Old 09-11-2019, 07:43 PM
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SuperG is offline
Join Date: Oct 2014
Location: Sydney, NSW
Posts: 117
Sky Glow and UHC Filters

I only do DSLR or OSC imaging with an ED80 and I've had a Baader Neodymium filter for ages and not really used it. I used it last month on a whim and it seemed to help immensely against the increasing impact of skyglow on nebula from Northern Sydney.

Question is will a UHC filter improve things over the Neodymium? Do you have any reccomendations to improve nebula contrast and any comparative examples?

I'm looking at the Astronomik UHC-E as price is really attractive ($189). I know there are dual band filters (ZWO Duo band and Optolong L-eNhance) but I'm not so sure about those.
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Old 10-11-2019, 12:38 PM
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HeavyT is offline
Join Date: May 2019
Location: South Australia
Posts: 46
UHC filter

Hi SuperG

I use a Baader UHC-S with my DSLR through an ED100. I find it helps a lot, cutting light pollution and resolving detail. I don't have comparative images without the filter as I've never done longer than 40 second exposures in my bortle 5 skies without it. But I'll attach a recent M17 with and without curves stretching so you can see the detail I've been able to bring out with the UHC-S. I haven't compared the specs of this filter with the filters you're considering though, I assume they might be similar. It's a duo Ha Oiii fairly broad "narrowband" pass filter, as I understand it. I'm very new to this, about 6 months in.

Hope this helps.
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Old 10-11-2019, 10:44 PM
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RyanJones is offline
Join Date: Jun 2018
Location: Melbourne,Australia
Posts: 1,238
Hi SuperG,

I am also a DSLR imager in Bortle 8 Melbourne skies. I tried CLS filters initially to deal with LP and they probably doubled my possible exposure time ( all other settings being equal ). With the UHC or the CLS style broadband filters there are always colour cast issues to deal with. Not that this is a big issue but it is something you will need to address in post processing. Then we move on to the UHC-E ( or similar). Better imaging filters for sure but they do require significantly longer exposures to achieve the same amount of luminance. They handle stars much better preventing bloating as much, generally giving a shaper image. Bare in mind though that longer exposure times require more accurate tracking/guiding. Finally we get to the Duos. I use the STC Duo although I know others that use the L-Enhance. These are genuine dual band narrow band filters. Because of their tight band widths they are absolute game changers but it comes at a price ( not just the hefty financial one ) . The required sub lengths are looooong. To be honest I think far too long for an 80mm refractor with a DSLR. This does depend on how good your camera is but upwards of 5 min exposures, youíre likely to get lots of artifacts in the image. DSLRs donít tend to like exposing for that long. If you canít take super long subs then the alternative is to take hundreds of subs. Of corse you could end up doing what I ended up doing and just doubling the size of your scope...... more money......

I hope this insight helps. My advice in short is grab the UHC-E and give it a go. If itís not giving you what you want, they tend to sell pretty quickly in the classifieds.


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Old 11-11-2019, 07:39 AM
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Dark sky rules !

skysurfer is offline
Join Date: Dec 2011
Location: 52N 6E (EU)
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Yes. I have an Astronomik UHC-E clipin, but it is also available as a normal 48mm filter.

UHC-E is very good. I use this filter even in Bortle 6 skies but can make pictures of faint red Halpha nebulas like IC1396 or IC1805 (Heart Nebula) with my unmodded 6D.

And I also used this filter once on the LMC and it shows lots of Halpha nebulas in the LMC.
Attached: NGC 7000 and IC1805 under Bortle 6 home skies, Vela supernova remnant (under better skies from Parkes NSW).
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Old 18-11-2019, 09:29 PM
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NorthernLight (Max)

NorthernLight is offline
Join Date: Sep 2008
Location: Auckland, NZ
Posts: 340
I started in Bortle 8 Melbourne skies, then added the CLS, then spectrum modified my 450D, then added a UHC, then bought the STC dual. All of these steps are improvements visibly in each image. The STC is a step up from UHC but totally superior to CLS, which is twice the contrast on naked sensor. The filters don’t change colour cast on modified DSLRs-only on unmodded ones.
Exposure times are not longer when using narrow filters. You’re just able to expose for that long without swamping the sensor with skies glow.
If you pick up noise on a 6 min exposure, either do more subs or get a better camera, maybe with cooling or focus on the winter months.

Clear Skies!
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