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Topics - renjaysunsdis

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I got my new 10" Dob yesterday and assembled it last night after getting the kiddos to bed. It came with a laser collimator, so I needed to collimate that before using it to line things up in the scope. I came up with a super-simple setup.
1. Drill a 2" hole in a 2x6 (I'm sure a 2x4 would work fine; I just had the 2x6 already laying around).
2. Place the lumber in a vise or build little legs on it. I like the vise because it doesn't move or slide around.
3. Place a 2" extender tube in the hole. Mine happened to fit nice and tight; but if it didn't, you could probably wrap a strip of paper or something around the tube to keep it tight in the hole.
4. Place a 1.25" adapter in the extender.
5. Place the collimator in the adapter.
6. Aim the laser at a piece of paper on a far wall (mine happened to be abut 25' away) and mark the spot. Turn the laser a quarter turn and mark the spot. Do this until you have four spots. Just be sure your parts are all flush and tight, especially each time you turn the collimator. Otherwise, accuracy will suffer.
7. Draw a spot equidistant to the four spots (I put some cross hairs on the new center spot to make it a little easier to see).
8. Adjust your collimator's screws until it's centered on the new spot.
Quick, easy, cheap, and effective!

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Beginners Forum / Flashlight instead of a finder scope?
« on: December 29, 2017, 12:57:35 AM »
Not very serious about this of course but had lots of fun sticking a flashlight into the back of my Mak and playing with the worlds biggest lightsaber. Actually does sort of work if you don't have a laser pointer.

Pointing at Vega - sorry for the crummy images. Best I could do handheld.
Attached Thumbnails




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I'm getting ready to buy a fixed length focal length eyepiece or two for use in both a 140mm-f/7 refractor with a 980mm focal length and also in a 100mm-f/9 refractor w/ 900mm focal length and in research "exit pupil" size is referenced. Is that the same as the size of lens of the eyepiece? Is there an optimal exit pupils size and if so how is that figured out?

thank you!

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ATM, Optics and DIY Forum / Schief vs Newtonian comparison question
« on: December 27, 2017, 09:16:37 PM »
The recent thread about the commercial viability of off-axis scopes went in some interesting tangents, (almost entirely tangential) and assertions were made which if I understand them--which maybe I don't fully, but maybe enough--would seem to say that a Newtonian configuration simply can't be bettered by an off-axis scope in terms of optical quality, notwithstanding obstructions and diffraction.

Nevertheless, it also seems that maybe the whole picture hasn't been considered. Or maybe it has. So...

For the experts...

Just curious, but shouldn't eyepieces be taken into account when comparing scopes for visual use? I don't think we'd be comparing my 4.25" f/27 Delmarva Schief to a 4.25" f/27 Newtonian--though that would seem to be a fair comparison and both would yield the same image size with the same eyepiece, and other similarities as well--but if we were comparing that Schief to a more common 4.25" Newtonian that I think most here would be thinking of, in the range of say f/4-f/8, the eyepieces couldn't be identical to give the same image size. How would the comparison be then? I'm asking--I don't know and am not taking a stand; for now...

How would the images we actually see at the eyepiece compare at say about 212X--which is about as high as conditions usually allow for my Schief in my backyard? Could be Barlowed or expensive eyepieces in the Newtonian, whatever works best, and say the Schief just uses a good quality 12mm ortho. And never mind eyerelief as long as the naked eye can see the image without actually touching the lens. And the Newtonian could be a bit larger to give the exact same amount of glass to the sky as the Schief.

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Reflectors Telescopes Forum / 6" f8 celestron skywatcher dob ?
« on: December 27, 2017, 01:10:19 PM »
I have a 12 inch parks miror, a10 my father made and an 8" he also made . all need to be recoated and I dont have any mounts anymore. I am not a milionare butI would like to upgrade from my 80mm ed refractor that I have had some prety awesome images of Jupiter and the moon. so I decided to get the sky watcher 6 f8 dob. I can fit that tube on my mount. the 8 would be getting on the way heavy side and I just want to do some imaging this summer.The scope should be here by the 6th.. Im just a wee bit woried its going to be a green soda lime glass miror Of so so quality. but then I could be wrong. my 80mm ed is a celestron and I am prety happy with it.
I just figured I would check here and see what you guys thnk.

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I have been looking for a good zoom eyepiece on a budget for a while and this tiny gem popped up.  Yep, thats a real Nikon 7-21mm zoom eyepiece for the same price, or less, of a cheap no name zoom.  Plus it'sfrom a brick and mortarauthorized Nikon dealer. While it is not quite as desirable since the MCII, it is an excellent zoom using a 40-60 FOV that initially sold for #130 back in 2006(search for "15-45X" in the connected official Nikon cost list from 2006).  I personally examined it and found it far better than some of the funding Plossls (Gosky, Sbvony, etc) I have laying around and ought to give the Meade and Celestron zooms a run for their money.

I will say you'll have to find/make a 1.25" adapter but there is a couple threads on the best way to do this on CN and elsewhere.  Despite creating an adapter, you still get a very nice zoom for under used Celestron or Meade zoom.
It is cousin as assessed by Cloudy Nightsand detailed images of the EP that's being marketed.

Clear skies and decent equipment on a pocket alter budget.Disclaimer
I am certainly not linked to the vendor or getting something for posting this.  While I had been thinking about picking up another EP for later when I could afford it, I figured that the community could be better served by letting everybody know about it.

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Light Pollution Topics / "The Detroit Success Story Visible From Space"
« on: December 24, 2017, 04:11:59 PM »
http://www.politico....-project-215159

However, the report appears to be celebrating how bright the town is from Space which is a bit unusual for a left of center book (origin: WaPo).

It speculates that when the photo was taken three decades back, with all the lights outside and being sodium, Detroit would be much dimmer.  (no real facts here).  Hard to compare since before the conversion ". . .half of its 88,000 streetlights were darkened..."

It'll be interesting to see comparisons of Chicago if they finish the LED conversion.   Contrary to Detroit, it will be more a of a 1:1 replacement.   This is possible with all the Suomi satellite.

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Beginners Forum / really bummed observing mars at its closest...
« on: December 24, 2017, 05:27:59 AM »
I had hoped for a lot more... the very first night 3 days ago, a bright tropical blob of snot - could as well have been a streetlight.   Seeing the past 2 days was today a round somewhat fuzzy circle but without a significance with or without filters.  It almost looked like a large star.

Its clouded over again - so I might not get more opportunities, I popped till mars was high up in the sky... I simply wanted to view it like perhaps jupiter using a inexpensive scope, with a hint of detail/colors

I started at 24 mm and worked my way up to 4.8 eyepieces - where did I go wrong?

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