alan4908

8 hours ago, vlaiv said:

I have an idea.

Looking at the image can be misleading. We don't know what sort of color processing has been done on the image. Was there color management involved and if image is boosted in saturation and such.

Simple intensity measurement in R, G and B channels recorded - raw data, together with camera specification and filter type will be a good starting point to see what sort of color object actually has, and to try to determine something about the spectrum of the light given off by object.

That would give us some idea of what object might be, or at least a clue about the nature of light it is emitting.

If I look at the data at the stages after Pixinsight's DBE (image is linear), Photometric Colour Calbibration (image is linear) and the Final (LRGB non linear) I get these RGB values:

So, this particular green blob has quite a peaky spectrum with respect to the red.  

1 hour ago, Xsubmariner said:

In my early stage of imaging I captured a set of frames for M33 and asked fellow Astronomy members at my society what was causing the two green areas in the image. In the end someone decided it was probably the ZWO filters in my 1600mm camera. I still don’t understand why it is in two localised areas and the rest of the image colour seemed ok, for my standard. 

It was processed with Neb4 with minor stretch, curves (contrast) used and saved JPEG.

Hmm interesting, I don't recall seeing anything green in my M33 images but I shall go back and check !

Alan

1 hour ago, ngc1535 said:

I would not assume that since an image is published as a NASA APOD that the colors are "accurate." The astronomers (Nemiroff and Bonnell) do not check for this, but are as knowledgeable as anyone in our active community that would spot the weird stuff. I do not believe this image was published as an APOD...but I could be wrong. A *better* assumption is that I took great care in the fidelity of the details and color for images I publish. 😁

Indeed, small green blobs that look like HII regions are, though uncommon, not really rare. It is all too easy to "remove green" blindly (or nowadays SCNR it out) and miss out on some interesting astrophysical things! This is where examining the data closely and letting it be is a good skill (one you have shown with your image!).  

 

Another good example of these green blob things is this image:

http://www.caelumobservatory.com/gallery/n6240.shtml

It happens to be in this galaxy that I discovered my own Supernova..but it was not related to these blobs!

Thanks for the response Adam and highlighting more green blobs...However, I'm still somewhat puzzled about what these green blobs actually are.

Alan

4 hours ago, vlaiv said:

Could be that the green thing is an artifact of some sorts? I mean, object is real, but the color ....

Hi Vlaiv

Yes, the colour is definitely interesting. 

Here's the image from Adam Block taken through a 20inch RC at the top of a mountain, I think he won an APOD for this so, I'm assuming that the colours are accurate.

I've used Registar to align with my own attempt and marked the location of the green blob. As you can see very green.  

3 hours ago, ollypenrice said:

Check it out for supernovae. I had a weird blue-green star in an M101 image which turned out to be an SNR remnant!

Yes - that is a thought. 

The Galaxy NGC3938 is located in the Ursa Major Cluster and is approximately 60 million light years from Earth. It has a large number of H II regions showing as pinkish regions on the LRGB image below.  I've also shown an annotated image which has identified some of the background galaxies that are also in the frame.  The galaxy doesn't seem to be often imaged, which perhaps is because it is relatively small, with an apparent size of 5.4 x 4.9 angular minutes.  The image below represents just over 13 hours integration time and was taken with my Esprit 150.

What is somewhat intriguing is the green(ish) blob which I've highlighted below.  Since you don't often encounter green objects in deep space, at first I thought it might be a processing artifact but I checked a higher resolution image from Adam Block and sure enough it is there, looking even greener.  The only thing that I could find at this location is the NED object SSTSL2 J115300.08 +440700.8, however, I not entirely sure what this object is - can anyone assist ?

Alan

NGC3938

NGC3938 (annotated)

Mysterious green blob

LIGHTS: L:32, R:11, G:21, B:15 x 600s, DARKS: 30, BIAS:100, FLATS:40 all at -20C.

Five images from 2019. All taken with my Esprit 150 in combination with a Trius 814.

Alan

M76

NGC1333

NGC3344

NGC4157

NGC6995

A close up of the open star cluster IC1848 which is embedded within the Soul Nebula (Westerhout 5). 

The LRGB image below, represents just over 21 hours integration time and was taken with my Esprit 150.

To capture the detail of the emission nebula, I gave it an Ha blend into both the Lum and Red channels. 

Alan

LIGHTS: L: 24, R: 17, G:20, B:11 x 600s, H: 19 x 1800s. DARKS:30, BIAS:100, FLATS:40 all at -20C. 

23 hours ago, han59 said:

Very nice image. The image details of NGC4216 are amazing!

There are more galaxies to see. I can't help you with the PI annotation, but here an alternative annotation by ASTAP of your jpeg file. (but I'm a little puzzled by the SDSS entries around NGC4216):

Thanks.    

I was quite impressed with the amount of detail revealed on NGC4216, as I mentioned above, I think this was mainly helped by a application of deconvolution on the lum data.

Thanks for the information on the ASTAP program, I shall investigate further !

Alan

20 hours ago, maw lod qan said:

Amazing! Thanks for the image.

Thanks for the comment ! 

19 hours ago, geeklee said:

That looks amazing.  IC771 looks interesting as well with it's differing colour.  Thanks for sharing. 

Thanks, yes IC771 does look interesting, I was quite surprised how blue it came out.

16 hours ago, orionoffelt said:

Nice image Alan good detail.

Bob

Thanks Bob - I think the deconvolution on the stacked Lum data helped to bring out the detail.

Alan

The galaxy NGC4216 is in the Virgo Cluster about 55 million light years from Earth.  It is shown in the center of the LRGB image below with two main companions NGC4206 (top) and NGC4222 (bottom). Also displayed are a few background galaxies. 

The inclination of NGC4216 is 89 degrees so, it is almost edge on, making the revelation of dust lanes difficult, so I was quite pleased that I managed to capture a few details.

I've also inserted an annotated version which shows the location of the background galaxies  (if there are any PI experts who know how to stop PI writing different annotation identifiers to the same object please let me know.....). 

The image represents 12.5 hours integration time and was taken with my Esprit 150. 

Alan

LIGHTS: L:19, R:12, G:14, B:30 x 600s. DARKS:30, BIAS:100, FLATS:40 all at -20C.

18 hours ago, ZiHao said:

Great image. Especially the tidal tail, really is an interesting feature to see.

Thanks for the comment.  Yes, I agree about the tidal tale, I was a little surprised about the length ! 

14 hours ago, Chris-A said:

Wow, that's really nice. Not seen this before but I guess, being a summer object, it's tough to get many hours on it.

 Thanks   - yes, it took me quite a long time to acquire this, just below 7months.....

14 hours ago, DaveS said:

Very interesting target, and well imaged.

Checking Stellarium, it should be possible to start imaging this from the second half of March through to the end of astro dark in mid May.

Thanks - looking at my captured data my imaging started at 13th May and finished 5th December, so quite a long acquisition period which is not helped by the fact that I'm surround by trees which limits my local horizon. Since I have to dodge trees, certain phases of the moon and bad weather, I  just let ACP work out when to image it.  FYI, at my location gets to about 75 degrees at dark end. 

Alan

Here's one you don't see often: - Arp297 which consists of four galaxies NGC5752, NGC5753, NGC5754 and NGC5755 all of which are located in Bootes.

NGC5754 and NGC5752 are approx 200 million light years distance whilst NGC5753 and NGC5755 are much further away, at approx 450million light years. The more distant galaxies don't appear to be interacting now, although the extended arms of NGC5755 indicate that an interaction may of occurred in the distant past. 

By contrast, a gravitational interaction of the closer two galaxies has produced an extremely long (275,000 light years) tidal tale which extends from the starburst galaxy NGC5752, which you can just about see this on the image below.  NGC5754 appears relatively unaffected by the collision. 

This LRGB image represents just over 11 hours integration and was taken with my Esprit 150.

Alan

LIGHTS: L:29, R:12, G:16, B:11 x 600s. DARKS: 30, BIAS:100, FLATS:40 all at -20C. 

9 hours ago, tooth_dr said:

Very nice close up.  I was looking at this image earlier, and tonight I started imaging B22.  It never dawned on me that this was in the middle of B22! 

Thanks.

Yes, this one is hiding in plain sight !

Alan

21 hours ago, Adam1234 said:

Very nice

Thanks for the comment ! 

Alan

SH2-112 is an emission nebula in Cygnus and responds very well to Ha imaging, so I decided to blend the result of my 3nm Ha filter into the Lum and Red channels in this LRGB image.  As you can see, there's quite a bit of detail within the nebula which is mainly from the Ha component of the image. 

It was taken with my Esprit 150 and represents just under 16 hours integration time.

Alan

LIGHTS: L:16, R:16, G:13, B:10 x 600s; Ha x 1800s. DARKS:30, BIAS:100, FLATS:40 all at -20C. 

22 hours ago, Gina said:

Nice one and great to see something different.

Thanks for the comment Gina. 

Alan

16 hours ago, wimvb said:

Great image. I had to look it up, it's an unusual target.

Thanks Wim - yes, it does not often appear, although it is often captured in wide field views of B22. 

