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Daniel Mounsey regarding Ed Grissom - Help

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#1 -George-

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Posted 02 April 2014 - 08:34 PM

Hey, I have read this a fair few times.

http://www.cloudynig...360923/page/...


I had a few questions relating to this if anyone knows, or if anyone knows how I can get in contact with Daniel Mounsey to ask him directly would be beneficial.

In summary, Daniel mentioned that Kennedy's 24" telescope provided better colour over the 30,000 or so dollar refractor setup, however, the refractor telescope provided a sharper image.

Then it basically goes on to say that Ed Grissoms 13.5" sonotube telescope provided the colour etc the 24" did and the sharpness/clarity of the refractor. So it basically combined both scopes strong points while lacking none.

My questions would be thus:

1: Is a Sonotube (I assume that means solid tube), more ideal for observing than a truss rod (i am not talking convenience but the actual quality of what you see)?

2: Could have the 24" telescope been made 'better' more like Ed Grissoms 13.5", with that sharpness that Grissoms had while still retaining that favorable aperture for planetary work, or is the 13.5" kinda the best here (given the read in the archive)? So basically was the 'lack of clarity' in Kennedy's 24" that grissoms 13.5" retained due to being 24" or other factors? Like, can that 24" have been as sharp as that Refractor (like grissoms one was) and still retained that colour etc of the 24"?

3: If Aperture = resolution, colour etc, higher resolving power, why did the 13.5" see 'the same amount of detail' as the 24" when that doesn't even make sense to because more aperture = more detail. - So, what is the point to a 24" or bigger telescope then when based on that article it seems the 13.5 is the best you gonna get?

#2 Astrojensen

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Posted 03 April 2014 - 03:43 AM

Why don't you just send Daniel a PM???


Clear skies!
Thomas, Denmark

#3 mark cowan

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Posted 03 April 2014 - 03:56 AM

That's perhaps too obvious...

Hmm, this is an archived thread - so the PMs don't work. OP, try this:

http://www.cloudynig...t=&User=165&...

Best,
Mark

#4 -George-

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Posted 03 April 2014 - 04:29 AM

Thanks,

I tried to Message on the archive and couldn't and didn't even know if he still existed here or not.

Thanks!

#5 Mirzam

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Posted 03 April 2014 - 07:58 AM

To my way of thinking there are a couple things going on that make the Grissom scope so effective. I do think that tube scopes offer some advantages for thermal management. A fan that exhausts air through a tube avoids problems related to airflow outside the tube, including heat from surrounding objects. In other words the optical path is more protected than in a truss, and a small fan can deal with the tube currents and mirror boundary layer quite effectively.

Another consideration with larger mirrors is that they tend to be thicker. This reduces the ability to achieve thermal stability under changing temperature conditions. Of course there are those rare nights when the air temps and the atmosphere are absolutely steady. The more typical case is that a large thick mirror will not be as perfectly acclimated as a somewhat smaller thinner mirror. I'd really like to know how much better a large mirror inside a tube would perform visually relative to a truss.

JimC

#6 pstarr

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Posted 03 April 2014 - 08:10 AM

this thread explains allot of how these scopes are constructed.

#7 Eddgie

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Posted 03 April 2014 - 08:22 AM

Sonotube is a type of material. It is a closed tube, but it is esentially a heavy would paper (cardboard) that has been treated to be water-resistant.

Far more important than the material that the tube is made of is the quality of the optics, the thermal stability of the mirror, and the local seeing.

Seeing rarely allow telescopes with more than about 12" to realize their full potential.

Many would put the size at less than that (see refractor forum) but I would put it more around 12" to 14".

Even 14" will struggle mightly to show its full potential at my own location more than about 20 nights a year. Biggest limit is atmospheric.

On a "Consistant" basis, if you are patient, I would say that there is not much beneift to going larger than this for planets unless you live someplace at high altitude with stable seeing.

Color is a function of apeture becuase the more light you can put into the eyeball for a given magnification, the more you stimulate the cones in the fovea.

This is a good thing because the a singe cone gives as much visual acuity of four or five rods. The more color you see, the closer the eye is photopic mode, which is where your eye has its full angular resolving power (about 1 arc minute of field).

But if seeing is limiting you, you see more color but no smaller detail. Still, color adds a lot to the view.

But to answer your question, for planetary seeing, a bigger apterture is only useful if seeing condistions allow it to come close to its full potential, and the bigger the apeture, the more difficult that becomes.

