Field of view

[furrysocks2]

I started looking at the sky about 18 years ago through an old 3-draw brass telescope which I bought for £30 at a car boot sale. Years ago I saw Mars as a disc, the angle of Saturn's rings and more recently showed the Cubs the Galilean moons of Jupiter. I had that bodge-fitted to some kind of vintage photographic tripod. No idea what the FOV was, but that was my first telescope and I still have it.

Fast forward to four years ago and I built an 8.5" f/7.6 dob, as my wife put it, just to prove that I could. All great fun - feeling like I had a big mirror, easy to set up and see Jupiter most nights, the moon but not a lot else. At some point during that build, I bought a 3" dob from Lidl, a couple of EPs and a pair of Revelation 15x70s. I knew the FOV was wider in the 3", narrower in the 8.5" and widest in the 15x70s, but never really grasped what they each were or how they related to the sky - as I couldn't see all of Orion's belt for example, it all felt a bit abstract.

Then everything went into storage and we had more babies, renovated the house, etc.

Last month, fetching the scope back out of storage, I was wanting to get into planetary imaging to try and get the best out of it before possibly passing it on, only to discover planetary viewing may be a bit naff for the next couple of years, and I can't see low elevations to the south from my garden. I did try to find Uranus one night as it was high enough and through that failed attempt, learned that I was looking at about 0.9 degrees. I started getting exited about video astronomy and learned that small sensors give a small FOV and large sensors can be rather expensive. For planetary, that's fine - a long newt with a small sensor in theory should frame planets well. But at an eighth of a degree, that's not a lot for not a lot else.

So wanting something a bit faster, I convinced myself to purchase an ST102 from a gentleman at the local astro club and then bought a 68 degree 35mm EP for it. I saw ~4.8 degrees of sky at a time tonight - wider than the 15x70s (which I don't use nearly often enough though that should change with the newly acquired monopod and pistol grip). That felt different to the long dob - I didn't need a finder and I didn't feel utterly lost.

I guess I've been hunting around for what it is I want to see or do. I started off way back with a couple planets, built a long dob expecting then to have to confine myself to planets and doubles and small targets. Then I got lured wide with a new frac and the idea that I can show the kids something live on a screen, for which both the long dob and the wider frac should serve a purpose. An old DSLR might yet be an idea, but I see that as a slippery slope.

 

Anyway, after packing up tonight, I had a brief contemplative gaze with the naked eye. Not a great night to do so with the moon, cloud and obstructions etc, but while doing so I realised that whatever it is that I've been doing, building, looking at, imaging, planning, learning about or whatever, I still don't know the sky nor how we fit in it. While using an equatorial mount for the first time this evening, there was perhaps a vague grasp of Earth's orientation and some sense of structure or frame of reference to all that is around us - that was novel for me. I've spent very few hours actually looking through an eyepiece, though I suppose I've tended to project myself there or thereabouts when not observing - thinking about scope limitations and field of view and the size of targets and expectations of what I can reach or resolve. Gathering light and restricting your field of view with optics is enjoyable, certainly, and there's also the enjoyment from looking through something you've made yourself, from showing others and to some degree from purchasing new astro kit.

But simply looking up at the sky, it's all still very unfamiliar to me. The thought I had before I finally came inside was that if you put all of the above aside then not knowing your way around the sky is a bit like an unfamiliar language - not hearing the distinction between words or being able to orientate yourself within a sentence. I don't know the constellations other than to point vaguely at half a dozen, but I don't know them well, their extent or how they relate to others. Until last week, I thought the bear faced the other way in Ursa Major, Cassiopeia to me is simply a pointer to the Double Cluster and M31 and Orion's going to rise "over there".

As hobbies go it's a good one, but a bit more naked eye and bino observing for me perhaps.

[iPeace]

I regularly play with Stellarium, and keep expanding my list of memory hooks. If those are the Twins, what is each of them pointing at? Etc.

