Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.



Advanced Members
  • Content Count

  • Joined

  • Last visited

  • Days Won


alan4908 last won the day on January 18

alan4908 had the most liked content!

Community Reputation

1,895 Excellent


About alan4908

  • Rank
    Sub Dwarf

Contact Methods

  • Yahoo

Profile Information

  • Gender
  • Interests
    Astrophotography ! ....at the moment I'm concentrating on deep space imaging
  • Location
    East Sussex
  1. I don't honestly know, all I do is crop my images until I get the prettiest picture ! In imaging, the field of view is determined by the focal length of your scope and the pixel size of your camera. To see the various FOV with a specific scope and camera and object have a look at https://astronomy.tools/calculators/field_of_view/ The Trius SX814 gives my set up an imaging scale of about 0.7 arc seconds/pixel, which is quite a high resolution. Alan
  2. Thanks for the comment wimvb. I did not detect any Ha or dust filaments during the processing of the image, so I decided on a strategy of not incorporating any additional Ha. Alan
  3. alan4908

    Deep Sky III

    Images taken with a Trius 814 and a Esprit 150
  4. I've had to look at your image and in addition to the horizontal lines you have a collection of dust donuts. To minimize these, I suggest take some flats, the most consistent and reliable method that I've found to do this is via an EL panel. If you find flats/darks/bias a bit of mystery then I'd getting a copy of Steve Richards excellent book "Making Every Photon Count" - https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html You can also minimize both of these unwanted effects in PS. The horizontal lines can be minimized by one of Noel Carboni tools called Horizontal Band noise reduction, the dust donuts via the context sensitive spot healing brush in PS. You can download Noel tools from https://www.prodigitalsoftware.com/Astronomy_Tools_For_Full_Version.html and represent excellent value at $21.95. Alan
  5. Thanks Olly. Yes, it does seem a little asymmetrical in the spiral arms. Hopefully, a few more images should be able to confirm this. Thanks Paul - yes, there does appear to be a lot of distant objects in the background. However, apart from the confirmed galaxies identified by the Pixinsight annotation script, I have no idea what these are.... Thank you Gorann. I shall look forward to seeing your rendition ! Alan
  6. Thanks - yes, the galaxy is at somewhat an unusual angle which you don't often see. The faint fuzzies terminology - Hmmmm, well I guess it does seem quite an insignificant phrase if you pause to consider what these faint objects actually are. Thanks ! Yes, there are quite a few faint background objects that the Pixinsight annotation routine didn't pick up. Thanks Mark - I hadn't come across that resource before - it looks very interesting. Alan
  7. Well, I couldn't find another image of NGC4157 on SGL so it's obviously not that popular a target ! The galaxy is located in Ursa Major about 56million light years from Earth and is approximately the same size as our own Milky Way. It is receding from us at 774 km/s. From Earth you see it almost edge on, however, a little of the core detail is visible. Three supernova explosions have been recorded in this galaxy. Processing this galaxy was less than straightforward due to the fact that it has a low surface brightness but it is also surrounded by bright blue stars. The LRGB image below represents 14.5 hours integration time and was taken with my Esprit 150. I've also attached an annotated version for the background galaxy fuzzy hunters. I hope you like it ! Alan LIGHTS: L:29, R:20, G:19, B:19 x 600s, DARKS:30. FLATS:40 all at -20C.
  8. Thank you Martin. Thanks Hi Carole Yes, the skies in parts of East Sussex do seem to be very good compared to the UK average. Generally quite dark and with good seeing conditions. I hope the weather is OK for your astro camp visitation. Alan Thanks Peter. I find that CCDNavigator is a very good tool for finding attractive looking objects to image - if you choose the advanced imaging catalog, it brings up colour thumbnails of numerous objects as imaged by various world class photographers. However, what is better is that you can filter the objects based on your local horizon/time of day etc. It also seamlessly integrates into ACP which is very handy for remote operation. Alan
  9. Gav That is a very good image. On the subject of the stars and CA - you can easily compensate for this in post processing. If you use PS, then I'd suggest you use this Adam Block technique - take the smudge tool and set the mode for colour at a strength of 25%. Use this to adjust the halos or any offending star colours. This allows you to smear the colour without impacting detail. (If you are interested in a star comparison with the Esprit 150, my M81 image is within my album Deep Sky III). Alan
  10. Thanks Richard - I'm glad that you liked it ! Alan
  11. Hi Chris Personally, I wouldn't make that assumption. I'd have thought that flatteners would have to be matched to the relevant scope if you wish to achieve an optimally flat field. Perhaps @steppenwolf could comment (a fellow Esprit 150 owner) ? Alan
  12. Hi Chris Yes, I do use a flatterer on the Esprit, it is the one dedicated to the scope- see here https://www.firstlightoptics.com/esprit-professional-refractors/skywatcher-field-flattener-for-esprit-150.html Alan
  13. Hi Vlaiv Sure ! Here's a crop of a FITS stack of Lum stacked data of a recent M51. I've limited the image to a small crop of the central region core and converted it to a FITs file. I'd be interested to understand the effect of binning on deconvolution since I've found this to be a powerful process for recovering maximum detail. Please note that this it has been stacked in Pixinsight so everything has been normalized between 0 and 1. Alan Mean L M51 core.fit
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.