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alan4908

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Everything posted by alan4908

  1. Thanks - yes, I was very happy with the detail on this one, helped by the superlum + deconvolution approach mentioned above. Thanks - Yes, I did find this difficult to process. An Adam Block PI technique that I found of use when processing this: given the very high dynamic range of the object, after HT stretching it so that you can see the halo, use HDMRT but only via selecting a preview with the preview encompassing the "blown out" parts. Then apply HDMRT to the preview. Use the script substitute with preview to obtain the result. You may need to blend in the result wit
  2. Thanks for the comment Alan. The faint halo rendition was helped by application of a so called superluminance (constructed from the noised weighted L, R, G, B stacks), deconvoluting this also helped in extracting the detail. Thanks - yes - I found it interesting to read up and understand a little more about this mysterious object. Thanks Alan
  3. For some reason, I've never imaged M94, so here's my attempt at this very unusual galaxy. M94 is approximately 17 million light years distant and contains both inner and outer rings. Star formation occurs in both rings but is mainly concentrated in the inner ring which is also known as a starburst ring, within this region, the rate of star formation is occurring so fast that it will exhaust the available interstellar gas supply well before the death of the galaxy. The extensive outer ring contains about 20% of the galaxies mass and consists of spiral arms when viewed in IR/UV, however
  4. Thanks for the comment. Agree on your HH comment - these are quite unusual objects. Thanks. VdB1 is close to the star Beta Cassiopeiae (or Caph) one of the main stars on the W (see below). Although it was out of the field of view for the above image, I was getting a bit of stray light contamination from this star which I eliminated via Pixinsight's DBE routine. Thanks. I must have a look at that book - it looks quite interesting. Alan
  5. Here's an image that you don't see often - vdB1 which is the first entry in the van den Bergh catalogue. VdB1 is a small reflection nebula in the Cassiopeia constellation. It's approximately 1600 light years distant and about 5 light years across. It consists of dust and gas which are illuminated by bright nearby stars. The scattered light from these stars appears blue since scattering is greater at shorter wavelengths. Another interesting object within the field of view, is a somewhat strange looking looped nebula. This is an example of star formation and several herbig-haro
  6. From the album: Deep Sky III

    NGC7008 is a planetary nebula located in Cygnus about 2800 light years distant and about 1 light year in size. The amateur astronomer Eric Honeycut named it the Fetus Nebula when he viewed it through his 22inch reflector. Planetary Nebula are one of the few astronomical objects that may appear green, so when processing this particular object you have to be careful when eliminating green from your image (eg SNCR green in PI) otherwise it will significantly change the colour balance of the object. Since it is so small and there's not much of interest in the background, I decided to
  7. Thanks - I'm not at all keen on the Hubble Palette, so I think I shall have a go with just Ha and OIII. I do already have an Astrodon 3nm Ha filter but I don't think I can justify further spending on a NII filter. Alan
  8. Thanks Dave. Have you seen any good hi-resolution NB images which would point me in the direction of which filters to use for the acquisition. I'm currently guessing Ha and OIII. Alan
  9. Thanks - yes, it does look a little bubbly - I think acquiring some narrow band data would help capture a few more details. Alan
  10. NGC7008 is a planetary nebula located in Cygnus about 2800 light years distant and about 1 light year in size. The amateur astronomer Eric Honeycut named it the Fetus Nebula when he viewed it through his 22inch reflector. Planetary Nebula are one of the few astronomical objects that may appear green, so when processing this particular object you have to be careful when eliminating green from your image (eg SNCR green in PI) otherwise it will significantly change the colour balance of the object. Since it is so small and there's not much of interest in the background, I decided to
  11. alan4908

    NGC4725

    From the album: Deep Sky III

    NGC4725 is the brightest member of a galaxy group in the constellation Coma Berenices and is about 40million light years distant and 130,000 light years in diameter. The structure is somewhat unusual, consisting of just one spiral arm which is tightly wound around the core and can be followed for about 1.5 revolutions. The spiral arm consists of dust and gases including bright blue stars and pinkish Ha regions which indicate star forming regions. Towards the center, much older, yellow stars can be seen. The galaxy is classified as a Seyfert Galaxy, indicating that the center contains a superma
  12. That is a very impressive image. Alan
  13. Thanks - I was pleased with the amount of detail - this was helped by the creation of a so called "super luminescence" which increased my SNR for the lum without impacting detail. This in turn allowed me to perform a stronger deconvolution, thereby extracting more detail. Alan
  14. NGC4725 is the brightest member of a galaxy group in the constellation Coma Berenices and is about 40million light years distant and 130,000 light years in diameter. The structure is somewhat unusual, consisting of just one spiral arm which is tightly wound around the core and can be followed for about 1.5 revolutions. The spiral arm consists of dust and gases including bright blue stars and pinkish Ha regions which indicate star forming regions. Towards the center, much older, yellow stars can be seen. The galaxy is classified as a Seyfert Galaxy, indicating that the center contains a superma
  15. Hi Adam Whilst I don't have an Esprit 100, I do own an Esprit 150 which is set up for automated imaging using filter offsets. I explored the details of this a couple of years ago and understanding the theory a little more greatly improved my results. So, you might want to take a look at this post:
  16. alan4908

