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.

sgl_imaging_challenge_banner_30_second_exp_2_winners.thumb.jpg.b5430b40547c40d344fd4493776ab99f.jpg

alan4908

Crab Nebula (M1)

Recommended Posts

My first attempt at the Crab Nebula.

The image is an LRGB with an Ha blend into the lum and red channels and represents about 14 hours integration time.  

5a2f91632763d_19_crop.thumb.jpg.3a37577ad759896cf3bc97c1067100ec.jpg

Alan 

LIGHTS: L:14,R:16, G:8, B:14 x 600s, H:11 x 1800s.

  • Like 28

Share this post


Link to post
Share on other sites
1 hour ago, graemlourens said:

Very nice Alain!

A very difficult target i found the Crab to be...

Kind regards, Graem

Thanks for the comment Graem.  Yes, it is quite difficult - I was pleased that I managed to capture a bit of detail.

1 hour ago, tooth_dr said:

Stunning, thanks for sharing.

Thanks ! :happy11:

1 hour ago, Barry-Wilson said:

Ooohh, lovely image Alan.  Well balanced and natural processing.  Good job.

Glad you liked it Barry. :hello: 

Share this post


Link to post
Share on other sites

A pretty fine first stab at the Crab it is too! Very natural and lovely colour.

What kit do you use?

Edited by coatesg

Share this post


Link to post
Share on other sites
15 hours ago, toxic said:

that is a lovely rendition of the crab :thumbright:

Thanks Chris. :happy11:

15 hours ago, coatesg said:

A pretty fine first stab at the Crab it is too! Very natural and lovely colour.

What kit do you use?

Thanks for the comment Graeme.

The equipment used was my Esprit 150 +FF with a SX Trius 814 CCD and 3nm Astrodon Ha filter, mounted on my 10micron GM1000HPS in unguided mode.

Share this post


Link to post
Share on other sites
22 hours ago, Sam said:

This is a fantastic image, I love the colour.

Thanks Sam.  Yes, I so do I :hello:

13 hours ago, MarsG76 said:

Nice result. excellent vein detail.

Thanks. I think that the details where helped by my decision to keep only the best quality subs.

  • Like 1

Share this post


Link to post
Share on other sites
20 minutes ago, alan4908 said:

decision to keep only the best quality subs.

I thought everybody did that... I always keep the best subs...

Share this post


Link to post
Share on other sites
19 minutes ago, MarsG76 said:

I thought everybody did that... I always keep the best subs...

I used to do that but I subsequently found that it depends on the image and what I want to achieve - to explain: I often rely on data rejection to eliminate aircraft or satellite trails which I find can be removed without degrading image quality. I also sometimes keep subs which have been taken in poor seeing, if I want to maximize signal but I'm not too interested in details. If I don't have many subs, I've also found that by experimenting with different rejection algorithms, that you can keep subs with significant star aspect ratio distortion (and still end up with round stars) provided that you use an appropriate data rejection algorithm.  My key leanings on this subject came from watching Adam Block's video tutorials on image processing, which I would recommend.

  • Confused 1

Share this post


Link to post
Share on other sites
9 hours ago, alan4908 said:

I used to do that but I subsequently found that it depends on the image and what I want to achieve - to explain: I often rely on data rejection to eliminate aircraft or satellite trails which I find can be removed without degrading image quality. I also sometimes keep subs which have been taken in poor seeing, if I want to maximize signal but I'm not too interested in details. If I don't have many subs, I've also found that by experimenting with different rejection algorithms, that you can keep subs with significant star aspect ratio distortion (and still end up with round stars) provided that you use an appropriate data rejection algorithm.  My key leanings on this subject came from watching Adam Block's video tutorials on image processing, which I would recommend.

If there is a satellite or meteorite streak through a sub, stacking will remove it... but if you're using subs where your stars are not round, "aspect ratio distortion", than that is a sign of motion blur effect in the reminder of the image softening out detail. I haven't heard of Adam Block or his methods so perhaps there is a trick to fox the motion blur, but to date I use stars in the center (or near center) of the frame to determine quality of the sub.

If the stars are round, no streaks or elongation than its a keeper otherwise I remove it. I find that by keeping only the best subs results in the best looking final image. If its too noisy or looks rough when stretching the stacked image than I just spend another night grabbing subs and re stack. Generally I end up with 40-50 subs of various lengths before I think I have enough data for good SNR and a relatively smooth image.  

Mind you though, I might end up with 2 or 3 subs that I delete in a nights session, and that's 3 at most on a bad night when something goes wrong with the tracking/autoguiding or the cursed clouds ruin it, and it's always on the 15, 20 minute or longer subs. So I don't cull too much data, rarely do I have a night where I spend a night of exposing subs where the seeing is so poor that my data is unusable.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By Davide Simonetti
      The Crab Nebula (also known as M1, NGC 1952 or Taurus A). This is quite an improvement on the last attempt at imaging M1 about two years ago. This time it was possible to bring out some of the filaments that make this object so interesting - this despite using a much shorter focal length making the object appear significantly smaller. The image is cropped rather radically to show more details in the nebula so the stars appear bigger than I would prefer, but on the original they look fine. 
      040 x 300 second exposures at Unity Gain (139) cooled to -20°C
      050 x dark frames
      040 x flat frames
      100 x bias frames
      Binning 1x1
      Total integration time = 3 hours and 20 minutes
      Captured with APT
      Guided with PHD2
      Processed in Nebulosity, Fitsworks, and Photoshop 
      Equipment
      Telescope: Sky-Watcher Explorer-150PDS
      Mount: Skywatcher EQ5
      Guide Scope: Orion 50mm Mini
      Guiding Camera: ZWO ASI120MC
      Imaging Camera:  ZWO ASI1600MC Pro
      Baader Mark-III MPCC Coma Corrector
      Light pollution filter

    • By semolex
      Hi all, here is my first image for this website and first challenge here

      M1 (Crab Nebula) - SNR in Taurus
      Narrowband image (Ha - 3 hours, OIII - 3 hours, SII - 3 hours)
      Taken with GSO RC 6" + ZWO ASI1600MM with ZWO EFW + Optolong NB filters.

      Thank you

    • By Hallingskies
      Vixen 114ED refractor, NEQ6, SXV-H9, 30 x 300s Ha and O3 subs, from December...
    • By Vicky050373
      M1 The Crab Nebula 08.12.2017
      William Optics FLT-110 and Atik 314L Monochrome CCD
      10 x 300 seconds H-Alpha, 10 x 300 seconds OIII, 10 x 300 seconds SII
      Stacked in Deep Sky Stacker and processed in Photoshop CS2
      False colour image by assigning SII to red channel, H-alpha to green channel and OIII to blue channel
    • By alan4908
      My first attempt at the Crab Nebula (M1). The cropped image is a LRGB with Ha blended into the Lum and Red channels and represents about 14 hours integration. I was quite pleased with the amount of detail revealed. 
      LIGHTS: L:14,R:16, G:8, B:14 x 600s, H:11 x 1800s. DARKS:30, BIAS:100, FLATS: 40.
×
×
  • Create New...

Important Information

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