Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Insulation jacket for Mak?

  • This topic is locked This topic is locked
269 replies to this topic

#226 Bean614

Bean614

    Viking 1

  • *****
  • Posts: 693
  • Joined: 05 Nov 2015
  • Loc: Mass.

Posted 18 February 2018 - 07:17 PM

'MrJones' wrote "but you still need the whole scope and mirror to equilibrate for best results".  

Actually, MrJones, you DON'T!.  You've apparently missed the point, and the real science, that was being made by 'yellobeard'!!

 

'Ron359' wrote "that insulating the tube will only prolong the 'agony' of cool down to equilibrium'.   I don't think you quite get it Ron.  You, and everyone, should just forget the word COOL!  This is not about a different way to cool-down your Scope more quickly.  It's about eliminating the air currents that cause lousy viewing.  It works in high or low humidity, high or low temperature deltas.  And you can use your scope, with no mush, distortion, plumes, etc., the minute you take it outside, providing the insulation has been applied inside!  Just forget "cooling", and EVERY other thing you were taught about what has to be done to an MCT or SCT prior to using it.  And, as to equilibrium, yes, at some point during the session, if it's long enough, there will probably be an equilibrium of sorts.  But, so what? The perfect views haven't changed all session.


 

#227 Jeff B

Jeff B

    Fly Me to the Moon

  • *****
  • Posts: 5933
  • Joined: 30 Dec 2006

Posted 18 February 2018 - 08:53 PM

I feel like some people are not understanding the main purpose of the insulation. It's the same as Newtonians where the idea came from - to insulate the tube and keep air currents from forming due to differential cooling of the tube. It's not really to cool the scope more slowly to somehow equalize cooling otherwise. The insulation is great for preventing tube currents and you can start observing sooner with it but you still need the whole scope and mirror to equilibrate for best results.

 

This being the case it certainly seems like the best plan is to let the scope equilibrate without insulation and then insulate for observing although it probably doesn't matter too much if you keep the back and front un-insulated.

 

Also, with active cooling (say TEMP-est fans) insulation probably doesn't make much or any difference unless you want to turn the fans off.

I guess I have to disagree.  Please see my post #177 and my follow up observing notes.  If the internal air mass cools very slowly, so will the main mirror and very little heat is shed from the optics to the air.  In forced air systems, the internal air cools quickly as it is quickly exchanged but the mirror always lags, shedding heat to the now much cooler air.  Boundary layer fans can and do help but the mirror still lags thermally.  It's the temperature differential that is a first order driver of heat transfer for a give system of cooling.  

 

But my direct observing experience with this insulation system shows there is a lot of merit to this approach.

 

Jeff


 

#228 James Ball

James Ball

    Viking 1

  • -----
  • Posts: 849
  • Joined: 22 Jun 2014
  • Loc: Western Kentucky

Posted 18 February 2018 - 09:38 PM

 

 

Having read this thread with much interest, I’ve still decided to get TEMPest fans for my C11 Edge, and in fact just ordered them.  At some point I’m going to fit up a reflectrix covering; it seems like such an easy exercise, why NOT do it? When I go to my dark sky site here in AZ, I can compare the fans with/without reflectrix.  There’s a pretty good temperature gradient there with the altitude and dry typically AZ air.  Thanks everyone for all the information here!

This has been an interesting thread of one side an age old argument.  Please report your findings.  Insulating may work well enough to help in high humidity environs but I think for those of us in low humidity environs where there are large and continuous drops in night temps, that insulating the tube will only prolong the 'agony' of cool down to equilibrium so the scope will continue to radiate heat all night.  Seems like simple physics and also why  SCT carbon fiber tubes were taken off the market as many reported they took forever to cool down to equilibrium.  I'm betting your fans will be far more effective.   

 

-I had a carbon fiber C11 for a while and it took forever to cool. In fact, I don't think it ever did in real use. I remember testing collimation indoors down a long hallway (110 feet or so). The temperature differential between my apartment and the hallway was about 2 degrees. I ran the Lymax fan with the C11 in the hallway for an hour and I still could not see a stable airy disk - plumes were still really evident. I had never seen this behavior in the hallway with the C8 and C9.25, but still I thought it must have been due to the aperture increase. Now I have an aluminum tube C11 and a Deep Space Products-installed TEMP-est fan. The difference was immediately noticeable between the CF and aluminum versions of the C11. That CF C11 was just not reaching any kind of equilibrium between internal components and tube temperature. Of course, it turned out my CF C11 also had an extra thick rear plate, according Deep Space Products. He had never seen one that thick on any C11. That could not have helped internal temps at all. The aluminium tube with fans works quite well. 

 

George

 

The difference between aluminum and carbon fiber is that aluminum is one of the best conductors of heat, just short of copper and silver.  Carbon fiber does not conduct heat well, it actually stores heat quite well though.  The reason it will not come to equilibrium quickly is because the heat is constantly being given off by the carbon fiber slowly over time. 

 

Easy to feel the difference, by placing your hand on the tube.  Aluminum you hand will feel cold because the aluminum is working as a heat sink to pull the heat out of your hand and transfer it into the cooler air inside the scope.  The carbon fiber will barely feel any colder than your hand and will quickly feel warm as it absorbs heat from your hand but doesn't transfer it quickly to the air inside.  But it will slowly release that heat over time even after you remove your hand.  The aluminum however will stop transmitting heat into the tube as soon as you remove your hand.


 

#229 Ron359

Ron359

    Apollo

  • *****
  • Posts: 1155
  • Joined: 21 Apr 2008
  • Loc: -105 +39

Posted 18 February 2018 - 10:10 PM

'MrJones' wrote "but you still need the whole scope and mirror to equilibrate for best results".  

Actually, MrJones, you DON'T!.  You've apparently missed the point, and the real science, that was being made by 'yellobeard'!!

 

'Ron359' wrote "that insulating the tube will only prolong the 'agony' of cool down to equilibrium'.   I don't think you quite get it Ron.  You, and everyone, should just forget the word COOL!  This is not about a different way to cool-down your Scope more quickly.  It's about eliminating the air currents that cause lousy viewing.  It works in high or low humidity, high or low temperature deltas.  And you can use your scope, with no mush, distortion, plumes, etc., the minute you take it outside, providing the insulation has been applied inside!  Just forget "cooling", and EVERY other thing you were taught about what has to be done to an MCT or SCT prior to using it.  And, as to equilibrium, yes, at some point during the session, if it's long enough, there will probably be an equilibrium of sorts.  But, so what? The perfect views haven't changed all session.

I'm sorry, no matter if you type your objection in all caps, you can't change the laws of physics.  If you take a warm scope outside and air temp is less than your scope's temp. it will transfer heat to the cooler air.  You can put insulation on the tube to slow the transfer, but it will still happen by radiation, contact and convection.  Happens every day when I put hot coffee into my thermal mug or thermos, and dam, despite the fact I spent $25 bucks on a good one, with two linings and supposed vacuum space between them, after awhile my hot coffee gets cold if its colder outside than the coffee inside!   

 

https://en.wikipedia...ermal_radiation

 

https://en.wikipedia...e_heat_transfer  

 

No one I'm aware of, amateur or professional observatories, insulates newtonian telescope tubes.  Just the opposite is the most common practice and has been for a decade or more.  Solid tube newts have almost totally disappeared from commercial markets and they totally disappeared decades ago from the big mirror observatory scopes. For the smaller newts that are made with (aluminum or steel) tubes, cooling fans are often added, not insulation!  Even the big observatory buildings are now open on many sides and have active cooling so they reach equilibrium quickly and stay there.  Tubes cause their own problems generating as the heat is given off so tubes are eliminated and newt mirrors are best cooled with side fans blowing air over the surface to break up the warm boundary layer which has been clearly proven forms over a cooling mirror.  There is no reason the same phenomenon doesn't happen in a closed SCT mirror and tube.  A closed SCT tube means there will be less convective transfer of the heat directly to the air, so fans will help the heat transfer by directing the warmer air out the sides instead of into the light path through the corrector.  The carbon fiber option for SCT tubes are no longer sold because so many complained they cooled very slowly as carbon fiber made a great insulator.

Insulating your tube after it equilibrates as you suggest, may help it not fall below the dew point in a humid environment, but that is not what most of the posts in this thread show people are intending to do.


 

#230 Rock22

Rock22

    Ranger 4

  • *****
  • Posts: 338
  • Joined: 28 Aug 2017
  • Loc: Diamond Bar, California

Posted 19 February 2018 - 03:05 AM

All I know is that it has worked for me so far, whatever the science behind it. I’m sure fans have their place for those more advanced, but for someone like me who has been at this for just under a year, I enjoy a solution as simple as insulating my MCT the way yellobeard and others in this thread have detailed.

I would say try it and see if it works for you. If not, another solution would probably work better for you. At this point, insulation has worked for me so far this winter... when the clouds have stayed away, anyway. And for the past two nights... it has been cloudy even though the forecast was for clear skies.

If I did have a gripe, it would have been with the weather forecast I see on my phone, and not the rationale behind insulating my Mak. Insulation works. Now, a better way of mounting my insulated Mak is something I need a solution for.
 

#231 MrJones

MrJones

    Vanguard

  • *****
  • Posts: 2436
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 19 February 2018 - 10:34 AM

"the real science, that was being made by 'yellobeard"

 

Mostly there is a lack of science and I've never heard of this person until he started posting in this thread. I first learned of this maybe 5 years ago? All we really have so far is observations, including that wrapping the scope in especially Reflectix does tame observable heat plumes and so apparently reduces temperature gradients inside the scope.

 

More than likely all of these ideas are interrelated but a main argument from me against the idea that the effect is due to slower system cooling vs. just tube equilibration is that the corrector (or meniscus) is still exposed and pointed at the sky, so suffers from radiative cooling same as always. In fact a main reason I really wanted to try this with my 6" SCT was to see if it prevented dew and frost so I wouldn't have to use a heater. Insulating this scope with Reflectix actually barely made a difference in especially frost forming on the corrector. So wrapping a tube prevents heat plumes but does not prevent frost on the corrector. To me this suggests that the temperature in the scope was not actually kept above ambient much longer than normal despite all the guessing that this should happen.

 

Also, I believe it is in fact important that this also historically works with open front Newtonians, reducing observable heat plumes despite the obvious ability to have air exchange at the open end. With these scopes it's even harder to argue that you are slowing down the system cooling with an insulated tube.

 

More experimental evidence needed IMO.


 

#232 Jeff B

Jeff B

    Fly Me to the Moon

  • *****
  • Posts: 5933
  • Joined: 30 Dec 2006

Posted 19 February 2018 - 11:27 AM

"More experimental evidence needed IMO."

 

Yes!  It's fun for me too.

 

I'm also going to wrap the tubes of my older AP "Blue Tube" Starfires.  Their tube inner diameters are very close to the aperture of the telescopes so they are very prone to tube currents, showing as a flat, "mushy"  sector in the out of focus stellar diffraction patterns.   I can disrupt them by moving the scope around but they will reform as the tube cools.  The Reflectix should basically eliminate any radiation of the OTA tube to the sky, and significantly reduce conductive & convective losses.  I may do one of my Mak-Newts as well.

 

Jeff


 

#233 Bean614

Bean614

    Viking 1

  • *****
  • Posts: 693
  • Joined: 05 Nov 2015
  • Loc: Mass.

