Different scope for birds and for stars? (2 Viewers)

[sbpbirder]

Hi, I'm just thinking about getting a budget scope and tripod for the few times we might want to carry one about when we go birding. We mostly just walk about carrying binoculars, but there are some very 'reasonably priced' scopes and tripods that are lightweight so I wondered about a New Year purchase, well it's my birthday soon too!

Anyway I wondered if someone could kindly explain the difference between the two types or is there not a difference.

And has anyone a cheap Svbony scope, I was looking at the Svbony SV28 20-60x80 or Svbony SV28 25-75x80, or even Svbony SV28 20-60x60 - I mean it's £48 on Amazon offer atm!

Thanks.

 

[mbb]

I don't know much about optics for astronomy. Some on this forum know much more about it and will probably help you out.

I would say there is mainly 1 huge requirement difference: for astronomy, you only need to be able to focus to a very, very, very far distance . That should allow to considerably ease the optical design. (Optical design is all about compromises: field of view, compactness and weight, eye relief, distortion, focus range...)
Second, practical difference: if it's raining, there are probably clouds above your head impeding any observations of stars, but not of birds. This probably explains why you'll find watertightness (or at least 'waterproofness' to some extent) as a more important feature for birding scopes.
Then there is the discussion of how portable the setup (scope+tripod) should be, but that depends on your observation style/context. (From the backyard? Close to the car? Long walks?)

I only have used birding scopes, but did use them to watch stars or planets or the moon occasionally, with some surprising results (e.g.seeing the rings of Saturn).

From here on, other forum members will probably have many more relevant things to say about it than me.

 

[Binastro]

Stars covers numerous objects.

So, it depends what you mean and also what experience you have.

The main thing for astro objects is a dark location.

The telescope is secondary.

Any spotting scope enhances the visibility of stars.

But astro scopes, as mentioned, are usually not waterproof and one can get a 6 inch to 10 inch Dobsonian telescope for the price of a spotting scope.
The Dobsonian telescope will outperform the spotting scope for astronomy, but is pretty useless for bird watching.

However, an astro refractor can be used for bird watching.

Regards,
B.

 

[wllmspd]

Good astro refractors can give better views that many spotters, but are usually heavier and as noted are not armoured or waterproof. The £200+level svbony spotters seem to have some good reviews. There are 50mm spotters out there that are light and provide reasonable views. I’d expand your bugldget, as £50 won’t cover the tripod needed for a scope, let alone the scope. A stable base means you’ll see more detail.

Peter

 

[sbpbirder]

I was just wondering what £48 quid got you My budget, as always is flexible, but I try and be 'realistic'. I've just bought a Rollei C5i tripod off Amazon warehouse for starters...

But I still don't understand the basic difference between a scope you point at birds and one you point at 'the night sky'.

 

[Binastro]

A bird scope is small, light and short so it can be carried around maybe for miles.

An astro scope is usually heavier, longer and larger and needs a heavier tripod.
An astro scope can weigh 50kg to 100kg to tonnes.

A spotting scope is usually one to 3kg or 4kg.

The downside is that the spotting scope is an optical compromise.
But often waterproof.

A really good astro scope can be used at 65x, 75x or even 100x per inch of aperture.
My Pentax 100mm f/12 refractor could be used at 300x and tested at 400x without any image breakdown.
The 12.5 inch Dall Kirkham was used at 265x, 400x and 600x plus on planets on nights of good seeing.
The 120mm refractors were used at 250x at 3 a.m. on a clock tower 4.7 miles away to reveal one arcsecond detail.
I doubt any spotting scope would equal that.

Rev Dawes of Dawes limit fame used his 6.3 inch refractor at about 420x on Jupiter and its moons.
Similar magnifications are used by other skilled observers today and in the past with fine telescopes.

Many spotting scopes can only take 30x, with a best of around 120x.

Spotting scopes are mainly used during the day.
Astro scopes are mainly used during the night, although some planetary observations can be carried out in daylight.

So we are talking about different beasts.

I have got good telescopes secondhand for £40 and £50.

Regards,
B.

 

[tenex]

But I still don't understand the basic difference between a scope you point at birds and one you point at 'the night sky'.

There's no "basic" difference, anything (within reason) can be used to some extent for either purpose, so it's just a question of what's most convenient for whichever you're doing the most of. Besides all the above, birding scopes generally have a 45° eyepiece angle or straight (depending on preference) which is handy for finding things around you, while 90° is typical for astro, allowing comfortable viewing near the zenith. Telescopes need large apertures to see faint nebulae, while a compact scope can work well in daylight and also do some casual astronomy, especially viewing the Moon. (Anything else will be challenging without unusually dark skies and good seeing.)

 

[wllmspd]

The diagonal erecting prism can often lead to a noticable “diffraction spike” (line) across bright stars/planets, using a 90degree mirror diagonal (results in a left-right) reversed image would eliminate this. So low power for nebulae and star fields a spotter would be fine (maybe a limited exit pupil compared to other options), the moon would be fine, planet viewing might be affected by the erecting diagonal issue above. If you are mainly into astro then get a decent small refractor (lots of options), if mainly birds then a reasonable spotter. Each has compromises doing the other job. started with the former and have moved towards the latter so own both….

Peter

 

[Binastro]

Most active visual astronomers in the U.K. don't use diagonals or prisms, but view inverted.

I rarely used a 90 degree mirror.

The average maximum elevation of a planet in the U.K. is less than 40 degrees.

It makes no difference to me whether the view is inverted or direct, and the normal sketches in the U.K. have south at the top.

Prisms or mirrors just add unnecessary reductions in optical quality.

Regards,
B.

 

[sbpbirder]

I'm mostly wanting to watch birds with a scope. I just thought it would be cool to be able to point it at the night sky occasionally. To which end I wondered if there was maybe one scope that would be easier 'dual-purpose' than an other. I'd seen 'stuff' about eyepiece size and being able to use one 'better' for night sky viewing and just wondered what things to look for.

So I'm looking for a birding scope that is lightweight(ish) that I can point at the night sky, about which I know very little - I can spot the Plough and Orions Belt and the moon! So I thought that as we live in the countryside maybe in summer I'd set up on the garden path and look at the night sky for half an hour or so.

Thanks for the info so far but it is mostly too 'complicated' for me to value. If I look for say a 20-60 x80 scope or a ? x60 scope which is easier to multitask with as I doubt it'll be a 'high-end' spotting scope and so any dual use probably wouldn't impact on that.

I'm still collecting information...

Edit: So I've just seen this scope mentioned and looked at it on Amazon and it says "Eye piece lens description - Barlow" what is that?

https://www.amazon.co.uk/Svbony-Spotting-20-60X80mm-Astronomy-Photography/dp/B08533P3W5/

Do I look to use one of these eyepieces with it?

Amazon.co.uk

"Svbony SV113 Eyepieces 1.25 Inches, 9mm Planetary Eyepiece 65 Degree Wide Angle "​

But one review says "I got the 9mm eyepiece. Image clarity and magnification seems good (mainly used for viewing the moon so far) but being new to astronomy I didn’t realise that this lens would give me a reverse image, so now I will need to buy another lens altogether or a ‘diagonal’, or an adaptor of some sort to get the image the right way round." Are there eyepieces that give you the image the right way around?

 

[Binastro]

A Barlow lens is a negative lens, usually a doublet, that increases the focal length of the objective.
It fits near the eyepiece.

Often 2x or 3x but can be 5x.

This increases the magnification by 2x, 3x or 5x, but it depends on the position of the Barlow.
A 2x to 3x Barlow just works by having an extra tube.

Where you are mid summer might be quite light, but at least warmer.

If you want to view the sky at night from a fixed location I would recommend an 80mm rather than a 60mm scope with a heavier tripod.
If it takes astro eyepieces these don't need to be expensive.

Star clusters, double stars. the Orion nebula, Jupiter's moons are suitable for spotting scopes.

Some astronomers only use spotting scopes or binoculars/monoculars.

Good astronomy can be carried out with unaided eyes from dark locations.

Regards,
B.

 

[jring]

Hi,

a high quality spotting scope can also serve as a nice entry level or grab and go astro scope - whlle I have a few astro scopes, my Kowa TSN-3 is my most frequently used instrument for looking at the stars when I only have a few minutes on the balcony or when traveling. When there is more time, the bigger guns get dragged out...

But it will be limited by the fact that is always a very fast refractor with a focal ratio of around f5.5 which needs more and/or more expensive lenses to perform as well as slower (and thus usually longer) astro refractors.

The different SV28 variants mentioned don't count as high quality spotting scopes. It is next to impossible to get a halfway decent pair of binoculars which much looser precision requirements at this price - even when made in China under conditions I would rather not thinks about.

They have plain glass doublets as objectve and will work best at 30x and ok up to 40 or 45x if you stretch it... but their non-removable zoom EPs will be have a very narrow apparent field of view at those magnifications and when they finally get a bit wider near the maximum magnification, the image will be blurry.
And since the EP is non-removable, you cannot simply use another astro EP without heavy modification.

