M45 - Glowing Gems

[Galen Gilmore]

I finally got a good image since my M42 I did nearly 4 months ago. An here is how it turned out.

M45 - The Pleadies

41 x 2m subs

10 darks

15 flats

15 bias

Orion Imaging LP filter

orange-yellow zone

Overall I am very happy with the result, especially after a lot of previous M45 fails. It also has the longest integration time for a photo that I have done so far at 1h 22m.

I also used a new (for me) processing technique to remove the intense gradient in the original image.

I need some tips on how to control bright stars, because in this image they are clearly blowing out of proportion. Small ones also look strange as they have these tiny little diffraction spikes compared to their size.

Any other constructive criticism is always welcome. 

[Demonperformer]

1 hour ago, Galen Gilmore said:

Small ones also look strange as they have these tiny little diffraction spikes compared to their size.

My personal opinion is the smaller the better.

Nice image.

[Galen Gilmore]

16 minutes ago, Demonperformer said:

My personal opinion is the smaller the better.

Nice image.

Sorry I meant to say that the dimmer stars (i.e. smaller in comparison to the brightest 7) look odd.

thanks

[Demonperformer]

Yes, but I would approach it the other way round. Personally, I really dislike diffraction spikes on stars and would seek a way to reduce those on the brightest stars rather than worry about the ones on the dimmer stars being too small. Just my personal opinion.

Which in no way should be seen as a diminution of my other comment that it is a nice image. You have captured a lot of very faint stars in it.

[tooth_dr]

I like that a lot. I’d say what I miss most when imaging with a refractor is the diffraction spikes. I really like them.

It looks a little black on my screen, perhaps you have clipped the bottom end of the histogram and have lost some of the faint nebulosity?

Great job though. 

[Galen Gilmore]

1 minute ago, tooth_dr said:

I like that a lot. I’d say what I miss most when imaging with a refractor is the diffraction spikes. I really like them.

It looks a little black on my screen, perhaps you have clipped the bottom end of the histogram and have lost some of the faint nebulosity?

Great job though. 

I did clip the histogram, but I had a lot of leftover noise from the gradient elimination. It's possible that I did also cut out some fainter nebulosity in doing so.

[tooth_dr]

4 minutes ago, Galen Gilmore said:

I did clip the histogram, but I had a lot of leftover noise from the gradient elimination. It's possible that I did also cut out some fainter nebulosity in doing so.

Can you post the original stack? How bad is the gradient if you are using a LP filter?

[MarsG76]

Nice Pleiades

 

[Galen Gilmore]

5 minutes ago, tooth_dr said:

Can you post the original stack? How bad is the gradient if you are using a LP filter?

The gradient was pretty bad. Top left corner was pitch black, whereas the bottom left was as bright as the nebulosity.

I will post the original stack tomorrow as it is 1:30 AM where I live.

[cuivenion]

Hi, nice image. I think you may have clipped the black point during processing so you're missing some nebulosity that would otherwise be in the image. It can be difficult dealing with a severe gradient though.

[wookie1965]

Stunning 

[Galen Gilmore]

Hi @cuivenion, @tooth_dr.

These are the original stacks with no processing done, the first one has the RGB channels aligned, the second one doesn't.

Pleadiesstack3.TIF

Pleadiesstack4.TIF

[cuivenion]

Here's my take on your data using Pixinsight. That was a severe gradient, almost like a full moon:

I couldn't really pull out more nebulosity than you have. Process was:

Crop-DBE-multiscale linear transform-autohistogram-histogram transformation-curves transformation-unsharp mask-colour saturation.

Lots of people round here with more experience than me so I'm sure some of them could have a look. Was fun playing with your data, I tried the same target but the stars were terrible (guiding problems).

 

[Galen Gilmore]

27 minutes ago, cuivenion said:

Here's my take on your data using Pixinsight. That was a severe gradient, almost like a full moon:

I couldn't really pull out more nebulosity than you have. Process was:

Crop-DBE-multiscale linear transform-autohistogram-histogram transformation-curves transformation-unsharp mask-colour saturation.

Lots of people round here with more experience than me so I'm sure some of them could have a look. Was fun playing with your data, I tried the same target but the stars were terrible (guiding problems).

 

Thanks, your go defiantly has more subtle nebulosity than mine does, less noisy as well. 

[alexbb]

I had a go on your data, you have some signal there, but I think you might try to get some better flats (with a white t-shirt and pointing to an uniform area of the sky maybe), put some sort of a hood in front of the scope if you have lights around and shield your scope's back (if you didn't) to prevent stray light from coming from behind - for all subs - lights, darks, bias, flats. You have some gradient which I couldn't really get out, it has a weird pattern. If you didn't take the camera off the scope, you can still try reshooting some flats.

Other than this, nice image, your stars look good. Keep shooting  

Alex

[Galen Gilmore]

6 minutes ago, moise212 said:

I had a go on your data, you have some signal there, but I think you might try to get some better flats (with a white t-shirt and pointing to an uniform area of the sky maybe), put some sort of a hood in front of the scope if you have lights around and shield your scope's back (if you didn't) to prevent stray light from coming from behind - for all subs - lights, darks, bias, flats. You have some gradient which I couldn't really get out, it has a weird pattern. If you didn't take the camera off the scope, you can still try reshooting some flats.

Other than this, nice image, your stars look good. Keep shooting  

Alex

Wow, thank you. It looks really nice now, thanks.

I took flats by putting a white t-shirt over my scope and a laptop with a blank white screen. Although the t-shirt wasn't secured very well.

[geordie85]

I had a little play with your RGB aligned data.

I didn't do much just a slight crop, a few runs of gradient xterminator, 1 run of AstroFlats Pro and a bit of saturation boost and noise removal.

[Grumpy_Git]

On 19/02/2018 at 07:31, MarsG76 said:

Nice Pleiades

 

Is that a come on? 

 

I really like this picture, I don't image but I am soaking up an awful lot of comments and knowledge while lurking.

 

My only comment on the image is that you have caught so many faint stars it seems like you have closed in to far and it's a shame there isn't more "space" around the pleiades.

 

Nick

[MarsG76]

34 minutes ago, Grumpy_Git said:

Is that a come on? 

hahahah... 

[MarsG76]

41 minutes ago, Grumpy_Git said:

Is that a come on? 

Who wouldn't??... the Pleiades sisters are hot...

[Grumpy_Git]

All 7 of them?