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Posts posted by alan4908

  1. 23 hours ago, peter shah said:

    star colour is great...nice work

    Thanks for the comment Peter. I did spend quite a lot of time on the star field colours, mainly because I acquired quite a few sub frames in non ideal conditions.  However, I agree, I think the end result looks OK - it is amazing what you can do in post processing !


    22 hours ago, ultranova said:

    Nice to see this cluster, not that often taken.

    nice star colors .

    well done 


    Thanks Paul - yes, not often see here - which probably due to its small apparent size.  As I mentioned above, even at 0.7 arc seconds/pixel, I decided to crop the image to create more visual impact.

    12 hours ago, michael.h.f.wilkinson said:

    Very nice capture. I should try this one with my 6" F/5 Schmidt-Newton 

    Thanks Michael  - good luck with your forthcoming capture.


  2. 23 hours ago, Knight of Clear Skies said:

    Nice image with the contrasting colours in the cluster, and appreciated the write-up.

    Thanks - glad that you liked the end result. :happy11:

    (I discovered that I had  a red glow around all my stars due to my FWHM of my red channel stars being much larger than the other colour channels. This was due to the fact that I acquired the majority of the subframes in non ideal conditions. However, I corrected for this effect by eroding the red channel through a star halo mask)


  3. 23 hours ago, Graham Darke said:

    That is lovely that Alan. This object is on my list to capture.  I've seen it visually a number of times but don't have an image of it yet. 

    Thanks for the comment Graham - good luck with your capture. :hello:

    Beware that it has a small apparent size,  I was imaging at 0.7 arc seconds/pixel but even at that level I decided to crop the image down to focus the viewers attention on the cluster.


  4. Discovered in 1788 by William Herschel, NGC 2419 is one of the most massive and brightest globular clusters but appears as a dim 9th Magnitude object due to its large (275,000 light years) distance from Earth. The bright blue star to the left of NGC 2419 in the image below is HD60771, which is much closer, being only 350 light years distant.

    In 1944, the American astronomer named it the “Intergalactic Tramp”, since it was once (erroneously) thought not to be orbit around our galaxy but rather wandering the space between Earth and the even more distant galaxies.

    More recent observations have confirmed that although NGC 2419 is very distant, it is still trapped by our galaxy’s gravity well, taking 3 billion years to complete an orbit.  The orbit places it even further away that the Milky Way’s most famous satellite, the Large Magellenic Cloud and even further away that the Small Magellenic Cloud.

    The image below was taken with my Esprit 150 and represents 11.3 hours integration time.




    LIGHTS: L:23, R:22, G:10, B:13 x 600s, BIAS:100, DARKS:30, FLATS:40 all at -20C.

    • Like 18
  5. On 10/02/2021 at 15:06, Sunshine said:

    Fantastic image, such subtle detail visible in NGC4248.

    Thanks for the comment :hello:

    23 hours ago, tomato said:

    Superb result, great framing, colour and detail.👍



    23 hours ago, peter shah said:

    love it....super colour and detail

    Thanks Peter  - I think I prefer the colour in this reprocess of the ED 80 data - this time I used Pixinsight's Photometric Colour Calibration process. 


  6. Whilst waiting for clear weather, I decided to reuse some data that was previously acquired by my Skywatcher ED80 and my Esprit 150.   I used the Esprit data to get maximum detail on M106 and its companion NGC4248, whilst I reprocessed the ED 80 data such that the resultant background showed very faint objects.

    The ED 80 data is LRGB whilst the Esprit data also contains a Ha blend into the red channel. On the processing side, I used RegiStar to align the Esprit 150 and ED 80 images and then used Pixinsight's Gradient Mosaic Merge to create a seamless image. 




    M106 (annotated)


    • Like 30
  7. On 20/01/2021 at 11:44, Richie092 said:

    Well that was definitely worth waiting for!

    Thanks :hello: - I don't think I could have done this without an automated set up.

    20 hours ago, MartinB said:

    Crikey, that is amazing.  I know there are some dark sky areas in your neck of the woods but didn't know they were this good.  Beautifully processed as well.

    Thanks Martin ! I'm fortunate to live at a location which (by UK standards) has very good dark skies. I'm also at the top of a hill which helps, although it does get rather windy at times.

    • Like 1
  8. My image generating productivity has been significantly decreased by the poor UK weather in recent months. Even with an automated observatory, my image capturing has been moving at a glacial rate. However, here’s the latest image to finally emerge from my set up – NGC 7497 :happy11:

    NGC 7497 is a spiral galaxy in the Pegasus constellation, approximately 60 million light years distant with a disc size of approximately 91000 light years.  The galaxy shows signs of warping indicating past interactions. You can (just) make out some HII regions in the image below that appear to be semi-randomly positioned within the galaxy.

