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image intensifer with 0.7nm ha filter

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#1 highfnum

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Posted 06 December 2012 - 09:03 PM

I just tried omega 7A ha filter with 80 pct transmission
With image intensifier
Very smooth image

#2 GlennLeDrew

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Posted 06 December 2012 - 10:29 PM

The title states 0.7nm (which would be a very narrow bandpass appropriate for solar prominences), yet the body of the post states 7nm (which is good for nebulae); which is it? And what did you observe fir this test?

#3 highfnum

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Posted 06 December 2012 - 11:16 PM

7A is 0.7nm 7A is angstroms
10A = 1nm
but I will check with spectroscope tomorrow
yes normally for solar - but solar Ha and I got a couple have low tramsmission rates
50 pct or less
this one for night sky has 80 pct
so II does not get photon starvation

I tried solar Ha on II - NG noise level skyrockets

i tried new one on horsehead tonight - best view in II so far

#4 highfnum

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Posted 07 December 2012 - 04:37 AM

one more thing
5-10 A is good form proms only for solar Ha filter types
a true solar filter to see surface has to be 1A (.1nm) and lower (0.7A)
thats 10 times more narrow than this filter

#5 Jim Chung

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Posted 07 December 2012 - 11:36 AM

Here's my dilemma. I've been experimenting with a wide bandpass Ha of about 20 nm and a superfast Schmidt camera modified for visual use, 300mm focal length and f/1.2 and when I view with a Gen 3 II in very light polluted Toronto I can't see that much. M42 is as visible as on the Collins I3 website but I cant make out the North American nebula and even M27 is very very hard to discern. Very disheartened because I wanted to use this superfast setup for public outreach.

Any comments?


Jim

#6 highfnum

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Posted 07 December 2012 - 12:13 PM

20nm seems very wide
10nm is the most open one I have
Also you must use shields from stray light
Do you have layout and any pics

#7 highfnum

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Posted 07 December 2012 - 12:14 PM

Go to my gallery I got lots of pics with ii

#8 Jim Chung

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Posted 07 December 2012 - 12:30 PM

I always thought the wide bandpass would compensate for the shift in peak filter transmission due to fast optics.


Your gallery is phenomenal. So the images you captured with your Canon are similar to what you see visually? And these were taken at a dark site, not city and without Ha filter?

Do you have any Ha filtered images?

#9 highfnum

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Posted 07 December 2012 - 12:37 PM

Most with Ha filter except galaxy shots
60 miles from center of Manhattan
Photos slightly brighter than human view
But all that is in photo you can see

#10 BrendanF

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Posted 07 December 2012 - 07:10 PM

Here is a nice Cloudy Nights article about image intensifier eyepieces and narrow band H-alpha filters:

Collins I3 "System"

#11 jdbastro

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Posted 07 December 2012 - 08:07 PM

So you are saying that you can see HII regions (like Rosette, Horsehead) with a 0.7nm H-alpha filter and your image intensifier (II)?

I have used a 7nm (Baader) and 12nm (Astronmik) h-alpha filter with my II's with great success on HII regions.

I am VERY surprised to hear that a 0.7nm filter would give you sufficient light input without light starving your II. Where did you get this filter from?

Thanks.

#12 highfnum

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Posted 07 December 2012 - 09:41 PM

I was happy about it also
There is as far as I know this the most narrow filter
For night time
Omega optical

#13 StarStuff1

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Posted 07 December 2012 - 10:37 PM

Rosette, HorseHead, Barnard's Loop, California, Heart and Soul Nebs, Pacman, etc are easy with a Gen III and Ha filter and a 70mm fast scope. I have experience with a Gen I but not Gen II.

#14 PEterW

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Posted 09 December 2012 - 11:55 AM

Anyone got any useful results with a narrow OIII (or SII etc) filter? Interested to see if things still work?

Cheers

pEterW

#15 highfnum

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Posted 09 December 2012 - 12:31 PM

I tried SII OIII - nothing as good as Ha
SII second best because its in red region
OIII nuttin much I3 do not work well in green area
when weather breaks ill try to get some test shots
until then nuttin to do but drink a little

#16 ccs_hello

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Posted 09 December 2012 - 02:04 PM

Jon,

A question for ya...
I thought Etalon is the popular mechanism to deliver sub-nm scale narrow-band imaging, while Omega Optical makes a lot of interference filters which rarely go narrower than 10nm?

Can you describe the narrow-band filter you use?

Clear Skies!

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#17 highfnum

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Posted 09 December 2012 - 02:34 PM

etalon is used for sub Angstrom - thats 1/10 of 1nm
like pst and lunt solar scopes .5-.9A - that is less than
1A and 10A = 1nm (etalon = mucho money)
Omega Optical method 10nm = 100A are the relative easy ones
but their method can go down to 1.5A (uh price goes up)
this narrowband is 7 to 8A interference filter
lately there has been progress in mnfg methods

once weather breaks im hoping to take series of shots
with spectroscope
it real cool looking thru a 1nm filter - you can see just how narrow it really is

the h-alpha line is about 1.2A wide
here is shot thru my spectroscope - the thick line
is ha - just think an etalon 'Goes inside that line!"

http://www.cloudynig...php?photo=17725







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