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alan4908

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Everything posted by alan4908

  1. 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
  2. I thought some of you might be interested in seeing an odd looking artifact in one of my recent images of the bubble nebula (see below). At first, I thought this was due to incorrect settings within Pixinsight's Winzorised stacking algorithm. However, on examining the individual subs everything was OK - no artifact, just a star. On closer examination of the individual subs, I noticed that the star sometimes appeared clearly and sometimes appeared hardly at all. So, I decided to see if the free ware program Aladin (https://aladin.u-strasbg.fr/ ) could identify the star. Plate solving t
  3. Thanks Giorgio - I'm pleased that you like it ! Thanks
  4. In an effort to improve on my image of the Bubble Nebula from a few years ago, I decided that my existing data needed a longer integration time...... so at a total integration time of just over 26 hours here's the result. The image, taken with my Esprit 150, is an LRGB rendition with an Ha blend into the Red and Lum channels. I was particularly interested in seeing how much detail I could extract on the bubble itself, so I decided that it looks best cropped. Alan LIGHTS: L: 33, R: 27, G:27, B:23 x 600s, Ha:16 x1800s, BIAS:100, DARKS:20, FLATS:40 all at -20C.
  5. I tend to follow the process steps as advised by Adam Block's PI tutorials - see https://adamblockstudios.com/categories/PixInsight if you want to watch a video of all this. 1. Align Ha image with the Red channel of the RGB image Given that your Ha data is actually encoded as RGB, you first need to extract the Lum. To do this correctly, apply RGBworking space, with all the parameters set to 1 to the Ha image and the RGB image. Then extract the CIE L* from the Ha (RGB) image and use channel extraction to extract the Red channel from the RGB image. Now apply star alignment to the H
  6. That is impressive ! I've also made some progress into Pixinsight and away from PS. I was helped enormously by the Adam Block tutorials on Pixinsight which you might also find of use: https://adamblockstudios.com/categories/PixInsight Alan
  7. alan4908

    M58

    From the album: Deep Sky III

    The galaxy M58 is located in the Virgo constellation and is approximately 65 million light years from Earth with a disk diameter of approx 110 thousand light years. It's relatively low in new star formation, having little hydrogen gas which is concentrated in its elliptical core. The core is relatively dim and is believed to contain a super-massive black hole of 70million solar masses. Images of this object are rare on SGL, so I thought I would attempt to capture it. The LRGB image below represents just over 10 hours integration time and was taken with my Esprit 150. If you look
  8. The galaxy NGC 4216 is located in the Virgo constellation and is approximately 55 million light years from Earth. It is one of the largest and brightest galaxies in the Virgo cluster. It appears at an inclination of 89 degrees such that its core is partially obscured by its outer dust lanes. Numerous other background galaxies can also been seen in the image below, some of which I've annotated below. Due to the poor UK weather, this object disappeared below my local horizon before my imaging run was complete, however, I'm reasonably pleased with the result. The LRGB image represen
  9. It is an interesting question. When I started astrophotography I noticed that with my SW ED 80 on an NEQ6 mount (non belt modified) I found that imaging at 1.4 arc seconds/pixel that I could get acceptably round stars (eg star aspect ratio < 25%) with up to 120s seconds exposures. However, I also discovered that for my site taking lots of short exposures significantly limited me in imaging faint objects. After a bit more investigation, I discovered that my optimum broadband exposure sub frame length for my site/set up was around 600s. A detailed discussion this subject can be found
  10. Thanks Martin - yes, they do make it a little more challenging. FYI I would have liked to gather a little more data on this one but it disappeared below my local horizon before my normal integration time was complete. Thanks Olly Thanks for the comment. I'm not normally a large background fan with small objects, however, in this case, it seemed the best option. Alan
  11. The galaxy M58 is located in the Virgo constellation and is approximately 65 million light years from Earth with a disk diameter of approx 110 thousand light years. It's relatively low in new star formation, having little hydrogen gas which is concentrated in its elliptical core. The core is relatively dim and is believed to contain a super-massive black hole of 70million solar masses. Images of this object are rare on SGL, so I thought I would attempt to capture it. The LRGB image below represents just over 10 hours integration time and was taken with my Esprit 150. If you look
  12. alan4908

