17 replies to this topic

[Thomas A Davis]

Took this tonight. This is a really rough image, and I have to fix a balance issue causing tracking issues before continuing. There is an obvious star in the core of the galaxy M90 not there in earlier images.  Check it out. No reports of it on the internet.  It shows in 5 second exposures.

EdgeHD 8 at F/10, ASI2600 MC Pro 300 seconds.

 

Tom

 

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[joshman]

I think that's just the core of the galaxy.

 

Many images on Astrobin show it has a very bright, almost star-like, core.

[Thomas A Davis]

Just as a followup.  It is not the galaxy core.  Actually showed, as a star, not the core.  This shot was through a passing cloud, so it does not show what succeeding exposures are now showing.  Looks to be the real deal.  Who needs to be notified?  

I've been doing astronomy since 1962, so not a newbie.

 

Thanks, Tom

[Thomas A Davis]

2 second exposures show it as an obvious star.

[acrh2]

You could post raw data for confirmation. Otherwise people will wonder if you messed something up while stretching.

[Thomas A Davis]

This is an older image taken with my MN190 MakNewt of the galaxy at full resolution.  Yes the core is bright, but not as bright as what I am seeing now with comparable aperture.  Something is going on.

 

Tom

[RichA]

Just as a followup.  It is not the galaxy core.  Actually showed, as a star, not the core.  This shot was through a passing cloud, so it does not show what succeeding exposures are now showing.  Looks to be the real deal.  Who needs to be notified?  

I've been doing astronomy since 1962, so not a newbie.

 

Thanks, Tom

International Astronomical Union?

[Thomas A Davis]

You could post raw data for confirmation. Otherwise people will wonder if you messed something up while stretching.

The image is unstretched.  The MN190 image is unstretched as well.  The first image IS raw data.

[Thomas A Davis]

International Astronomical Union?

Sounds right.  I've never had a 2 second exposure show a galaxy core this brightly.  I certainly would have noticed it in the earlier images I've taken of the galaxy.

 

Thanks, Tom

Edited by Thomas A Davis, 18 May 2025 - 10:40 PM.

[joshman]

Sounds right.  I've never had a 2 second exposure show a galaxy core this brightly.  I certainly would have noticed it in the earlier images I've taken of the galaxy.

 

Thanks, Tom

Can you upload the raw *.fits file somewhere? as well as a comparison files from an earlier imaging session?

[Thomas A Davis]

No, too large.  What I posted was the FITS file converted to a JPEG.  No stretching done to it.  Forget it.  If it is real, someone will post it.  Struck me in the face at 2 seconds how bright and starlike it was.  Long exposures will usually burn in cores.  Take this one of M104 I shot last night.  Sorry I didn't try to mislead anyone.  Stand down.

 

Tom

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Edited by Thomas A Davis, 18 May 2025 - 10:54 PM.

[imtl]

The image is unstretched. The MN190 image is unstretched as well. The first image IS raw data.

I'm sorry but both images look stretched. I think if you want to report this you need the raw files submitted.

Edited by imtl, 18 May 2025 - 11:02 PM.

[TOMDEY]

It's the core of the galaxy... lots of spirals have a bright ~star-like~ core. Even M31 has that. M90 is one that has an unusually bright core. In this case it's your processing and soft focus that just enhances that illusion that it's a single star.   Tom

[Thomas A Davis]

I'm sorry but both images look stretched. I think if you want to report this you need the raw files submitted.

The second image was stacked, not stretched.  The first is as it came off the camera.  I simply converted the RAW FITs file to a JPEG.  Zero stretching.  Not going to argue this. You can not post an 11.7MB FITs file to this group.  I saw a bright starlike object in 2 second subs to start this off.  The first image was shot at F/10 and had a minor tracking issue.  I had to reduce the size of the image to post it, but did not process it.  The two second subs were well focused and sharp.  Never saw any galaxy core this bright and this sharp in a 2 second exposure.  Again, forget it.  Its the core but never looked this bright to me. Sorry, I will not bother anyone here again. I've been imaging for over 40 years, so maybe entitled to one mistake.  Sorry.

Edited by Thomas A Davis, 19 May 2025 - 12:13 AM.

[SoCalPaul]

I know what I think I saw
And what I thought I seen
And what was coming and what was going
And everything in between

 

- Lucinda Williams

 

:-)

[rj144]

The second image was stacked, not stretched.  The first is as it came off the camera.  I simply converted the RAW FITs file to a JPEG.  Zero stretching.  Not going to argue this. You can not post an 11.7MB FITs file to this group.  I saw a bright starlike object in 2 second subs to start this off.  The first image was shot at F/10 and had a minor tracking issue.  I had to reduce the size of the image to post it, but did not process it.  The two second subs were well focused and sharp.  Never saw any galaxy core this bright and this sharp in a 2 second exposure.  Again, forget it.  Its the core but never looked this bright to me. Sorry, I will not bother anyone here again. I've been imaging for over 40 years, so maybe entitled to one mistake.  Sorry.

Post a link to Google Drive or something similar.

[Thomas A Davis]

Finally figured this out.  Very simple answer.  F/10.4 (2120mm focal length on the EdgeHD 8 according to plate solving using my ASIAir Plus) versus F/5,3 with the Mak-Newt.  The core on M90 is so much like a point source (star) that it will have the same brightness regardless of F/Ratio.  The galaxy will be dimmer with a shorter exposure.  The combination of a passing cloud during the first posted exposure and the F/10 issue made the star-like core appear much brighter than the galaxy around it than it would at F/5.3 (by a factor of almost 4X).  Since I've only recently started imaging at F/10, an understandable, but not to be repeated error.  As to posting the FITs, I do not have a Google account, and again, the posted JPEG was a straight conversion from FITs to JPEG without a histogram stretch.  The other posted images were stacked and the M104 definitely stretched. My error, figured it out, we can move on.

 

Thanks, Tom

Edited by Thomas A Davis, 19 May 2025 - 11:03 AM.

[Thomas A Davis]

Here is a final from last night with processing done. Still had a small guiding issue, but better.  As you can see the core looks pretty normal after enough exposure.  Again, sorry for yelling fire in a crowded theater.  The file is cropped and shrunk down from full resolution.

 

Tom

 

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