Attn Nikon Astrophotographers or those with hot pixels

Forums Forums Get Technical Software Attn Nikon Astrophotographers or those with hot pixels

This topic contains 4 replies, has 3 voices, and was last updated by  chupathingie 7 years, 7 months ago.

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  • #2622

    kashari
    Participant

    Capture NX2 now has an ‘astro noise reduction’ filter which I just noticed last night. I haven’t found much on it yet except this thread at dpreview:
    http://forums.dpreview.com/forums/read.asp?forum=1021&message=40152389

    There were issues with some D7ks having hot pixels in regular exposures, so this should help solve that too.

    Nikon finally released a 64bit version of CNX2. I installed it last night on Win7 and whew, what a difference! I love this software so much, I pray to the Nikon gods daily for them to make it live forever! 😆

    #45640

    chupathingie
    Participant

    I shoot with a Canon, so not much use to me (also using Linux, so even the Canon tools are of no use to me), but this looks like a gret addition to their software for folks dealing with single images. Those shooting a stack will be (or should be) using dark frames to accomplish the same thing. I’d love to see a comparison between the new routine and dark frames; if it can actually replace dark frames, that would free up a great deal of time for imaging that normally gets used snapping off frames with the lens cap on… I spend an hour or more acquiring darks for each set of lights I collect.

    #45641

    ravnostic
    Participant

    I dunno…seems really clean, but where are the stars? For the casual shooter, though, it’s a gimme. I’m going for the hard route chupa mentioned (and…it is hardz). Too bad rain is moving in just when I get my days off this week. Sux.

    #45642

    chupathingie
    Participant

    Oh—reminds me… one technique that gets a lot of use is to nudge the scope in a random direction slightly between shots. This moves the hot pixels against the star field so they don’t reinforce themselves when stacked. Dark frame subtraction will leave a black spot behind in one of the color channels if the hot pixel saturates. Moving the field around distributes that dark spot and mixes it in with good data from other pixels during stacking. A sigma combine will remove that dark pixel entirely, but only if it shows up in different spots.

    #45643

    chupathingie
    Participant

    I dunno…seems really clean, but where are the stars?

    The comments thread for that review brought the same issue up with a number of comparison shots (the shot showing the hot pixel reduction is really impressive). One poster said it removed the fainter stars, but the comparison shots showed little difference on that count that I could see. The samples that showed the sky were obviously high f-stop or short exposures (by astrophotography standards). M42 barely showed as a fuzzy. The stars were gravy, I’m thinking; bonus background to the night shot of the architecture and trees. The shot was already overexposed for the highlights on the building, any longer would have ruined it.

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