What can I see with 10x50 binoculars in Bortle class 4?

[AryaanHegde]

TL;DR Summary

Which messier objects can I see with 10x50 binoculars in a bortle class 4 location? Can you give any tips to a person just starting out and trying to find these objects?

I'm just starting out with amateur astronomy and decided to buy a 10x50 Celestron Up-close G2 binoculars. I believe that tomorrow is the planet parade (the aligning of 6 planets) and I'd like to catch a glimpse of it. In the bortle 7 location that I'm in, I could only see a handful of stars (that too with the bins, they weren't even visible to the naked eye). So, I've decided to drive about 10 miles to a bortle 4 location at about 5 in the morning.

So, I just wanted to know what I could see with my binoculars? Would the planets be visible? Apart from that I'd love to catch a glimpse of some nebulas and the Andromeda galaxy. Just wondering if they would be visible as well. And since I'm just starting out, do you have any tips for me? Since I didn't see any of the Messier's in my current bortle 7 location, I'm wondering if I might be missing something. Do you have any suggestions for spotting them?

Thanks a lot.

 

[.Scott]

First, when it comes to Mercury, I would stick with either the naked eyes of with a telescope on a steady mount. By the time it is visible, the Sun will be precariously close to rising - and precariously close to Mercury in the sky.

Per John E. Bortle, a Bortle 4 location is described: "The maximum naked-eye limiting magnitude is 6.1 to 6.5, and a 32-cm reflector used with moderate magnification will reveal stars of magnitude 15.5.".
Of course, you will be using a 50mm (2-inch) aperture, not your naked eyes, nor a 32-cm (12.5-inch) aperture.

Compare this to an estimated limiting magnitude formula provided Astronomics.com:
estimated magnitude = 7.5 + 5 log aperture (in cm)

So, given unknown Bortle), Astronomics estimates 7.5+5log(32) for the 32-cm scope = 15.
Warning: This next step is wrought with potential errors. But you're only looking for an estimate - a prediction. And the error introduced in this step is likely to be the least of those error factors.

We will calibrate that Astronomics formula to match the Bortle 4 sky by adding 0.5 to the estimate:
So, the rough estimate for a 32-cm aperture in a Bortle 4 sky is: 8+5log(32) = 15.5.
Using this "calibrated guesstimate", your binoculars in a Bortle 4 sky might be: 8+5log(5) = 10.5.

Some of the things we are not considering is how steady your binocular form is and how well you can get the field of vision lined up with your pupils. For a better answer, prepare a list of stars in the magnitude 9 to 12 range, so that when you visit this site, you can record which ones you see and which you cannot. That is the experiment that will give you the real answer.

But there's more:

First: Most of those planets are going to be close to the horizon - and a Bortle 4 sky is much, much better looking up than over. It varies from night to night, and it is usually better in the morning than in the evening.
CNN has a good article on this planet alignment: CNN Article
Expect to see Mars, Saturn, Jupiter, and maybe Mercury with your naked eyes. Binoculars might give you Uranus. Without practice, Neptune may be a problem. It's about magnitude 8, so you won't see it before you aim the binoculars. And once the binoculars are up, you won't see any of the sky except near Neptune. So, good luck.
The alignment was best this morning - but the (bright) moon is moving away for the views later this week.

Something else you may want to include in your plans is T Coronae Borealis. You should be able to find it through binoculars. This star is not visible to the naked eye - not now. But it is expected to go nova within the next few months. Then, for several days, it's expected to be plenty bright enough for casual viewing. But it's in a kind of neglected part of the northern sky - so finding it ahead of time is worth the effort. You'll need a star chart. If someone simply pointed to the constellation for you, all you would see would be random mostly-dim stars. It's not conspicuous like the Big Dipper (tecnically, as "asterism") or Orion.

 

[phyzguy]

You're probably going to be disappointed by the "parade of planets" which was hyped by people who never look at the sky. Most of the planets will be too close to the sun to see. Uranus and Neptune are not visible with the naked eye and even if you found Uranus with your binoculars, it would just look like a faint star. So Saturn and Mars is probably all you will see.

Having said that, there are many Messier objects you can see with your binoculars. The Andromeda galaxy (M31) and the Orion nebula (M42) are two of the best.. Get a good book on the Messier objects and try to see how many you can find.

 

[Vanadium 50]

A planet through binoculars or a small telescope looks a lot like a planet with the naked eye. However, you might have a shot at the moons of Jupiter.

 

[russ_watters]

A planet through binoculars or a small telescope looks a lot like a planet with the naked eye. However, you might have a shot at the moons of Jupiter.

That's not exactly true/understates it, especially for a huge pair of binos like a 10x50. The moons of Jupiter can be seen in any but the crappiest binoculars and a decent pair can resolve a disc on bigger planets, the rings of Saturn and at 10x50 maybe Jupiter's stripes.

Jupiter's angular size is 30-50 arcsec. A 20/20 vision chart letter is 5 arcmin tall. So at 10x magnification at its worst (which Jupiter is near now), the disc is the same size as a letter on the vision chart. Think about it like resolving a letter E with inverted colors (3 light, 2 dark stripes).