Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Best light pollution filter for a bortle 9 zone?

  • Please log in to reply
17 replies to this topic

#1 krenyi

krenyi

    Sputnik

  • *****
  • topic starter
  • Posts: 28
  • Joined: 16 Jun 2019

Posted 19 August 2019 - 05:29 PM

As title stated, what is the best LPS filter for high light pollution area? 

 

I'm using IDAS D1 filter and stuff came out alright after ALOT of post processing. Plus it is near impossible to frame object right, since I can't see anything beside some bright stars, and the test exposures (up to 60s) just comes out almost completely white, I just have to pray that my polar alignment was good and the object is even in frame and not cut off. 

 

I'm using D5300 (unmoded) and Z61 with field flattener. 

 

Do I have to resort to narrowband filters? I do strongly prefer broadband filters, so that I'm not spending double or triple the time capturing Ha, OIII and/or SII... Thank you!


Edited by krenyi, 19 August 2019 - 05:33 PM.


#2 pfile

pfile

    Fly Me to the Moon

  • -----
  • Posts: 5129
  • Joined: 14 Jun 2009

Posted 19 August 2019 - 05:37 PM

if you can find a camera control package that works with the nikon and supports plate solving, that will solve the pointing problem you have.

 

when i was doing this i felt the CLS gave too much of a color cast.

 

are you saying that 60s exposures thru the filter are completely white? that actually sounds pretty hopeless if so.

 

rob



#3 Augustus

Augustus

    Fly Me To The Moon

  • *****
  • Posts: 7902
  • Joined: 26 Dec 2015
  • Loc: Connecticut

Posted 19 August 2019 - 05:38 PM

Gasoline


  • Stelios likes this

#4 Jim Waters

Jim Waters

    Mercury-Atlas

  • *****
  • Posts: 2761
  • Joined: 21 Oct 2007
  • Loc: Phoenix, AZ USA

Posted 19 August 2019 - 06:47 PM

NB filters would your best bet, only bet for imaging.  But expect very long sub times.



#5 17.5Dob

17.5Dob

    Fly Me to the Moon

  • ****-
  • Posts: 5159
  • Joined: 21 Mar 2013
  • Loc: Colorado,USA

Posted 19 August 2019 - 07:09 PM

If you don't want to invest in a monocam/ NB filters, your only choice is to drive somewhere darker to shoot your dSLR


Edited by 17.5Dob, 19 August 2019 - 09:40 PM.


#6 Ballyhoo

Ballyhoo

    Soyuz

  • *****
  • Posts: 3814
  • Joined: 22 Jul 2011
  • Loc: San Diego

Posted 19 August 2019 - 08:40 PM

I got the Astronomik CLS for a red zone, I think bortle 5 or 6, but it should be fine for you too. I am sorry you asked about LPB and you got a lot of responses but other things but I woud consider the CLS



#7 krenyi

krenyi

    Sputnik

  • *****
  • topic starter
  • Posts: 28
  • Joined: 16 Jun 2019

Posted 20 August 2019 - 12:36 AM

I got the Astronomik CLS for a red zone, I think bortle 5 or 6, but it should be fine for you too. I am sorry you asked about LPB and you got a lot of responses but other things but I woud consider the CLS

I actually had the Skytech CLS CCD clip in filter for Canon before I switched to Nikon.

 

I was able to see faint DSO I was looking at through test exposures, as oppose to nothing. But I thought the IDAS filter is a little better? 


Edited by krenyi, 20 August 2019 - 12:36 AM.


#8 krenyi

krenyi

    Sputnik

  • *****
  • topic starter
  • Posts: 28
  • Joined: 16 Jun 2019

Posted 20 August 2019 - 12:39 AM

if you can find a camera control package that works with the nikon and supports plate solving, that will solve the pointing problem you have.

 

when i was doing this i felt the CLS gave too much of a color cast.

 

are you saying that 60s exposures thru the filter are completely white? that actually sounds pretty hopeless if so.

 

rob

This is what North America nebula looks like after 60s sub at around 11pm. It is right at the center... I was lucky that it pointed the right way.

Annotation 2019-08-20 003823.jpg

 

And this is what it looks like after a load of processing.

