> Milky Way in different filters

  • Posted on: 1 June 2020
  • By: tihomiry

This is a comparison of my not modified Pentax k5 DSLR and the same, but modified one without IR-cut filter.
Removing the IR-cut filter not only increase sensitivity by 1-2 stops, but also slightly increase the resolution as the IR light (despite not being that much detailed) pass trough the byer RGB mask without filtering.
Below we can see a shot with UHC-s filter as well, witch give us best contrast and brightness of the H-alpha objects as Lagoon nebula (M8). Thus it needs the longest exposure 120s against 60-90s for the other filters. You can see the beautiful Galactic horse dark nebula on the shots :)

Milky way in Sagittarius in different filters

Reading a new product that claims to be 100x time more powerful then conventional telescope, I realise that this is just an astrograph with a digital camera that is doing stacked images and show them trought eyepiece or App.

I am so impressed with the K5 ability to quickly gather signal from nebulas (Quantum efficiency) and galaxies, so I decide to take one more K5 and to remove the IR-cut Filter of the old one.

Recently I got one very good lens the Asahi Takumar 135mm 1:2.5. This is fast telephoto lens and from my point of view a good lens should be with aperture from 1:1,2 to 1:2,8.

Moon at 45% illumination and 70x magnification. With aperture of 200mm,14,1 stops dynamic range, color depth of 23.7 bits at this image there are slight color variation on the moon surface that reveals it’s structure.

This is the beginning of my research on how dark the sky could be and what is benefit of a dark sky for astrophotography. I was inspired from those 2 sites. First one presents mathematical model of how dark the sky is.

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