"Telescope Provincialism" on CN

 

havasman

Voyager 1

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Posted Today, 03:57 PM

My TV 2x is invisible to me except for the magnification increase. I like it just fine and think it's very good. It is for use with Tak Abbe Orthos, probably the highest fidelity eyepieces I have. Morpheus are excellent eyepieces. Barlows are specialist tools that have, by way of being included in beginner kits I think, become thought of as required in a kit. I think the important Barlow Q is do I need one and why do I want one. Mine is for taking the focal length of a TAO below the point where eye relief practically approaches zero. A Barlowed eyepiece retains its original ER.

 

When I read the amateur reviews that say one fine Barlow stands head and shoulders above another I look at the associated gear and consider the objects used to judge. Usually neither much mirrors my choices so I discount the value of the review as it relates to my observing tools. Somebody using a ~large world class APO refractor to look at the moon and planets is really playing a different game than I and using different tools too. So their well drawn and clearly expressed opinions are maybe not particularly applicable to my needs.

Edited by havasman, Today, 03:59 PM.

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One of the things I see on CN is that people are often trying to find someone in their EXACT same circumstance so they feel they can have a "real" conversation about some topic.  But finding someone who essentially shares the same equipment and views is like finding your long-lost twin.

You're basically trying to find someone who has your same exact thoughts and feelings.  Why even try to find that perfect "someone" if that person is staring right back at you in the mirror? 

This weird desire also speaks to an inability to see connections and extrapolate results from different systems and different people.  

When your psychology is dominated by this 'doppleganger-desire'-feedback loop, I suspect you've entered an early stage of dementia where the interesting mysteries of the world have become threatening and confusing.

Venus Study from 9/24

 

This is my best effort after about 7-8 tired mornings shooting with the C11 and UV setup.  

After some sharpening in PS, I was able to bring out some of the larger cloud structures.  I know there are some very thin bands in the south (and probably the north) but I couldn't quite tease them out.  There are certainly hints of them but I need better seeing and more aperture to get them.  In my 16 runs on the planet, there was only one run that came close to showing the thinner lines.

Seeing is routinely awful in the pre-dawn hours toward the east for me.  One morning, I did stay up til 9 am and tried to shoot Venus as it rose higher than 30 degrees but the seeing never settled.  My tube just got warmer and warmer due to the sun hitting the dew shield and scope body.

I think I need an open tube scope that I can run with a fan continuously to deal with the heat currents.  I don't think the SCT is a great choice for Venus (though there are some good images from C14's).  I guess I could try to fabricate a white dew shield and maybe completely cover the tube in Reflectix.   And/or I could try wrapping the outer part of the dew shield in aluminum foil.

In my 1200 years in this hobby....

 ...Or when I last talked to Copernicus about premium APOs...

...Or when I told Su Song to move the NCP further from Polaris...

...Or when I told the young Eudoxus that Earth didn't really move much unless one was wearing one's favorite x-ray glasses purchased from the penultimate page of the latest Aquaman comic...

Suspected Scam on CN

 https://www.cloudynights.com/topic/743653-complete-idiot-needs-help-pretty-please/

enddumper

Lift Off

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Posted Yesterday, 08:02 PM

hey guys thanks for reading and helping new rookie out. i just purchased a brand new in case  Astro-Tech TMB-92 Signature Series 92mm f/5.5 Apochromatic Refractor scope for $1199.00 the other day. My basic use is for terrestrial - Celestial viewing only, absolutely no astrophotography .   

 

basically i need informed guys to tell me what other basics ill need for this 6lb boat anchor, other than the tripod which i have figured out already, and is this my best option for which my intended uses are for, again thanks for any and all informed input because purchasing mistakes is digging into my beer money             

Edited by junomike, Yesterday, 08:52 PM.

 ____________________________

 

I've seen posts a few times where some "regular" person says they're excited about an incredibly great deal they got in regards to a telescope.  Sometimes an avid amateur will stumble across a rare find at an estate sale or garage sale.  But most of the time it turns out to be a scam where the poster (OP) didn't realize they just gave their money to a scam site.  Usually a call to a credit card company fixes the issue.  And of course, the person will need to monitor their credit card account closely as the fraudsters will probably sell/distribute the cc number.

But sometimes you get the above post which eventually leads to a post about how the "lucky" purchaser bought their scope.  It ends up being some sort of scam where the whole reason for the post is to get people to "discover" the scam site.  It's really targetting newbs who only see how much money they can save.  Newbs often don't do their due diligance because they don't know who to trust.

There are a few red flags here.  First, the OP's first post ever is about a great deal.  Mostly, I think folks would ask first to get a sense of the trustworthiness of a potential seller.  Second, the OP seems to know what the actual value of a TMB92 scope is.  But he also claims to be a rookie.  Third, for some reason this poster referred to the scope as a "boat anchor" which might just reveal his/her sense of humor.  But it might also be a Freudian slip revealing that the OP actually knows the value of the scope to be equivalent to a useless boat anchor.  Fourth, the linguistic ticks of the poster are interesting.  In the first sentence, the OP drops an article...  "a" new rookie...   You can draw your own conclusions here.  Fifth, and perhaps most revealing is that there is an added space before the description of the telescope.  If you copy paste what he/she's listed, the first Google hit is a well-known scam site.  No legitimate seller of that scope lists the scope as a "signature series" scope.

Caveat...

 

WinJupos Comparison

 

Having tried a series of 5-11 sets of stacked images de-rotated in WinJupos, I think it's fair to say that you really need like 15-16 sets of stacked images to improve the image.  While the de-rotated image isn't as good as a really good 3 min RGB stack from the previous night, it's a definite improvement.  

I should clarify by saying that not only are we reducing noise in the WinJupos image, but we are getting smaller scale detail which is not available in the single stacked image.

My slight frustration with WinJupos is that most of my attempts have only cleaned up the noise but haven't done much to reveal more small-scale detail.  Had I done this comparison back in August, I would have then instituted a policy (lol) where I always collected 15+ runs of any planets.  For Mars, that's like 45-60 minutes of data.  For Jupiter, that's 45 minutes at most.  

I have derotated a few Jupiter runs, but since I didn't know how many runs would make a difference, I was just doing like 5-7 runs on Jupiter, taking a long break (an hour or longer), then doing another 5-7.  

Chrisotpher Go has mentioned that he does like 5-7 runs in excellent seeing and many more in comparatively worse seeing.  

Also, it's probably worth mentioning (again) that you really need to pay attention to how WinJupos is aligning the images.   Sometimes if you don't pay attention, WinJupos will move the planet slightly from one stack to another which I'm sure is compromising the nature of the stacking.

There are some weird color issues that I couldn't quite fix.   When I did the first Registax wavelet sharpening, I sorta pushed it and in the process, I began to see odd colors (bluish-red).  I didn't really pay attention but then in the final sharpening, I had to deal with it.  And after fifteen minutes of goofing around with the colors, I was too burnt out to go further.  Another color related-issue is that the atmospheric blue "halo" was more orangish.  Again, I can fix this, but I just thought it was interesting that pushing wavelets too hard and de-rotating in WinJupos gave me this "false" color.

Excellent Post About Using Topaz and PI

For all the crappines on CN, there's occasionally a really useful post:

https://www.cloudynights.com/topic/742075-i-gave-topaz-a-whirl/?p=10690138

I wouldn't be suprised if the mods remove it (or just move it) because it's too useful for the average idiot who reads CN.  😝

Dealing with Artifacts in Autostakkert and Registax in Planetary Files

This is another one of those "note to myself" posts so I can remember how I got through some techincal problems with Autostakkert and Registax.

There are a number of reasons why you'll get artifacts in Registax while using wavelets.  Hm...I mean that there are many pathways to artifacts in Registax.  

(In the interest of clarity, I should mention that the artifact generally appears in Registax when using wavelets; or it appears in PS when sharpening.  Sometimes, the artifacts are so severe that you can see them in the stacked TIF file.  If you see the latter, it's not worth bothering with Registax or PS.  This means you need to move some alignment points (sometimes you even need to start over) and stack again.)

Here's a list of things that can lead/contribute to artifacts:

1)  In Autostakkert, putting alignment points OUTSIDE a planet's edge.  This sometimes happens if you let Autostakkert automatically insert alignment points.  It can obviously happen due to human error if placing them manually.

2)  In Autostakkert(AS), putting alignment points ON the planet's edge.  This sometimes is fine with really steady video footage.  But when you play your video in the preview window and you see the planet's edge moving a fair bit, that edge alignment point can someties be on the OUTSIDE of the edge.  (The lesson here is to move the alignment point INSIDE the edge by a fair bit.)

3) In AS, it's tempting to use a bunch of small alignment points all over.  The reason I've done this in the past is that -- in my experience -- AS will produce a relatively more detailed and contrasty stacked file with a bunch of smaller alignments points versus a small number of large alignment points.   But you are guaranteed to have a greater chance of artifacts with small alignment points.   Again, with really good video footage, you can get away with a lot of small alignment points.  With average data (or worse), you are asking for trouble.

4)  In AS, there's a "Quality Estimator" (QE) setting that I've discussed in the past.  It generates a graph that resembles a seismograph data sheet.  I've noticed that when the graph touches the bottom axis for more than a moment (guessing for 3% or more of the total), you may encounter weird ovals in the stacked image.  The fix is is to change the QE setting so that the generated graph stays off the bottom axis.***

5)  This is also related to the above remark...   If your QE graph is really compressed where it looks like a fat line instead of a zig-zag graph, then you may encounter artifacts that you cannot eliminate with ANY alignment point scheme.  Usually, there is some QE setting that will "widen" the line so that it resembles a zig-zag.

5) The video footage was shot TOO CLOSE to the edge of the frame.   I've had this happen due to laziness OR when trying to dodge a piece of dust in some part of the frame.   It gets to be a REAL problem if the planet goes off the edge for any period of time.  In the video footage preview window, you can "scrub" through the video by moving a slider.   You can also hit "delete" (space bar) to remove any "bad" frames where the planet is too close to the edge or has moved off the frame.  The problem is that if you had the planet move off the frame for more than a second, you will need to "spacebar" (remove) A LOT of frames.  Sadly, I've spent 20-30 minutes removing frames on just one clip.  It's monotonous and sometimes artifacts still appear.

6) Speaking of dust...  a dust bunny will get stacked and create its own artifact.

7) Undetected moon on Jupiter surface.  You really need to place an alignment point on the moon, but sometimes you can't quite see where the moon is located.  AS will think the moon is some surface detail, but it will look distorted.

7) Really NOISY video footage...  In an effort to really "push the edge" of the number of frames, I've shot at like 250+ fps with high gain settings.  The resulting footage is often noisy and will produce artifacts.    Also, if you are shooting through clouds or poor visibilty, you can end up with really noisy video with no details.   Noisy images don't inherently produce artifacts, it's just that they are LIKELY to produce artifacts depending on your alignment points.

8)  Overexposed image.   If you make the mistake of shooting with the histogram pushed to the right, you can often get artifacts.  This can easily happen when shooting Venus.   It gets brighter and brighter as it rises and you forget to change your settings.

9)  Alignment points near a terminator.  I've noticed that when setting alignment points near the terminator of Mars, they will produce artifacts that look like partial circles.  The solution is to try fewer alignment points with a much larger size.

There are probably tons more scenarios where you can get artifacts, but I'll add to this list as I remember more of them....

So, I'm kinda of getting to the point of usng small and medium alignment points with 8-10 larger alignment points interspersed around the edges.  Also, I'm using alignment points sparsely near the terminator of Mars.

 

There are some "best practices" to list after reflecting on all of this, but I'm too tired to compile them right now....  :(

 

***Sometimes you can't avoid the graph from hitting the bottom.  The fix has been to UNCHECK the "Laplace" option box.  But I've found that this will oftentimes result in stacking bad files with good files.   Not sure how to remedy this.

Another excerpt from a CN thread where bias is not allowed to be discussed

Bean614

Apollo

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Posted Yesterday, 07:00 AM

"Fellows what do you think.....".....???????

 

Are women not allowed to comment?

• dron2015 and plot0015 like this

#3 aaube

Ranger 4

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Posted Yesterday, 07:27 AM

That was uncalled for.

 

Bean614, on 24 Nov 2020 - 05:00 AM, said:

"Fellows what do you think.....".....???????

 

Are women not allowed to comment?

#4 Bean614

Apollo

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Posted Yesterday, 07:29 AM

Why?

#5 imtl

Apollo

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Posted Yesterday, 07:52 AM

Moderator hat : ON

 

Because,

 

Fellow: "a person in the same position, involved in the same activity, or otherwise associated with another."

 

And also because the OP is not native in English and there is a language barrier. 

 

Now please no more of this and STAY ON TOPIC. We welcome all astronomers here and we don't really care who and what you are. Just be nice and enjoy the hobby and communicating with all people.

 

Moderator hat: OFF.

 ---------------------

More like "ideological police cap": ON forever.

 

Myths of Small Aperture Beating Large Aperture

 I was looking for informtion on the pros and cons of the C14 vs C11 and came across this post on CN:

RickV

Posted 25 June 2016 - 01:00 AM

...

I just came home tonight from a star party.  Seeing was average.  My Orion 120mmED 'apo' doublet outperformed a 25 inch Dobsonion - showing more detail on Jupiter, Mars and Saturn.  But... if seeing were excellent, then I have no doubt the 25 inch circus cannon would have blown me out of the sky....

 

Sometimes a myth becomes a delusion and this is one of those cases.  There are one of several problems that could explain the account.   The first possiblity was that the dob in question was not collimated properly so no views above maybe 100x would be sharp.   A second possibility is that the optics could have been bad -- we have no info on the type of mirror/secondary.   There were tons of crappy large mirrors made in the 80's, 90's and early 2000's by "reputable" opticians where the scopes could never deliver better than 150-200x performance on any night.  It's also possible that the optics were not cooled and were subsequently significantly overcorrected.   Large dobs need a few hours to acclimate (with fans runing) and this seems a possibility.

The other rarely mentioned situation is the inexperience (stupidity?) of the observer.  I've been with observers at star parties who have NEVER looked through a big dob (25+ inches).  Some newbish observers can't deal with Mars or Jupiter being so bright.   They are literally blinded and can't see any contrast on planets even though the view is presenting immense detail.  OR when observing faint features in a galaxy, the observer can't make out any detail because 99% of their observing is done on bright DSO's and planets through small scopes.  Again, low-contrast detail is lost to the self-declared expert who has no business looking through large telescopes. 

But the myth goes on and on -- especially on CN.  The little scope outperforms the giant scope in all "real" situations.  The little scope can beat the seeing better than a large scope because of atmospheric cells, etc, etc.  The back-handed compliment of the big scope being a "canon" -- obviously the wrong tool for astronomical observation.  And yet the million-dollar observatories with their "big scopes" must obviously be doing something wrong.  They really should be using $500 80mm refractors because in the "real world", the small scope always outperforms the big ones 90% of the time. 

Yeah...

Added later..... more non-sense from a CN idiot:

aztrodog

Sputnik

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Posted 25 September 2020 - 11:15 PM

I appreciate different points of view, so here is mines to balance out some of the earlier postings. Personally I did not find either of my two superb 14” SCT or friend’s high end Dob to provide better, more detailed views than either a 6” or 7” APO. I owned two C14s, both of which I used extensively under South Florida steady skies. I also had access to my friend’s 16” Starstructure / Zambuto mirror. As good as those scopes were, I vastly preferred the views in my 7” APO and my friend’s Tak152. The purity and aesthetically pleasing views in the refractors were simply unmatched by the larger scopes. Trust me, from the financial point of view I would have loved for the SCTs or Dob to blow away, leave in the dust or _______ (fill in disproportionate statement) the 7” APO.

----------------------

Purity of views, eh?   What's next, Hitler had the best optics because he was all about racial purity?  C'mon.  Also, whenever someone says, "trust me..." when it comes to telescopes, it's usually bullshit.   The properly cooled and collimated C14 will always give the same (or better) views AT THE SAME MAGNIFICATION.   This numbskull is likely comparing his 7" APO at 100x vs the C14 at 300x.  And yes, the 7" APO will provide a crisper view at that unfair magnification difference.    But push the 7" apo to 300x and you will see a dimmer, fuzzier view.   Push both scopes on a night of decent (you don't even need perfect) seeing to 500x and you'll see the real difference.  

I think there's also a HUGE issue that no one focuses on (ha): Experience with small AND low-contrast detail.  I've mentioned this before but I think some people have the equivalent of 480p resolution in terms of eyesight while others have 4k resolution.   What I mean is that some people CAN'T MAKE OUT SMALL DETAIL in an image.   On top of that, I believe some people CAN'T DISCERN ANY SHADES OF SUBTLE CONTRAST.  Contrast differences have to be huge for some people.  It never occurs to them that they may be "unskilled" as a visual observer.  

We are a visual culture and it never occurs to anyone that there may be different degrees of visual acuity amongst the population.  Some of it is natural, but for visual astronomers, it's also skill-related.

I guess if you don't see it, it doesn't exist.   Which I think is a perfect metaphor for blindness.

And don't get me started on the "balance out" metaphor.  

There's a lot of ridiculous, erroneous and just plain bad discussion on the Refractor forum.  I think a lot of it is transparently an attempt to justify one's current equipment list -- especially if you own an expensive APO.

-----------------------------

Another example of "small scope delusion":

bobhen

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Posted 13 December 2020 - 07:32 AM

Jon Isaacs, on 12 Dec 2020 - 3:35 PM, said:

In my experience, that is not the case. The 6 inch is being limited by seeing and diffraction, a larger scope is only limited by seeing.

 

This is easily seen with double stars. It takes better seeing for a 4 inch to split a 1.15" (Dawes limit) double than for an 8 or 10 inch to split that same double.. The airy disk is smaller.. i remember one night a year or two back.. Antares was low on the horizon, I took a look in the 22 inch, I thought I saw the companion. I cranked it up, there is was.. not pretty but  bright and widely split.. 350x.  It's a tough split in a 5 inch in decent seeing.. That's when I realized just how small that airy disk is.. It's 0.50" in diameter to the first minimum. It can take a lot of aberration from the seeing. 

 

 

These "limits" are not hard and fast, there is no point at which better seeing won't help a given scope show more.. if you set the limit for a 6 inch at 1", the planetary views will still be better in 0.5" seeing.

 

Jon

My experience is different...

 

I have compared my 210mm Mewlon to my Tak TSA 120 side-by-side on many nights. They ride side-by-side on he same mount.

 

The Mewlon has smooth mirrors and high contrast and is almost twice the diameter of the TSA 120 and yet on many nights does not show any more planetary detail than the 120mm refractor.

 

It takes above average seeing and the planets to be reasonably placed for the Mewlon to “start” to pull away. And these were side-by-side observations. Even my AP 155 refractor bumped into seeing on most nights.

 

In truly excellent seeing, a high quality 6” refractor (or any high quality telescope) can do 90-100x per-inch on Saturn. How many nights did that happen in the 17-years I owned the 6” refractor – zero. Some nights I did use 450x but most nights the scope was running around 275x, far below its capability – because of the seeing and nothing else.

 

Roland Christen used his 10” Mak to observe the Encke Gap in Saturn’s rings using over 800x when he was in Florida. He never saw that feature from his observatory back in IL, nor did the scope use that much power. It can’t from that location.

 

If one isn’t using 90 to 100x per inch on Saturn then seeing is limiting the scope’s capability or the optics aren’t good enough or both.

 

Chaz (CHASLX200) has posted here many times that he has used 1000x on the planets with his high quality Newtonians in his excellent Tampa Florida seeing. I had a 15” Dobsonian for many years with a near perfect Galaxy mirror and never came close to those powers from my PA location.

 

That’s my experience, for what it’s worth.

 

Bob

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I've seen A LOT of bad posts by this bob character.   I still believe that some people can't see low-contrast detail through telescopes.  Bob is obviously one of them.  A low-contrast but detailed image appears as a fuzzball to some very unskilled but long-lived observers.   It's unfortunate.