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Questions about eyepiece filters

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#1 ReganJamesFord

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Posted 06 December 2018 - 02:09 PM

I have a Celestron C5 spotting scope, that came with a 45* erect image diagonal and a 25mm, 1.25 eyepiece.  It's my first scope and I'm trying to figure it out.  I have a few questions regarding filters. 

 

1- Do planetary filters help in focusing?  In other words, if I'm viewing Neptune and it's blurry, no matter how much I focus, is there a filter that helps?

 

2- I love using my scope for long distance nature watching.  Sometimes when it's hot, really sunny or when I'm looking over a body of water, my view has a little atmosphere/heat aberration.  Is there a filter to help with terrestrial viewing?

 

3- Lastly, I currently have a stock 25mm Celestron Plossl, a Celestron 8-24 zoom ep, and ES 82* 14mm wide view ep. Will all 1.25 filters work with my set up? Or could someone recommend a set of filters for what I have? 

 

Thank you.



#2 rowdy388

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Posted 06 December 2018 - 02:26 PM

1) No. The image is probably blurry because you are magnifying beyond the seeing conditions.

    No filter will help with that. Neptune is tiny and requires high mags and good seeing.

 

2) No. When the sun is out and you are trying to use high magnifications near the earth's surface,

there will be lots of that atmospheric/ heat aberration you mentioned. No filter helps. Just have to

settle for lower magnification for a clearer image.

 

3) Yes. Any 1.25" filter will work. Some people like colored filters. Mine just sit unused. The only

filters I recommend are narrowband filters such as UHC or Olll and only with exit pupils over 3mm

for deep sky. 


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#3 sg6

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Posted 06 December 2018 - 02:41 PM

Agree with Rowdy = No, No, Yes.

Filter will not make it all sharper. Old reason if they did we would buy a cheaper scope and a filter not an apo costing multiple times as much.

 

The air is moving, heat haze, you cannot do anything about it. Scopes tend to show its presence more.

 

Most 1.25" filters fit but not all. One or two manufacturers have an unfriendly habit of making their filter threads just a little different. However will throw in that filters are likely not the answer to whatever problem you may be thinking of.

 

Filters only remove something, so add filter and in the general way the image is less bright. The trick is to know the scope, the object and the filter and if all thought out the result may be "better" but it will not be brighter.


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#4 ReganJamesFord

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Posted 06 December 2018 - 02:52 PM

Thanks friends! Maybe the fuzzy planet was because of the cold weather, city lights, poor viewing and rookie operator. The magnifications was between 50 and 100. I think the atmospheric turbulence was the culprit, because the planet would go from real fuzzy, to not very fuzzy in a matter of seconds without me touching the scope. Is that possible?

#5 photoracer18

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Posted 06 December 2018 - 02:56 PM

Ditto, no, no, and yes. For spotting scope use just stick the 45 degree diagonal and the zoom in and adjust your power to what the atmosphere is giving you. I suggest buying a Celestron prism diagonal for astro use assuming you have the F10 spotting scope and not the F6 telephoto version.

#6 RalphMeisterTigerMan

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Posted 06 December 2018 - 02:58 PM

You may want to consider going with a standard 90-degree mirror diagonal, dielectric would be best if you can. It will make a difference in image quality.

 

Also, your threads on the back of the C5 will accomodate a 2 inch focuser. This coupled with a 2-inch diagonal will open a whole new "universe" for you. I do not know your budget, but it will make a big difference. Also, 45-degree prism diagonals are notorious for providing "crappy" images when it comes to fine detail on lunar and planetary images. Look into it and see what will fit your budget.

 

RalphMeisterTigerMan


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#7 Napp

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Posted 06 December 2018 - 03:00 PM

Thanks friends! Maybe the fuzzy planet was because of the cold weather, city lights, poor viewing and rookie operator. The magnifications was between 50 and 100. I think the atmospheric turbulence was the culprit, because the planet would go from real fuzzy, to not very fuzzy in a matter of seconds without me touching the scope. Is that possible?

That’s the nature of planetary observing.  The natural tendency is to push power to see more but the atmosphere gets in the way.  You stay with the eyepiece for long periods just to catch those fleeting seconds when the atmosphere allows a clear view of the target.  Sometimes it’s better to back off the power a bit to crisp up the view.


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#8 Barlowbill

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Posted 06 December 2018 - 03:01 PM

Seeing conditions can change numerous times over the course of one viewing session.  Mother Nature!  Enjoy when it is good and gripe when bad.


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#9 Starman1

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Posted 06 December 2018 - 03:44 PM

I have a Celestron C5 spotting scope, that came with a 45* erect image diagonal and a 25mm, 1.25 eyepiece.  It's my first scope and I'm trying to figure it out.  I have a few questions regarding filters. 

 

1- Do planetary filters help in focusing?  In other words, if I'm viewing Neptune and it's blurry, no matter how much I focus, is there a filter that helps?

 

2- I love using my scope for long distance nature watching.  Sometimes when it's hot, really sunny or when I'm looking over a body of water, my view has a little atmosphere/heat aberration.  Is there a filter to help with terrestrial viewing?

 

3- Lastly, I currently have a stock 25mm Celestron Plossl, a Celestron 8-24 zoom ep, and ES 82* 14mm wide view ep. Will all 1.25 filters work with my set up? Or could someone recommend a set of filters for what I have? 

 

Thank you.

You've gotten good answers.  I have little to add.

Some points:

1) Terrestrial viewing will be between 20x and 60x, and the higher powers will not be usable after about 10am due to heat turbulence.

2) Atmospheric seeing conditions are ALWAYS the limit to power 

3) for astronomical observations with your 125 (an excellent scope, BTW), ditch the 45° diagonal and replace it with a 90° star diagonal

for astronomy.  Why?

--it is more convenient to use when the scope points up

--it has a much larger clear aperture, allowing you to use eyepieces with a wider apparent field and, hence, larger true field

--it will be optically more accurate, leading to sharper images.

 

Just be aware that magnifications will be limited by the atmosphere:

4-10x/inch (20-50x) low power for astronomy--images least damaged by atmospheric seeing.

10-20x/inch (50-100x) medium power for astronomical observations.  Best for general use on nearly all deep sky objects.

20-30x/inch (100-150x) high power for astronomical observations--moon, planets, double stars, small star clusters.  Affected by the atmosphere, be careful to apply a few rules:

--don't observe at high power directly over a roof top.  Roofs bleed heat all night long and cause local air turbulence.

--don't use high powers immediately after taking the scope outside.  Let the scope acclimate and cool down for at least an hour before attempting high power

--don't observe objects below 30° altitude.  The air is too thick and there will be a LOT more turbulence and chromatic blur.  If you have to (like a low planet), don't expect sharp images most of the time.

--look at the twinkling of the stars.  They will appear steadier and display less turbulence in the scope when the atmosphere is calm.  This often occurs a couple days AFTER a front has come through,

and the air may not be as transparent as it was.  For sharp high power images, though, we want stable air.

30-50x/inch (150-250x) ultra high powers, mostly for the Moon and double stars.  Not usable very often, but when you get a night where such magnifications are usable......magic!



#10 vtornado

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Posted 06 December 2018 - 04:47 PM

hello ReganJamesFord, and welcome to cloudy nights!

 

Everybody is spot on in their advice.

Here is some more ... as if you need any ...

 

If you are trying to view Neptune, you want to optimize your viewing for planets.

1) Put your scope outside for 1 hour before viewing.  Some of the fuzziness may be

tube currents, that are due to bringing in a warm scope to a cold outside.  This can

be solved by wrapping your scope with insulating wrap, but that is for another day,

before Neptune gets away from you.  Without Mars as its neighbor it is going to be

devishly hard to find.

 

2) View when Neptune is highest in the sky, don't view too late when it is heading for the horizion.

The higher it is in the sky the less atmosphere you have to look through.  I have not consulted my

charts, but it might reach that point around 6:00 PM???  I saw Mars last night finally through

a hole in the clouds and at 9:30 it was pretty far down.

 

3) I would try using 10mm eyepiece at first, then maybe try a lower focal length eyepiece.

 

4) If you can help it do not view Neptune over a nearby road, or neighbors roof.  These give off

heat plumes at night.   Large stretches of grass are best to look over.  Baseball field?

 

Regarding filters.   I use an Orion Ultrablock.   It helps on some nebula, if you are in heavy light pollution.  The only colored filter I have used that let me see more planetary than what I can see without one is an 82-A (light blue).  Most of the planetary filters sold in kits are way too dark.  If you want to

play around with them I suggest you buy used here.

 

good luck in your hunt.

This is first day in 3 weeks here where it is sunny toward evening.

I'm looking forward to tracking Neptune down too.

 

VT



#11 epee

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Posted 06 December 2018 - 05:10 PM

Agree and confirm all the answers you’ve gotten. Filters are like sunglasses, they can block certain, or all, wavelengths of light but they will never make something swimming in what amounts to mirage hold still. Even so, just like amber lenses can cut haze, a yellow or amber filter can help sharpen the daylight view; but only by blocking scattered blue light, not by beating heat shimmer.

Edited by epee, 06 December 2018 - 05:11 PM.

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#12 ReganJamesFord

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Posted 06 December 2018 - 05:16 PM

Thanks all!! Great advice
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