Quote:
Originally Posted by Ukastronomer
I have the ASI 178MM (for Solar) with my Daystar Ha.
The Mono camera has no IR filter (unless I am mistaken)
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It appears you're not mistaken as the Spectral REsponse: QE v Wavelength curve (attached below for the ASI 178MM) shows significant response well past the visible light range and into the near infra-red at wavelngths of 700 nm and longer, suggesting that there is no specific IR cut filter fitted.
Quote:
Originally Posted by Ukastronomer
and I removed the IR cut filter from my NexImage 5 camera understanding that imaging the Sun was better without them.
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That's a different camera which I don't have the spectral response of: however;
IF the Next Image 5 camera's IR cut filter was let's say too drastic, it may have eliminated some of the wanted Hydrogen Alpha (656.3 nm) response
and so removing it in that case may be beneficial. It's not possible to say that with any certainty without knowing the spectral response of the camera.
Quote:
Originally Posted by Ukastronomer
Therefore why would you add an IR blocking filter (other than to reduce heat) to a diagonal, surely that defeats the puropse of not having a filter in the camera ???, and under 80mm it is not needed anyway in the scope
Thanks
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IF you're not using the Quark H-Alpha Eyepiece Solar Filter with the ASI178,
THEN consider that....
The Sun has considerable spectrum outside the visible light range (see 2nd attachment). If you were imaging The Sun then adding a IR filter, would certainly (as you say) reduce transmitted heat, but it would increase sharpness/contrast by reducing the bloating/de-focus caused by the likely inability (or reduce ability) of the telescope's optics to focus evenly across the entire (Very Wide) input bandwidth of the light entering the telescope, well past 700 nm.
ELSE...
Don't worry about it. Conceivably it might extend the life of the upstream optics/coatings/camera due to reduced bandwidth and heat
OR, If the Telecentric Optics inside the Quark H-Alpha Eyepiece Solar Filter, PRECEDE its internal Solar filter then maybe there's a benefit
Best
JA
