Is there any point in a planisphere?

[JTDUK]

Hi guys,

So I got my planisphere... I have to be honest is seems pretty useless. I got the Philips one and I am sure I am following the instructions right, but it doesn't seem very accurate at all? 

I've found that, rather than match the date and time and line it up with north, it's much easier just to find the plough and orientate the map to that. The whole plastic oval thing seems pointless. It also seems that things aren't that clearly matched with what's actually in the sky! I've been finding the constellations by just Googling images!

Does this sound standard, or have I bought a dud planisphere?

[Sunshine]

You do not have a dud, a planisphere is the abacus of astronomical tools, it just shows which constellations are visible at any one point in time from horizon to horizon. It is not in any way a substitute for a star chart or, much less digital means like phones or Ipads etc.

Edited May 10, 2021 by Sunshine

[Kimboman]

Hi I agree there are much better tools available to find your way around the constellations but I started with a Philips planisphere.

You get a good idea from using one and once you locate the plough this points the way to other constellations .

I have a few planispheres and my favourite is the oldest one picture enclosed

[dobblob]

I began my astronomical life with a Planisphere and it remains my "goto" when all else fails. If I need a quick reference to what's going on up there and not wait for my computer to boot up especially after several months of weather induced inactivity and I forget what the sky should look like , it's ready at hand!

It should be included in a "disaster kit" for when a Carrington event hits and we all loose power. The Planisphere needs no power or batteries.

Talking of widespread and enduring power failures, I am proof against that too. As long as I maintain a good charge in my batteries I can image all night long for several nights. My rig is computer free. Of course then comes the problem of processing. My old slide rule really won't do the job....

[AlexK]

Planisphere is like a wall calendar. But if you don't know constellations, not aware of sphere to surface projections, don't know what the LAT, ST, LMT, UT, LST means, it's nearly useless in the field. But you can use it to learn all of the above. And even get an inner sense of the astronomy time building up gradually. Just hang it on the wall (see the hole in the corner) and move it like every week. Then memorize what's displayed on it, i.e. at around 10pm LMT, when passing by on your daily route. The wall in front of the toilet is a good learning place for it as well 🤣

Just by the way, here is my pocket planisphere which is always with me (in the center) I watch it at midnight LMT:

 

Edited May 11, 2021 by AlexK

[Louis D]

I've been using a "The Night Sky" 20°-30°N Large Planisphere for over 20 years as needed.  You just line up the standard time with the date and either hold the south side over your head when facing south or the north side when facing north.  There is some distortion near the edge, but it's not horrible.  It's pretty accurate about what is up and shows the motions well during the night.  It's handy for quickly getting oriented when you haven't been out under the stars for a while and requires no batteries or boot time.  It is useless for planets, I'll say that. 🙄 They also make versions for 30-40°N, 40-50°N, 50-60°N, and a catch-all southern hemisphere version.

I lined mine up for 9pm standard time on May 10th and took these scans so you can see for yourself what it shows.  It would be nice if it included a few more brighter objects.

South:

North:

[JTDUK]

Thanks for the responses guys.

I'm very keen to avoid any kind of app at this stage. I was just curious about the planisphere really, as so far I have not actually found anything with it. I looked at pictures in a book to identify the plough (after some delay before I realised it was called something else in the States) and then found everything else from that.

Mind you, I suppose its easier at the moment as there are only like 6/7 visible constellations here.

[AlexK]

The above double-sided one is a way better design compared to the classic one. First of, it has much less distortions. Clean to comprehend, and even has lines teaching you the bright constellations stars finding with pointing figures. E.g. Arcturus is on the extension of the UMa "handle".

Regarding planets not charted, Louis, you supposed to watch for the ecliptics line on that chart (dashed). Planets are bright stars. So if you follow the ecliptic line on the sky and stumble upon a bright star not charted on the planisphere, that's a planet (or an UFO). You can learn distinguishing outer planets by their color. While Venus and Mercury are day and night in brightness and always close to the Sun. Also, there is a common misconception that planets do not blink compared to stars, but that's referring way back into the days with no industrial pollution to speak about much.

[NGC 1502]

My Philips planisphere lives in the lid of my eyepiece box. It’s a very valuable tool for a basic idea of what’s currently in the sky but is not intended as comprehensive star chart.  It’s great for planning a session under the stars, it shows which constellations are well placed and then good star chart will show what objects are in each constellation.

As others have said a planisphere requires no batteries, zero boot up time, and of course doesn’t ruin your dark adaptation.

Ed.

[AlexK]

54 minutes ago, NGC 1502 said:

... and of course doesn’t ruin your dark adaptation.

How so? You have to use a bright enough flashlight to see its large white low contrast blinding beauty  

On a side note, it's easy enough to remember all these ~100 black (or blue what have you) dots and skip that redundant step for good while planning. A good star chart will show you what's up and what's not anyway.

[Carbon Brush]

I have always used a planisphere for planning. Not necessarily for this evenings viewing.
Sit in a chair, no batteries, no internet, no computer.
What month will Orion be high enough to look at M42?
Will next year be good for Saturn?

[NGC 1502]

56 minutes ago, AlexK said:

How so? You have to use a bright enough flashlight to see its large white low contrast blinding beauty  

A dim red torch (flashlight) is best.  Mine is adjustable in brightness. Once your eyes are dark adapted then a very dim red light is adequate.  Of course if you’re planning a session during the day then no artificial light is needed.

Cheers from across the pond from Ed in the UK.

 

[NGC 1502]

AlexK, looking at your equipment list I see you have an Astroscan.  I have one as well, bought from Adrian Ashford who used to work for Sky & Telescope magazine. When he moved back to the UK he brought his Astroscan then sold it to me. It had its collimation tweaked by Gary Seronic, the front optical window with attached secondary mirror can be shimmed.

Enjoy your Astroscan under your Californian skies 😁

[oscar_camilleri]

I agree a planisphere is a must have tool and the time it takes to master one ( which is not that long) will prove invaluable.  Like it was mentioned before , the sphere does not require batteries and will not let you down.  It is not meant to replace a detailed star chart, but it is helpful in getting you familiar with the night sky at different times of the year, until you master the constellations and can distinguish them at a glance.  The planisphere can also be used to track  where the planets are supposed to be in the sky, most of the good ones will have a set of time codes on the back ( usually covering a period of 10 years from publication) which you can then line up to the elliptical to get a very good idea of where you should be looking.  Another useful use is to calculate sun down and sun up .

 

Not sure if it is allowed here ( mods please delete if not allowed) , but here is a link for a youtube video which goes on the ins and out of using a planisphere.   

 

[Zermelo]

I have accumulated four, somehow.

The only way that a Planisphere can be "wrong" is if it was designed for a substantially different latitude than that of the observing location. My Philip's version is for 51.5°N, which is close enough not to matter. And you need to take account of local time vs UTC, where appropriate.

I'd agree with the other comments - a Planisphere has its place (showing you what parts of the sky are visible at different times on different dates), but it will only show the brightest stars, it won't show DSOs, nor planets. So you need to use it in conjunction with other tools for planning sessions. And while it can be handy to have out when you're observing (I use it for those "which constellation is that, just over there" moments) the inevitable distortions in the projection mean that it can't reliably be matched up, quantitatively, with the real sky ("that object is on a straight line between Arcturus and Regulus, about one-third of the way there").

For session planning, I use Stellarium on a laptop to check the position of potential targets at different times of the evening. I have various obstructions at my regular viewing location, so I incorporated a local landscape into Stellarium, which is another advantage (though I'm sure some people have done the same thing with a Planisphere, by sticking bits of card onto the upper surface!).

I think Planispheres can also be effective for engaging children, and in explaining the motions through the night and through the year. Yes, I know they all use apps, but there's something very satisfying about turning the parts yourself and seeing the effect.

And perhaps there's also a feeling that you're communing to a degree with the ancients, even if your disc is made of printed plastic, not engraved brass.

[DAVE AMENDALL]

How would you fancy going down the garden on a windy night with this one !................Dave

[M40]

I must admit to using my Phillips planisphere a lot. I find it easy to use to find/confirm the bright stars for initial star alignment. I basically set the time and date, put my thumb on the North point, point it North, line the rivet hole up with Polaris and bend it around the horizon. Probably completely the wrong way to use it but it works for me 😜

[Louis D]

12 hours ago, AlexK said:

The above double-sided one is a way better design compared to the classic one. First of, it has much less distortions. Clean to comprehend, and even has lines teaching you the bright constellations stars finding with pointing figures. E.g. Arcturus is on the extension of the UMa "handle".

Regarding planets not charted, Louis, you supposed to watch for the ecliptics line on that chart (dashed). Planets are bright stars. So if you follow the ecliptic line on the sky and stumble upon a bright star not charted on the planisphere, that's a planet (or an UFO). You can learn distinguishing outer planets by their color. While Venus and Mercury are day and night in brightness and always close to the Sun. Also, there is a common misconception that planets do not blink compared to stars, but that's referring way back into the days with no industrial pollution to speak about much.

Oh, I know all that now, but starting out 23 years ago, not so much.  I don't even have to look at constellations to know where the ecliptic is during the different seasons now.  I just have a feel for its path across the sky having followed so many solar system objects over the years.

[Tiny Clanger]

17 hours ago, JTDUK said:

Hi guys,

So I got my planisphere... I have to be honest is seems pretty useless. I got the Philips one and I am sure I am following the instructions right, but it doesn't seem very accurate at all? 

I've found that, rather than match the date and time and line it up with north, it's much easier just to find the plough and orientate the map to that. The whole plastic oval thing seems pointless. It also seems that things aren't that clearly matched with what's actually in the sky! I've been finding the constellations by just Googling images!

Does this sound standard, or have I bought a dud planisphere?

A planisphere will be as accurate as such a small and generalised map can be, as long as you bought a planisphere for the correct latitude  for the UK, usually 51.5 deg, North on the Phillips  ones,  altho'  I also have a 'Greenwich Star Disc' which says it is for 50to 58 north , I bought it because it is blue printing on a white background and which makes it easy to read .

Be sure to use GMT not British Summer Time , and be aware that such a thing cannot take account of your height above sea level, obstructed horizon etc. Setting it accurately, then ensuring you keep  the two layers firmly pinched together and perhaps  initially holding it up over your head to help orient yourself might help. I find turning the whole thing , both layers still firmly pinched in place , (for children's use , or passing it round several people, I've temporarily taped the layers in place with a bit of masking tape round the north rim) so the horizon direction on the disc overlay (east & west horizons are printed on the Phillips one, all four on the Greenwich disc) matches the direction I'm looking .

Yes, Stellarium is more accurate, more detailed and more informative, as are any number off similar programs and 'phone apps , but a planisphere is a simple analogue tool which can teach a lot about the night sky, is portable, waterproof , cheap and requires no power.  If we should get a nice big Carrington class event that knocks out the power grid (or has it turned off to avoid damage : this is the astronomy version of the Zombie Apocalypse), those of us with simple paper sky maps and planispheres will be out enjoying those suddenly dark skies

[AlexK]

18 hours ago, NGC 1502 said:

AlexK, looking at your equipment list I see you have an Astroscan.  I have one as well, bought from Adrian Ashford who used to work for Sky & Telescope magazine. When he moved back to the UK he brought his Astroscan then sold it to me. It had its collimation tweaked by Gary Seronic, the front optical window with attached secondary mirror can be shimmed.

Enjoy your Astroscan under your Californian skies 😁

Cheers back NGC 1502!
That's right. The Astroscan is the observing ergonomics high end of all times! And definitely a keeper! I got it from a fellow colleague amateur astronomer for free specifically for my son some years ago. Because this marvel is not for sale! Only for giving! But I considering it mine too as I play with it more than him  Care for it well! Yours is even more unique! And it looks like manufacturers are not rushing a new model into production anytime soon for some weird reason

By the way, you can find several mods and outfits I've done to/with my Astroscan on my blog. I have collimated the secondary and primary by shimming as well myself. It gives amazing views with the 9mm WO 101 AFOV!

To stay on the subject: I do love planispheres.
When I was a kid (8-18 y/o) I had a 2 meters in diameter, 7 colors printed press, laminated, DIY cardboard pieces backed, classic planisphere in Russian mounted by my father on the concrete anchor in the wall of my room. For the horizon overlay I've made a huge wire ring hanging down from that same screw (in later years back then I have added the overlay wire following my local urban horizon line carefully modeled over the course of several observing nights bending it between matching stars). I've made hourly marks from two old broken wall clocks (brass digits) on separate plaques glued to the wall around the chart's disk, azimuth points were made from red copper wire rings on the main aluminum wire...
Needless to say that after literally living between stars for so long in my childhood I now know constellations' stars very well. If you point to any star in the sky, I can immediately tell its name/greek letter/flamsteed number, even if it's barely visible between trees. Or I always immediately noticing any "extra" stars (being that a planet, comet, an artificial airborne/space light source). Or, when I see any movie, or a piece of art (e.g. in computer games) depicting some starry sky, I can immediately tell if that's "our sky" or some alien/fantasy one because constellations stars are so obvious and familiar...
But I would never even consider a planisphere as an observer's tool. Learning, demoing, studying - OK, but at the eyepiece I strongly prefer a handheld eyepiece view chart.

EDIT: Simple orienting? Nah. Good digital chart has several much more effective basic orienting methods starting from mirroring the 180 degrees view projection, which makes the screen working as a "star compass" with constellations down on the table matching directions to real constellations in the sky. all the way to the StarSense Explorer software, actually "seeing" where the phone is pointing between stars and telling you where to move the telescope...

Edited May 12, 2021 by AlexK

[AlexK]

10 hours ago, Tiny Clanger said:

If we should get a nice big Carrington class event that knocks out the power grid (or has it turned off to avoid damage : this is the astronomy version of the Zombie Apocalypse), those of us with simple paper sky maps and planispheres will be out enjoying those suddenly dark skies

Unless that would also involve our Sun turning into the Black Hole (what an astronomer's paradise is that! See a BH and die!), I will be still enjoying my ODA (Observer's Digital Assistant, a.k.a. dedicated astronomy smartphone) which objects database equals in ink and paper (required to print them all) to several tons of paper charts. Because I have a briefcase-size-folding 150 Watt solar panel (works well enough even in the overcast to charge a phone). That's the last resort after I have exhausted my 500 watt/hours power brick, 4 x 3-8 Amp/Hours pocket 5V power banks, and the ODA spare battery (yes it's still has a replaceable battery as that was the ODA selection goal!), not to mention two smaller solar panels for hiking and EDC, my in-car dynamo, and the small 1 Kwh gas generator (Oh, no! That one is out as it will power my fridge with cold beer)...
Nope, I'm still good without the planisphere during the apocalypse (a.k.a. TEOTWAWKI) 😂

Edited May 12, 2021 by AlexK