Posted 19 February 2018 - 04:45 PM

MrJones, I understand your point when you say "I really wanted to try this with my 6" SCT was to see if it prevented dew and frost".  Perhaps your C6 wasn't totally wrapped, or wrapped incorrectly.  If you read my post, #110 in this thread, I think you'll see that I was also interested in preventing dew or frost, and did my tests with a temperature Delta of around 45F.  And the temperature outside was well below freezing.  Several others have had very similar, if not identical results.  And, just a cursory investigation on yellobeard's posts, plus comments on his theories by well respected CN members, should be enough impetus to take him seriously.  I hope you have better results in the future.


 

#234 Rob McKenna

Rob McKenna

    Sputnik

  • -----
  • Posts: 40
  • Joined: 09 Feb 2013

Posted 19 February 2018 - 11:35 PM

Yellow beards idea. In my humble opinion:

 

Whether you keep your scope in your house, in your

garage, a shed or in an observatory, so long as you wrap it

in sufficient insulation material to slow down, as much

as possible, the heat exchange between the scope and the

outside temperature, no interior components of the scope

will be 'capable'of setting tube currents in motion .

Because they are all at the same temperature.

 

Remember, wherever you keep your scope in the daytime,

if it is there for a sufficiently long time, all it's component parts

will be at the same temperature. (In thermal equilibrium).

The tube material itself, the primary, secondary, their baffle

tubes and casings.

 

It does not matter the temperature of your scope.

 

The whole idea is to retard cooling so that all the scopes

component parts cool at, as near possible, the same rate.

 

It is therefor imperative that the scope be insulated, ideally,

at all times.

 

No more, or at least very minor, tube currents.


 

#235 Rock22

Rock22

    Ranger 4

  • *****
  • Posts: 338
  • Joined: 28 Aug 2017
  • Loc: Diamond Bar, California

Posted 20 February 2018 - 02:04 AM

And that is what I have been doing and it worked again tonight. I started an early session at 8pmand finished at 10pm. Got the cigar galaxy... with my neighbor’s patio light on! My patio was lit up and I could make out M82 in my 180mm MCT.

The temperature difference (or delta as the more scientific members refer it as) was greater today between my garage and the night air. We are having a cold wave for a few days and I wanted to get done before the temp hit 39F here 30 miles east of Los Angeles in the San Gabriel / Pomona Valley area.

Even after just 10min (I’m getting better at mounting my telescope with the insulation on) from a 65F garage to a 45F patio I could do my two star alignment and make out the Castor double star. I had just one layer of Reflectix on my tube and two on my dew shield and mounted the telescope. Then I wrapped my second layer on and it still worked. It was the best two hours I’ve had with my new scope since getting it. The sky was finally cloudless and moonless again, so I took advantage of the conditions.

I really don’t think I could have had such a great short session before freezing my behind off if my Mak wasn’t insulated. I did do as good a job as I could to make a good insulation system, and it has paid off. My wife is happy that I can get to bed early and I got to see the Cigar galaxy for the first time.

I could not see it in my 127mm achromat with all the light pollution I have here. I think I’m going to try insulating my refractor just to see if that would make a difference. At least I will be able to recognize what I’m looking for now.

Look, I have no vested interest in this thread in making the case for insulating a catadioptric. Proper insulation works for me, and I want others to benefit from it. If you were my neighbor (not the one who leaves their porch light on all night and smokes pot daily albeit legally now in California) even work with you to make one for your scope!
 

#236 MrJones

MrJones

    Vanguard

  • *****
  • Posts: 2436
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 20 February 2018 - 10:10 AM

My previous posts here are 46, 56, 57. I did a Reflectix shield wrap for my 6" ACF and yoga mat for C11. Reflectix is certainly a better insulator but thermal issues are also much smaller in a 6" SCT vs. 11". I also have a heater for the C11 that I used some but was seeking to not have to use and have tried active cooling with it that also worked well. This is my fan in the diagonal thing posted elsewhere in this forum.

 

In the end with my C11, what worked best was active cooling to get the scope to ambient temperature as fast as possible, then add the yoga mat and keep the fan on. Despite not preventing frost and dew to my satisfaction, even the yoga mat was enough to really reduce thermal gradients and get rid of heat plumes. Adding the dew strip of course help a lot with dew and frost but I did more testing without it as my goal was to not have to use it. With my 6" SCT, in the end I kept it in the unheated garage on the mount so it'd be closer to ambient temperature as this seemed to work best.

 

I'm not sure where all of you have been but we've been talking about the insulation blankets here for 5 years. I remember Tanveer (TG) who has posted some in this thread was one of the early proponents of Reflectix dew shields that turned into full thermal blankets.

 

Anyway, all data is welcome but what has worked best for me is still getting the scopes to ambient temperature AND using the insulation, not running out of the house into the cold with a warm scope wrapped in insulation.


Edited by MrJones, 20 February 2018 - 10:12 AM.

 

#237 Bean614

Bean614

    Viking 1

  • *****
  • Posts: 693
  • Joined: 05 Nov 2015
  • Loc: Mass.

Posted 20 February 2018 - 04:48 PM

"I remember Tanveer (TG) who has posted some in this thread"

 

Yes, he has.  Unfortunately, he advised everyone to put the insulation AFTER bringing the scope outside.  But he's due a LOT of credit for devoting a good chunk of time and effort tackling the thermal issues we all face!


 

#238 MrJones

MrJones

    Vanguard

  • *****
  • Posts: 2436
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 20 February 2018 - 08:01 PM

So that's at least 2 people with far more experience at this that disagree with you.


 

#239 Ron359

Ron359

    Apollo

  • *****
  • Posts: 1155
  • Joined: 21 Apr 2008
  • Loc: -105 +39

Posted 20 February 2018 - 08:15 PM

"I remember Tanveer (TG) who has posted some in this thread"

 

Yes, he has.  Unfortunately, he advised everyone to put the insulation AFTER bringing the scope outside.  But he's due a LOT of credit for devoting a good chunk of time and effort tackling the thermal issues we all face!

This whole thing could be settled with real objective data instead of counting subjective anecdotes.  Simply hook a video cam (EAA, DLSR video or webcam or whatever) up to your scope and take it outside into cold night air from a warm house both with and without insulation and equilibrated first and not.  Be sure to write down your inside and outside temps, and humidity and times.  If you can, measure the temps inside your tube. Put an out of focus star in the FOV and hit the record button. Or point it at a double star in focus and record.  Post your hypothesis and then your results.  Think of it as a science fair experiment.  If your going to claim this is as big a deal as finding the Earth is not flat, then use the scientific method to prove your claims.  Visual anecdotal evidence is non-scientific and will not be accepted.  


 

#240 Bean614

Bean614

    Viking 1

  • *****
  • Posts: 693
  • Joined: 05 Nov 2015
  • Loc: Mass.

Posted 20 February 2018 - 10:42 PM

If I wasn't strictly visual, and actually owned a camera that could take a video, I would have done it months ago.  But I'm sure someone else will take you up on your challenge.  As to "Visual anecdotal evidence is non-scientific and will not be accepted.",  how wonderfully pompous!  It wasn't that many decades ago that 'visual anecdotal evidence' was all we had (Newton, Galileo, Messier, et al).  And their observations were, and are, science.  And if you've read my original, fairly long and boring, nightlong report, you will note that I had, as I always do when investigating one thing or another, additional observers present, and multiple other scopes as a ''control group'.  I get the feeling that even should you see clear evidence of the video kind, posted here, you will find yet more hoops for all of us to jump through. Finally, these were not my claims, but those of others, including yellobeard. And, as I was a doubter, I simply went to the hardware store, and spent $25 on a roll of good Reflectix.  And I wrapped a few of the SCT'S I had at hand, and tried it.  If you like, I can send you the $25 for the Reflectix, in case the reason you haven't done it yourself is that you can't see investing a red cent in something that you don't believe will work. Just let me know.....


