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Topics - micfullprovlo

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Most mirror cooling fans, I believe, are mounted behind the mirror blowing on the back and up the tube. I have heard that some reverse the fan, still behind the mirror, but drawing air down the tube and out the back. Which way is better? It seems that by cooling the mirror blowing up the tube would cause the heat in the mirror to add to the thermals. With the air being drawn down the tube, would there still be thermals or would they be eliminated by the reverse flow? Would the mirror cool faster one way than the other, or would the cooling time be the same? Do you just cool the mirror then turn the fan off, or leave it running for the whole observing session? Your thoughts or findings! Thank So!

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Mounts Questions & Expirience / Took the AZ-EQ plunge
« on: January 04, 2018, 10:14:17 AM »
Just pressed "pay" on SW AZ EQ6-GT, and I feel like
First I was going for the Orion Atlas, found out with help here, that it's a black SkyWatcher. And as SW it was much cheaper. Ordered it from the UK. I'll start practising more with PHD2, and just enjoy visual observation until I can get a new camera, probably next year (this years astro-budget is now officiallyspent).

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We truly live in interesting times...

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

GW170817 is a gravitational wave signal observed by the LIGO/Virgo collaboration on 17 August 2017, and is the first such event simultaneously observed in telescopes with an electromagnetic counterpart.[1] The signal, which had a duration of about 100 seconds, is the first gravitational wave detection of the merger of two neutron stars, and was associated with a soft short gamma-ray burst GRB 170817A,[2][3] found in NGC 4993.[4] No neutrino candidates 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 shows 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 observed in binary neutron stars that will merge within a Hubble time, this mass range reduces to 1.17 to 1.60 solar masses.[1] The total mass of the binary system was between 2.73 and 3.29 solar masses.[1]
The neutron star merger event is thought to be a kilonova. Kilonovae are candidates for the production of half the chemical elements heavier than iron in the Universe.[4] A total of 16,000 times the mass of the Earth in heavy elements is expected to have formed, including about 10 Earth masses of gold and platinum.[13]
It is not known what object was produced by the merger. Candidates are a neutron star heavier than any known neutron star today, or a black hole lighter than any known black hole.[11]

That is a LOT of precious metals...

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ATM, Optics and DIY Forum / Foucault tester LED-lightsource
« on: December 31, 2017, 10:19:11 PM »
The size of the light-source will show a big difference in contrast. A few months ago I made myself a brand-new (printed) FT and tested this phenomenon. As a matter of fact I had to narrow down the light-source to have a good contrast. Why I had to narrow the LED lightsource to almost a pinhole I do not understand. In the past I used a full sized 5mm -not flattened/sanded- bare LED. It was one of the first (when they got in production) white powerLED's. It still puzzles me why I made razorsharp, high contrast for so many years and suddenly, with my new built FT, using a similar white powerLED, contrast of my focograms is completely gone when I try to use a full sized (new) LED.
And yes I know many of you will say : impossible, and lots of you guys use a slit and also sanded LED's and other possibilities. But the fact is, for years I made (literal) thousands of focograms during course. All taken with that bare LED. Why can't I reproduce these same high quality focograms with a new bare LED..?
What has changed in LED manufacturing...?

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Beginners Forum / Orion Astroview 6 EQ or 130 ST
« on: December 28, 2017, 11:57:37 PM »
Well this is my first post. Hi, I'm Dan from Alberta Canada.

A number of years ago I bought a Meade ETX 80 with the 494 handset. I figured it would be neat and liking to play with technology I figured it would be easy to hook up to a laptop and steer around the sky. Nothing but a pain in the butt and I soon got frustrated and put it in a corner. I would imagine this is a frequent refrain and experience.

I recently took it out again and started playing with it. Computer stuff still doesn't work but I got the handset working properly. The other night I was looking at saturn. It looked like a bright star and the lack of any detail left me wanting more telescope.

I have kind of settled on the Orion 130 ST or the Astroview 6 EQ. My logic is leaning towards the 6 EQ because of the larger aperture and thinking in the long run as I grow in this hobby I will be happier with the scope.

Am I wrong?

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Eyepieces Questions & Recommendations / Q about Expanse Eyepiece & Clones
« on: December 28, 2017, 11:51:02 PM »
Hello eyepiece ladies and gentlemen.

At an ever increasing age, I think I'd like to retire my small collection of Plossl eyepieces. They are very good and reasonable in price, but the eye relief has been becoming a more important issue.

So, my plans are to eventually, as funds permit build a small set of 82<sup>o</sup> Explore Scientific eyepieces. ES is my favorite company, for several reasons, and I find their eyepieces comfortable and capable, and (especially when they throw a sale on) affordable.

That's not to take away anything from any other brand at all, they are just in my zone.

In the meantime, and to fill in any FL gaps, I've picked up two, used in good condition Orion Expanse types. One a 6mm Expanse and a 15mm clone, on the way to in the mail.
I read somewhere they are based on the Erfle design. Does anyone know it that's true? If not, what design are they close to, if known?

Also, anyone with these, I'd welcome your assessment.

Thanks very much. Oh and I'll use these with a 6" f/6 DOB, a 102mm f/9.8 Ach, and a 80mm f/7.5 C80ED.

joe


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ATM, Optics and DIY Forum / Aluminum as Newtonian tube material
« on: December 28, 2017, 03:35:22 AM »
I was curious if rolled aluminum, being light and reasonably strong would be a good material to make a solid tube newt's tube from or if it would be too thermally sensitive and cause the telescope to come out of collimation. Thanks!

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Eyepieces Questions & Recommendations / XT8 EPs
« on: December 27, 2017, 11:46:59 PM »
I've got a new XT8 and I've only got the 25mm Plossl that came with it. I live in Southeast PA with a nearby "yellow" area on darksitefinder. I'm debating between the Explore Scientific 82 degree kit (30mm, 18mm, 11mm, 6.7mm) for $630 or a Delos 6mm, 12mm, and Nagler Type 5 31mm. First, are these wise collections? For my area? It somewhat approximates the 6"-10" Dobs recommendations on Televue's site. Second, double the cost is a hard nut to swallow given that I'm brand new to the game but everyone raves about the Delos.

I started with astronomy by looking at binoculars and everyone raved about the Fujinon 10x50s. After some comparison shopping, I bought the Fujis so I'd like to avoid the swapping around. But the Fujis are a steal of a deal in comparison to something like Swarovski. So I'm not clear if the ES pieces are the Fujis of the EP world and the TVs are the Swaros.

Thanks for the insight. And I hope my binocular analogy wasn't too strained.

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ATM, Optics and DIY Forum / Machine alt-az refractor head
« on: December 27, 2017, 10:51:05 AM »
I would like to machine a alt-azimuth head suitable for mounting a 15# refractor. There are many examples of pipe mounts and Berry "dob style" mounts. I am looking for something closer to the commercial metal alt-az heads. I have a Harbor Freight 8x10 metal lathe and modest skill using it, so this is a good excuse to build something with it. In the longer term, I would like to add encoders for a DSC. I already have a sturdy tripod.

Plans, pointers, tips, or photos from someone who has built something like this would be greatly appreciated.

Of course, it would be a lot easier to just buy a head, but then I would not be hanging on the ATM forum, would I?

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General Astronomy & Observing / 2016 Messier Hunters Club
« on: December 25, 2017, 09:36:28 AM »
Hopefully I can find some people who are interested in keeping track of their Messier finds here, with the goal of finding allof themin 2016.  It would be a nice way of encouraging each other to stick with the search and also share stories of their experience.  Here are the club rules and ideas.
1) This isn't a race to see who will tote all the Messiers first.
2) The goal of each member is to watch every Messier in 2016 and the aim of the team is to get as many members as we can to finish the list.
3) Simply post your progress with this particular thread and keep upgrading it.  (Since we're seven days to 2016 you can post any Messier you have seen in the last week)
4) Any visual method of observation is acceptable.  If you are like me and like to brag that you just used a non-computerized telescope subsequently do this.  Note: items found on a screen are not acceptable.  The actual photons will need to go in the object, through some kind of glass, and/or refracted or reflected by it, and in your eye.  Of course, the naked eye is acceptable.
5) If you do not discover this thread until months or weeks after Jan 7, you can still post your findings as long as they had been after 1-1-16, assuming you have kept precise records.  As this isn't a race which would not be a problem.
6) And obviously you can start your list when you want.  As seasoned observers understand you do not require an entire year to find all the Messiers.
7) Here's an example of what one of your posts must look like, even though you can lay them out anyway you want.  The main thing is to notify me once you have completed the list.
4-17-16 Observed Messiers 65, 66 and 84
Used six inch operated reflector
Total found so farthis year: 58
And it would always be nice to list any other info about your night.
At the end of the year I'll be throwing a ticker tape parade for those who completed the list.  Rather than confetti falling it'll probably be 50 dollar bills.  (unless I change my mind and choose just to compile a list and forgive everybody) Happy searching!!!

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General Astronomy & Observing / Atlas users,Keeping your place
« on: December 24, 2017, 06:45:05 PM »
I've tried a couple of ways to keep my place on the graph with clear plastic tabs but this works better for me.,I also put a 2 FOV circle to coincide with my own starhopping EP.,If you buy a fantastic magnifier that function could be used as well.,The $1 ones in the Mart don't work for magnifying.,. ,Cheers.,

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