02-08-2025, 04:10 PM
(This post was last modified: 02-08-2025, 04:16 PM by Mike Watterson.)
They might need to be cooled to improve performance?
Up to 1100 nm IR https://dagemti.com/introducing-ir-2000-camera/
and
https://www.photonics.com/Articles/Measu...ras/a22473 They mention HgCdTe detector response, I presume a detector or camera made from Mercury-Cadmium-Telluride. I'd not heard of it before. https://en.wikipedia.org/wiki/Mercury_cadmium_telluride
But apparently discovered about 50 years ago.
Also very far away objects are more IR by two mechanisms:
1. The well known "red shift" due to higher speed.
2. Frequency downshift caused by interstellar gas. So some sources might not be as far away / as fast as previously thought.
Closer stars and even brown dwarfs have plenty of IR.
So there is some advantage in buying a computerised mirror based 'scope that takes a camera adaptor. A lens based one might attenuate the IR more and focus is more affected?
Up to 1100 nm IR https://dagemti.com/introducing-ir-2000-camera/
and
https://www.photonics.com/Articles/Measu...ras/a22473 They mention HgCdTe detector response, I presume a detector or camera made from Mercury-Cadmium-Telluride. I'd not heard of it before. https://en.wikipedia.org/wiki/Mercury_cadmium_telluride
Quote:HgCdTe is the only common material that can detect infrared radiation in both of the accessible atmospheric windows. These are from 3 to 5 μm (the mid-wave infrared window, abbreviated MWIR) and from 8 to 12 μm (the long-wave window, LWIR). Detection in the MWIR and LWIR windows is obtained using 30% [(Hg0.7Cd0.3)Te] and 20% [(Hg0.8Cd0.2)Te] cadmium respectively. HgCdTe can also detect in the short wave infrared SWIR atmospheric windows of 2.2 to 2.4 μm and 1.5 to 1.8 μm.
But apparently discovered about 50 years ago.
Quote:Advances in Infrared Photodetectorshttps://www.sciencedirect.com/topics/phy...-telluride
1 Introduction
Mercury cadmium telluride is a nearly ideal material for infrared sensor applications because of its strong IR absorption, its adjustable wavelength sensitivity, and its favorable semiconductor properties. Since the first investigation of this material system, more than fifty years ago (Lawson et al., 1959), a great amount of resources has been devoted to the development and application of HgCdTe-based sensors. Today HgCdTe focal plane arrays are widely used for both military and civil purposes.
Also very far away objects are more IR by two mechanisms:
1. The well known "red shift" due to higher speed.
2. Frequency downshift caused by interstellar gas. So some sources might not be as far away / as fast as previously thought.
Closer stars and even brown dwarfs have plenty of IR.
So there is some advantage in buying a computerised mirror based 'scope that takes a camera adaptor. A lens based one might attenuate the IR more and focus is more affected?