 

#241 Bean614

Bean614

    Viking 1

  • *****
  • Posts: 693
  • Joined: 05 Nov 2015
  • Loc: Mass.

Posted 20 February 2018 - 10:54 PM

"So that's at least 2 people with far more experience at this that disagree with you.". I'm not sure that this was directed at me.  But, if it was, it's certainly time for me to give up!  After all, TWO people disagreed!  Geez, what got into me!?  Imagine, thinking I could continue on when the overwhelming odds of 2 to 1 were against me.   By the way, you mentioned that those two people had "far more experience at this".  First, how did you determine that?  Next, the folks at IBM had FAR more "experience at this" than Bill Gates or Steve Jobs.  I suppose they just should have folded up their tents, eh? I think yellobeard, and the other scientists who are seriously going down this road will wind up producing results that will benefit all of us, even the non-believers.


 

#242 Ron359

Ron359

    Apollo

  • *****
  • Posts: 1155
  • Joined: 21 Apr 2008
  • Loc: -105 +39

Posted 21 February 2018 - 12:22 AM

If I wasn't strictly visual, and actually owned a camera that could take a video, I would have done it months ago.  But I'm sure someone else will take you up on your challenge.  As to "Visual anecdotal evidence is non-scientific and will not be accepted.",  how wonderfully pompous!  It wasn't that many decades ago that 'visual anecdotal evidence' was all we had (Newton, Galileo, Messier, et al).  And their observations were, and are, science.  

  Galileo made actual measurements and drawings, and founded modern science of physics based on measurements that could be published and repeated instead of just believing what Aristotle said.  Newton also made measurements and derived the mathematics to describe behavior based on measurements.  Tycho made measurements with visual only instruments that were well documented and precise enough so they could be analyzed mathematically by Kepler.  And then Percival Lowell, a very experienced observer, made no measurements, and photos didn't show them, but he made incredibly precise visual maps of the canals and life on Mars and wrote about them for years.  Most astronomers were very skeptical, but he convinced many people they existed, until 1964, a passing Mariner disproved it all.  So much for pompous science!  

Image 2-20-18 at 10.21 PM.jpg


 

#243 Bean614

Bean614

    Viking 1

  • *****
  • Posts: 693
  • Joined: 05 Nov 2015
  • Loc: Mass.

Posted 21 February 2018 - 12:44 AM

"Most astronomers were very skeptical, but he convinced many people they existed, until 1964, a passing Mariner disproved it all.  So much for pompous science!"

    I wasn't calling the science pompous, and I think you know that.  But, about your statement, Exactly!!!  For over 50 years people were taught that "you must cool your SCT to outside ambient before using".  And 99.9% (think elephants in a long column, trunk to tail) went right along with it, myself included.  Then along comes an optician from the Netherlands to disprove the "accepted wisdom".  And I will gladly send you the $25 for the Reflectix.

   Now, about another literary gem: " Visual anecdotal evidence is non-scientific and will not be accepted." ????  ''will not be accepted".  Really?  By whom?  You?  In case you haven't noticed, save for some of the imaging forums and a few others, just about EVERY statement you read on these forums, from telescope, mount, and eyepiece reviews, to 'first light' comments on anything, to comparison reports on everything, is "visual anecdotal evidence".  Gee, why don't the good folks at Astronomics just close the forums down?  And your $25 is waiting for you...


 

#244 Freezout

Freezout

    Messenger

  • -----
  • Posts: 450
  • Joined: 09 Aug 2017
  • Loc: North Europe, Bortle 4 zone, altitude 11 meters

Posted 21 February 2018 - 02:56 AM

I’m personally starting to insulate my Maksutov-Cassegrain and tested it while not even all the layers are in place. As far as I understood, the purpose is to have it before going out (if not permanently like I’m doing), and it seems also the most logical to me. For now the view quality increases very, very noticeably.