Then, when the clear night finally occurs, I first take the time to scan the entire visible sky, name all the visible constellations, determine which will disappear below the horizon soonest and which will be rising.

Now, almost a year on, it's gratifying to literally see the sky come full circle, so to speak.

And I love using my binoculars. Still the most enjoyment by aperture.

[popeye85]

Yep I do the same-while waiting for the scope to cool down and my eyes to adjust to the dark I have a look up and get my bearings so to speak while adding another constellation to the memory bank-going from a GOTO scope to a manual had helped loads aswell. 

I sometimes think that I spend so much time looking at tiny bits of the sky trying to find clusters and galaxies that I forget how incredible it is to just take a step back and look at the sky as a whole.

 

[domstar]

The kids got a little plastic planetarium with a lidl science kit. It turns with the hours and the months. It really helped me understand how the stars fit together in the sky and what is happening when the hours and months progress. I suppose I should have understood it before but I'd never really considered it before. So simple and beautiful.

[ronin]

In a way you likely only need to know half a dozen in order to get around, I suspect I could come up with about double that  if I had to stand outside and identify that number. Will say in your defence how 2 stars make up Canis Minor is questionable. So some "constellations" are a bit questionable.

I use the sort of ones you mention to get across the sky to another. At outreach event people find that sort of semi-impressive. I am impressed that I can remember - although did get one completely wrong once. However as the target object was behind trees no-one realised.

The reflector sounds like a good item, please use it more often.

I have told people myself that the planets are poorly placed presently, but a week ago in a Norwich car park I was looking at a fairly easy Venus and Mars was above and left of it. Not exactly in a "poor" position. But is was early evening just after it had turned dark. By 9 or 10 it was too low. Maybe we are expecting it to be high, south and glowing away magnificantly where as the reality is perfection is not going to happen.

Also I see that assorted software says something is at 20 degrees, sounds low until I head out and actuall see it, when 20 degrees is actually fairly well up. Happened to me a few years back for Antares. Everything said it was scraping the horizon, reality was it was that big bright red one up there well above the houses. Not really horizon scraping.

Jupiter will be around I think March this year (at night/evening) and Saturn I think July time. Both will I guess be happily high enough to get in some good observing. So get the reflector up, damn sure it will be good on them.

[barkis]

The Universe is a vast place,  and even that understates it's size.  The first thing to get into your mind,  is what you see from your place on earth changes as the year progresses,  but everything returns to the same place year on year, as regularly as a clock.   Another fact to realise,  is that most of what you see,  is part of the Milky Way Galaxy,  our Galaxy.   The only external Galaxy available to the naked eye,  is The Andromeda galaxy,  which can be seen with the naked eye at. roughly top left of the constellation of Pegasus,  an easy to find constellation,  because it's main stars form a great square shape in the sky.  The Andromeda galaxy is about three stars in from the top left one,  and slightly above yhat point.  If you look carefully on a clear night when Pegasus is high in the sky,  you can make out a smudge of light,  which is the galaxy. In a good telescope,  you can make out the dust lanes in the galaxy.  Long exposures with telescope camera combination shows the galaxy in all it's glory,  together with it's two companion galaxies, if the field of view permits their inclusion in the frame.  

The Planets of the Solar System do change positions as the orbit our Sun,  just as the Earth orbits it too.  The outer Planets move more slowly in their orbital paths,  simply because they are much much further away from the Sun.                The stars you see change position nightly due to the earth's rotation,  but their other movements are due to the earth rotating around the sun,  which provides us with the sighting of other stars in our galaxy.             Another thing to  consider,   is we can only view  the sky from our hemisphere,  the northern hemisphere.  The Southern Hemisphere is denied to us,  unless we take trip way down south to Australia for example,  who have different constellations,  to explore. There is much more to  explain,  but you can buy a Planisphere which will let you  see how things change month on month through a year.                                    The most important thing to remember,  Astronomy is great fun,  and a lot of pleasure is gained from just observing,  learning the sky and it's  residents,  systematically,  with the aid of a book,  or star chart  searching for specific objects.   Just simply enjoy yourself,  and help others to do the same when  you have become proficient at what you do.                                                             Good Luck,  and good hunting. 

[Nyctimene]

furrysocks 2,

thank you for your honest and open report.

As I read this, a suggestion came to my mind, which I found some months ago in the CloudyNights forum. It was adressed at beginners, but in my opinion applies  to each stargazer: "Spend at least 30 minutes of each observing session just sitting in a chair or laying on a blanket and simply looking" (Cloudy Nights - General Astronomy -  General Observing and Astronomy - If you could start from the beginning - page 3, scroll down to the post of "justfred" from March 7, 2016; very good topic anyway).

I almost always finish my observing sessions spending at least a few minutes gazing at the sky naked eye or with widefield bins, just to renew that sense of wonder again. To me, the stars and constellations are like old friends at that moments, bringing back memories, when I first saw them. It's rewarding. So, get out your bins and star map, go to an area with really dark skies, and enjoy.

Stephan

[popeye85]

24 minutes ago, Nyctimene said:

 

I almost always finish my observing sessions spending at least a few minutes gazing at the sky naked eye or with widefield bins, just to renew that sense of wonder again. To me, the stars and constellations are like old friends at that moments, 

To me that is the 'true' nature of stargazing-and more often then not is the most enjoyable part of the night.

[furrysocks2]

Thanks to all for the replies.

I was given a star finder a few years ago by my father in law - his father was a mariner. It's a Similux 2102-D, as shown here. It allows you to estimate the altitude and azimuth of 57 stars. If I could identify at least some of those stars in the sky, that might be a meaningful step forward. In fact, a few weeks ago when I was working on the new scope, I had a conversation with a neighbour which was the first time we'd spoke - he's an ex-navigator.

Along with the star finder set, there's another disc that given dry and wet bulb temeratures will give you relative humidity and dew point. I may have a Philips planisphere somewhere but it's not currently in my box of astro bits. I also used to have a Stellarscope, but that's gone. Finally, in a folder somewhere, I've got a printed set of star charts (B-SET from http://www.uv.es/jrtorres/triatlas.html). For all those items, I think I can recall two occasions on which I referred to one of them.

A short while ago, I was intrigued enough to have a play with the aaplus library for computational astronomy, which implements the algorithms in the book "Astronomical Algorithms" by Jean Meeus. I succeeded in calculating the topocentric horizontal coordinates for the major planets on an Arduino DUE. A bit of a waste of time but it satisfied a curiosity.

I've got the TED app on my phone and found this nice wee 10 minute talk on the astrolabe - https://www.ted.com/talks/tom_wujec_demos_the_13th_century_astrolabe.

 

My 8yo son said to me today, "wouldn't it be cool to have a robotic telescope outside and a projector in my bedroom to show bits of the sky on my ceiling" - little does he know...  I'll get him out with me for a peer through the ST102 soon.

Finally, the 3/8 nipple and tripod adaptor for my 15x70s have arrived, so I can get the monopod pieced together.

[westmarch]

Hi there,

like you, most of us are more familiar with some constellations than others. In the past, I was lucky enough to be in New Zealand - the sky there really was a foreign country and language.  It was like looking up at the sky for the first time.  The Magellanic Clouds are spectacular and constellations like Scorpio come alive out of textbooks for the first time.

There is always another hill and another vista, that's what makes astronomy so enjoyable. 

[furrysocks2]

I was on Borneo a number of years ago for a couple of months and other than using the position of the sun to tell the time during the day and once, the moon at night, I paid no attention to the sky at all. Pity.

[SilverAstro]

Many years ago I spent some time in Brazil, not only were there too many stars visible ( exceeding dark and clear) all the once familiar constellations were upside down It is surprising how quickly one becomes lost when there is no pole star behind your right shoulder

[popeye85]

I even get that at home! Doing most of my observing during the winter months that on the very rare occasion I get it during the summer I can't reconise anything!

