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# All Activity

This stream auto-updates

1. Past hour
2. ## CCD inspector

Honestly don't believe a word it says. Have spent a good while trying to adjust tilt using cc'd inspector before giving up on it and getting a better result in minutes doing it by visual inspection.
3. ## SkyMax 127 or...?

Pretty sure SCTs are in the same category. One thing I haven't been able to get a definitive answer on is whether or not extending focus further back on Maks adds spherical aberration to the image as it does with SCTs. Does anyone know if moving focus far off of the design focus point for Maks adds aberrations to the image?
4. ## Where does idea of infinite size of universe come from?

Ok, yes, indeed as mathematical concept we can have something like bounded set with infinite number of elements. This is fairly simple to see - let's take simple case of set of real numbers between 0 and 1. This set is bounded - there is upper limit and lower limit and there is a number which is greater than distance between any two set members - like 2, if we define distance to be difference of two numbers. We can "apply" such a model to hypothetical universe, but we can easily see that such universe is "unphysical" - density is infinite, all "elements of reality" have only one property - value and there is infinite number of elements of reality that are in principle - "unknowable". Spatial extent of any element is infinitesimally small - or 0, and by "unknowable" I mean that there is a bunch of numbers - irrational numbers that can't be specified - one would need infinite amount of information to exactly specify them (infinite number of digits to be written down - which can only be done in infinite amount of time). This is interesting game to play actually - we can observe another set of numbers that has similar premise but different properties - let's take only rational numbers in range of 0 to 1. This set is also bounded, there are infinite number of elements, there is no lower limit on how "close" two numbers can be, density is infinite, however this sort of set is "sparse". We know this by virtue that on real line between 0 and 1 we have real numbers. Now if we split real numbers into two subsets - rational and irrational and remove irrational numbers - there must be some sort of "hole" left in that place and there is some sparseness in the set - and yet again - density is infinite and set elements are infinitesimally close Mind bending stuff really
5. ## Just got me boarding pass

I remember you saying you were a Terry Pratchett fan. The journey will seem shorter if you're laughing a lot. Let's hope fellow travellers have a sense of humour.
6. ## Solar Halo

Impressive solar halo on show right now in W. Yorkshire.
7. ## New Products from Sky-Watcher

The new Sky-Watcher 2020 catalogue is out and contains details of some interesting new products RA Motor Drive for Starquest & AZ-EQ Avant (20952) This will please owners of Sky-Watcher Avant telescopes. (ETA 3-4 months). Rotational Adapter for Evostar 72ED (20500) The Sky-Watcher Evostar 72ED is a bestseller so it is good to see a rotator is in the pipeline. (ETA 2-3 months). Sky-Watcher CQ350 Pro Mount (20309/20293) A centre-balanced equatorial mount from Sky-Watcher. We weren't expecting that. (Still in development so we don't have details or an ETA). Sky-Watcher Synscan Starwand (20990) This one looks fun... (ETA not available)
8. ## Focuser tilt problem solving

Don't think I can carry on with this. Going to have to take apart and try and sort it.
9. ## Hello

Welcome. I have no experience of such a scope but if you have any specific questions, just ask. Have fun on the learning curve.
10. ## Orion Nebula With a Star Adventurer

Here’s the full frame.
11. ## Longcase Pendulum Clock

Printed the crutch and tried to assemble it all but found the anchor wouldn't fit so redesigned it and just finished printing it.
12. ## Where does idea of infinite size of universe come from?

I accept that vlaiv . But could not my infinite universe with infinite "stuff" not refer to the infinite number line I have used as my measuring stick. The infinite stuff therein being the numbers. Is it possible for any infinite system to have an infinite value of one property while not another? And what if the mathematical model links those two variables, if one is infinite what doe that imply of the other? I honestly have no idea. Jim
13. ## Some spring doubles with a 3 inch Newt

My first scope, which was a gift, was a Celestron 76mm F/9 Reflector. You can see identical-looking scopes under a dozen brand names. They come on a wobbly fork mount atop a lightweight, bouncy tripod. I wouldn't recommend this setup. The main challenge at higher powers is keeping a target in view long enough for the vibrations to stop. The kit did it's job in my case though. Once I'd observed the Moon, the Pleiades & Jupiter I was hooked on the hobby ! I soon acquired a 200p F/5 and I haven't looked through the Celestron since. But I wondered how the little Newt might perform on a better mount. I retrieved it from the loft , made a pair of tube rings & mounting plate from some scrap timber and bolted the scope to my EQ3-2 diy GoTo. With just a 3 inch aperture and city light pollution, double stars were the obvious targets. ( 21st May, from 11pm BST ) Zeta2 Corona Borealis, 6.5", a pair of white stars, like headlights in the distance, split at x70 but better at x140 (10mm Plossl & SW 2x deluxe Barlow.) Nu1 CoBo, 355", a wide, matching 5th Mag orange pair of cat's eyes in a 32mm Plossl (x22) with an unrelated third yellowish 7th Mag neighbour, forming a sharp triangle. Sigma CoBo, 7.2", a 5th & 6th Mag yellow pair split at x70 Xi Bootis, 5.3", yellow primary with faint white secondary to the NW, good at x140 Pi1 Boo, 5.5", a blue/yellow dumbbell at x70, clear split at x140 Izar(Epsilon Boo), 2.9", with the magnitude difference this was more of a challenge for the little scope but the secondary was visible as a lump on the first diffraction ring to the N of the primary at x140. The secondary looks grey to my eye in the 200p but here any colour was lost in the primary's orange glare. STF 1639 (Coma), 1.9, couldn't split this one, too tight for this scope I think. And to finish what else but the Double Double (Epsilon Lyr), 2.2", always fascinating & clearly split at x140 with a satisfying black line between each pair. The little F/9 reflector produced smaller, tighter stars which seemed more stable in poor seeing compared to the 200p, with fainter diffraction spikes. Great fun ! So once you seperate the OTA from the awful accessories that it comes with & put it on a steady mount the 76mm Newt is a handy little grab & go scope. I'm glad I rescued it from the spiders.
14. ## APT and Blind plate solving Problem with ASPS

Have you ever asked @Yoddha ivo for help on APT forum with regards to getting blind to work , he is very helpful at resolving issues you may have http://aptforum.com/phpbb/viewforum.php?f=24&sid=4fe9aba1b0f71cba44ac731f5957b766
15. ## Just got me boarding pass

The complete works of Terry Pratchett should work (I have read them all, but they are always worth a reread)
16. Today
17. ## Just got me boarding pass

And just over a year to wait too Michael. Don't forget to take reading matter to last for the 7 month trip. Enjoy the sights on the way . Ron.
18. ## when i do polar alignment?

it is sound better that the mount will stay on (i also saw a video that the guy there use polemaster and his mount is on) and when you say home position, what is that means? i know the the scope in home position aimed to polaris and the mount - the counterweight is facing down... thank you!!!
19. ## What did the postman bring?

A used 9x50 Erect Image Finderscope courtesy of Ebay. Besides a scratch or two not noticed unless you look for them, it's great with clean and clear optics. My dodgy knees and creaky neck can have a rest now. Woohoo!
20. ## Is the initial star alignment necessary if you plate solve?

In common with everyone else who has replied to this, I just do a solve and sync in lieu of star alignment after polar aligning, but I don't think anyone has mentioned that it's definitely a good idea to do this well away from the celestial pole. Plate solving near the pole is likely to give rise to some significant alignment errors, so I generally try to get somewhere with Dec < ~50° for my first solve/sync.
21. ## Crescent Nebula in HRGB

I did give it a "go" myself, but the images were not the same size/orientation/registered and without stars was impossible to register them, so I gave up. Carole
22. ## Bresser achro AR-152S experiences

Some discussions on the Astrozap 152S and 152L petzval (Same as Bresser) https://www.cloudynights.com/topic/173485-astrozaps-5-and-6-achros-any-good/ and the SGL Member review for the F/5 petzval
23. ## Best 16 inch Dobsonians

Although, an upgrade from a 10” to a light 16” should be well worth it; even if the mirror is of only ok quality. I upgraded from a 10” Skywatcher Dob to an OOUK 16” 6pv mirror Dob. Not what you would call ‘Premium’, but definitely worth the jump. Paul
24. ## Fitting a Celestron Focus Motor to an Edge HD 8

First a big thanks to FLO (ordered yesterday, arrived this morning - fitted ). Simple. For once I followed the instructions and everything went well. From removing the old rubber focuser adjustment knob and flange to fitting the motorised focuser. All required tools were in the box although I found the cross head screwdriver a bit short so used one of my own. I was expecting the shaft grub/locking screw (socket headed) to tighten sooner than it did but that really was the only bit giving me any concerns. I downloaded and installed the software from FLO's product page before connecting the focuser and re-booted the laptop. I'll be using this with a non-Celestron mount so opted for the Ascom driver (newest dated). Plugged in a 12VDC supply and USB lead to the laptop, opened the Celestron software, connected and hit calibrate. Calibration took a few minutes as the focuser drove from one extreme to the other and back to it's original position. I then played sending it to different numbered positions. More seriously I looked a the backlash settings and ended up with a '5' setting. The white indicator on the focuser makes watching for instant motion very easy. So need to try this in anger at some stage... I'll update once I have a chance.
25. ## Atlas Of The Heavens

Lovely old star atlas by Antonin Becvar,in great condition,though cover is a bit faded complete with plastic overlay.£ 50 + p.p. paypal gift please.
26. ## Where does idea of infinite size of universe come from?

Ok I sense you are toying with me now so I will accept the challenge; may I take an infinity of time to consider? Didn't Einstein invoke a comparison of sitting on a hot stove compared to a park bench with a pretty girl to describe time. That may have had to to with relativity of time I suppose. Ok so, I exist as do you or say water or a rock or light , heat, radio waves, or the electron. I don't think any of those would require a physical infinity for their existence to hold. We may be able to describe each of their nature's using an expression of mathematics which in turn may or may not rely upon the operator we call infinity. I think that is what I am getting at regarding my difficulty in accepting a physical infinity ! Jim ps I can well understand why Cantor was driven mad by this although that may be fake news pps. If infinity does have a physical nature would we be able to physically measure it to confirm its existence; would information be able to span the infinity of whatever property it exits in? Would that require an infinity of time? I have no idea - arghhh
27. ## Flatteners/Reducers/Filters/OAG/Red Dot & more!

Tilt adapter arrived safely, thanks Aidan
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