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best filter for nebula

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#1 wheelers4life

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Posted 29 October 2019 - 08:23 PM

I have a celestron edge hd 8. I hust recieved my .7x reducer today. I am looking for a filter that I can use to try out on nebula. I have read many differnt types of filters. Most seem to say for visual. What would be good for EAA I was thinking about a skyglow, narrowband filter or ultra contrast filter. I have been looking at the ring, lagoon, viel, orion, and horsehead filter. have been looking at some clusters as well. I need the 2 inch that will go on my zwo asi 294 pro mc cooled

Thanks



#2 Umasscrew39

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Posted 30 October 2019 - 04:01 AM

By far the best is the Optolong L-eNhance filter for nebulae.  I use it on my C11" EdgeHD with my ZWO ASI294MC Pro for emission nebulae and have gotten excellent results. 


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#3 NaNuu

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Posted 30 October 2019 - 05:32 AM

I agree, if observing in heavy light polluted areas, a dual- or tribune filter is a very good thing. There are different brands (i.e. I'm experimenting with an IDAS NB1 filter, essentially the same thing), so you might search for "dual band filters".

 

But be aware that these filters cut out much of the light hence usually you will need much longer single frame exposures to get something to see. 


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#4 sudeepban

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Posted 30 October 2019 - 06:28 AM

I feel like the Optolong L-eNhance filter is the one I most consistently hear of people using with success, and I've considered it as a next step for improving my EAA setup (8SE, 294MC Pro, f/6.3 reducer) given the light pollution an hour north of NYC. I had a couple of questions about adding it:

1. Would this be useful for imaging nebulas only? No use for galaxies?
2. Where in the optical train does it go exactly? Could it impact backfocus for the reducer?
3. Are these useful for visual as well as imaging? I have 1.25" filters and eyepieces, do I need to go for 2.00" for use with the camera?

#5 Umasscrew39

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Posted 30 October 2019 - 07:01 AM

I feel like the Optolong L-eNhance filter is the one I most consistently hear of people using with success, and I've considered it as a next step for improving my EAA setup (8SE, 294MC Pro, f/6.3 reducer) given the light pollution an hour north of NYC. I had a couple of questions about adding it:

1. Would this be useful for imaging nebulas only? No use for galaxies?
2. Where in the optical train does it go exactly? Could it impact backfocus for the reducer?
3. Are these useful for visual as well as imaging? I have 1.25" filters and eyepieces, do I need to go for 2.00" for use with the camera?

I also suffer from LP and bad humidity just north of Orlando.  So, I know what you mean.

 

1- I have tried it on M31 and some star clusters.  It is ok but not great.  Suggest you try something like the Optolong L-Pro, the IDAS LPS D-1 (has worked well for me in the past), or one of the many UHC filters on the market.  Frankly, I've not found many to help much on galaxies.

 

2- Depends on your setup.  I use a filter wheel which goes before the reducer which connects directly to the scope.  So, it is camera-filter wheel with filter-reducer-scope using appropriate spacers to meet backfocus requirements.  This does not impact backfocus requirements.  Other options for filter placement are in the ZWO instructions.

 

3- I never tried it for visual.  Both sizes work well with a camera.  


Edited by Umasscrew39, 30 October 2019 - 08:34 AM.


#6 Clouzot

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Posted 30 October 2019 - 08:25 AM

Jim Thompson started a very interesting comparison of LP filters for EAA in this forum. You may want to check it out!

I recently got two different LP filters: the ubiquitous Optolong L-Enhance (mentioned above), and the IDAS LPS-D2. Both came as 2" filters, which I can easily thread into my Hyperstar.


My current setup: C9, ASI183MC uncooled, Hyperstar v4, Sharpcap.

 

I ran some quick comparisons with and without the IDAS fiter, on the same night. My sky is probably between Bortle 6 and 7 (the Milky Way is not visible).


Here is a side-to-side comparison of M33 with either the IDAS, or no filter at all.

In both captures:

- No flats, as can be seen from the vignetting.

- Gain 118, 30s subexposures

- no Sharpcap enhancements applied

- Sharpcap livestack histogram autostretch for both captures.

- no general histogram stretch

 

The only difference is the resulting histogram: the IDAS cuts a lot of light, so at this gain and exposure, there's little signal. I had to balance whites manually to compensate for the filter's tendency to put everything off, but the IDAS image retains its greenish cast...

 

Total integration time: 18min30s with IDAS, 20min with no filter.

 

Interestingly, the IDAS brings lots of detail that are barely visible in the no-filter shot. It also cuts stars (which an IR/UV cut would do as well I gather). On the negative side of things, it also gives that unnatural colored look to nebulas.

 

M33_compare.jpg


Edited by Clouzot, 30 October 2019 - 08:26 AM.

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#7 Clouzot

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Posted 30 October 2019 - 10:49 AM

Here's a comparison shot of part of the Cygnus Eastern Veil (NGC 6992 etc) between IDAS LPS-D2, Optolong L-Enhance and no filter, all done with the same setup as above. This was the first light of both filters, so please bear with me!

 

No filter: 20x30s = 10 min total

Optolong: 20x30s = 10 min total

IDAS D2: 17x15s = 4m15s total

 

I realize that shooting 15s subs with the IDAS instead of 30s and integrating twice less wasn't my best move (at least for comparison purposes) grin.gif

 

It's really, really hard to compare apples to apples with these filters, as the histogram black/mid/white points and the white balance will always be different from capture to capture.

 

What is again evident is the contrast you can gain by using this type of filter. But they really need longer exposures, probably more like 45s or 1 minute even at f/2. It's already a bit too much

That, in turn, implies a better mount, a better polar alignement... Not something you want to fiddle with during an EAA session.

NGC6992_comp.jpg


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#8 wheelers4life

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Posted 10 November 2019 - 06:46 PM

Quick question. My zwo asi 294 has what looks like an adapter that holds a 1.25 filter and screws in very close to the sensor. Has anyone seen this. Would it be ok to use. I can knock off a heft amount going with 1.25 filters instead of 2"

#9 donstim

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Posted 10 November 2019 - 10:27 PM

Yes, that is an adapter for a 1.25 inch filter. It puts the filter very close to the camera sensor. I feel it works well, and that it what I've been using.

#10 Ptarmigan

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Posted 10 November 2019 - 10:38 PM

Quick question. My zwo asi 294 has what looks like an adapter that holds a 1.25 filter and screws in very close to the sensor. Has anyone seen this. Would it be ok to use. I can knock off a heft amount going with 1.25 filters instead of 2"

I have a ZWO ASI294MC Pro and I have used the adapter that allows 1.25 filter to be close to the sensor. I have had no trouble with it and I use the Lumicon Deep Sky filter.



#11 wheelers4life

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Posted 10 November 2019 - 11:43 PM

Thanks. Yall are awsome
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#12 Clouzot

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Posted 28 August 2020 - 04:55 AM

A very quick filter test I did yesterday with a simple setup :

 

- EvoGuide50 (50mm ED doublet refractor)

- AZ-GTi in equatorial mode

- city center, Bortle 8

- 75% moon

- 30s subs, 10 minutes integration

- livestacking and color balancing in Sharpcap

 

comparo M27.jpg

 

Each to their own, shall we say... The L-Enhance clearly wins (signal-wise) on this one object, but I'm not sure I like the turquoise cast (faint stars, M27 itself) it gives, which I couldn't correct during the livestack despite all my efforts. The IDAS is far more balanced but gives less SNR.

 

(links to the original, no flats FITS for testing purposes:

NO FILTER : http://dl.free.fr/m75o9gNfM
LENHANCE : http://dl.free.fr/oTocUWlcR
IDAS LPS D2 : http://dl.free.fr/oVjg3VXwB

)


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#13 JMW

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Posted 31 August 2020 - 01:04 PM

I appreciate this thread. I was all set on buying the Optolong L-eNhance filter. I read a little more on the imaging forum and found about the Optolong L-extreme. It has a pair of 7nm wide pass bands for Ha and OIII. My home is very light polluted. I am going to get the Optolong L-extreme when they get back in stock.

 

I have been waiting for the smoke to clear for the last 9-10 nights. I have a new ASI2600MC Pro to try out. Since the moon is almost full I was going to try it with a 7nm Ha filter. I may have to wait another 3-4 nights for the smoke to clear out. I am waiting for the ZWO M42 filter slide so I can used it with my refractor or in front of my Hyperstar lens on the C11 EdgeHD.


Edited by JMW, 31 August 2020 - 01:24 PM.


#14 Clouzot

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Posted 01 September 2020 - 04:39 AM

@JMW you may also have a look at the IDAS NBX (should be pretty similar to the L-Extreme, perhaps a bit wider though).
Re. the Hyperstar, maybe your model could already accept a filter? Mine does, it’s somewhat impractical as you have to remove the camera but it’s reasonably close to the sensor so reduces the reflections to something manageable

#15 JMW

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Posted 01 September 2020 - 11:06 AM

I have the M42 filter drawer from ZWO on order. I will have it Saturday. It goes directly in front of the camera and will be useful for Hyperstar with a diameter smaller than my ASI2600MC Pro and for my use on my refractor or Newtonian.



#16 Barkingsteve

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Posted 01 September 2020 - 11:17 AM

I use the altair astro tri band filter from my bortle 8-9 skies with my 294mc pro and it works great. Here is a spreadsheet from last year from Space Oddities on the stargazers lounge forums that may be of interest.

 

363873377_Screenshot222.thumb.jpg.022747af1b43df8d786e2589e3149549.jpg



#17 Clouzot

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Posted 01 September 2020 - 02:36 PM

I have the M42 filter drawer from ZWO on order. I will have it Saturday. It goes directly in front of the camera and will be useful for Hyperstar with a diameter smaller than my ASI2600MC Pro and for my use on my refractor or Newtonian.

How does the LExtreme react to the fast F/D of the Hyperstar? Maybe the Starizona guys know (I bought the L-Enhance from them and they assured the shift would be insignificant - and it is, but it’s way wider than the L-Extreme)

#18 JMW

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Posted 01 September 2020 - 05:23 PM

I don't own it and haven't used it yet. I have been primarily using a SVR102T refractor with 0.8 focal reducer/flattener. My 2nd most common imaging scope is an f/4 10 inch newtonian. It has been about 4-5 years since I had the C11 EdgeHD mounted for imaging. I don't like to use Hyperstar at home because light pollution is too bad.

 

I use the Hyperstar setup mostly when I go to dark sites for multi-night star parties like the GSSP or OSP. I imaged a lot when my wife was going back to school for her BSN but now she comes on all the GSSP and OSP trips. I prefer not to image when she is with me since it feel like I am ignoring her. 

 

I have been imaging at home more or doing EAA since she is nurse and goes to work very early. I go out and image after she goes to bed.


Edited by JMW, 01 September 2020 - 05:29 PM.



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