The60mmKid

Here's the specific tripod: https://fotopro.eu/en/product/p-2-mini-p2h-2/ There are many similar tripods sold under different brand names. I think the main thing is to get any mini tripod that: - has rigid, extendable legs since this provides stability and adjustability to suit different binoculars and bodies... - includes a ball head if possible since these are small and light.. - doesn't include a center column since (I assume) this would get in the way. The chair is a generic zero gravity lawn chair. I'd suggest using any zero gravity lawn chair that you find comfortable. I've owned a couple that were basically the same, but some are sold with different cushioning and various bells and whistles.

Also: Because the legs rest on your shoulders, not your chest, you don't get any movement from your heartbeat. There's may be a little movement from breathing, but this is minimized with a little practice.

I call it the London Method. It's an £80 mini tripod/ball head (tightened into the shown position) with one leg removed. It provides a significant degree of stabilization for small- and medium-sized binoculars. With this method, the view through my 18x70 binoculars is steadier than it is through my 8x30 binoculars handheld. It works standing and sitting, and it's easy to compensate for the altitude by just slightly adjusting where the tripod legs contact your shoulders. With a little practice, you can pan around with the binoculars almost as fluidly as you can when simply holding them in your hands. It works for observing near/at zenith. It weighs less than 1 lb. and easily fits in carry-on luggage. In my opinion, this is the best way to bridge the gap between handheld observing and using a parallelogram mount. It's a game changer for me, and I hope that others benefit from it, too.

In an era of polycrisis, I find it comforting to look up and know that life glistens elsewhere even while suffering permeates this little planet of ours.

A lovely book that evokes so much nostalgia for me 😊 Do you mean biblio.co.uk? If so, I think clarification is in order. Biblio is a platform that allows independent bookshops/vendors to sell (typically used) books. They have an excellent international reputation and track record of ethical practices, such as carbon-offset shipping (which isn't at all a perfect solution but that at least draws attention to the climate emergency). Although I haven't looked, my guess is that people who complain on Trustpilot are mainly upset about a specific vendor and are erroneously blaming Biblio, which is just a platform. I've bought from Biblio for years with no problems at all, and I wouldn't want to see their reputation incorrectly harmed... especially because they provide an alternative to the actually harmful businesses from which we can easily purchase used books.

£1950 pair of 70mm binoculars and a comfortable lawn chair.

I like this because it looks like a big Astroscan. Cute!

To remember what I am.

Another nice thing about refractors is that they often come in twos. This is more challenging to accomplish with reflectors.

Be careful... There are people out there who would be tempted to take full advantage of such an opportunity 😇

I love this. Part of what thrills and comforts me about stargazing is the passage of time and the relationship with the night sky. There's nothing like seeing a constellation or favorite sight (i.e., "object") again after a couple seasons have passed. I regularly find myself saying, "Hello, old friend," and really meaning it. Then, I wonder if they're glad to see me, too. I can't help but feel they are, gazing back at me while my life passes so quickly in relation to their own.

There have definitely been some good points made about observing doubles in general... But again, the specific question was about the theoretical limitations of a 70mm instrument with 18x magnification to resolve equal magnitude doubles, only considering the variables of aperture and magnification (and, thus, assuming perfect conditions and eyesight for the sake of the theoretical exercise). Some of the responses related to aperture, but not magnification. Others related to magnification, but not aperture. And others introduced other variables. If we don't know how to calculate using these two variables, that's totally fine. But I think it's helpful to keep the actual question in mind. I found @lunator's reply most relevant and am eager to observe an 8" equal pair and report back.

I don't want to be taken seriously, and I love the word stargazer 🙂 Part of what I love about it is the lack of seriousness.

Helpful. Thanks 👍

Many of the conversations on splitting doubles that I've seen online make claims like, "___ telescope can theoretically split ___ doubles," while taking for granted that atmospheric conditions and eyesight are uncontrollable and important variables. (For example, I don't mind claiming that my FOA-60Q can split 2" equal doubles, and I don't feel the need to offer caveats about seeing and eyesight since I assume most of us know about that already.) So, I anticipated a similar reply when asking about binoculars. I figure most people asking such questions on such a forum know about the impacts of seeing, etc., so that's partially why I'm surprised that we seem to be considering binoculars in a different way than we do telescopes in this instance.

Why is that we talk about theoretical limits of telescope resolution all the time but uncontrolled variables suddenly plague us when it's binoculars 🤔 Am I missing something?

This does help! Based on my observing experience, that seems like a realistic split with the given aperture and magnification. I will observe a relatively equal ~8" pair with my 18x70s and report back.

I'm looking for a way to account for aperture (70mm) and magnification (18x) and that assumes perfect eyesight and optics, which is usually what we do when we talk about telescopes' theoretical ability to split doubles. I'm aware that we usually use higher magnifications for splitting doubles 😉 I have experience with that. But sometimes one wishes to use a certain instrument!

Ok, but here magnification and aperture (i assume, perhaps incorrectly) are both variables, in addition to the others mentioned (i.e., eyesight, optical quality). So where does that leave us?

After further reflection, my confusion has returned. You mention 3.33' (arc minutes) here, whereas @Mr Spock mentioned 3.3" (arc seconds). Based on my observing experience, the former strikes me as quite wide, and the latter strikes me as quite close. Also, is aperture not a variable in this calculation? Would there not be a difference between the resolving ability of a 18x70 binocular and an 18x35 (hypothetically) binocular? That's surprising to me since aperture plays a clear role in the resolving ability of telescopes.

But maybe I'll round up to 3.34" to play it safe.

Perfect! Not to brag, but I have excellent vision and a magnificent pair of binoculars 😏 3.33" doubles: Here I come!

I appreciate the replies, but I don't think they address the question unless I misunderstand. The formula and tool calculate for a 70mm instrument, but my question also involves the fixed magnification of 18x. There's no way my 18x70 binoculars are going to split 1.7" doubles... as cool as that would be 😉

There's a reason I became a social scientist 😞 My mathematical abilities are hopeless to the extent that I often forget how old I am. Please help me. I want to know the minimum separation between equal magnitude doubles that is resolvable in 18x70 binoculars. I understand how to figure this out using aperture alone, but when magnification becomes a variable, I feel like I'm 15 years old again, sitting in physics class praying to various premodern deities for answers.

This, of course, depends on how we theorize existence. https://plato.stanford.edu/entries/existence/