Starship Asterisk*

Ann wrote: ↑Tue Oct 15, 2019 2:24 am

MarkBour wrote: ↑Mon Oct 14, 2019 6:58 pm

Ann wrote: ↑Mon Oct 14, 2019 2:13 pm
That's exactly what M31 looked to me back in 1972(?), except that the core of the galaxy was yellowish!

I'm just glad that as a child, your reaction to the backyard viewing of Andromeda through a small telescope was one of wonder and careful observation, as opposed to "Mom[Dad], it's too cold out here. I want to go inside."

I didn't use a telescope. We had nothing of the sort. I had spread a blanket on the cold snowy ground and lay flat on it, scanning the sky with my parents' moderate-sized binoculars. It took many years before I saw the Andromeda galaxy again, and then it was all gray. I have never seen color in it again.

Boomer12k wrote: ↑Mon Oct 14, 2019 9:38 pm It usually takes SOME processing to get a good, or better image... My M27. The dingy one is the original...the other was photoshop with auto contrast, auto color, auto level...taken with my 10" Meade LX 200 in 2012... 40 frames or so...maybe around 30 seconds each.

Even Astrophotoger, Tony Hallis, said, "Wow!"...he helped with some suggestions.

You want to see details... you need photography... you want a better image to see... you need processing...you want better images...you need a better CAMERA...

It can be quite the hobby...
:---[===] *

MarkBour wrote: ↑Mon Oct 14, 2019 6:58 pm

Chris Peterson wrote: ↑Mon Oct 14, 2019 2:41 pm

Ann wrote: ↑Mon Oct 14, 2019 2:40 pm

All I can say is that I had no expectations whatsoever as to what Andromeda would look like. I was startled and delighted by the pale yellowish color. Not that I wouldn't have loved it even better if the color had been blue, but my point is, I didn't expect any color but I did see it. And I didn't know back then that galaxies typically have yellow cores.

You say I didn't see the yellow color of the center of Andromeda. I say I did.

I suspect you have atypical color vision.

I'm just glad that as a child, your reaction to the backyard viewing of Andromeda through a small telescope was one of wonder and careful observation, as opposed to "Mom[Dad], it's too cold out here. I want to go inside."

MarkBour wrote: ↑Mon Oct 14, 2019 7:17 pm

keesscherer wrote: ↑Mon Oct 14, 2019 7:38 am The 223 Luminance images with 300 second exposure where made between 12 nov 2018 and 4 oct 2019. I make around 12 images per night when there is no Moon above the horizon and M31 is at least at 30 degrees altitude. For each night i make a stack and use that stack to do a blink comparison with a reference stack to find novae in M31. And so after a while you end up with a lot of subs and every now and then i make a stack with all the collected subs. To find Asteroids i also make stacks without "sigma clipping". The Asteroid will show up as a short line, there is 1 in the middle top in this image, just below the letter "c" of "October". It is Asteroid 334168 ST119 imaged on 4 october 2019 (6.3km diameter, magnitude 20.8). The image featured here showed a nice airplane/ Satellite trail frame around M31.

I really like this APOD! Shows a little of what's involved. And it's especially nice that Kees is answering questions here. Thanks for explaining and pointing out that asteroid line. If you go further to the right, still very near the top of the image, there is another, longer, line segment, but it bulges in the middle and both tails are fine points. I'm guessing that was a meteor, is that right?

keesscherer wrote: ↑Mon Oct 14, 2019 7:38 am The 223 Luminance images with 300 second exposure where made between 12 nov 2018 and 4 oct 2019. I make around 12 images per night when there is no Moon above the horizon and M31 is at least at 30 degrees altitude. For each night i make a stack and use that stack to do a blink comparison with a reference stack to find novae in M31. And so after a while you end up with a lot of subs and every now and then i make a stack with all the collected subs. To find Asteroids i also make stacks without "sigma clipping". The Asteroid will show up as a short line, there is 1 in the middle top in this image, just below the letter "c" of "October". It is Asteroid 334168 ST119 imaged on 4 october 2019 (6.3km diameter, magnitude 20.8). The image featured here showed a nice airplane/ Satellite trail frame around M31.

Chris Peterson wrote: ↑Mon Oct 14, 2019 2:41 pm

Ann wrote: ↑Mon Oct 14, 2019 2:40 pm

Chris Peterson wrote: ↑Mon Oct 14, 2019 2:27 pm

Telescopically, the core of M31 isn't bright enough to stimulate color vision. So your impression of color was coming from your brain, not from the galaxy.

All I can say is that I had no expectations whatsoever as to what Andromeda would look like. I was startled and delighted by the pale yellowish color. Not that I wouldn't have loved it even better if the color had been blue, but my point is, I didn't expect any color but I did see it. And I didn't know back then that galaxies typically have yellow cores.

You say I didn't see the yellow color of the center of Andromeda. I say I did.

I suspect you have atypical color vision.

Chris Peterson wrote: ↑Mon Oct 14, 2019 2:41 pm

Ann wrote: ↑Mon Oct 14, 2019 2:40 pm

Chris Peterson wrote: ↑Mon Oct 14, 2019 2:27 pm
Telescopically, the core of M31 isn't bright enough to stimulate color vision. So your impression of color was coming from your brain, not from the galaxy.

All I can say is that I had no expectations whatsoever as to what Andromeda would look like. I was startled and delighted by the pale yellowish color. Not that I wouldn't have loved it even better if the color had been blue, but my point is, I didn't expect any color but I did see it. And I didn't know back then that galaxies typically have yellow cores. You say I didn't see the yellow color of the center of Andromeda. I say I did.

I suspect you have atypical color vision.

Ann wrote: ↑Mon Oct 14, 2019 2:40 pm

Chris Peterson wrote: ↑Mon Oct 14, 2019 2:27 pm

Ann wrote: ↑Mon Oct 14, 2019 2:13 pm

I love it! That's exactly what M31 looked to me back in 1972(?), except that the core of the galaxy was yellowish! :D

Telescopically, the core of M31 isn't bright enough to stimulate color vision. So your impression of color was coming from your brain, not from the galaxy.

All I can say is that I had no expectations whatsoever as to what Andromeda would look like. I was startled and delighted by the pale yellowish color. Not that I wouldn't have loved it even better if the color had been blue, but my point is, I didn't expect any color but I did see it. And I didn't know back then that galaxies typically have yellow cores.

You say I didn't see the yellow color of the center of Andromeda. I say I did. :wink:

Chris Peterson wrote: ↑Mon Oct 14, 2019 2:27 pm

Ann wrote: ↑Mon Oct 14, 2019 2:13 pm

keesscherer wrote: ↑Mon Oct 14, 2019 1:21 pm

The "before" and "after" images are made with the same data, but both have to be stretched so that the histogram fits the brightness levels from 0 to 1.
An unstretched image looks like the one attached, only the core of M31 is visible, the rest is way too dark.
M31-unstretched.jpgThe levels in both images are different to begin with including background level. With both histrogram stretches i have tried to make the backgroundlevels equal as much as possible so "the mouse over" would not flicker too much. I did not match all the other levels as i wanted to keep the processing to a minimum.

I love it! That's exactly what M31 looked to me back in 1972(?), except that the core of the galaxy was yellowish!

Telescopically, the core of M31 isn't bright enough to stimulate color vision. So your impression of color was coming from your brain, not from the galaxy.

Chris Peterson wrote: ↑Mon Oct 14, 2019 1:53 pm

GeoX wrote: ↑Mon Oct 14, 2019 1:17 pm
Silly question I guess but
are we looking at the “top” of the galaxy or the “bottom”?

Galaxies don't have "tops" and "bottoms".

Ann wrote: ↑Mon Oct 14, 2019 2:13 pm

keesscherer wrote: ↑Mon Oct 14, 2019 1:21 pm

E Fish wrote: ↑Mon Oct 14, 2019 12:59 pm It seems to me that the central bulge gets brighter in the after image and the disk is more defined. Did you also remove atmospheric distortions?

The "before" and "after" images are made with the same data, but both have to be stretched so that the histogram fits the brightness levels from 0 to 1.
An unstretched image looks like the one attached, only the core of M31 is visible, the rest is way too dark.
M31-unstretched.jpgThe levels in both images are different to begin with including background level. With both histrogram stretches i have tried to make the backgroundlevels equal as much as possible so "the mouse over" would not flicker too much. I did not match all the other levels as i wanted to keep the processing to a minimum.

I love it! That's exactly what M31 looked to me back in 1972(?), except that the core of the galaxy was yellowish! :D

keesscherer wrote: ↑Mon Oct 14, 2019 1:21 pm

E Fish wrote: ↑Mon Oct 14, 2019 12:59 pm It seems to me that the central bulge gets brighter in the after image and the disk is more defined. Did you also remove atmospheric distortions?

The "before" and "after" images are made with the same data, but both have to be stretched so that the histogram fits the brightness levels from 0 to 1.
An unstretched image looks like the one attached, only the core of M31 is visible, the rest is way too dark.
M31-unstretched.jpgThe levels in both images are different to begin with including background level. With both histrogram stretches i have tried to make the backgroundlevels equal as much as possible so "the mouse over" would not flicker too much. I did not match all the other levels as i wanted to keep the processing to a minimum.

GeoX wrote: ↑Mon Oct 14, 2019 1:17 pm Silly question I guess but are we looking at the “top” of the galaxy or the “bottom”?

E Fish wrote: ↑Mon Oct 14, 2019 12:59 pm It seems to me that the central bulge gets brighter in the after image and the disk is more defined. Did you also remove atmospheric distortions?

De58te wrote: ↑Mon Oct 14, 2019 12:22 pm Hi Kees. Nice photo. About the disappearing "stars". I noticed by flipping between the regular photo and the "annotated" photo that there are about seven or eight "stars" that vanish, and they are all in a straight line parallel to the lines on the left. Also most appear to be the same, a bright point of light with a dimmer companion on the left. They may be the same object. However with an exposure time of five minutes they likely aren't planes, but more distant Earth objects. Could they be artificial satellites or even a passing asteroid?

saturno2 wrote: ↑Mon Oct 14, 2019 4:33 am I like me M31 in full color !!