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HyperTuned CGEM and G11wG2 SV115T20, Meade SN-8, AT-66, and modified 20d. Nebulosity, SkyTools3, TSX, and Pixinsight.
Photo: Qhy9 mono + qhy 5x2" filter wheel and Baader 2" LRGB, Ha, O3 and S2 filters , Meade DSI Pro 2 as guider, TS 9mm off-axis guider Binoculars: Nikon Action 12x50 Telescopes: Skywatcher Evostar 120ED f7.5 APO + TS 2" flattener Mounts: HEQ5 Pro Eyepieces: Nagler 11mm type6, Pentax XW 7mm, Televue 2X barlow 1.25"
Quote: The photographic LRGB filters include UV/IR blocking so if you use such with your Atik you should not worry about such problems.
Quote:hungerford:- if you are using an achromatic refractor (or anything other, just very low-end type (cheap) telescope) than that's pretty normal- even an ED refractor is not perfect in UV, i.e. namely in Blue channel the UV leaks in and makes really bigger B-channel stars then it should (on one side, the B-stars are normal to be bigger as stars are either yellowish or bluish and that color must be shown somehow, on the other side, using e.g. IDAS LPS-P2 that cuts out UV or Baader UV/IR Block that blocks from 420nm to 6xx something really helps! - I am using it with my ED).- CCD filters - are you using dedicated LRGB CCD filters for CCD imaging? they are supposed to cut UV/IR. But that's not completely true. The Astronomik or Baader or OrionUSA filters are far from perfect, they all leak. On the other side Astrodons are "perfect" but have other problem - in the Blue color they pass 100% (have 100% transmittance) already before 400nm wavelength (like from 380nm up) and this is problem for all refracting optics (lenses...) while this is perfect for mirror systems (reflecting optics). I am using Astrodons with IDAS LPS-P2 or with Baader UV/IR when I do LRGB imaging with my only ED-like telescope. For Newtonian I do not need to.what I describe are common issues that took me 2-3 years to understand and discover and resolve good luck!
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Quote:Hi PavelIs some UV really a big issue?ThanksAndy
Quote:Quote: The photographic LRGB filters include UV/IR blocking so if you use such with your Atik you should not worry about such problems. True but if you have a CRGB filter set the C (Clear) filter has no IR block. The debate rages on whether it is advisable to use C or L with reflecting telescopes with reasonable arguments on both sides depending on your goals. I bought my first filter set used and the seller had no idea if his was a clear or luminance filter. Simple to test -- if your IR TV remote works through the filter it is a clear filter if it doesn't it is luminance. Turned out his set was LRGB. Rick