And just to clarify the effects of seeing, seeing is often rated in arc seconds. This indicates how far away from the center of a bright star light will be scattered by the seeing conditions, and gives a rough idea of how small the smallest detail the scope will be able to resolve will be.

For example, if seeing is 3 ars seconds, this means that as details get smaller than this size (and this is 1/5th the current diameter of Mars) it becomes very difficult for the telescope to resolve it as a shape. You might still see it as a blur on the surface of Mars, but it would not show much other detail, regardless of how big the scope was.

As seeing improved to 1 arc second, someone using a 10" scope could now start to resolve details near the capability of the instrument (1/15th the size the instrument).

When seeing is excellent, a 14 inch apeture can resolve sub arc second detail (features on Ganymede, which is only itself about 1.7 arc seconds in size when the planet is fairly close to us).

So, apeture gets you more, but only when seeing allows, and seeing rarely allows apetures more than 12" to 14" to hit their potential, much less larger apertures.

#8 dr.who

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Posted 03 April 2014 - 11:43 AM

If it's who I think it is, Daniel works for Woodland Hills Camera and Telescope. www.telescopes.net

#9 skyward_eyes

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Posted 03 April 2014 - 11:45 AM

Yea, he works today as well, just call the store and ask for Daniel.

#10 -George-

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Posted 03 April 2014 - 07:32 PM

So what exactly is the point to larger aperture then?

If it is all limited to 12-14", isn't the point to larger (20-45" - Websters etc) pointless then?

Or is this more for 'gathering more deep space" while planetary work is no better than something much more convenient like a 8-14"?

I live 1025m above sea level in the country away from everything, so my seeing is generally excellent.

So between 2 optically identical 12" scopes, 1 solid tube 1 truss rod... am I better off with the "solid" tube if convenience is not an issue?

Does not using a cover on truss rod's eliminate that thermal problem of outside interference, making it it identical to a solid tube?

#11 Pinbout

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Posted 03 April 2014 - 07:47 PM

http://www.intellica.../JetStream.aspx
Quote:

 live 1025m above sea level in the country away from everything, so my seeing is excellent. 
[/quote]

Seeing is effected by the jet stream, the high layers of air moving very fast.



#12 Bob Abraham

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Posted 03 April 2014 - 08:10 PM

So what exactly is the point to larger aperture then?
If it is all limited to 12-14", isn't the point to larger (20-45" - Websters etc) pointless then?


If you enjoy consistently mega excellent seeing, and it seems you might, and you don't have to worry about practical stuff like lugging a huge scope to-and-fro sapping your enthusiasm, then all the models (and a bunch of practical experience from many people, though not all people) suggest you should get as big an aperture as you can, up to about 1m if you want to look at planets, and up to infinity if you want to look at DSOs. But it's also important to make sure the mirror is of very high quality, and also to make sure you've thought through how to to deal with practical stuff like thermal issues (cool down, boundary layer, etc.) and collimation. But assuming you've got those aspects figured out, I believe that going big will get you awesome views of everything (except of wide-field vistas and arguably of double stars, which I find look prettiest when using a relatively small aperture so that the stellar airy disk + rings is well formed and stable).

Does not using a cover on truss rod's eliminate that thermal problem of outside interference, making it it identical to a solid tube?


I think it depends greatly on the nature of material used to make the cover, but if it's insulating then I don't see why not.

Bob

#13 bobhen

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Posted 03 April 2014 - 08:31 PM

So what exactly is the point to larger aperture then?

If it is all limited to 12-14", isn't the point to larger (20-45" - Websters etc) pointless then?

Or is this more for 'gathering more deep space" while planetary work is no better than something much more convenient like a 8-14"?

I live 1025m above sea level in the country away from everything, so my seeing is generally excellent.

So between 2 optically identical 12" scopes, 1 solid tube 1 truss rod... am I better off with the "solid" tube if convenience is not an issue?

Does not using a cover on truss rod's eliminate that thermal problem of outside interference, making it it identical to a solid tube?


Larger aperture gathers more light making deep-sky objects easier to see. Larger aperture also has the “potential” to resolve more details on the moon and planets BUT your local seeing will limit that potential.

In most places and on the vast majority of nights the resolving potential of a 14-inch telescope will never be reached. There are exceptions of course. Here in the northeast that upper limit is probably around 8-inches or less on most nights. And this past winter even that was probably optimistic! But if you live in Florida, the nights a 10-plus inch telescope can reach its resolving potential are more numerous.

Seeing has nothing to do with how dark your sky is.

Solid tube or open truss it all depends on how the scope is designed. Keeping warm air out of the light path is the objective. This includes initial cool down and thermal management throughout the night.

A cover is important BUT so is an extended front end and most truss scopes tend to keep the top end cage as small as possible because of weight. There are, of course, other design details that are important as well.

For the moon and planets: Your local seeing, the quality of the optic (high quality is even more important than for deep-sky observing),and mechanical design (including thermal management) all have to be considered. Tracking, portability, weight, and cost are also considerations.

Bob

#14 Pinbout

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Posted 03 April 2014 - 08:35 PM

And this past winter even that was probably optimistic!



that's because the jet stream was just hanging down across the country all winter long with the idiotic polar vortex wobble. almost the entire country was bad.

#15 -George-

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Posted 03 April 2014 - 08:54 PM

Well I have the option to buy a Solid Tube, or Truss Rod style 12".

The truss rod style is $500 more than the Solid tube. If the Solid tube can control the environment of the scope better, then there is no sense buying the Truss Rod because I have all the space for either. I also live in Au, not Canada/US etc, so the seeing I get here according to AU astronomers is very, very good.

That $500 then leaves me something for accessories as well.

On other hand, if there is some drawback to a solid tube over a truss rod (not talking about carrying, just viewing) then the extra $500 makes sense.

The reason this even became a question is because I have heard some say "The best views I ever got of saturn was in a solid tube", then, reading all that Ed Grisom stuff, and seeing all the types of scopes made for/by him are all 'solid tube' not truss rod.

So hence I wondered "Is there some advantage to this over a covered over truss rod?"

Now, if one wants to EQ mount like Grisoms scope, can a Truss Rod style scope be EQ mounted or not?

Is there such thing as a 20+" solid tube scope or are all these truss rod style, in which case for deep space observing, whether the solid tube is better or not is irrelevant because it doesn't exist at that size and a 20" truss will see more deep space than a solid tube 14" or whatever is 'max'.

#16 Wol

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Posted 04 April 2014 - 11:20 AM

You could just put a dob on an equatorial platform...

Regards

#17 Daniel Mounsey

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Posted 07 April 2014 - 07:15 PM

My questions would be thus:

1: Is a Sonotube (I assume that means solid tube), more ideal for observing than a truss rod (i am not talking convenience but the actual quality of what you see)?


Portability aside, sonotube is much better than any truss for several reasons. There are also specific metal tubes which I've heard can be used unpainted or you would want to insulate the inside of metal tube with cork inlay or a dormant flock material. Either way, the key is to keep the tube as dormant as possible. That means the least possible reaction to temperature.


2: Could have the 24" telescope been made 'better' more like Ed Grissoms 13.5", with that sharpness that Grissoms had while still retaining that favorable aperture for planetary work, or is the 13.5" kinda the best here (given the read in the archive)? So basically was the 'lack of clarity' in Kennedy's 24" that grissoms 13.5" retained due to being 24" or other factors? Like, can that 24" have been as sharp as that Refractor (like grissoms one was) and still retained that colour etc of the 24"?


Kennedy does world class work. If I hear otherwise, I am extremely skeptical because I've tested several of his scopes and they are all outstanding. I know he's extremely particular. It's difficult to say what would happen. In the Big dob's defense, it wasn't actually designed for planetary observation. The scintillating had nothing to do with the quality of the optics, that has never been a question. Larger telescopes gather a lot of light and it's easy to see any artifacts in the image. The 13" Kennedy had NO scintillating whatsoever! It was rock solid and totally aesthetic, exactly like a a huge apo refractor. What the 13" Kennedy Gave up in aperture compared the the 24" Kennedy, it made up for because of superior thermal management on Grissom's part.

I've tested quite a few telescopes in great seeing conditions but so far these optimized Newtonian's in 8" 10" on up are the finest planetary telescopes I've ever seen based on my many experiences doing this stuff. It's a combination of good aperture and solid thermal performance. My observing buddy Jorge who had the 8" TMB during that particular shootout actually has a 16" F6 Kennedy optic he's kept stored for several years. It's already been star tested and it's perfect. This issue was when he used it, I think it was in a fiber glass tube and fiber glass didn't perform well. I remember going to Grissom's one day and he had a few large fiberglass tubes by the trash with various holes in them from tests he did. I said what's this! He said they didn't work good enough compared to the cheap sonotubes.