    M100

    From the album: Deep Sky III

    M100 is located in the Virgo cluster at a distance of 55million light years, it is one of the brightest and closest galaxies within the cluster. It's a spiral galaxy with a pronounced bar at its centre. Quite a few supernovas have been found here, the most recent being in 2019, designated SN 2019ehk which was discovered on 29th April. The LRGB image represents 12.3 hours integration time and was taken with my Esprit 150.
  13. Hmmmmmm.....however, just for you Stuart: here is the result of the image which results from the stacking of the three 600s red sub frames which contain the supernova. Unprocessed, apart from the stretch and the arrow !
  14. I use the following software for processing my images - you can see the results by going to my gallery. I seem to have collected quite a lot of software over the years.... 1. Pixinsight - now my main processing source. 2. Photoshop - now mainly used for cosmetic corrections and colourisation. This used to be my main processing source along with CCDstack. 3. CCDstack - I still use this for calibration and sometimes permanently stretching images since it is so easy to use. One day I shall move to using PI for calibrating my images. 4. Registar - I use this for registering
  15. alan4908

    SH2-201

    From the album: Deep Sky III

    An annotated version of SH2-201 showing the main objects within the image.
  16. alan4908

    SH2-201

    From the album: Deep Sky III

    SH2-201 is a small emission nebula located in Cassiopeia. It is often captured as a by product of the commonly imaged Soul Nebula (SH2-199), which is partially shown here to left of the SH2-201. On the annotated image (also in this album) I've also marked the location of a Herbig-Haro object (HH-163). These transient objects are formed when high speed narrow jets of partially ionized gas from new born stars collide with nearby clouds of gas and dust. Typically, they only last a few tens of thousand of years. On the processing front, I decided to process the nebula separately from t
  17. Thanks ! - yes, it was taken with my trusty SX Trius 814 - which gives me an imaging resolution of 0.7 arc seconds per pixel. I was a little concerned when I first used it with my Esprit 150 since I thought the imaging resolution might be too small, however, it turned out that for my set up/site that it appears about optimal. Alan
  18. Thanks Alan. On the Esprit 150 - Yes, I'm very happy with the scope, it is excellent quality for the price. On the SN - unfortunately, the SN only appears in three of my Red sub frames so, attempting to force their inclusion isn't going to work - I'd just end up with a red SN . Personally, I doesn't bother me since a SN just appears as another star, albeit in an unexpected position. Thanks Martin - yes, my site (aka back garden) in East Sussex is quite dark (no street lights), it is also relatively high which seems to help with good seeing. The only downside is that it does get
  19. M100 is located in the Virgo cluster at a distance of 55million light years, it is one of the brightest and closest galaxies within the cluster. It's a spiral galaxy with a pronounced bar at its centre. Quite a few supernovas have been found here, the most recent being in 2019, designated SN 2019ehk which was discovered on 29th April. The LRGB image below represents 12.3 hours integration time and was taken with my Esprit 150 (For those that might be interested: the data was gathered between Feb and May 19 , so I was wondering why I couldn't see the supernova in the image. On exami
  20. Thanks Knobby Thank you Alan.
  21. Thanks Peter. Hi Rodd Yes, Narrow Band imaging is great for revealing detail but in my opinion you cannot beat LRGB from naturalness. I do agree it is difficult, particularly when you have nebulosity around. Yes, it is a crop, although not very much has been chopped ! Alan
  22. SH2-201 is a small emission nebula located in Cassiopeia. It is often captured as a by product of the commonly imaged Soul Nebula (SH2-199), which is partially shown here to left of the SH2-201. On the annotated image below, I've also marked the location of a Herbig-Haro object (HH-163). These transient objects are formed when high speed narrow jets of partially ionized gas from new born stars collide with nearby clouds of gas and dust. Typically, they only last a few tens of thousand of years. On the processing front, I decided to process the nebula separately from the starfield b
  23. alan4908

    Sunrise over M76

    From the album: Deep Sky III

    M76, which is also known as the the Little Dumbbell, Cork or Butterfly Nebula is a planetary nebula about 4.5 light years across and approx 4000 light years distant. It was formed about 10,000 years ago when the central dying star lost a huge amount of matter. The structure of the nebula has two inner lobes and two fainter outer ones. High Ha emissions are present along with OIII emissions which create a the teal (blue/green) cast. As for the title, the bright star reminded me of Sunrise on Earth, hence the name. (For the more literal among you, the bright star is HD10498 which ha
  24. It is not necessary to purchase CCDstack (although it is a very good program). When processing in Photoshop, Adam primarily uses CCDstack for a Digital Development Processing (DDP) stretch of the luminescence image such that the object of interest will end up with a lum level that is around 180 (ish) - if you end up with lum values more that 200 then it will be very difficult to colour. So if you don't have CCDstack, then all you need to do is find a program that can perform a DDP or similar stretch on the lum data. Alan
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