    The galaxy is viewed away from the plane of our own galaxy, through a mass of dust and gas known as Integrated Flux Nebula (IFN), which resides in our own galaxy and is approximately 600 light years distant. The stars within our galaxy act together in an integrated fashion to faintly illuminate the gas, hence the name.

    In 1985, the astronomers Magnani, Blitz and Munday (MBM), decided to catalogue the various IFNs and the one shown is known as MBM 54.

    The image also features many stars and a several background galaxies. Some of the stars are closer to Earth than MBM 54 and appear sharp and distinct (eg the bright blue star at the top, middle) and some are more distant.  The more distant objects will therefore appear fuzzy if they are viewed though dust and nebulosity.

    The LRGB image below represents just under 16 hours integration time and was taken with my Esprit 150. 



    LIGHTS: L:37, R:20, G:20, B:18 x 600s, DARKS:30, BIAS:100, FLATS:40 all at -20C.  

    • Like 8
  9. A second attempt at the Witch’s Broom Nebula (NGC6960), this time in narrowband. It took me 3.5 months to acquire the data, which was caused by a combination of poor UK weather and the partial obstruction by trees at my location. Anyway, better late than never....:happy11:

    Although imaged in narrowband, I tried to go for realistic looking colours so started with Ha mapped to red and OIII mapped to blue with a synthetic green generated from a Ha/OIII mix.  After a few hue adjustments, I ended up with a colour image which mainly gave blue/reddish stars and nebula. I found that detail could be boosted by creating a super luminance image from the individually stacked narrow band stacks and then deconvolving the result which I then blended into the colour result via Pixinsight’s LRGB process.

    The image below was taken with my Esprit 150 and represents 16.5 hours integration time.


    LIGHTS: Ha: 15, OIII: 18 x 1800s; DARKS:30, BIAS:100, FLATS:40 all at -20C.

    • Like 7
  10. NGC 896 is an emission nebula located in Cassiopeia about 7500 light years away. It is also the brightest part of the Heart Nebula (IC 1805) but has a separate classification, since it was the first part of the nebula to be discovered.  The dominant red colour arises from hydrogen line photon emissions created by intense ultraviolet emissions from nearby stars. It is a star forming region and also home to many dark lanes created by interstellar gas. Some very bright blue stars compete in the nebula illumination, resulting in a blue/red cast in certain parts of the image.

    The LRGB image has an Ha blend into both the red and lum channel and was taken with my Esprit 150. It represents 18.5 hours integration time.



    LIGHTS: L:22, R:18, G:11, B:12 x 600s; Ha: 16 x 1800s. DARKS:30, BIAS:100, FLATS:40 all at -20C.

    • Like 6
  11. 21 hours ago, andrew s said:

    I prefer the original colour balance. Nice subject well framed.

    Regards Andrew 

    Thanks for the comment Andrew. In terms of the colour balance, I was drawn to change this when I checked the histogram levels which shows that the original image is quite unbalanced at the lower levels, however, I also like the "more blue" effect in the original.

    I I think the credit for the framing goes to CCDNavigator (where you can preview the image for your given FoV) and ACP, for actually getting the object in the center of the FoV.  As an aside, CCDNavigator was recently made compatible with ACP Expert which enables you select objects to image through a view mouse clicks, which I really like. 


    21 hours ago, ultranova said:

    A nice close up of that area,

    you have certainly done it justice, great colours and processing.

    Nicely done


    Thanks Paul ! :hello:


  12. Located in the Cygnus constellation about 6000 light years distant, NGC6914 is a blue reflection nebula consisting of VbB131 and VdB132.  

    Surrounding NGC6914 are reddish areas of hydrogen emission nebula which provide a dramatic colour contrast to the blue nebulosity.  The contrast is further increased by regions dark nebulosity (LDN 899).

    The stars are also a notable feature of the image since embedded within the nebula is the star cluster Cygnus OB2 which consists of about 100 class “O” (yellow)  and 2500 class “B” (blue-white) stars.

    The image was taken with my Esprit 150 and represents 16.5 hours integration time. It is an LRGB image with a Ha blend into both the Red and Lum channels.





    LIGHTS: L:21, R:17,G:12, B:16 x 600s; Ha:11 x 1800s. DARKS:30, BIAS:100, FLATS:40 all at -20C.

    • Like 8
  13. 15 hours ago, Allinthehead said:

    That's a beauty Alan👍

    Thanks :hello:

    14 hours ago, Erling G-P said:

    That's a stunning looking image!

