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Increasing the exit pupil in heavy light pollution

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#1 GR1973

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Posted 04 April 2020 - 09:16 AM

I want to observe M 37 in my area with Bortle scale 2. I observed M 36 and M 38 with success. I tried to observe M 37 with Panoptic 19 ( exit pupil 1.32). I did not succeed

 

Do I have better chance if I use my 32 Brandon with more than 2 mm exit pupil ? Dose increasing the exit pupil work with dim objects in heavy light pollution?

 

My scope is Questar 3.5 BB


Edited by GR1973, 04 April 2020 - 09:16 AM.


#2 davidmcgo

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Posted 04 April 2020 - 09:29 AM

No, other way around.  Higher magnification up to maybe 100x will help the stars stand out more.

 

Dave


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#3 davidmcgo

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Posted 04 April 2020 - 09:30 AM

Also, shielding your head around the eyepiece with a deep hood really helps.

 

Dave


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#4 sg6

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Posted 04 April 2020 - 09:31 AM

Might, as all you are doing is decreasing the magnification so getting a smaller but slightly brighter image. However M36 and M37 are so similar I would have expected both to be visible or both not to be visible.



#5 rcwolpert

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Posted 04 April 2020 - 08:09 PM

I looked at the Aur clusters 2 nights ago with the Questar 3.5 and Panoptic 19mm and wrote these notes:

M38: ~20 stars seen and some unresolved brightness at the center.
M36: Brightest of the 3 Aur clusters with some 30 pinpoint stars
M37: Seemed to be smallest and dimmest of the 3 clusters, but still nice to view.

 

I’m in a very bright gated community, so I think our observations should be about the same. I’d try again. You should definitely be able to pick it up.

 

Bob


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#6 Jon Isaacs

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Posted 04 April 2020 - 09:00 PM

No, other way around.  Higher magnification up to maybe 100x will help the stars stand out more.

 

Dave

 

:waytogo:

 

Stars, being points of light, don't change brightness at low to medium magnifications.  The sky glow/light pollution dims dramatically with increased magnification, double the magnification, the sky is 1/4 as bright.  This means the contrast is 4 times as great.  

 

Crank up the magnification. 

 

Of the three clusters, M37 is the most difficult because it lack bright stars. 

 

Jon


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#7 GR1973

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Posted 05 April 2020 - 05:17 AM

Thank you all for your nice suggestions. I observed it yesterday. My site is the white area of light pollution. I used setting circles with dialling the Alt/Az Coordinates. This has been described in another thread

 

and I found it more than excellent. It was impossible to locate the three Auriga clusters with methods other than coordinates dialling. I used my 24 Brandon (Contrast is higher than 19 Panoptic with recessed

 

eye lens and better shielding). It was a very dry day with 25% humidity. I saw the central star with two or three stars embedded in minimal haze that came and go. With averted vision, I saw few more stars.

 

Shielding the eyepiece with my hand was essential to see this faint cluster. When I engaged the internal barlow, all disappeared except the central star. This time the Brandon 24 beat Panoptic 19.  


Edited by GR1973, 05 April 2020 - 05:57 AM.

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#8 JamesMStephens

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Posted 05 April 2020 - 04:09 PM

What is your location, GR?



#9 GR1973

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Posted 05 April 2020 - 04:14 PM

What is your location, GR?

30 degree North


Edited by GR1973, 06 April 2020 - 09:07 AM.


#10 munirocks

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Posted 10 April 2020 - 03:49 AM

M37, The salt & pepper cluster, is one of my favourites. It is a very delicate and pretty cluster with no bright stars, and you're doing well to find it in light-polluted skies. Use the surrounding clusters to make sure your mount/setting circles are spot on (adjust alt-az lower down in the tripod if necessary), find it, then crank up the power to help it pop out. The longer you look, the more you see.


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#11 GR1973

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Posted 10 April 2020 - 04:07 PM

M37, The salt & pepper cluster, is one of my favourites. It is a very delicate and pretty cluster with no bright stars, and you're doing well to find it in light-polluted skies. Use the surrounding clusters to make sure your mount/setting circles are spot on (adjust alt-az lower down in the tripod if necessary), find it, then crank up the power to help it pop out. The longer you look, the more you see.

Thank you . Today, I checked the mount and setting circles with Polaris and M 38. I found M 37 with 19 Panoptic .

 

Then I engaged the barlow. I saw many stars that pops up and go with averted vision. With direct vision I saw the central star and three or four stars. All stars are in /or form an oblong.

 

Yes, The longer I look the more I see till my vision got exhausted.


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#12 RichA

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Posted 27 April 2020 - 07:45 PM

I want to observe M 37 in my area with Bortle scale 2. I observed M 36 and M 38 with success. I tried to observe M 37 with Panoptic 19 ( exit pupil 1.32). I did not succeed

 

Do I have better chance if I use my 32 Brandon with more than 2 mm exit pupil ? Dose increasing the exit pupil work with dim objects in heavy light pollution?

 

My scope is Questar 3.5 BB

I used a Clave 40mm and a genetic Celestron 32mm Erfle for deepsky years ago in a light-polluted sky.  There is no question increasing the power dramatically improves the distinction between a bright sky background and a DSO.  The Clave was inferior, despite have better-corrected optics.



#13 Simoes Pedro

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Posted 28 April 2020 - 08:15 AM

Baader Neodymium will help with light pollution. However, based on my experience, the effect is very minor, but has been proven to be the difference between detecting and not detecting an extremely faint object.

 

The great advantage of this filter is that it has a slight blueish tint which balances the orange cast of light pollution.

 

I second previous opinions. Increasing magnification actually allows you to see more.




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