If some people are happy by putting their Reflectix after, good for them, nothing impede them to try one day to put it before, and see the difference (in my opinion, an improvement), anyway no reason to fight!

Please do not share pictures of people slapping others! That’s no more a gentlemen discussion.
We’re on an astronomy forum, so we all love each other, we’re are an endangered specie under threat of light pollution…

 

Freezout

 

P.s.: by the way, cold can enter in a room, if wind blows some mass of air colder than the inside temperature, but Batman is globally right.


 

#245 gfstallin

gfstallin

    Viking 1

  • *****
  • Posts: 865
  • Joined: 08 Aug 2015
  • Loc: Cheverly, Maryland USA

Posted 21 February 2018 - 03:53 AM

Folks, it is getting a little sporty in here. See what works for you under your conditions and with your scopes. If nothing else, it is a cheap experiment if it does not work for you. There are so many variables, even with the same telescope and same observer, as to make universal arguments for or against insulation conjecture at best this point. We're all using different scopes, in different climates and elevations, and with different temperature regimes. It would be interesting to compare what works best and with what equipment so as to see if we can pin down reasons why it seems to offer good results for some people and maybe poor results for others. 

 

P.S. 

-Freezeout is right about cold entering a room - pressure and density differentials come into play as well, second law notwithstanding. 

-I love that Batman meme and saved it to my computer. 

 

George


Edited by gfstallin, 21 February 2018 - 03:54 AM.

 

#246 AndyBooth

AndyBooth

    Explorer 1

  • -----
  • Posts: 53
  • Joined: 08 Jul 2009
  • Loc: Nottingham UK

Posted 21 February 2018 - 04:45 AM

Hi all,

I received purchase of a Skymax 180 Mak last last thursday.

i went out on friday night with no insulation.

delta was 18 degrees C.

It took around 45 minutes  to get a stable condition to collimate, with several heat plumes.

Saturday, i made a dew shield of yoga mat, with a layer of Reflectix on top, and made a two layer insulation blanket of reflextic around the tube, rear cell, and finder stalk.

Sunday i went out with essentially the same delta in temp. Insulated inside, then taken outside.

Virtually no heat plume ( I think dovetail needs some more attention), and same condition to collimate by the time i had aligned the mount ( around 6 mins).

I had the same experience Sunday night at delta 14 degrees C.

I have no interest about why it works, but it has worked for me.

I am not an armchair philosopher, or critic, but a practical, I’ll try that to see if i get a result man.

Thanks to all for suggesting, it took me an hour to construct, at little cost, and gave me immediate benefit to my observing time.

The scope has already given me better images than my 12inch newt on double stars ( usually limited by seeing), so I am pleased all round, am waiting for planets now


Edited by AndyBooth, 21 February 2018 - 04:47 AM.

 

#247 MrJones

MrJones

    Vanguard

  • *****
  • Posts: 2436
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 21 February 2018 - 11:04 AM

"So that's at least 2 people with far more experience at this that disagree with you.". I'm not sure that this was directed at me.  But, if it was, it's certainly time for me to give up!  After all, TWO people disagreed!  Geez, what got into me!?  Imagine, thinking I could continue on when the overwhelming odds of 2 to 1 were against me.   By the way, you mentioned that those two people had "far more experience at this".  First, how did you determine that?  Next, the folks at IBM had FAR more "experience at this" than Bill Gates or Steve Jobs.  I suppose they just should have folded up their tents, eh? I think yellobeard, and the other scientists who are seriously going down this road will wind up producing results that will benefit all of us, even the non-believers.

You posted one observation. It was an ok one with interesting results. Nonetheless I am more likely to believe someone who has done something 100 times in a controlled manner over 100 people that have done it once.

What I noticed over multiple observations is that my scopes were still equilibrating over time as the image would continue to settle down and improve. This was much easier to see in my C11 but does need to be separated from changing sky conditions that can also occur over the same couple of hours. If you conclude that your scope still shows signs of equilibrating even after being insulated a logical conclusion is that it would be beneficial to equilibrate it as much as possible up front. Tanveer wrote pretty much the same thing in post 117 and elsewhere.