    Glad you liked it - it is a pity that it doesn't appear a little more often here.

    9 hours ago, John Nodding said:

    Cracking image! Should be called the My little Pony Nebula. 👀


    Thanks Noddy - yes, it is quite amazing what the brain sees when you star at nebula's for a while....

  14. LBN 438 is a dusty nebula located in the Lacerta constellation which is also known as the sand worm (from the Dune science fiction series) or the shark nebula.  It doesn’t appear very often on SGL, probably because it is so faint !

    It is illuminated by interstellar radiation known as Extended Red Emission (ERE).   ERE is a relatively recent discovery (1975) and is a photo-luminescence process whereby hydrogenated amorphous carbon is illuminated by interstellar photons in the 500 to 1000nm spectral range.  Although the nebula also contains ionized hydrogen, it only emits a relatively weak Ha signal, so I decided to only use broadband filters to acquire the target.  

    The LRGB image shown below was captured with my Esprit 150 and represents just over 13 hours integration time.

    At the top of nebula is a reddish glow, which I presume is due to ERE.  The nebula is surrounded by very bright blue stars which can detract from the relatively faint nebula, so these have been stretched much less than the rest of the image and then blended back into the main image.  If you look closely at the background you will also be able to see various small background galaxies (eg middle left).

    I hope you like it.




    LIGHTS:   L:31, R:17, G:15, B:17 x 600s; DARKS:30; BIAS:100; FLATS:40 all at -20C.

    • Like 12
  15. On 26/09/2020 at 10:21, Allinthehead said:

    Great image Alan, I can't recall seeing detail like that in this target.

    Thanks - I believe my imaging resolution of 0.7 arc seconds per pixel helps to bring out the details but it also makes imaging capture more challenging, particularly as I image unguided.



  16. 11 hours ago, peter shah said:

    that is up close and personal....great FOV...love the detail you have in the reflection...great job

    Thanks Peter. 

    8 hours ago, Laurin Dave said:

    Marvellous image with lovely colours of an interesting object and only 12hrs..  Any idea what the blue Arc above left of VdB 152 is?  


    Thanks for the comment Dave.  Hmmmmm..... I had a look in Aladin but cannot see anything marked so I presume it must be a faint reflection nebula, although the shape suggests some form of shock wave.  While I can see the object in other images, most scientific attention has been directed towards on the other side of Barnard 175 where the various remnants of the supernova explosion can be seen.  

    8 hours ago, steppenwolf said:

    Lovely - some amazing dust as well as the reflection nebulosity

    Thanks Steve .:happy11:

    4 hours ago, gorann said:

    Outstanding image Alan! Amazing details. Really good advertisement for the Esprit 150!

    Thanks - yes, the Esprit 150 is an excellent scope - if anyone is in the market for a large refactor, then it is definitely worth considering, particularly given the price compared to the competition..... :hello: 

    • Thanks 1
  17. 22 hours ago, Adreneline said:

    Excellent! A very impressive image.

    Thanks for all the background info too.


    Thanks Adrian !


    22 hours ago, ultranova said:

    Wow admire your dedication to the image...I know this one is not for the faint of heart..

    It's come out very nice  indeed, colours and processing to match.

    Well done


    I'm glad you liked it Paul  - and you are correct in that the wide dynamic range of this object makes it a challenge  :happy11:


    21 hours ago, MarkAR said:

    Stunning image, beautifully processed.

    Thanks for the comment. :hello:


  18. In the constellation Cepheus, at 1400 light years from Earth, lies vdB 152, a small blue reflection nebula located at the tip of the dark Bok nebula Barnard 175.  Embedded in the dark nebula is the Herbig Haro object HH 450. The faint red streak to the right of the reflection nebula is a supernova remnant known as SNR G110 + 11.3 which appears to be approaching vdB 152.

    Some of my notes for those that might be interested:

    Reflection nebulas are created when a nearby star illuminates the gas of at a nebula at an insufficient energy level to ionize the gas but strong enough to create light scattering that makes the dust visible.  Reflection nebulas mostly appear blue because particles in the nebula scatter blue light more efficiently than other wavelengths.

    Bok nebulas are isolated and relatively small dark nebulas containing dense dust and gas from which star formation can occur.

    Herbig Haro objects are bright patches of nebulosity that form when fast moving narrow jets of partially ionised of gas, ejected from a newly formed star, collide with nearby gas and dust at several hundred km/s.

    The LRGB image below represents 12 hours integration time and was taken with my Esprit 150. An annotated image is also shown.





    LIGHTS: L:28, R:13, G:14, B:17 x 600s, BIAS:100, DARKS:30, FLATS:40 all at -20C.

    • Like 24
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