The SV406P ED from your last post uses extra low dispersion or ED glass in what is probably also a doublet objective. When made to tight tolerances (or by having the luck of the draw to get a good example), it might offer a nice view at the maximum magnification of 60x that its zoom offers and maybe a bit more with a separately bought 1,25" astro EP... here the zoom EP is removable and the scope even offers the possibility to use 1,25" astro EPs without an adapter.

The term barlow does not really make sense as a description of an eyepice type. A barlow in common astro terminology means an extra lens, that is inserted by the user into the light path just before the eyepiece to increase the magnification.
Many more expensive astro EPs come have an integrated barlow without it being mentioned... because 99% of the users don't care...
A more correct description for the EP would be "3x standard zoom EP 8-24mm" (don't quote me on the focal length) - followed by "with inegrated barlow" if you wanna be extra picky or add some marketing blurb...

Joachim

 

[sbpbirder]

The SV406P ED from your last post uses extra low dispersion or ED glass in what is probably also a doublet objective. When made to tight tolerances (or by having the luck of the draw to get a good example), it might offer a nice view at the maximum magnification of 60x that its zoom offers and maybe a bit more with a separately bought 1,25" astro EP... here the zoom EP is removable and the scope even offers the possibility to use 1,25" astro EPs without an adapter.

Hi, I 'struggled' to know which of the scopes had removable EPs. I reckon if it doesn't say it is then it isn't. But this is where your understanding is to you 'common knowledge' and to me 'what'? I meant to ask why was it 'good' to be able to have a 1,25" astro EP? What do they give that the 20-60 EP doesn't?

I don't get 'literally' what is good for looking at the night sky, whereas I understand better what makes a good birding scope (not fully appreciated, but somewhat known). So how does a 1.25" EP make a birding scope better for looking at the stars/moon?

Edit: Oh and I am appreciating everyone's answers, it's just that I understand some better than others.

 

[Binastro]

It doesn't make it better, but gives a wider range.

The magnification can be increased by using either short focus astro eyepieces or a Barlow lens.

With a Barlow, because the focal ratio of the objective is longer, say f/11 instead of f/5.5 simple eyepieces work, but have smaller fields.

I also have no problem using 100x or more with spotting scopes and accept the aberrations.

Regards,
B.

 

[jring]

Hi,

and even if the quality and or design of the scope does not allow for higher magnifications than 30 or 40x the views will be much more impressive with a wide angle astro EP of 65 degrees afov or more than looking through a thin tube with the zoom at roughly 40 deg afov...

And yes, with spotting scopes that don't mention 1,25" EPs, it will be difficult (as in buying or making an adapter) to impossible to use astro EPs. And if a removable EP is not mentioned, it's probably not, as that makes things a lot cheaper to manufacture and easier to get some degree of waterproofing.

Joachim

 

[Mark9473]

Most active visual astronomers in the U.K. don't use diagonals or prisms, but view inverted.

That would be on Newtonian reflectors only, right?
On refractors and catadioptric scopes, eye placement without a diagonal is problematic for most people.

 

[Mark9473]

So I've just seen this scope mentioned and looked at it on Amazon and it says "Eye piece lens description - Barlow" what is that?

https://www.amazon.co.uk/Svbony-Spotting-20-60X80mm-Astronomy-Photography/dp/B08533P3W5/

I think it's safe to say the eyepiece on that spotting scope is not of the "barlow" type. It's probably a translation mistake. Could they have meant "zoom"?

 

[sbpbirder]

Thanks for everyone's input, the mists are clearing!
So I will start looking for a scope with a removable 1.25" EP and lightweight!
I'm now really looking forward to our short break to Gran Canaria where I have arranged an evening astro trip to see the night sky with experts!

 

[dwatsonbirder]

So I will start looking for a scope with a removable 1.25" EP and lightweight!

With a limited budget, you may want to try and track down a Pentax PF65 - that should fit the bill as a compact scope accepting 1.25" eyepieces whilst giving a decent view. The Celestron fieldscopes (ideally with 65mm ED glass as a minimum) are another good budget option, although considerably larger and heavier than the Pentax.

 

[sbpbirder]

With a limited budget, you may want to try and track down a Pentax PF65 - that should fit the bill as a compact scope accepting 1.25" eyepieces whilst giving a decent view. The Celestron fieldscopes (ideally with 65mm ED glass as a minimum) are another good budget option, although considerably larger and heavier than the Pentax.

Thanks, I'll check those out. My preference is a limited budget, my intended purchases often start out that way, but end up different. Nowadays I allow personal practicalities to overcome budgetary restraints - so I do know that we won't want to take a 'heavy' scope around with us, and if lightweight is more costly it's actually a saving as it will at least get used!

Edit: I've just checked the price of a Pentax PF65 EDAII - I think that's all my money! It's a big leap from a £48 Svbony!