Binoculars upgrade

[alanjgreen]

Wowsers, heres a bargain at FLO clearance

https://www.firstlightoptics.com/offers/offer_hawke-endurance-8x56mm-binoculars_79615.html

[Stu]

Might be nice, although not so light at nearly a kilo. I had a pair of Barr & Stroud 8x56, similar spec and really liked them for astro. They do have a 7mm exit pupil so you need dark skies to get the best out of them.

[Nyctimene]

Dinoco,

the 7x50s look really nice and well kept, without damages of the lacquer coat or the leatherette coating. If you get nice, sharp views of the Pleiades and of Orion without double vision (or headache after a while of observing), I'd keep the binos and make use of them.

A (coarse) method to check collimation: cover the  objective lens, that has the diopter wheel on the eyepiece side (usually the right half of the bino), and focus on a bright star in the middle of the field of view. Uncover the right-sided lens, and deliberately defocus the (same) star's image with the diopter, so that it will appear as an evenly lighted disc. With proper collimation, the (left-side) sharp star image should appear in the middle or rather close to the center of the defocused star disc of the right side. Having the binos mounted for this procedure is helpful. If collimation seems to be out of range, ask here; the experts will give you a lot of support and advice.

Hope this helps

Stephan

[Olli]

Have just used these binos again as the conditions were really good tonight and could see the Triangulum Galaxy through them, I think it was anyway. Was incredible ( first time seeing a galaxy) even though it was a grey fuzzie. And could see all of Orion as well (can usually see just his belt and sword )including the nebular just about. So it’s making me even more excited on getting a telescope.  

[Nyctimene]

Congrats for spotting M 33; its difficult for observers in suburban skies and indicates a rather good dark sky area you are living in.  Continue, and keep posting!

Stephan

[Olli]

9 minutes ago, Nyctimene said:

Congrats for spotting M 33; its difficult for observers in suburban skies and indicates a rather good dark sky area you are living in.  Continue, and keep posting!

Stephan

Thanks, hopefully can use them more next week had to stop as it’s rather chilly! I’m fortunate enough to have quite good skies as I live in a small village with basically 1 street light on my road. But when I look more south I do see the dreaded yellow glaze.I think it was M33, need to double check, what ever it was it was a nice site, spent about 20 minutes looking at it  need to get better at knowing my constellations. But had never properly looked at Orion like that before one of my favorites.

[Ags]

M31 is nearby and is an excellent binocular target; it is also easily visible even in urban skies. M31 looks like a bright central core with two faint "wings" on either side, while M33 is much more diffuse and blobby, and of course much fainter. The reason is we see M31 edge-on, so more stars are packed into each square arcminute of sky, while M33 is smaller and viewed face-on, so the starlight in the galaxy does not stack up in the same way - instead we are just looking through a thin layer of M33 stars into deep space.

[BinocularSky]

On 03/02/2018 at 12:47, Stu said:

Collimation for binoculars just means that the two channels are aligned properly.

... to each other and to the hinge. (If the optical axes are not parallel to the hinge, if you change the inter-pupillary distance they will no longer be aligned to each other either; this is called "conditional alignment", i.e. alignment is conditional on the IPD not being changed).