44 replies to this topic

[JimP]

For the past several weeks, I have been reading up on binoculars, and binocular telescopes. Trying to decide between the two has been a task. The major reasons for my confusion have to do with aperture and cost. The first consideration for me is/was a Cannon 15 x 50 IS binocular. Binocular telescopes I am considering include APM or Oberwerk 80/82 and 100. Cost becomes a bit confusing as, for example, an Oberwerk SD 82 costs just about the same as an Oberwerk 100 ED.

My concern about the Canon IS binoculars is the aperture which is 50mm, less that 2". That seems too small.

My interest is scanning the Milky Way and viewing open clusters. I have large aperture refractors for the Moon, planets and double stars so viewing them is not a consideration. But the Canons can be hand held while the BT's require a tripod and mount (extra $$$). Anyway being in doubt should I just give up? One last big concern for me is that I can figure out the size of the FOV but that doesn't really help me with what the actual view is like.

 

JimP

[TOMDEY]

I recently got the Cannon 12x36 IS III and love it. Ultra light, comfortable, sharp, and the stabilization is completely quiet and extremely responsive. I have bigger binos also, but this one is Soooo comfy for scanning the heavens and also for bird watching/hiking. The exit pupils are ~only~ 3mm, so the night time imagery won't be as bright as other "regular" binos with larger exit pupils.    Tom

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[edwincjones]

JimP

 

I think your question comes down to a tripod, or hand held.

Tripods adds stability but limits mobility.

2" is adquate for scanning the milky way and larger open clusters

and compliment telescopes.

I would suggest waiting on the 100mm binocular option until you have had more experience with smaller binoculars.

 

bottom line-it is  your personal preference 

 

edj

[Rich V.]

It's a tough decision to make without someone nearby who can give you a taste of what a BT can really do. Star party or club event, perhaps?

Since high mag isn't your need, I'd be comfortable with an ED model. No need for paying for SD glass for lower power MW cruising. 25x-30x100 is amazing for MW star fields.

You have to provide for a mount, another part of the package. More cost.

Try before you buy if you can.

Rich

[Echolight]

For Milky Way cruising, I think I'd be tempted by the nearly 4 degree true field of view, and relatively low weight, of the BT-70XL-ED.

[sevenofnine]

The "Milky Way and open clusters" can be viewed just fine with a pair of 15x70's IMO. A light weight tripod from a seated position holds them just fine. So does a Obie H/D pistol grip monopod. I enjoy my bargain Oberwerk LW but if you want more robust then the Deluxe is a good choice. All for a lot less $$$$$.

Best of luck to you and your decision! 

 

https://oberwerk.com...15x70mm-deluxe/.

Edited by sevenofnine, 21 March 2023 - 07:25 PM.

[jrazz]

Why not start with an inexpensive 8x42?

 

 The wider ones with 8°+ could be easily hand held, give you a big exit pupil, and very wide views. Most of us usually have something like that with us even when we are using the bigger instruments. 
 

The view of the Milky Way from a dark site through a wide binocular is mesmerizing. 

[ihf]

Get the Canon 15x50 and don't look back.

[JimP]

Why not start with an inexpensive 8x42?

 

 The wider ones with 8°+ could be easily hand held, give you a big exit pupil, and very wide views. Most of us usually have something like that with us even when we are using the bigger instruments. 
 

The view of the Milky Way from a dark site through a wide binocular is mesmerizing. 

I actually do have a Swarovski 8X42 binocular. Certainly easy enough to try them out. Thanks!

 

JimP

[edwincjones]

Any decent binocular works for the MilkyWay,

just avoid the cheap junk,

and you do not need the top of the line-but they are very nice

 

edj

[Astronoob76]

Just my 2 cts -- when I decided to get an 18x50IS Canon, the thought process was as follows: if I want the same comfort while observing, I'd need to get a good high mag bino and a p-mount which together will end up costing just the same, So I bought the Canon.

That being said, I don't use it as often as I thought because of weight and ergonomics. For wide field views of the milky way I'd nowadays prefer a Kowa 6.5x32 or even a "starfield" 2x54 (those are actually amazing as you can fit whole constellations into the FoV).

[Erik Bakker]

Jim,

 

When you say "My interest is scanning the Milky Way and viewing open clusters", how dark and clear are the skies you intend to use your new binoculars/BT's under?

 

Under dark to very dark skies, I find a big, larger than 5mm exit pupil beneficial for those types of observation. With a 7mm being my personal favorite, with my own pupils still opening up to 7mm. If yours do too, that would make me recommend a high quality 7x50, 8x56 or 10x70 with excellent center to edge performance for those uses under dark and clear skies.

 

Having used all three  extensively, I think the Nikon SP 7x50/10x70  and Swarovski SLC WB 8x56 are great performers for scanning the Milky Way and viewing open clusters under dark skies, with the SP's being the more specialized instruments, dedicated to astronomy/infinity observing and the SLC 8x56 the better allrounder for both day/night, near/far observing, with the added benefit of more eye relief and easier to adjust eyecups.

 

Since I do not wear glasses when observing, that last point is of no consequence to me, but can be important to eyeglass wearers.

[JIL316]

Jim,

 

When you say "My interest is scanning the Milky Way and viewing open clusters", how dark and clear are the skies you intend to use your new binoculars/BT's under?

 

Under dark to very dark skies, I find a big, larger than 5mm exit pupil beneficial for those types of observation. With a 7mm being my personal favorite, with my own pupils still opening up to 7mm. If yours do too, that would make me recommend a high quality 7x50, 8x56 or 10x70 with excellent center to edge performance for those uses under dark and clear skies.

Having used all three  extensively, I think the Nikon SP 7x50/10x70  and Swarovski SLC WB 8x56 are great performers for scanning the Milky Way and viewing open clusters under dark skies, with the SP's being the more specialized instruments, dedicated to astronomy/infinity observing and the SLC 8x56 the better allrounder for both day/night, near/far observing, with the added benefit of more eye relief and easier to adjust eyecups.

Since I do not wear glasses when observing, that last point is of no consequence to me, but can be important to eyeglass wearers.

Would a 8x56 or 10x70 be as beneficial in Bortle 4 or 5 skies or is it too light polluted at that point? (I was thinking of getting a 10x50 but if a 10x70 would produce better views of the stars that’s something to consider!)

Edited by JIL316, 22 March 2023 - 07:12 AM.

[Erik Bakker]

The benefits from 7mm exit pupils start at around Bortle 4 and continue to improve under darker skies. Their ease of their calm views stays at Bortle 5, but a 5mm exit pupil will produce a darker sky background. Under those conditions a 10x50 may present you an image you prefer. That said, I have come so accustomed to the 7mm exit pupil views, that I perceive all smaller exit pupils as "dark". Dark skies and good vision help getting the most from 7mm exit pupil instruments. With brighter skies or less visual acuity, upping the image scale and darkening the background with a 5mm exit pupil can help to see more. But for me, the 7x50 and 10x70, with their 7mm exit pupils, rule.

[Astronoob76]

Would a 8x56 or 10x70 be as beneficial in Bortle 4 or 5 skies or is it too light polluted at that point? (I was thinking of getting a 10x50 but if a 10x70 would produce better views of the stars that’s something to consider!)

My light pollution is similar and I definitely see a difference between 10x50 or 10x56 -- in a positive way. I don't think the light pollution (I live in Bortle 4-5 transition zone) is severe enough to use a smaller exit pupil.

I very much enjoy using my Fuji FMTR 7x50 under my local skies. It's not like the sky can get any brighter than what you see with your own eyes. Maybe the 2x54 can give that impression however. But a 7x50 cannot.

[JimP]

Bortle 4.2 

 

JimP

Edited by JimP, 22 March 2023 - 11:05 AM.

[Erik Bakker]

Bortle 4.2 

 

JimP

7x50 or 10x70 

[Erik Bakker]

Under those skies, the 10x70 will have a lot more sparkle to the stars in the Milky Way and open clusters show more stars and detail.

 

Under Bortle 3 and darker the 7x50 will start to show really nice sparkle in the stars of the Milky Way too. The true width of the 7x50 field is nicer though. Also for larger light and dark structures in the Milky Way.

 

The 7x50 is easer to hand hold than the 10x70 of course.

 

On most nights, I find choosing quite difficult and end up observing with and enjoying both.

 

The SP 7x50 and SP 10x70 I have are almost identical, with just a different magnification, aperture and true field. 

The NL 10x42 did provide a much wider field at 10x, but I found I enjoyed the views and viewing experience with the SP 10x70 more. But  that is a personal thing. YMMV.

[JIL316]

Is there a way to get an exact reading on bortle scale? I’ve looked up certain websites that will show the amount of light pollution on a map but it seems outdated.

 

any insights?

[Erik Bakker]

These Bortle charts are approximations and educated guesses. Reasonably close, but not exact.

[jrazz]

There are light pollution maps which can help you find dark sites: 

https://www.lightpol...FFFTFFFFFFFFFFF

https://darksitefind...39.008/-105.392

 

 But the best thing to do is buy a sky quality meter and measure yourself: http://unihedron.com/projects/sqm-l/

[Fiske]

SQM-L meter readings are exact.  Values are in MPSAS (Magnitudes per Square Arc-Second).

[Rich V.]

The only way I can compare one location to another is to take a reading with my SQM-L. Bortle numbers on charts and maps are very approximate.

Rich

Sky brightness is hard to estimate otherwise, and even in one location it can change from day to day and even hour to hour.

[JIL316]

There are light pollution maps which can help you find dark sites: 

https://www.lightpol...FFFTFFFFFFFFFFF

https://darksitefind...39.008/-105.392

 

 But the best thing to do is buy a sky quality meter and measure yourself: http://unihedron.com/projects/sqm-l/

According to one of the websites - I’m in a bortle 5 site - near the edge of bortle 6     Looks like I’m getting a 10x50 after all lol

[jrazz]

Like others have said above, these sites are a great way to get an estimate of best possible conditions.

But sky quality can change a lot! Get a sky quality meter. It’s really worth it!

My house is in Bortle 4 territory but will easily go down to Bortle 5 if the setting isn’t good. Measuring the sky quality is something I do to help me figure out which instrument is likely to be the best given the conditions and whether I should drive out to my local Bottle 3 dark site.

Edited by jrazz, 22 March 2023 - 01:34 PM.