HomeStar - 21st Century Home Planetarium

Featured on Slashdot on June 12th, 2006, under Toys, Space, and Science.


Pat once told me that he har­bours an inex­plic­a­ble com­pul­sion to be in space. His belief is that when he’s final­ly there, he’ll have all the answers. Life. God. 42. The meta­phys­i­cal impli­ca­tions don’t make sense, yet this is what he tru­ly thinks. It’s a strange hole in the log­i­cal being I know as Pat, and only the enig­mat­ic curios­i­ty of the night sky can do this to some­one.

I’m no excep­tion. Something borne in us from child­hood is a fas­ci­na­tion that stems from the unknown. The stars pro­vide enough for us to won­der about for a life­time.

Unfortunately, for those who live in the city, there’s lit­tle chance to see the sky with­out “sky glow”, the annoy­ing phe­nom­e­non that drowns out a large num­ber of stars vis­i­ble to the naked eye and tele­scope alike. As a by-prod­uct of indus­tri­al­iza­tion, light pol­lu­tion has tak­en the sparkle out of the stars, and this is where the HomeStar comes in.

What Is A HomeStar?

Thumbnail: Hoodie view

According to the offi­cial Homestar web­site, (trans­lat­ed through Babelfish):
“It is the plan­e­tar­i­um for world­wide first opti­cal type home. It is pos­si­ble to exceed sev­er­al thou­sand num­bers of stars that to project approx­i­mate­ly ten thou­sand thing stars it can see gen­er­al­ly with naked eye of the human.”

According to me, the Sega Toys HomeStar is a home plan­e­tar­i­um. It turns any room into an astro­nom­i­cal the­atre, by pro­ject­ing up to 10,000 stars onto a wall or ceil­ing.

Alternatives to the HomeStar until now have been rather crude. has a list of Top Toy Planetariums, and most of them aren’t above $40 USD, giv­ing kids a few fuzzy points of light on a near­by wall. There’s also the StarDome, which offers a bet­ter image, at the cost of a much more sig­nif­i­cant invest­ment. This includes a week of con­struc­tion, elec­tri­cal work, as well as a steep­er price.

The HomeStar is mid-ranged geek toy. It’s pro­vides an extreme­ly detailed star field, while remain­ing portable and afford­able ($239.00 USD as of June 2006).


  • Weight: 1 kg
  • External size: W16.7 x H15.9 x D15.1 cm
  • Power source rat­ing: Input — AC100V, 50/60Hz / Output — DC5V, 1.2A
  • Electric pow­er con­sump­tion: 3w
  • Electric bat­tery life: 6 hours
  • Power source: Private AC adapter / pri­vate elec­tric bat­tery box

The HomeStar also comes with three fea­tures. There’s a ran­dom shoot­ing star gen­er­a­tor, which projects an ephemer­al comet that flies through the stars. A sleep timer allows the unit to turn off auto­mat­i­cal­ly after a set amount of time. The pro­jec­tion can also rotate, to sim­u­late the rota­tion of the earth.

Package Contents

Thumbnail: Box front

Thumbnail: Box back

Thumbnail: Package contents

I ordered my Homestar from Audiocubes, a sort of mid­dle-man to Japan. The order was placed on a Thursday, shipped on Sunday, and arrived on Tuesday. Not bad.

The Homestar comes in a styl­ish box, with pic­tures of the night sky on the side.

In the box

  • HomeStar
  • Two north­ern sky discs (with and with­out con­stel­la­tions)
  • AC Adapter
  • Explanation Handbook
  • Explanation CD
  • Battery Box

Thumbnail: Homestar instructions

Unfortunately, all doc­u­men­ta­tion, as well as the expla­na­tion CD, are in Japanese. As sim­ple as it is to use the HomeStar, there are some rather intim­i­dat­ing images in the man­u­al that make me feel like there’s some­thing I should know.

One can also pur­chase two south­ern sky discs, but at an extra $80 USD, I did­n’t think it was worth the price. I don’t think they can be shipped sep­a­rate­ly, so the deci­sion should be made before order­ing.

Design And Construction

Thumbnail: Starball front

Thumbnail: Starball back

The HomeStar usu­al­ly comes in two colours, sil­ver and black, although lim­it­ed edi­tions have spe­cial gra­di­ent and pas­tel colours. It comes in a mat­te fin­ish, while the well-designed sil­ver base adds a nice con­trast. Soothing curves give it a mod­ern look. It’s styl­ish enough that it can be stored almost any­where out in the open with­out look­ing out-of-place. I chose the black so that it would­n’t stand out in the room, although this also means that it’s hard­er to see in the dark, mak­ing it poten­tial­ly eas­i­er to break.