16 hours ago, ollypenrice said:

Pleasingly original and rather spooky as an object...

Thanks - it's quite different from my normal output.  The style of the image reminds me a bit of an old dark oil painting.

16 hours ago, Skipper Billy said:

This is just lovely. It's a new one on me. Well done - beautiful image.

Thanks for the comment 

16 hours ago, alan potts said:

Beautiful and one I have never seen before.

Alan

Thanks Alan !

9 hours ago, astro mick said:

Lovely image Alan.Very unusual.Love the Flame.

Mick.

Thanks Mick 

Here's one you don't very often - the reflection nebula  IC2087, which is embedded in the dark nebula Barnard 22.   Since reflection nebula's are normally blue, I'm not too sure why this one is orange(ish)....I guess it must be the combination of the light from the bright blue star (out of frame), which is makes the background blue/purple, interacting with the dark brown/red of the dark nebula. 

IC2087 is also known as the little flame which seems appropriate  since the stars above it appear like sparks from a small fire.  For those with keen eyes, you'll also see a small red blotch above the fire, this isn't a processing artifact but a Herbig-Haro object which is a patch of nebulosity associated with newly born stars.   

So, you get quite a few interesting features in this image which was taken with my Esprit 150 and represents just under 10hours integration time. 

Alan

LIGHTS: L:12, R:15, G:12, B:20 x 600s, BIAS:100, DARKS:30, FLATS:40 all at -20C. 

16 hours ago, Tzetze said:

I hadn't noticed the red misalignment and to be honest I still can't see it but this is either due to a slight red/green blindness on my part or I don't know what I'm looking for.   I'll use your recommended settings in future though. Thanks again, that's very helpful.

I find the best way to inspect collimation errors is to pick an individual star and then zoom in on it to inspect it in detail. What you should see is all the colours aligning, in your case the red channel is slightly misaligned.  To explain a little further, if I select a star at the right hand edge of the frame I get the image below. The star should be blue but you have a red misalignment effect as shown below in this highly magnified image. Hope this helps !

Alan

Very good. I do like the colours !

In terms of points for improvements that you've asked for: on the core you might want to try using PI's HDR multiscale transform to see if you can obtain more detail.  Select an area somewhat larger than the core as a preview, then apply HDR to only the preview using the settings of your choice. When you are happy with the result, run the script substitute with preview (under utilities). Your HDR core image with then be automatically incorporated into the main image (hopefully) without a noticeable join. I used this Adam Block technique on my own effort and managed to get good core results - see my album Deep Sky III.

The other suggestion is that your red channel is not quite aligned to the other channels, you can see this quite clearly on the right hand side of the image. I presume this is due to a slight collocation error.  To correct for this in post processing - in PI's (latest release) in star alignment try selecting thin plate splines as the registration model and then check the distortion checkbox.  

Alan

14 hours ago, JamesF said:

Love the detail in the clouds around that central star.

James

Thanks. Yes, I think its my favorite part of the image, although that central star is bright !

Alan

21 hours ago, ollypenrice said:

Bravo! Something new and more than a little interesting.

Olly

Thanks Olly. It will be interesting to see if this post encourages some more attempt at this object.    

17 hours ago, don4l said:

That's lovely!

Thanks, much appreciated !

Alan

17 hours ago, x6gas said:

Wot Olly said.  Lovely.

How did the integration time split down by filter?   Whoops I see this at the bottom of the image - apols.

Many thanks for the comment. 

Alan

Vdb24 is a blue reflection nebula in the Perseus constellation which is embedded within the larger dark (reddish/brown) nebula LDN1442.  It seems quite a rarely imaged object, I found only two examples on Astrobin and zero on SGL.  It's quite an interesting image to process since the dark (brown/reddish) nebula tends to distort the star colours, particular the blue stars, pushing them towards the red end of the spectrum.  It also has quite a few very bright blue stars, including one that acts to illuminate the reflection nebula itself. 

Anyway, here's my effort which represents just over 14 hours of integration time.  The image is an LRGB and was taken with my Esprit 150.

Alan

 LIGHTS: L: 30, R:13, G:21, B:21 x 600s, DARKS:30, BIAS:100, FLATS:40 - all at -20C. 

9 hours ago, Older Padawan said:

Wow what a beautiful shot!!

Thanks for the comment 

Alan

11 hours ago, MartinB said:

A proper soap suddy bubble Alan and nice and smooth thanks to the time you've given it.  Excellent!

Thanks Martin. 

Yes, the extra time definitely helped with the bubble definition, although I still struggled getting good star colours. I think I need more practice.

Alan