    SH2-115

    From the album: Deep Sky III

    SH2-115 is a faint emission nebula in the Cygnus constellation about 7500 light years distant. It is normally imaged in narrowband, however, since I prefer natural looking colours, I went for a LRGB composition with an Ha blend into the red and lum channels. The image below represents about 17 hours and was taken with my Esprit 150. I encountered an interesting challenge in the processing stage of the above image in that I discovered that I had also acquired high levels of scattered light from an out of field star. These rays appeared in all the Lum, Red and Green subframes. Having anal
  17. alan4908

    NGC3718

    From the album: Deep Sky III

    My first attempt at NGC3718 which lies at a distance of about 49 million light years from Earth. It's a very unusually looking galaxy, featuring a twisted dust lane in the central region. To the right you can also see the companion galaxy NGC3729 which, occurring to radio measurements, appears to be interacting with its larger partner. At the top of the image, Hickson 56 can be seen, a grouping of five small galaxies that are estimated to be about 390 million light years away. The LRGB image represents just under 16 hours and was taken with my Esprit 150.
  18. Thanks Alan Thanks for your detailed comments. In acquiring the image, I did wonder if I could detect some star forming regions, so in acquiring the image, I also decided to try to capture some emission data via my 3nm Astrodon Ha filter. Unfortunately, even after 7.5 hours (15 x 1800s), the resultant stacked Ha image just looked like a grainy version of the stacked red channel. So, unfortunately, no more detail, only noise was revealed. I therefore decided not to use the Ha data. I should point out that I'm not implying that there aren't any star forming regions in M109 - it is
  19. Thanks for the comment. Yes, I was quite happy with the amount of detail that I managed to acquire. Thanks for the comment. On your blue processing point, I believe the blues are an accurate representation. For instance, take a look at these images from three accomplished astrophotographers: Adam Block - http://www.caelumobservatory.com/obs/m109.html Robert Gendler - http://www.robgendlerastropics.com/M109.html On the small blue stars and the blue tint of the small background galaxies, these also appear accurate - for instance, have a look at this APOD from Bob
  20. My first attempt at M109, a galaxy located in Ursa Major which is about 55 million light years distant. In the image below you can also see quite a few other background galaxies - the ones marked PGC37553, PGC37700 and PGC37621 have recession velocities very similar to M109 and are classified as dwarf companion galaxies. The LRGB image below represents 16.5 hours integration and was taken with my Esprit 150. Alan M109 M109 (annotated) LIGHTS: L:37, R:21, G:23, B:18 x 600s. DARKS: 30, BIAS:100, FLATS: 40 all at -20C.
  21. Thanks Carole Hi John Yes - masks are interesting objects to experiment with.. In Pixinsight, I found that the free GAME script (http://www.skypixels.at/pixinsight_scripts.html) is very flexible, allowing you to create "elliptically holes" of specific sizes in your black mask at specific locations. Alan
  22. Good luck with your processing, I'm sure you will get there ! By the way, I didn't understand your comment on applying multiple masks simultaneously, could you elaborate ? Alan
  23. Thanks for the comment John I found it quite difficult. The main problem for me was the background and the starfield, rather than the galaxy. Specifically: 1. There are some quite bright stars around the galaxy which if you stretch them at the same level as the galaxy, become too bloated. I resolved this by stretching some of these separately and then blending them into the image. 2. Since I image in non-ideal conditions (eg the UK), I often obtain red halos around blue stars, this arises from the FHWM of the red stack being slightly larger than the blue stack. I resolved t
  24. Thanks for the comment Geoff. Thanks - yes, it looks like it has gone through a lot - also the interaction with its companion galaxy is interesting. Thanks - on the cropping front, I did consider a much tighter crop but this time I opted for the interesting object suspended in space look. Thanks Brian Alan
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