The unit is much lighter than expect­ed, but not to the point where it feels flim­sy. I imag­ine that inside is sim­ply a lens used to focus the stars, a motor to rotate the discs, and a light source.
Shaking the sphere does­n’t cause any rat­tling.

Buttons are sol­id, with good tac­tile feed­back. The focus ring is much too loose for my pref­er­ence, although this may be good because it can take quite a lot of turn­ing to get the stars to the right sharp­ness. I also have a dif­fi­cult time remem­ber­ing which direc­tion to turn the know for clos­er or fur­ther focus, as there’s no visu­al mark­ings on the unit itself. I bet there are Kanji char­ac­ters for clock­wise and counter-clock­wise some­where in the man­u­al.

Thumbnail: North hemisphere disc

Thumbnail: North constellations disc

Thumbnail: Disc close-up

The image discs are much more sol­id than they look in the pic­tures. They’re about 3mm thick, made of stur­dy plas­tic that does­n’t bend. The thing to be most care­ful of is get­ting the sur­face of the disc scratched. Although this would­n’t actu­al­ly ruin the thin black lay­er of stars sand­whiched between the plas­tic, may it may still alter the image.

Using The HomeStar

Thumbnail: Ceiling projection

Thumbnail: Starball back open

Stucco ceil­ings are not a prob­lem; the starfield shows up crisp and clear on mine. The HomeStar should be placed in the mid­dle of the room. If it’s too much to one side, the depth of field is too nar­row to con­tain both sides of the field, result­ing in a stretch. Unfortunately, this isn’t always easy or con­ve­nient. The effect can be seen in the pic­ture on the left. However, it does come with a bat­tery box that allows for more porta­bil­i­ty. This is sup­posed to last up to six hours, but the AC cable is long enough that I haven’t had to use this yet.

The pro­ject­ed image does­n’t include the entire sky, just a por­tion of the disc. This makes the rota­tion fea­ture much more valu­able, as it cycles through the sky once every six min­utes. It’s a very sub­tle effect. Often, I’ll have to ask a sec­ond opin­ion whether the stars are actu­al­ly mov­ing. The image can be slight­ly dizzing; I’m remind­ed of the morn­ing of a hang­over, when the entire room seems to spin.

Thumbnail: Colour coded lights

There’s very lit­tle light leak­age from the HomeStar, and this is a very impor­tant fea­ture. The mode LEDs are rather dim, and the pro­jec­tion lens is recessed inside the unit enough that you can’t eas­i­ly blind­ed if you hap­pen to walk by the unit. Any stray light will wash out the stars; light pol­lu­tion exists inside the house now, with super­bright LEDs on many elec­tron­ic units. I find myself cov­er­ing up the LEDs from my blue­tooth charg­er and speak­er pan­el when using it.

The shoot­ing star gen­er­a­tor is a lit­tle dis­ap­point­ing. The small comet comes at a set inter­val, and at the same loca­tion every time. Not quite the mys­ti­cal, ran­dom effect that I was hop­ing for.

For those with glass­es, the use of the HomeStar becomes a lit­tle more lim­it­ed. After tak­ing your glass­es off to go to bed, the star­ry ceil­ing becomes some­what of a blur, depend­ing on the strength of your pre­scrip­tion. There’s still a sparkle in the eyes, but it’s not the same effect of sleep­ing under the stars that you pay for.


The HomeStar very effec­tive­ly sim­u­lates a clear, star­ry night. With a dark­ened room, the effect becomes quite roman­tic. It can’t match the actu­al night sky while camp­ing or out in cot­tage coun­try, but for peo­ple who live in dense­ly pop­u­lat­ed areas, it does the job well. Makes a great gift, espe­cial­ly for peo­ple who have every­thing, and kids with space-themed rooms. Astronomy (and even­tu­al­ly astropho­tog­ra­phy) is some­thing I hope to afford some day, but until then, the HomeStar will give me the enough of the heav­ens that I need. A high­ly rec­om­mend­ed item, if price isn’t a prob­lem.


  1. The Homestar Earth Theater is not worth the mon­ey, the pico pro­jec­tor is JUNK and the image pro­jec­tion is worse than awful. It is noth­ing more than a Homestar Pro (which isn’t worth the mon­ey either) with a very, very cheap pico pro­jec­tor-save your mon­ey!

  2. I have lost my adapter for Homestar Earth theatre& no longer have the box. I have con­tact­ed Sega and for­tu­nate­ly for some rea­son they don’t know ridicu­lous. This mod­el was only Sold in Japan. I’ve nev­er under­stood how to work it I got it because I’m obsessed with the north­ern lights with all the direc­tions in Japanese I have no idea but I have lost the input out­put the whole entire pow­er adapter because it does have sound can you please help

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