!
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Re: Messier 110

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Sirius and Venus have negative magnitude!
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Re: Messier 110

Post by Graeme »

HansV wrote:
28 Oct 2020, 20:32
Sirius and Venus have negative magnitude!

Yes. Oops!

The Sun is -26.74

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Re: Messier 110

Post by Rudi »

Thanks Ken and Graeme. :cheers:
Just needed to fill in that gap.
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Re: Messier 110

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Graeme wrote:
28 Oct 2020, 07:37
A satellite galaxy of the Andromeda galaxy.
Slightly on-topic for a change (it won't last!), The Guardian Science (podcast) has two episodes in which they conduct a thought experiment of what it would be like to descend (?!!???) into a black hole.
I learned something new.
(1) All black holes are identical in the sense that all electrons are identical.
(2) Black holes don't exist in a place; they exist in a time (I think I got that right)

Journey into a black hole: part 1 – podcast

Journey into a black hole: part 2 – podcast

Cheers
Chris
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