Soul Nebula with a new scope Skywatcher Evostar ED72 (thanks FLO)

[carastro]

I decided to buy the Skywatcher Evostar ED72 to replace my WOZS71 as I could never do anything about the tilt from the two bolt drawtube system holding on the camera and filterwheel.  With my other Skywatcher scopes I fitted a Baader click lock which screws in and squeezes the camera tight and I eliminated tilt in these scopes with this method.  I am sure there are tilt adjusters, but since I change my kit around and disassemble it to go to Astro camps regularly, I did not want to have to keep fiddling with that.  There was no way of fitting a Baader click lock onto the WO scope, so I decided it was time to change the scope.

The ED72 has some other features I prefer too, so have been testing it out over the last week.

This is the Soul Nebula taken from Bortle 7/8 skies in SE London

Skywatcher ED72 and Atik460EX
Taken over 2 nights with Baader ultranarrowband filters.
Ha 30 x 600
Oiii 15 x 300 binned x 2
Sii 15 x 300 binned x 2
Total imaging time 7 1/2 hours - taken over 2 nights.

 

I am not a fan of the latest trend of removing most of the stars in an image but getting rid of the 1000s of really tiny ones can make for a cleaner image.

Her is a version I did with some star reduction.  Which do you prefer?

Edited October 9, 2022 by carastro

[AstroGS]

4 minutes ago, carastro said:

I decided to buy the Skywatcher Evostar ED72 to replace my WOZS71 as I could never do anything about the tilt from the two bolt drawtube system holding on the camera and filterwheel.  With my other Skywatcher scopes I fitted a Baader click lock which screws in and squeezes the camera tight and I eliminated tilt in these scopes with this method.  I am sure there are tilt adjusters, but since I change my kit around and disassemble it to go to Astro camps regularly, I did not want to have to keep fiddling with that.  There was no way of fitting a Baader click lock onto the WO scope, so I decided it was time to change the scope.

The ED72 has some other features I prefer too, so have been testing it out over the last week.

This is the Soul Nebula taken from Bortle 7/8 skies in SE London

Skywatcher ED72 and Atik460EX
Taken over 2 nights with Baader ultranarrowband filters.
Ha 30 x 600
Oiii 15 x 300 binned x 2
Sii 15 x 300 binned x 2
Total imaging time 7 1/2 hours - taken over 2 nights.

 

Great image - well done! This is the proof that a good image does not need £££££ of an investment on equipment. Really great skills here.

[assouptro]

Lovely first light Carole and a great advert for the ED72

You’ve framed it really well and I love the dark bok globule detail around the “eye” 

Thanks for sharing 

Bryan 

Edited October 8, 2022 by assouptro
typo

[Rodd]

Wow. Very nice.  

[Varavall]

On 08/10/2022 at 14:46, carastro said:

Her is a version I did with some star reduction.  Which do you prefer?

The first image without star reduction. Some brightness/contrast in the nebulosity is lost with the star reduction, well at least to my old eyes 🥺

[Xiga]

Very nice indeed Carole. I love those gold and cyans! 

I think you could safely lower the black point a tad more, just to darken the sky background and help the nebula stand out a bit more. 

ps - I prefer the one without the star reduction. It looks like this was shot with a narrow bandpass Ha filter, is that right? I've found that since getting one of the 3.5nm Baader Ha filters, i now usually only need to do a very small amount of star reduction. 

[geeklee]

On 08/10/2022 at 13:46, carastro said:

Her is a version I did with some star reduction.  Which do you prefer?

Both really nice images Carole with loads of detail and lovely palette.

Like many others I prefer the first image - stars / star count looks great.  The ultra narrow band filters do such a good job of this, as mentioned by some others.

[barbulo]

Good job @carastro

I also prefer the first one. Not an excesive amount of stars.

Thinking about buying a refractor some day, I keep looking forward to see more from that ED72. Did you use FF/FR? Did you find any trouble in managing stars colours during processing? 

[teoria_del_big_bang]

New scope serving you well I see, that is another great image (or images).
For me there is not much in it but if I were pushed I too would probably say the image without star reduction is the better of the two.

I have not had a clear sky since coming back from Kelling (and didn't see much there either - maybe it's just me 🙂 

Steve

Edited October 11, 2022 by teoria_del_big_bang

[carastro]

51 minutes ago, barbulo said:

Did you find any trouble in managing stars colours during processing

Not really as these are narrowband stars.  Never a true colour anyway. 

Yes l used a x 0.8 focal reducer. 
 

Carole

Edited October 11, 2022 by carastro

[carastro]

50 minutes ago, teoria_del_big_bang said:

I have not had a clear sky since coming back from Kelling (and didn't see much there either - maybe it's just me 🙂 

Oh dear Steve.  Yes this is the telescope  l was after at Kelling had to buy it new in the end.  Also have a prospective buyer for the WO scope. 
 

Interesting that you all prefer the one without the star reduction since that seems to be the latest “fad” by image processors.  But good to know.  
 

