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.

  • Announcements


Stub Mandrel

Advanced Members
  • Content count

  • Joined

  • Last visited

Community Reputation

6,344 Excellent


About Stub Mandrel

  • Rank
    Main Sequence

Contact Methods

  • Website URL

Profile Information

  • Gender
  • Location
    Staffordshire UK
  1. Less than 1% illuminated crescent tonight (16th)

    Do observations of chip shops count as astronomy?
  2. Horsehead HA + rgb

    Very nice, but using Ha for luminance means you have 'lost' the blue reflection nebulae near the bottom. Are they in your blue data? You could replace the missing red subs with Ha ones...
  3. Favourite Class Of Object, And Reasons

    The Milky Way.
  4. M101

    Drizzle comes into its own for planets, when s/n ratios are very high with thousands of frames.
  5. All excellent - congratulations. I detect a theme beginning with 'O' :-)
  6. I'll have it if you want to give it away
  7. Moral dilemma

    Ok, this is a version of the full image. I created a masked layer around the tiny galaxy, but not big enough to include the nearby stars. I then used 'screen' to make the galaxy brighter and then used curves to brighten it further and darken its surroundings to match the wider background. Although I've put a reprocessed version of this image in the galaxy challenge, it doesn't include this boost to the little fella.
  8. The human eye is brilliant at pattern recognition and seeing small differences. There's an excerpt from one of my images after initial 32-bit stretch in DSS and BEFORE proper processing: Here's an excerpt from a stunning image by Tom Mattheson http://www.guidescope.net/galaxies/ngc2903.htm Just a tiny extract: If you look at my image you can see the faint galaxy in Tom's image just shows on mine, but it seems that it is only a tiny bit above the background. My inclination is to apply my usual processing to bring out the big galaxy and hop this accentuates the little one. There are all sorts of dirty deeds I could do to bring out the small galaxy (I tried a few) but they all felt little different to 'airbrushing' in a pale patch. Is there a 'morally acceptable' technique to bringing out that little patch aside from going to darker skies and getting lots more subs?
  9. Over the last 24 hours I have, on and off, been running all sorts of different DSS permutations on my NGC2903 data. It seems using cooled flats and cooled dark flats both help reduce the noise. A further improvement is achieved by blurring the master flat. I finally eliminated the streaky pattern - by not using bias frames AND not setting the dark point to zero. The final step will be to produce cooled bias frames and see how they work - I never suspected that minimum length exposures could suffer from significant thermal noise, but it seems they might.
  10. SHOW US YOUR NEWTS........

    Brilliant. I like practical.
  11. Too many options.

    Hard not to go for the flame and horsehead nebs which will come out well with your new camera. Set the camera in 'portrait' orientation and get alnitak towards the top right of the frame (in portrait) - liek teh Plieades it's one target where you definitely DON'T need GOTO!
  12. Capturing 'Darks' the next day

    I found that sorting my darks into medium, cold and freezing nights worked well, having lots of darks seems to be more important than exact temperature match (with is impossible using exif data anyway). You can build up a dark library this way. I have got darks by putting the camera in the fridge before now...
  13. Google says the DBK21 has 5.8 x 5.8 um pixels. The QHY163 has 3.8um pixels. If you bin the QHY163 you will effectively get 7.6um pixels. For planetary you generally want pixels as small as possible so unless you are using a big barlow and very high power I would just use the QHY163 without binning as otherwise your planets will come out smaller than you are used to. If the camera supports 'area of interest' you may be able to speed up capture and reduce filesize at 1:1.
  14. M101

    Very nice, do you have good dark skies? I struggle to get M101 to stand out from the murk.