 

#248 Ron359

Ron359

    Apollo

  • *****
  • Posts: 1155
  • Joined: 21 Apr 2008
  • Loc: -105 +39

Posted 21 February 2018 - 11:06 AM

"Most astronomers were very skeptical, but he convinced many people they existed, until 1964, a passing Mariner disproved it all.  So much for pompous science!"

    I wasn't calling the science pompous, and I think you know that.  But, about your statement, Exactly!!!  For over 50 years people were taught that "you must cool your SCT to outside ambient before using".  And 99.9% (think elephants in a long column, trunk to tail) went right along with it, myself included.  Then along comes an optician from the Netherlands to disprove the "accepted wisdom".  And I will gladly send you the $25 for the Reflectix.

   Now, about another literary gem: " Visual anecdotal evidence is non-scientific and will not be accepted." ????  ''will not be accepted".  Really?  By whom?  You?  In case you haven't noticed, save for some of the imaging forums and a few others, just about EVERY statement you read on these forums, from telescope, mount, and eyepiece reviews, to 'first light' comments on anything, to comparison reports on everything, is "visual anecdotal evidence".  Gee, why don't the good folks at Astronomics just close the forums down?  And your $25 is waiting for you...  

Who be "Pompous"?!

 

In addition to your previous posts, Bean wrote in p-mail; "And I know it's tough to un-learn/reject/re-think evrything you've learned. It was pretty tough for folks to grasp, back in the day, that the Earth was not only round, but not the center of the universe. Heck, it took the catholic church ceturies to get that, if they ever did. As Jon Issacs states in an early post in this thread, this is a 'New Paradigm', and old entrenched thinking has to be thrown out."  

 

 Yes, for $25 and your claims, I'm supposed to agree with you that using a roll of reflectix on a tiny 6" telescope is on par with the science of Galileo, Newton, Tycho and Kepler and overturning the teachings that the Earth is center of the universe -which was based on visual anecdotal evidence BTW.  If anything, astronomy and science gives most people a humbler, less pompous perspective on life.   done.  


 

#249 Ron359

Ron359

    Apollo

  • *****
  • Posts: 1155
  • Joined: 21 Apr 2008
  • Loc: -105 +39

Posted 21 February 2018 - 11:58 AM

Folks, it is getting a little sporty in here. See what works for you under your conditions and with your scopes. If nothing else, it is a cheap experiment if it does not work for you. There are so many variables, even with the same telescope and same observer, as to make universal arguments for or against insulation conjecture at best this point. We're all using different scopes, in different climates and elevations, and with different temperature regimes. It would be interesting to compare what works best and with what equipment so as to see if we can pin down reasons why it seems to offer good results for some people and maybe poor results for others. 

 

P.S. 

-Freezeout is right about cold entering a room - pressure and density differentials come into play as well, second law notwithstanding. 

-I love that Batman meme and saved it to my computer. 

 

George

I agree, although a CNs forum could serve as a platform for crowd-sourcing citizen science of all those variables.  This experiment could provide real data to scope manufacturers or just those looking for good advice based on more than just opinions.  It could also be done with computer modeling using the known laws of Thermodynamics and material properties. Overall, this thread has outlived its utility.  


 

#250 will w

will w

    Apollo

  • *****
  • Posts: 1286
  • Joined: 13 Aug 2006
  • Loc: oxpatch,ms

Posted 21 February 2018 - 01:12 PM

Well the way i look at all this. If it works then use it. If it does not work dont use it . As for the scientific data of how this works does not mean much to me. From reading the posts here from the ones who have tryed it . There more +s than -s. So it must work. Maybe it will not work for everyone, but you will never know untill you try it for yourself.So i am giong to try it out. will w


 


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics