BinocularSky

On 01/08/2020 at 13:44, Woking said:

The celestron skymaster pro bins specifically remark about it's central rail allowing RDF fitting. Just want sonething similar on a higher quality pair of 20x80s though.

They provide the appropriate fitment as part of the kit. You might be able to get one separately.

The August edition of the Binocular Sky Newsletter is ready. Astronomical darkness returns to the southern part of the UK this month, and we have:

* Farewell, Comet NEOWISE
* Welcome, Dwarf Planet Ceres
* Perseids

I hope this helps you to enjoy these lengthening evenings, especially now we have the return of the return of astro-dark.

To pick up your free copy, just head over to http://binocularsky.com and click on the Newsletter tab, where you can subscribe (also free, of course) to have it emailed each month, and get archived copies.

Last chance to see...

Had a look last evening at about 11pm BST, just above Mel 111 (and a streetlight!); nucleus easy in 10x50, but needed AV for the tail.

I didn't get on with the Naturesport (but that was ~20 years ago, and I think they've changed since then; some people really like them). A friend has a Mistral which he really likes. I've reviewed the Pentax and like them a lot - review here.

I do put them on 20x80s, but only because I use them for outreach - it makes it easier for beginners to find stuff by themselves.  One has a central bar, one doesn't.

Here's the pic of the RDF on the old-style Opticron Oregon. The RDF shoe is attached with some 3M mounting tape ( you could probably work out a temp arrangement wit hzip-ties if you wanted.

On 01/07/2020 at 15:07, kerrylewis said:

I think in your editing of the newsletter you've left in the note about the Venus lunar occultation from last month

Drat! I did. Thanks for letting me know; I'll correct it.

Edit: Now corrected.

The July edition of the Binocular Sky Newsletter is ready. Astronomical darkness returns to the southern part of the UK this month, and we have:

* Yet another "promising" comet
* Asteroid Ceres
* Neptune and Uranus return

I hope this helps you to fill your evenings (actually, more likely pre-dawn mornings!) enjoyably.

To pick up your free copy, just head over to http://binocularsky.com and click on the Newsletter tab, where you can subscribe (also free, of course) to have it emailed each month, and get archived copies.

I have 3 different parallelograms - wouldn't be without them - I don't see the point of buying decent binos then ruining the experience by mounting them inadequately:

Universal Astronomics T-mount - used with my 37x100

Astro-Devices Mk III and Virgo Skymount (now sold as the Orion Paragon) - both with 20x80s, mostly for outreach.

I've also reviewed the Orion Monster and the 10Micron Leonardo for S@N mag; links to reviews here.

On 06/06/2020 at 17:42, Trikeflyer said:

I used Astro toms plans -    http://www.astro-tom.com/projects/binomount/binocular_mount.htm

Takahashi Astronomers! How I regret not getting some when I had the chance 20-odd years ago!

Late to the party again - I've reviewed both these; see here.

On 19/06/2020 at 15:57, mark81 said:

I have a feeling the Skymasters may have been stopped down a bit - but I may be wrong.

Yes - the SkyMaster Pro are nothing like the "ordinary" Skymaster - you get the full 80mm here.

Apropos a question somebody asked about magnetars and FRBs:
https://skyandtelescope.org/astronomy-news/astronomy-news-newborn-magnetar-radio-beat/

Pete did this talk at Solarsphere last year - in for a treat!

23 hours ago, Kluson said:

Actually it was Fenland Paul who said that not me.

Oops - apologies for the misattribution.

On 15/06/2020 at 09:22, Kluson said:

• ...The tripod is bordering on hopeless - very wobbly when handled - but once I’d removed the extension pillar it has was robust enough for a dslr and heavy lens.  I operate the dslr remotely so don’t need to handle it much. 
• The whole arrangement felt a lot less secure when I attached my 70ed...

It's a terrible tripod! I put my Star Adventurer on a second hand (ie cheap) Manfrotto 055 if I'm just using the DSLR, or an 075 if I want to use my little Skymax 90 (pushing it - OK for visual).

Looking over some very good talks we've had at the various clubs I belong to and would gladly see again:

Any of Mary MacIntyre's talks on practical imaging

Anything from Bob Mizon on Dark Skies issues

The Formation of Stars and their Planetary Systems by Dr Claire Davies (U of Exeter Protoplanetary Disc and Planet Formation Imaging Group,)

Probing the Dark Universe by Dr David Bacon (U of Portsmouth Institute of Cosmology and Gravitation) - I've attended this talk 3 times; different each time as new observation,etc. modify our understanding

Apollo - the Inside Story by Dr David Whitehouse

Quasars: Engines of the Ancient Universe by Dr Nick Higginbottom (U of Southampton Astronomy Group)

14 hours ago, Wyvern said:

Great talk Steve,

Thanks, Les. Must get up your way when this "stuff" is over - not least because I've promised Sam a bino session for Elan Valley.

All the best...

1 hour ago, Tenor Viol said:

I know that some people commented on the audio quality.

Thanks for your input on that. Did some tests on my microphone this morning, and I think it might be on the way out. Just ordered a decent headset which I hope will improve things (I have talks coming up tomorrow and Wednesday!), and I've also just tried out our club's wireless mic which is also an improvement -- too late for last evening, unfortunately.

My favourite talk! 🙂

They are Kunming United Optics BF3s - essentially the same as (say) the Aculons or Bressers that Lidl sell periodically. However, KUO do alter the coatings and prism materials (and, I suspect but have no evidence, the eyepieces) depending on what the brander (in this case, pentax) specifies.

20 hours ago, bomberbaz said:

Be careful trying to find it, you are not that far away from the sun afterall and it only takes one bad move.

It's a bit more than 20 degrees away, so should be easy enough to find a location where (say) a building blocks the Sun but allows you to see Venus/Moon. An important thing is not to leave your kit unattended after ingress, unless you cap the aperture (& the finder!); it only takes (say) motor failure and the Sun could be uncomfortably close when you return to try to get egress.

19 hours ago, John88 said:

Sorry to hijack, I was thinking about the 20x80 pros too. Would these be useable on a monopod with a manfrotto 222 that I have or a bit unwieldy and better suited to a tripod?

I didn't actually try them on a monpod when I had  them for testing, but given that I used to routinely use the Helios Apollo 15x70, which is  about 80g heavier that the SkyMaster Pro 20x80, on a monopod, I'd be surprised if it wasn't OK, especially if you tweak the tensions on the 222 to suit the weight.

One additional little tip that may help with locating the egress position: use the cusp angle. The cusp angle for my location (approx 50.9N, 1.8E) is 55S, which means that an angle drawn at the centre of the Moon between the southern tip of the illuminated crescent and the egress point will be 55 degrees - or, for the less precise among us, "nearly a third of the way from the bottom to top of the crescent, going around the dark limb (which we can imagine, but probably not see)",

The pro is better. By some margin. My review of the 15x70 is at http://binocularsky.com/binoc_reviews.php and I did the 20x80 for Sky at Night mag in January (you don't need something like the 10 Micron Leonardo to hold it; a trigger-grip head is fine) https://www.skyatnightmagazine.com/reviews/binoculars/celestron-skymaster-pro-20x80-binoculars-and-10micron-bm100-leonardo-mount-review/

Here's the 20x80 on a cheap trigger-grip:

Just to echo what others have already said:
There's maybe half a dozen objects that the 7x50 might be a bit better on, but only under very dark skies, so the 10x50 is the better choice; it's often considered to be the sweet spot for hand-held binocular astronomy. The Oly DPS is better than most in that price bracket.

19 hours ago, Dannomiss said:

Even though I udnerstand the lense shake and stability

You can steady them a lot by holding them properly. Use method 2 (triangular arm brace) on http://binocularsky.com/binoc_hold.php. FWIW, the "model", as a young child, independently "discovered" M34 holding his 10x50 binos like that, then devised a star-hop to show me what he'd found. If they're steady enough for a sub-10yr old to do that, they're steady enough! 🙂

 If you think that your eyes might be "out", just try the binoculars upside down; that should tell you. 🙂

There's no such thing as "regular collimation"; collimation is binary: binoculars are either collimated or they aren't. Binocular collimation is a process by which the optical exes are made parallel to each other and to the binocular's hinge - anything else is miscollimation. Miscollimation can be in any direction; any vertical component is called "step" or "dipvergence"; any horizontal component is called "convergence" (your eyes converge to try to unite the  images) and "divergence" (the opposite). You rarely get one without the other.

(NB: There are two conventions for which is called which in horizontal misalignment;  "eyes converging" is the one I prefer to use for convergence; "binocular axes converging" is the other.)

You can handle quite a lot of convergence (our eyes naturally do this when we look at something close), and very little step. Approximate tolerances in the apparent field of view are:
Step: 15 arcmin
Horizontal Convergence: 45 arcmin
Horizontal Divergence: 20 arcmin

Divide these by the magnification to get the actual tolerance.

In the image shown in your link to the Oberwerk site, the collimating screw moves the image diagonally, so it will affect both step and convergence/divergence.

The article also mistakenly says that it's easier to collimate in daytime; it isn't (unless you are doing it on an optical bench, which most of us aren't). Your visual system tries to adjust for any miscollimation, so you need to fool it by making it "think" that each eye is actually seeing something different. Common ways with a star are:
* Defocusing one side: you collimate to put the focused point in the middle of the unfocused blob.
* Use anaglyph glasses (or coloured cellophane sweet wrappers) so the image are different colours; merge them
* Used crossed Bahtinov masks (one horizontal, one vertical) and merge the diffraction patterns.

The Bahtinov method is most precise, but it is more precise than it needs to be; the defocusing method is usually adequate. However, note that none of this (or anything on the Oberwerk page) will guarantee you true collimation, because it ignores the axis of the binocular's hinge so, if you change the IPD, the optical axes will probably no longer align.

That's probably far more than you wanted to know... 🙂