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Old 27-08-2018, 11:38 PM
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astronobob (Bob)
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Does LRGB Imaging cut through Light Pollution ?

Howdy Astro-liano's / IISpacer's

I have a noob question

As a couple may know, I have myself a mono asi 290 uncooled with the mini 5 position electric filter wheel & LRGB Filters which i have just loaded the filters into and will attach to my 10" F4.6 newt - not much hitting the sensor, but thats ok for now!

Anywho, I was looking at the Luminance filter and it doesNot look very dark, hence my question, does this Luminance filter actually cut through Light Pollution or do I need a Ha Filter and/or something else ?
I am guessing the RGB filters do cut through Light pollution but not 100% sure either ?

All new to me, I have never even held such filters before today
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Old 28-08-2018, 12:08 AM
LewisM
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Nope, LRGB filters do NOT cut through LP - only Narrow Band (NB) does: Ha, OIII, SII etc. (actually these filter out the LP bandwidths, not "cut through")

Using LRGB filters yu'll suffer the same as with an OSC CCD or DSLR.

BTW, a luminence filter should be perfectly transparent
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Old 28-08-2018, 08:10 AM
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Bob, some LRGB mono users who image under LP have chosen to replace their Lum filter with an IDAS LP filter, which will help a great deal, but not so much with some of the newest LED street lighting.
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Old 28-08-2018, 08:29 AM
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Some RGB filter sets leave a gap to reduce the effect of older style street lighting, but as noted by Andy that doesn't help with new LED street lighting.
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Old 28-08-2018, 12:04 PM
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astronobob (Bob)
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Quote:
Originally Posted by LewisM View Post
Nope, LRGB filters do NOT cut through LP - only Narrow Band (NB) does: Ha, OIII, SII etc. (actually these filter out the LP bandwidths, not "cut through")

Using LRGB filters yu'll suffer the same as with an OSC CCD or DSLR.

BTW, a luminence filter should be perfectly transparent
Appreciated very much Lewis & sorry for my lack in definition on 'cutting through' yes should be 'cut out' ...
& Yes, this Lum Filter is totally transparent, apart from a slight tinge, most likely a coating of protection or anti glare or some sort but yes very transparent !
Geeze, astronomy for this duck - one step forward - two steps backward
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Quote:
Originally Posted by Andy01 View Post
Bob, some LRGB mono users who image under LP have chosen to replace their Lum filter with an IDAS LP filter, which will help a great deal, but not so much with some of the newest LED street lighting.
Cheers Andy I do have a baader uhc-s filter which apparently blocks both sodium & mercury street lighting - I have two streetlights, both within 100mtrs, both being one of each color Being an older suburb, I doubt any LED's will be installed anytime soon, touch-wood
Have only used the uhc-s a few of times, years ago, didnt like it due to star colors being drastically shifted, tho maybe worth more experimentation ?
,
,
,
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Quote:
Originally Posted by RickS View Post
Some RGB filter sets leave a gap to reduce the effect of older style street lighting, but as noted by Andy that doesn't help with new LED street lighting.
Cheers for your confirmation there Rick
BTW, looking forward to your wide fields with ya new kit, man, sheese, that was a dads-day pressy, more like a 2 yr investment for this duck
Kind Rgrds ...

Last edited by astronobob; 29-08-2018 at 11:20 PM.
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Old 28-08-2018, 05:50 PM
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ZeroID (Brent)
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From my understanding the 'L' filter is a UV\IR cut filter. That's what ZWO told me when I enquired and bought the 1600mm-c kit with EFW and filters. Is this not the case ?
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Old 28-08-2018, 06:40 PM
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You are right Brent, Luminance usually blocks anything below 400nmm and above 700nm. I believe Lum filter is meant to be used with refracting telescopes to help controlling chromatic aberration of light that is invisible to human eye but nonetheless picked up by the camera - without such filers stars would have been larger/more bloated with fast refracting telescopes that are commonly used for imaging.
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Old 29-08-2018, 11:26 PM
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astronobob (Bob)
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Quote:
Originally Posted by ZeroID View Post
From my understanding the 'L' filter is a UV\IR cut filter. That's what ZWO told me when I enquired and bought the 1600mm-c kit with EFW and filters. Is this not the case ?
Cheers for adding this Brent, very informative Now you have cursed me with Filter researching to do which is a very good thing - i think
,
,
,
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Quote:
Originally Posted by Slawomir View Post
You are right Brent, Luminance usually blocks anything below 400nmm and above 700nm. I believe Lum filter is meant to be used with refracting telescopes to help controlling chromatic aberration of light that is invisible to human eye but nonetheless picked up by the camera - without such filers stars would have been larger/more bloated with fast refracting telescopes that are commonly used for imaging.
Thank you for the added 'clarity' <- pun, there Suavi, interesting indeed
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