›

Capturing Andromeda/GHS

Charles Schreiner
in General
I am about to start a longer project (for me) with M31. I have shot it once before and used a manual HDR process with varying exposure lengths using Photoshop (but now use Pixinsight for core processing tasks). 

After looking at the GHS content, I was wondering if I should again shoot varying exposure lengths. It seems GHS, done well, can handle a wide dynamic range. But I am also thinking even if the processing is more complex, it would still be better to start with 3-4 exposure lengths and after merging them, apply GHS. 

What would you recommend? 

Thanks,

Chuck

PS: This content is really good. Like being back in college. Takes me a couple of viewings & good notes to really get it! 


Comments

  • BlockHeadBlockHead
    I am not a fan of mixing of exposure times- to date I have found it unnecessary and generally a poorer solution. HDRMT or GHS or a combination of them should be able to handle M31 pretty easily. 

    On this note, I assume you have seen two videos...

    1. The update workflow video on M42.
    2. The GHS videos in stretch academy.

    -the Blockhead
  • Charles Schreiner
    Thanks. I have seen the GHS videos but not the M42 update.

    One more question: should I limit exposure time to ensure I don't overexpose core? I assume so.

    PS: Amazing that one can just ask you a question and get such a quick response. Truly!
  • BlockHeadBlockHead
    Yes..but only to a degree. I would argue that for most cameras and telescopes you should be able to expose for 3-5 minutes and still have a stellar nucleus. An overexposed "star" in the center is fine. You do not want an "egg" thing that is a blob in the middle.
    -the Blockhead
  • Charles Schreiner
    Thanks! 

    This will (hopefully!) be the 3rd image I get printed (on metal) to hang on our living room wall. Crescent Nebula and East Veil so far. 2 yrs into this hobby, starting to see at least the basics fitting together.

    I really appreciate your course and help.
  • Stan Howe
    about multiple exposures. I remember watching a video where you explained how it is possible to combine multiple exposures, but I cannot find it. I took a bunch of images at 300 sec, then got looking at them and realized my stars looked bloated. i took more at 120, still appeared like they were pretty saturated, i took more at 60 seconds which didnt look terrible different than the 120. I then tried to integrate them all using WBPP by setting the exposure tolerance to 241 seconds. I was also separating the RGB channels and recombining, but In the masters folder I cannot find an image where the 3 exposure were combined. what am I doing wrong?
  • BlockHeadBlockHead
    Stan,

    Can you find the three master lights in each channel and use Channel Combination?
    -the Blockhead
  • Stan Howe
    yup, I found those, I'll give that a try tonight

  • Stan Howe
    no, that didn't work, Channel Combination only allows me to pick 1 file per channel and WBPP left me with 3 per channel.
    see screen shot
    MasterLights .JPG
    867 x 341 - 96K
  • BlockHeadBlockHead
    No, this is not correct. It is still giving you distinct integrations based on either exposure time or filer name. It is troubling that your OSC data has "Luminace" in the name (why?). You have also run things more than once which is confusing. You should probably start from scratch (clear all of these files) and make certain the configuration is correct. You sad you changed the exposure tolerance. I am REALLY finding it hard to believe you. You adjusted the POST processing exposure tolerance right?

    So once you have started over, I suggest show screenshots of all WBPP windows. You can generate the screenshots with a single click of the Diagnostic button ("generate screen captures").

    -the Blockhead
  • Stan Howe
    LUMINACE  is the name I gave my IR/CUT filter (I hope to do Mono someday, and have a filter wheel, but taking baby steps).

    The first run took my PC almost 24 hrs, I only changed the tolerance for the 2nd run. I changed it in the Lights ta, so that was my error. I have to run to help my daughter move, but changed just the two tolerance values and the preview shows that it will now combine the images as expected.

    I'll try one more re-run while im out today, if that does not work, i'll restart from scratch as you suggest.
  • Stan Howe
    that worked, thanks
Sign In or Register to comment.