Annotation 2019-08-20 004622.jpg


  • bobzeq25 likes this

#9 krenyi

krenyi

    Sputnik

  • *****
  • topic starter
  • Posts: 28
  • Joined: 16 Jun 2019

Posted 20 August 2019 - 12:51 AM

NB filters would your best bet, only bet for imaging.  But expect very long sub times.

Yes, that is what I'm trying to avoid, long imaging sessions... that might stretch over days. Since I have early wake up time, I can not stay up late. 



#10 krenyi

krenyi

    Sputnik

  • *****
  • topic starter
  • Posts: 28
  • Joined: 16 Jun 2019

Posted 20 August 2019 - 12:56 AM

If you don't want to invest in a monocam/ NB filters, your only choice is to drive somewhere darker to shoot your dSLR

I have considered to do that, but sitting in the dark by myself for 2+ hours in the wild isn't the most romantic sounding thing to me. I could bring my dob to do visual while I wait, but you can't see anything interesting visually unless you drive hours away from the city, which means no sleep. 

 

It is just too much work to do for me for imaging... 



#11 krenyi

krenyi

    Sputnik

  • *****
  • topic starter
  • Posts: 28
  • Joined: 16 Jun 2019

Posted 20 August 2019 - 12:59 AM

Any Baader/Optolong filter that is good? I have heard of the Triad quad-band filter, but that thing costs more than my imaging setup...



#12 james7ca

james7ca

    Fly Me to the Moon

  • *****
  • Posts: 7331
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 20 August 2019 - 03:24 AM

When doing deep space astrophotography it is quite common to get very heavy color casts in your images. Without filters and assuming that you have your camera's color balance set to daylight you'll usually get a very green image, but when using so-called light pollution filters that color can even be toward blue. Of course, heavy light pollution can also color tint your image toward red (generally). So, don't expect to see much in the way of faint detail until you've color balanced the image or have neutralized your background. This may be why your image in post #8 looks so "bad" prior to any processing.

 

Quite frankly, if you have very severe light pollution the only filter that will probably help is an H-alpha and then only if you are imaging emission nebulae (although SII will also work, but most objects don't have a lot of emissions in SII).

 

Of course, you can always concentrate on objects like star clusters and planetary nebulae which are often so bright that they can be captured under a level of light pollution that would normally "kill" anything else.

 

You may want to review the following thread (has lots of information about light pollution filters and their use with DSLRs):
 

  https://www.cloudyni...s/#entry5950255



#13 Chuckwagon

Chuckwagon

    Viking 1

  • *****
  • Posts: 748
  • Joined: 23 Jan 2008
  • Loc: Orem, Utah, USA

Posted 20 August 2019 - 03:25 AM

if you can find a camera control package that works with the nikon and supports plate solving, that will solve the pointing problem you have.

APT supports Nikon and plate solving.



#14 pfile

pfile

    Fly Me to the Moon

  • -----
  • Posts: 5129
  • Joined: 14 Jun 2009

Posted 20 August 2019 - 08:38 AM

This is what North America nebula looks like after 60s sub at around 11pm. It is right at the center... I was lucky that it pointed the right way.

attachicon.gif Annotation 2019-08-20 003823.jpg

 

And this is what it looks like after a load of processing.

attachicon.gif Annotation 2019-08-20 004622.jpg

well those do look pretty typical of an image taken in LP with some kind of LP filter. i think the CLS might be a little stronger at cutting LP but the color casts will be worse. i had no luck imaging galaxies thru that filter but emission nebula are fine.

 

since i switched to a mono cam with astrodon filters, i'm able to do RGB from this red zone but i have to put 30-40 hours on each target, which is hard. with an uncooled DSLR i think what i'm doing now would largely be impossible.

 

rob



#15 krenyi

krenyi

    Sputnik

  • *****
  • topic starter
  • Posts: 28
  • Joined: 16 Jun 2019

Posted 20 August 2019 - 12:18 PM

When doing deep space astrophotography it is quite common to get very heavy color casts in your images. Without filters and assuming that you have your camera's color balance set to daylight you'll usually get a very green image, but when using so-called light pollution filters that color can even be toward blue. Of course, heavy light pollution can also color tint your image toward red (generally). So, don't expect to see much in the way of faint detail until you've color balanced the image or have neutralized your background. This may be why your image in post #8 looks so "bad" prior to any processing.

Quite frankly, if you have very severe light pollution the only filter that will probably help is an H-alpha and then only if you are imaging emission nebulae (although SII will also work, but most objects don't have a lot of emissions in SII).

Of course, you can always concentrate on objects like star clusters and planetary nebulae which are often so bright that they can be captured under a level of light pollution that would normally "kill" anything else.

You may want to review the following thread (has lots of information about light pollution filters and their use with DSLRs):

https://www.cloudyni...s/#entry5950255


I guess my main problem is alignment with the DSO. It’s impossible to see if I frame it right, or if it is even in frame most of the time.

But I’ll try out APT and see.

#16 bobzeq25

bobzeq25

    Hubble

  • *****
  • Posts: 16784
  • Joined: 27 Oct 2014

Posted 20 August 2019 - 12:48 PM

This is what North America nebula looks like after 60s sub at around 11pm. It is right at the center... I was lucky that it pointed the right way.

attachicon.gif Annotation 2019-08-20 003823.jpg

 

And this is what it looks like after a load of processing.

attachicon.gif Annotation 2019-08-20 004622.jpg

You're doing GREAT, for the time you've been at this.  That's an unmodded camera????

 

Tips.

 

Be sure to do gradient reduction in processing.  From the above image, I assume you are?

 

Platesolving is the way to go for acquiring the target.  I like PlateSolve2.  Once you've learned it (and it's one of the easier things to learn), it's fast.

 

Look at the histogram of a subexposure, either on the back of the camera, or in a terrestrial editing program.  Once it's 1/3 of the way over from the left, you gain _nothing_ with a longer exposure.  The correct thing then is to shoot more subs.  With one of my cameras, a recent image used 150 X 15 seconds, at F2 (which needs less total imaging time).  No (not so) magic light pollution filter was used, nor would one have been useful on this target.

 

http://www.astrobin....3196/B/?nc=user

 

320 X 7 seconds would have been better, too many stars are saturated.

 

Recognize that long total imaging times are required to do this well in light pollution.  It's just math, and there's no magic alternative.  Over time, signal tends to build, noise tends to average out.

 

My rule of thumb is one hour minimum, two is better, four is good.  My best results come from imaging the same target over multiple nights.

 

The ultimate solution is a cooled mono astro specific camera, and narrowband filters.  But then you are limited to certain targets.

 

My skies are Red Zone, Bortle 7, mag per arc sec squared low 18s.

 

That's it, in a nutshell.  More details on any of it on request.  <smile>


Edited by bobzeq25, 20 August 2019 - 01:07 PM.


#17 2ghouls

2ghouls

    Viking 1

  • *****
  • Posts: 750
  • Joined: 19 Sep 2016

Posted 20 August 2019 - 12:50 PM

I agree with others that platesolving should fix your framing issue if you can get it to work.

 

If you don't go forward with platesolving for some reason, I used to have the same problem as you when I shot with a DSLR in Bortle 9. What I used to do to fix it is plan out the exact framing I wanted with Imaging Toolbox or Astronomy Tools. Then take a screenshot, raise the contrast, and invert the image in photoshop, and print that out black and white. Using that it was easy to frame off the patterns of bright stars.



#18 RJF-Astro

RJF-Astro

    Explorer 1

  • -----
  • Posts: 89
  • Joined: 13 Aug 2018
  • Loc: Zeist, Netherlands

Posted 20 August 2019 - 04:09 PM

Yes, that is what I'm trying to avoid, long imaging sessions... that might stretch over days. Since I have early wake up time, I can not stay up late. 

This might be an extra reason to look at Ha. You can start your session earlier with Ha and you can image regardless of the moon. I currently do a lot of black and white Ha only and I find it very rewarding. Structure and detail come out nice, stars are small. It is a great way to practice techniques and work towards full narrowband or HaRBG. A modification or dedicated astro cam along the way will help.

 

Before I switched to a dedicated mono camera and narrowband, I used an unmodded D750 with and Optolong L-pro filter. It was ok I guess, but I did not see that much difference compared to no filter. I have bortle 6 here, so relatively easier for RGB. I would not want to go back to the DSLR though.

 

Now last month I was on holiday in a bortle 3/4 zone and I took my DSLR and tracker. That was a different story. With 30-60 minutes you get awesome RGB detail and color. Check my Astrobin for some examples of the above. 


  • bobzeq25 likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics