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Messages - Ryan Hernandez

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121
Beginners Forum / Re: First Time at "Dark" Site
« on: December 29, 2017, 02:41:44 AM »
Yes. I remember my first view of M51 was through an 80mm f/6 refractor out on a beach. I had failed to see the same object from my urban home with an 8" SCT.

Again, even in the city, I knew from the star field that I was looking right at it - but it wasn't there.

122
Mounts Questions & Expirience / Re: cgem mount pulse guiding
« on: December 28, 2017, 10:57:18 AM »
Yes you can do either ST4 or pulse guiding via the ascom driver. The performance is identical from what I've found.

123
Light Pollution Topics / New Mexico: Mag/sq arcsec and Bortle
« on: December 27, 2017, 10:06:11 PM »
I have the incredibly good fortune of living in the Magdalena Mountains in central NM.  I've estimated that I live in the Bortle grey zone as I cannot see shadows cast by the Milky Way.I picked up a SQM-L amd measured sky brightness at nautical twilight in the evening and morning, taking several readings and averaging.  In the evening I was recording 21.50 mag/sq arcsec, and this morning, 21.90.  Pretty dark.I would have thought that these readings would be more appropriate for a Bortle black zone.As an aside, don't pack your bags for Mag (as we call it).  The mountains entail hefty scintillation.  The air here is pretty busy, though it settles down by early morning.

124
Reflectors Telescopes Forum / What did you name your REFLECTOR ?
« on: December 26, 2017, 11:01:57 PM »
Error: You cannot process articles with only whitespaces

125
We truly live in interesting times...

https://en.wikipedia.org/wiki/GW170817

GW170817 is a gravitational wave signal detected by the LIGO/Virgo collaboration on 17 August 2017, also is the first such occasion simultaneously observed in telescopes having an audible counterpart. [1] The sign, which had a duration of approximately 100 seconds, is that the first gravitational wave detection of this merger of two neutron stars, also has been associated with a soft brief gamma-ray burst GRB 170817A, respectively[2][3] found in NGC 4993. [4] No neutrino applicants consistent with the source were found in follow-up searches

This pretty much confirms that short gamma ray bursts are from merging binary neutron stars.  This also reveals where much of the elements heavier than Iron come from:

The gravitational wave signal indicated that the gravitational wave event was associated with the collision of two neutron stars[6][7][12][9] with masses between 0.86 and 2.26 times the mass of the Sun (solar mass).  If a low spin is assumed, consistent with those detected in binary neutron stars which will merge within a Hubble time, this mass range decreases to 1.17 to 1.60 solar masses. [1] The total mass of the binary system was involving 2.73 and 3.29 solar masses. [1]
The neutron star merger event is believed to be a kilonova.  Kilonovae are applicants for the production of half the chemical elements heavier than iron from the Universe. [4] A total of 16,000 times the mass of the Earth in heavy components is expected to get formed, including about 10 Earth masses of gold and platinum. [13]
It isn't understood what object was produced by the merger.  Nominees are a neutron star heavier than any known neutron star now, or a black hole lighter than any known black hole. [11]

That is a good deal of precious metals...

126
Had my CGX. ES80ED & ES127ED outside for the third time because I purchased it back just before Christmas of 2016.  I took 2 minutes unguide of M104 & M13 after 2+4 alignment - ASPA another 2+4 alignment after the ASPA.

Both M104 & M13 did not appear too bad so I took a 3.5 minutes unguide of M51 just to see how the CGX perform unguided together with the ES80ED, ES127ED sitting on top of it.

Below are the unprocessed pictures I upload to AstroBin this morning, I am still new with all the uploading items.  Please let know if there is better way to upload images

M51
http://www.astrobin.com/297353/

M104
http://www.astrobin.com/297343/

M13
http://www.astrobin.com/297349/

127
Light Pollution Topics / Questions about light pollution
« on: December 24, 2017, 02:56:47 PM »
Hello Everybody,

I am a brand new member of forum.I'm not a native speaker so I will attempt to write in easy English.  My location of observation is suburbs of Istanbul  located in red zone for the time being.  I am now quite young and want to move to a darker spot in the future.   I've finished reading this subforum about LP and found it fairly depressing.  I want to ask a few questions to clean this up for me. - Can I find a house that will remain in precisely the same bortle skies scale course for at least 20 decades.

- Will a few floodlights nearby contribute a significant sum to overall sky glow even if you don't see these directly?  While I've moved to a rural area if I worry about lights nearby when I dont see these directly. ( No light trespass)?

- Why is this great thing about LP that bad as it's said in forums?  This subforum made me extremely cynical about future of my hobby.
Timur

128
Does anyone know if brand new (2017+) Losmandy G11GFT mounts come with the one part worm upgrade that everybody appears to be purchasing for elderly G11's, or is the OPW update still crucial to buy even for new G11GFT mounts?  Thanks!

This is the specific mount I'm asking about: https://www.bhphotov...rial_mount.html

129
Beginners Forum / Storing my mak?
« on: December 24, 2017, 04:53:53 AM »
So I've been maintaining my 127 mak in my garage so it's quicker to acclimate in chicago's beautiful winter weather.   Is it secure to do so, caps on and such?  Is this a bad idea in the summer when it becomes hot?  I am a bit worried about heating coming in and outside in the wintermonths,  but is this a good idea?  I believe that the cold will be OK, and I believe I should bring it inside for the summertime, but any guidance would sure be appreciated!  As always, thanks in advance!

130
Beginners Forum / Re: New to the forum!
« on: December 24, 2017, 04:50:10 AM »
<p>Welcome.
</p>

You could also find some good scopes on Ebay, Shopgoodwill, here on Cloudy Nights, and craigslist.

Being new, you probably are not sure of what kind or kind of telescope to get.  You will receive a lot of replies, since there are many here who are prepared to help.

You mentioned "old" telescopes, and a few of those previous scopes are pretty excellent.

Maybe begin with somewhat 60mm classic refractor, like Tasco,Sears, Swift, etc..  It could wet the appetite fora bigger scope.  A 6" Dobson telescope will provide good views of these deep space objects, as well as the planets.  It is going to also be easy to move around.

Combine a local astronomy club.  Many clubs have loaner scopes for beginners to use.

Just have to be aware, not every telescope has great optics, and may be a disappointment.  So, here on CN you'll find a lot of good advice on which ones to purchase.

131
Beginners Forum / Re: Other hazards to viewing: Earthquakes, etc
« on: December 24, 2017, 12:32:18 AM »
In Southern California the displaced immigrant population is so large that most wooded open spaces close to the city are infested.  Going out solo to observe one has to think about this.  I believe in the good in people but dire conditions that they survive struggles their morality.  As a result I only proceed distant where a range of different astronomers will go or be far from the city.
Bruce

132
General Astronomy & Observing / M42 in Sky and telescope.
« on: December 23, 2017, 10:54:23 PM »
When exercising problems involving spherical area like apply, e.g., when calculating the flux recieved from angularly massive resources, it happened to me to derive the identical f/ratio if a surface is illuminated by a source filling a complete 180 degree hemisphere.

I worked out the problem starting from the angular place for an f/10 equal, then doubling the region as suitable for one f/stop increments until reaching the place to get a 180 degree hemisphere.

F/10 is 5.71 degrees, for a place of 25.6 square amounts.

A 180 degree hemisphere contains 20,626 square degrees.  That can be 20,626/ /25.6 = 805.5 times larger area than for f/10.  In terms of f/stops:

2^9.65 = 805.5, meaning a hemisphere is 9.65 f/stops brighter than f/10.

This leads to a 180 degree hemisphere as being equal to f/0.3183.

This happens to equal 1/pi, that's the proportion of the radius to a 180 degree arc.

Why cannot a faster f/ratio obtain?  In the end, one might conceivably construct some hyper-fast system which has an entrance pupil 4X larger than the focal length, for f/0.25.  Or an entrance pupil 5X that the f.l., for f/0.2.

Ah, but the luminance of a pupil doesn't act as a surface tangent to its own center.  Instead, it behaves as a section of a sphere.  And so the simple and naive tangent function is wrong.  While it holds reasonably well for less speedy f/ratios, it becomes increasingly inaccurate at rapid f/ratios.  On the point that the suitable limit of f/0.318 corresponds to the tangent calculation of 1/infinity!  Or in technical terms, which is clearly nonsensical, for it implies infinite brightness.

To understand this, picture the following:

The daytime sky is covered with a smoothly uniform, overcast stratus cloud of completely uniform surface brightness.  A fully opaque tent is built that has a hole in the roof 5.71 degrees in diameter as seen from ground level.  This hole would be equal to a f/10 pupil as seen by the focus of this kind of objective.  (The presence or absence of a focusing lens is immaterial here as a result of target's uniformity in surface brightness.)  A light meter is put on the ground directly below the pit, and a reading taken.

Subsequently the tent is whisked away so that now the whole hemisphere of sky is observed.  The meter (supposing it correctly takes in a complete hemisphere) may or vide a reading 9.65 ceases, or 805 times brighter.  Because a 180 degree hemisphere introduces a good angle (angular area on its *curved* surface) 805 times larger than does a 5.71 degree diameter of the exact same curved surface.

To stress the way the angle, defined by a spherical surface of radius based on the observer/sensor, is the important variable, I present a very different case:

Imagine some strange object in space that is essentially a circular, thin sheet shining like a star, of uniform surface brightness, which we see from directly face on.  We approach to a space at which it subtends, say, 90 degrees and stay in place.

Originally this disc is level.  We've got a metered reading of its overall light hitting us.

Subsequently the disc bulges out toward us, like a section of a sphere, like the center is much nearer than the perimeter.  The surface brightness remains unchanged.  Our meter supplies exactly the same reading before.

Subsequently the disc bulges inward, introducing to us a bowl-like aspect where the center is further than the perimeter.  The surface brightness still remains unchanged, and our meter supplies the same total light hitting it.

Note that instead of a flat disc, when bulging out or at the surface region of the disc itself increases since the perimeter is fixed in place.  But since the angle we see is unchanged, the total light received in unchanged.  The lesson here is that for a source with surface area, whatever its real topology and space variation on its surface, what is that the angular place it presents, and that is always treated as a section of a surface adapting to a sphere based upon the observer/sensor.

Back to our disc of light.  We fly up to it, so as to be basically in contact in order for it to fulfill a 180 hemisphere.  We have a meter reading (the meter being effective at carrying in 180 degrees.)

Now the disc warps so it lumps from us, forming a hemisphere together situated in the center.  Its surface brightness remains the same, it still occupies a hemisphere because we see it, and so our meter accounts the same light input prior to the altering fit.  In spite of the true surface area having increased considerably from apartment to hemispherical.

Again, given a fixed surface brightness (which is invariant with space, incidentally), the total flux obtained depends entirely on the solid angle subtended by the source.  In most cases we treat the origin like lying on a spherical surface concentric about us, no matter its true morphology and topology.

I am hoping this is not too muddled and confusing.

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