Carole

Edited October 11, 2022 by carastro

[teoria_del_big_bang]

17 minutes ago, carastro said:

Oh dear Steve.  Yes this is the telescope  l was after at Kelling had to buy it new in the end.  Also have a prospective buyer for the WO scope. 
 

Interesting that you all prefer the one without the star reduction since that seems to be the latest “fad” by image processors.  But good to know.  
 

Carole

When all the star removal tools appeared (or at least good working versions) I think there was a glut of actual starless images appearing but to be honest it didn't really seem to last that long as they were different but do look so unnatural.
However, I do think star removal does have a place in processing for a few reasons. These are things I have read about and have been trying so it maybe there are other ways, or maybe better ways to do the same thing as I am still learning all this 🙂 

• Some images of nebula are swamped with stars and that does detract from the main target image and so some star reduction does help the final image (in my opinion). But for me even your image without any star reduction is not swamped by stars and looks perfectly natural and can still see the target.
• Some images with feint contribution from one, or more, of the filters, need quite some stretching to bring out the detail and it can help to separate the  stars early on in the processing and add them back later to prevent the stars becoming saturated as an alternative to star masks.
• For NB images there is the opportunity to remove the unnatural colour stars if you managed to take some short RGB images just to capture the stars, and then use tose to add to the image instead.
• I also have used star removal on the luminance to bring out the detail of the nebula without swamping the stars.

I think the latest star removal tools seem pretty good at not leaving artefacts on most images,.
As I say this is very much my thoughts and these may not be the best way to achieve what I am after so would be happy for others to educate me 🙂 

Steve    

Edited October 11, 2022 by teoria_del_big_bang

[carastro]

I agree Steve, star reduction does help to reveal the detail in the nebula, but sometimes I think this is overdone.,

Carole 

[alacant]

4 hours ago, carastro said:

star reduction does help to reveal the detail in the nebula, but sometimes I think this is overdone

We see so many images with so few stars, they look unreal. So much texture and context is lost without them. It's such a pity that star removal seems to have become a routine part of processing.

If you really must, a big +1 for @carastro's take on this; don't over do it!

Cheers

 

Edited October 11, 2022 by alacant
spell

[teoria_del_big_bang]

1 hour ago, carastro said:

I agree Steve, star reduction does help to reveal the detail in the nebula, but sometimes I think this is overdone.,

Carole 

Totally agree.
But I think THIS great image just posted by @gorann is a good example of what I mean by some images being swamped with stars and the starless approach (albeit just during the processing not the final image) really helps.

But having said that @alacant has a point and I guess the amount of star reduction is down to personal taste but as with a lot of things in processing often subtle changes can give better results.

Steve
 

Edited October 11, 2022 by teoria_del_big_bang

[ollypenrice]

I like both your images, Carole, and don't think there is a clear winner. However, narrowband stars are small and tight anyway and the nebulae more structurally defined than in broadband. This means that NB images are in less need of star control for two very significant reasons. It's in broadband images that the separation of stars from nebula comes into its own by allowing far more decisive processing.   I don't see the new technique as being only, or even primarily, about reducing star size. Rather, it's about enabling a more assertive processing of the rest of the image, a processing which would damage the stars or cause them to become oppressive. It is so much easier to enhance local contrasts (to borrow a term from Noel ) with the stars removed.

2 hours ago, alacant said:

We so many images with so few stars, they look unreal. So much texture and context is lost without them. It's such a pity that star removal seems to have become a routine part of processing.

If you really must do it, a big +1 for @carastro's take on this; don't over do it!

Cheers

 

Perhaps they look unreal because we're used to seeing large stars which are, in fact, simply an artifact of the imaging system?  To my eye a nebula looks far more real when it it not obscured by a bombardment of stars.  Small stars in images have been with us for a very long time, of course. The technique for creating them was and is simple but expensive: use a multiple metre telescope with minute spot sizes. Do the professional images with small stars look unreal?  Not to my eye. But, sure, like any technique it needs to be used sympathetically.

I also think it's a wonderful technique for budget or portable imagers since it allows small telescopes to create the large telescope look. It also transforms camera lens images, the star size being the perennial give-away with lens shots. A Samyang 135 goes from good to astounding to my mind.

I used to envy the NB imagers their tiny stars and strong local contrasts. Now I feel I'm entering this territory in broadband.

Olly

Edited October 11, 2022 by ollypenrice
Typo

[Skyline]

The images are very deep, this I would want to image with my EVO62, just dealing with stupid problems atm. Its nice to see people imaging with affordable equipment.

[jjohnson3803]

They're both fabulous pix.  I lean just a smidge toward the reduction.

[mackiedlm]

Both great images Carole and I dont think either is significantly better. If really pressed I would go for the second with the reduced smaller stars.

I agree with others that starless images are not for me. I think your image above does not really benefit much from the star reduction because the stars are not overly intrusive in the first place,

But take an RGB image of, say, the veil nebula, and it becomes difficult to appreciate the detail and beauty of the filaments because there are stars everywhere. In that case star reduction really improves the final image in my eye. But, as has been stated - in moderation.

But the real value of star removal (as already shown by Olly and Gorann) is the ability to remove stars, process the nebula, replace stars and then reduce the stars a little,.

 

David