3: If Aperture = resolution, colour etc, higher resolving power, why did the 13.5" see 'the same amount of detail' as the 24" when that doesn't even make sense to because more aperture = more detail. - So, what is the point to a 24" or bigger telescope then when based on that article it seems the 13.5 is the best you gonna get?


It's difficult to answer that question. There are a number of factors which could contribute to it. Remember that the 8" apo also revealed the same details but they were harder to discern compared to the 24" dob. This was quite an amazing night and was easily sub arc second. Just so you understand, that same 8" refractor has outperformed my 12.5" dob and a few other scopes of mine. When you are in the right place at the right time, you just never know what will happen. I suppose that's what makes it exciting sometimes. There are sometimes no absolute answers to these questions but I can assure you aperture isn't everything unless it's different size refractors.

#18 Starman1

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Posted 07 April 2014 - 07:56 PM

Hey, I have read this a fair few times.

http://www.cloudynig...360923/page/...


I had a few questions relating to this if anyone knows, or if anyone knows how I can get in contact with Daniel Mounsey to ask him directly would be beneficial.

In summary, Daniel mentioned that Kennedy's 24" telescope provided better colour over the 30,000 or so dollar refractor setup, however, the refractor telescope provided a sharper image.

It is harder to achieve thermal equilibrium with larger optics and larger optics are more affected by seeing conditions that smaller apertures.

Then it basically goes on to say that Ed Grissoms 13.5" sonotube telescope provided the colour etc the 24" did and the sharpness/clarity of the refractor. So it basically combined both scopes strong points while lacking none.

Thermal equilibrium and less affected by seeing. It's one of the reasons I stuck with the 12.5" size (though not the only one).

My questions would be thus:

1: Is a Sonotube (I assume that means solid tube), more ideal for observing than a truss rod (i am not talking convenience but the actual quality of what you see)?

From the standpoint of thermal control of the interior of the tube, yes. Based on weight or transportability, no.

2: Could have the 24" telescope been made 'better' more like Ed Grissoms 13.5", with that sharpness that Grissoms had while still retaining that favorable aperture for planetary work, or is the 13.5" kinda the best here (given the read in the archive)? So basically was the 'lack of clarity' in Kennedy's 24" that grissoms 13.5" retained due to being 24" or other factors? Like, can that 24" have been as sharp as that Refractor (like grissoms one was) and still retained that colour etc of the 24"?

Well, that depends. IF the 24" mirror is perfectly cooled to ambient, and IF the 24" is perfectly collimated, and IF the seeing is better than 0.34", THEN the 24" will out-perform the 13.1" on planets. The 24" will always outperform the 13.1" on deep-sky objects.

3: If Aperture = resolution, colour etc, higher resolving power, why did the 13.5" see 'the same amount of detail' as the 24" when that doesn't even make sense to because more aperture = more detail. - So, what is the point to a 24" or bigger telescope then when based on that article it seems the 13.5 is the best you gonna get?

Do you buy a 24" scope to only observe the Moon, planets, and double stars? Of course not. Look at a galaxy--any galaxy--through both and you'll immediately understand the why of 24".

#19 -George-

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Posted 08 April 2014 - 05:17 AM

Thank you for the responses.

So having a Sonotube would be the same as having an aluminum tube inlaid with cork? - since both a dormant and don't fog up like metal does in the cold (I assume this is why?)

Does the Cork need to be thick or just 1-2mm? Would this reduce the aperture of the scope?

Other than that, I appreciate your time in answering my query.

I decided to buy a 12" Solid tube scope. It is an aluminum case I believe, (cheap starter scope - GSO 12" with minimum 1/12 Wave length error mirror - Whatever that means)

However these readings help give some insight how to even improve the seeing of this scope.

Would it be a good idea to inlay this with cork or not worth it on an $850 scope?

Other than that... the Fan that has always been mentioned to use to keep the scope at equilibrium... Is this referring to the Fan that the scope already comes with, or are we talking a normal house fan to 'blow' at the scope? I was a little confused on this point.

I just want to do what I can even with this scope to increase its 'seeing' without it costing $$$$ to do so. Make the most of what I got mentality i suppose.

Otherwise, I am very interested in deep space, perhaps more so than Planets, so Aperture is the way to go for me.

#20 kenrenard

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Posted 08 April 2014 - 06:11 AM

George,
I have read Daniel's post a few months back and used a computer fan and made a baffle with some paneling. I suspended the baffle with some hair ties from my daughters. That alone made a great difference in planetary detail in my humble mass produced 8 inch newt. I can feel air blowing out the front of the scope with the fan on and the hair ties keep the fan from causing vibrations. If you haven't tried a baffled fan its a good cheap way to get your scope cooled.

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#21 Mirzam

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Posted 08 April 2014 - 07:47 AM

I would say that if the scope comes with a fan, the main concern would be whether the rear is properly closed (as with the baffle above) and whether the fan is vibration free. If the fan is too forceful the speed can be reduced by using a converter to lower the supply voltage.

I'm pretty sure that the new scope will have a steel tube, so insulation of at least a couple millimeters of cork or flockboard will be useful. You will not reduce the aperture because the tube is going to be quite a bit larger in diameter than the mirror. If you were building a scope with a new tube, having 1" clearance (or even more) all the way around the primary is good practice.

Make sure that your out-of-focus star images are perfectly round. If they seem a bit oval, (and your own eyes do not have any astigmatism), test to be certain that the mirror is not held too tightly by the mirror cell. This may involve loosening the mirror clips enough to allow a tiny bit of mirror movement.

JimC

#22 Starman1

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Posted 08 April 2014 - 12:35 PM

So having a Sonotube would be the same as having an aluminum tube inlaid with cork? - since both a dormant and don't fog up like metal does in the cold (I assume this is why?)


Well, a metal tube will conduct heat from your hand and you will see thermal issues in the image. Insulating the tube will stop this. It could be either internal or external.

Does the Cork need to be thick or just 1-2mm? Would this reduce the aperture of the scope?


1-2mm wouldn't make much difference at all to the open aperture, which is usually larger than the mirror, anyway. The issue with these Chinese scopes is that they give barely enough clearance between mirror and tube. There should be an absolute minimum of 3/4" (2cm) between the mirror edge and the inside of the tube. If less than this, tube currents are far more likely to be visible in the star images and lining the interior with a thick liner becomes ill-advised. Your best bet, because it enhances contrast in the scope at the same time it helps insulate the tube, is to flock the interior with flocking paper from Protostar. Additionally, these scopes have the secondary a bit too close to the upper tube opening. This increases the possibility of dewing of the secondary and allows extraneous light to enter the bottom of the eyepiece from over the edge of the tube opposite the focuser. Plan on adding a foot-long dewshield to the top of the scope. This enhances contrast, reduces dewing, and keeps body heat out of the visible field of the scope.

Other than that, I appreciate your time in answering my query.

I decided to buy a 12" Solid tube scope. It is an aluminum case I believe, (cheap starter scope - GSO 12" with minimum 1/12 Wave length error mirror - Whatever that means)


The tube is steel, so definitely needs flocking/insulating. The 1/12 wave mirror is an RMS figure (a sort of average) on the surface. That means the scope should meet the criterion of 'diffraction-limited' performance, i.e. the optics won't prevent the image from being all the aperture can show. The odds are good that this is approximately what you will get.
You need to pay attention to cooling, collimation, and conditions. See my essay here I have other essays on the site about choosing eyepieces and other basic astronomy information.

However these readings help give some insight how to even improve the seeing of this scope.

Would it be a good idea to inlay this with cork or not worth it on an $850 scope?


It is ALWAYS worth flocking a tube. This makes a noticeable difference in contrast. The insulation improvement is an added bonus.

Other than that... the Fan that has always been mentioned to use to keep the scope at equilibrium... Is this referring to the Fan that the scope already comes with, or are we talking a normal house fan to 'blow' at the scope? I was a little confused on this point.


Mirrors start the night warmer than the air. As they lose heat, there forms a warm layer of air in front of the mirror called 'the boundary layer' which causes refraction of the image. This layer dissipates as the mirror cools to the ambient temperature. Without a fan blowing, it never will. So plan of powering your fan to run the entire night unless your environment only cools a couple degrees at night. Fans blowing up the tube also help prevent dew on the mirrors. If your mirror is warm from the house, having a house fan blow massive amounts of air up the tube helps cool the mirror more quickly. Plan on taking the scope outdoors at sunset, turning the fan on, then starting to observe 90 minutes later when it's dark. That 90 minutes won't cool the mirror completely, but you'll start the night with much better images than you would otherwise.

I just want to do what I can even with this scope to increase its 'seeing' without it costing $$$$ to do so. Make the most of what I got mentality i suppose.

Otherwise, I am very interested in deep space, perhaps more so than Planets, so Aperture is the way to go for me.


A 12" full-tubed dob is just fine for the house. It's a bit more ungainly to transport, compared to a truss scope. But it'll be easy to use and you'll see a lot. It's a great place to go, size-wise. In superbly dark skies, as many as 30,000+ DSOs are visible. In a city, a lot fewer, but just remember, nebulae and galaxies are THE hardest objects to view. If your sky is light polluted, star clusters (both types) and planetary nebulae are usually easier.
Think about dark adaptation, also. Dark adapting requires 30-45 minutes outside, away from light, to see the most your eye can see. Remember this when viewing fainter objects.

#23 -George-

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Posted 08 April 2014 - 07:24 PM

Thank you for that. I am now just clarifying that I have understood correctly.

The Fan the scope comes with is fine (perhaps add a general fan to it prior to going out) - Leave the fan that the scope comes with on all the time while observing... this means some sort of battery power source needed to keep the fan going?

The fan itself is not a vacuum (sucking air out of the tube from the bottom) but instead blowing the air upwards towards the secondary mirror where the eyepiece is... ?

I forgot my binoculars outside last night, i went to get them around 10:00pm... completely wet, lenses, eyepieces, the entire metal frame all covered in dew/water.
The fan is used to prevent this happening to the mirror?
The flocking paper/cork is used to help in this not happening to the inside of the tube?

Is flocking paper better than cork or is it the same thing just depending what one rather visualy?

Does this need to be applied thick, or as mentioned, 1-2mm is enough, as long as it is covering the surface?

External/internal corking/flocking was mentioned. If the external gets done, the internal does not?
Inside more preferable than outside if can only do one side?
Or doing both the outside and inside with cork/flocking paper is ideal? (again thickness should be...?)


#24 Starman1

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Posted 09 April 2014 - 12:19 AM

[quote name="-George-"]Thank you for that. I am now just clarifying that I have understood correctly.

The Fan the scope comes with is fine (perhaps add a general fan to it prior to going out) - Leave the fan that the scope comes with on all the time while observing... this means some sort of battery power source needed to keep the fan going?[/quote]
Yes.
[quote]
The fan itself is not a vacuum (sucking air out of the tube from the bottom) but instead blowing the air upwards towards the secondary mirror where the eyepiece is... ?[/quote]
Yes.
[quote]
I forgot my binoculars outside last night, i went to get them around 10:00pm... completely wet, lenses, eyepieces, the entire metal frame all covered in dew/water.
The fan is used to prevent this happening to the mirror?
[/quote]
No, but air movement helps prevent condensation. The primary is down at the bottom and unlikely to dew. The secondary can dew, but air movement helps slow it down.
[quote]
The flocking paper/cork is used to help in this not happening to the inside of the tube?[/quote]
No, it is used to reduce scattered light in the system and to prevent the presence of your body heat from causing a warming of the tube and heat currents inside the tube.
[quote]
Is flocking paper better than cork or is it the same thing just depending what one rather visually?[/quote]
Flocking paper is thinner, self-adhesive, and FAR darker than flat black paint at low angles. The inside of the tube gets VERY dark when it is used. It's insulating characteristic is incidental.
[quote]
Does this need to be applied thick, or as mentioned, 1-2mm is enough, as long as it is covering the surface?[/quote]
Just enough to prevent heat from your hand or body from warming the air inside the tube.
[quote]
External/internal corking/flocking was mentioned. If the external gets done, the internal does not? [/quote]
Depends. Flocking is done to reduce scattered light. Insulating is done to prevent heat from being conducted by the tube. You could do both.
[quote]
Inside more preferable than outside if can only do one side?[/quote]
Yes, for looks, primarily.
[quote]
Or doing both the outside and inside with cork/flocking paper is ideal? (again thickness should be...?)
[/quote]
Well, if flocking the interior, adding some form of insulating cover externally would be useful. Cork is fragile, but there are other forms of self-adhesive insulating material. I also recommend a black area around the focuser so peripheral vision sees no light.

#25 -George-

-George-

    Vostok 1

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Posted 09 April 2014 - 04:17 AM

Ok thank you for that.

As I looked at protostar for the Flocking paper I also came across 'baffling' the scope = better than Flocking paper...

uhm? I don't understand what that is.


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