[JOC]

With my very recent 'really need to know' I've started to pay a whole load more attention to the night sky and I am working on my constellation ID's.  At the moment the easy ones are Orion, The Plough (but, somehow I've always known those.  I can rough out the little bear, Cassiopeia, I've found a nice 5 sided shape that Capella is in - I've just learned online that the constellation is Auriga (the 'charioteer' apparently) - apparently that constellation has a 'tail' of stars, but I don't see them yet.  Castor/Pollux and Gemini I'm working on - I can often find the two stars, but without Stellarium struggle to 'see' the rest of it.  Once I see Orion I can find Aldebarran - as it's the socking great big bright object just above it (it's a good view in the telescope too), and Pleiades above that.  I also now know where to find M42 (my current favourite target as I struggle to make out the 'cloud' around it) and of course currently I'm having no problems with Venus or locating Mars next to it.  The obvious star patterns are very easy to spot I suspect 90%+ of the Northern hemisphere knows the Plough and Orion, but the more esoteric ones are harder - like the 'sides' of Gemini.  Stellarium is truly wonderful in the way that you can turn the pictures and star outlines on and off to help spot them.  It would be even better if I could hold the mobile phone camera up to the sky and have it identify exactly the bit I had aimed at LOL

[furrysocks2]

I'm intending to start by identifying the "navigational stars" by name and being able to hop between them. Here's a nice wee video I found along those lines:

https://www.youtube.com/watch?v=tQ-f5AWoKBk

[JOC]

furrysocks2 your reference to 'navigation, caused me to wonder about the earliest times that navigation by the stars was used.  That search led me here http://www.southernfriedscience.com/sailing-by-starlight-the-lost-art-of-celestial-navigation/ and it was an interesting 3 minute read

[popeye85]

31 minutes ago, JOC said:

. L It would be even better if I could hold the mobile phone camera up to the sky and have it identify exactly the bit I had aimed at LOL

It it's the stelarium app you have then this function is definitely available. Just toggle on and off the symbol highlighted-should work.

[JOC]

popye85 - Ooo....is that what that symbol does - I hadn't twigged that one - I'll give it a try :-D

[furrysocks2]

My first piece of homework... a list of 40-odd (above 30 degree south) to try to tick off over the course of a year.

[LukeSkywatcher]

Ive been observing for 37 yrs. I learned to "walk before i could run" (which is ironic coming from a wheelchair user). What i mean by this is that for the first 27 yrs of observing i had nothing but a pair of 10x50 bins and a 10" Philips planisphere to guide me. 

I only bought my first telescope in 2008 (cant seem to stop buying them since). I'm quite comfortable navigating my way around the Autumn,Winter and Spring night sky. The summer night sky i am almost at a loss to do so simply because i have never really observed during the summer months. My bad.

Naked eye navigation (no star charts etc) comes with experience/practise. When i look up at a clear sky, for the most part, the constellations jump out at me and seem to be the brightest things i see. They shine like beacons. All the other stars fade into the background (maybe i have night blindness). 

I always end a telescope session with having a quick 30 min scan around the night sky with 10x50 bins. If i dont take a scope out, i'll be using my 20x90 bins and in that case i'll end my session with just gazing upwards with my eyes and drinking in the view.

[LukeSkywatcher]

I read a few yrs ago a nice easy way to spot planets with the naked eye:

"If it twinkles,its a star. If it doesnt, its a planet". Maybe not always true to a degree but its never let me down on the average night.

[furrysocks2]

7 hours ago, LukeSkywatcher said:

I read a few yrs ago a nice easy way to spot planets with the naked eye:

"If it twinkles,its a star. If it doesnt, its a planet". Maybe not always true to a degree but its never let me down on the average night.

I hope so - I've been telling folk the very same.

[rockystar]

On ‎09‎/‎01‎/‎2017 at 11:24, JOC said:

would be even better if I could hold the mobile phone camera up to the sky and have it identify exactly the bit I had aimed at LOL

I'm waiting for the app that will literally project the lines onto the sky