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Date: 01 Jul 2007 13:18:53
From: JimC
Subject: Inexpensive planetarium projector?
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At TSP this year one of the interesting new "toys" demonstrated by one
of the vendors was an inexpensive (around $250) "star projector" that
projected a moving pattern of stars on the ceiling, producing a quite
spectacular display. As understood, this particular unit is, in fact, a
toy, since the pattern of stars it produces isn't at all accurate or
representative of an area of the night sky. However, it suggested to me
that such a projector could be useful and educational, particularly for
demos for novices, etc. Particularly in areas such as ours (near
Houston), in which overcast skies and hot, humid weather have been the
rule for many weeks, good viewing nights are few and far between,
limiting observing time and making scheduling difficult. (Also, I have
to take time to refresh my own memory of the sky on each rare observing
session.)
I suspect that there are sophisticated professional and
semi-professional projection systems (sorry I forgot the correct
technical term) available at substantial prices, but does anyone know of
any relatively crude but less expensive instruments intended for home
use or for small groups? - For example, I'm thinking of a basic,
relatively unsophisticated unit that would project the constellations,
Messier objects, and perhaps a few hundred stars with moderate accuracy,
and perhaps with some form of adjustment for time, seasons, etc. - Some
sort of slide projector, or perhaps a wide-angle video projector with
DVD or software input?
Jim
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Date: 02 Jul 2007 12:39:46
From: Dave Gede
Subject: Re: Inexpensive planetarium projector?
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> Looking back at my notes, I see that it was not the Sega that had
> problems, but a unit Discovery Stores were selling during the
> holidays. The Sega looks pretty good--if you can get one and don't
> mind spending 200 bucks or so.
Anyone have any first hand experience with the Sega Homestar Pro
models? They seem to be abundant (5 or so) on e-bay. Most have
high shipping (probably due to import taxes), but they all come with
voltage adapters.
They look interesting, but we all know from the pics on the side of
the telescopes at the big box stores, pictures can be deceiving.
Just wondering...
Thanks,
Dave
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Date: 01 Jul 2007 22:28:20
From: thad@thadlabs.com
Subject: Re: Inexpensive planetarium projector?
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On Jul 1, 4:13 pm, RMOLLISE <rmoll...@hotmail.com > wrote:
> [...]
> It depends on what you want. Quite a few of us still hold onto and
> love our old Spitz Junior Planetariums, even though they are "toys."
> The depiction of the sky they project is not bad. Not bad at all.
> [...]
Whew, that brings back memories. I recall seeing one in school
circa early 1950s, and a Google search just found this:
<http://www.antiqueradio.org/spitz01.htm >
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Date: 06 Jul 2007 17:47:27
From: JimC
Subject: Re: Inexpensive planetarium projector?
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thad@thadlabs.com wrote:
> On Jul 1, 4:13 pm, RMOLLISE <rmoll...@hotmail.com> wrote:
>
>>[...]
>>It depends on what you want. Quite a few of us still hold onto and
>>love our old Spitz Junior Planetariums, even though they are "toys."
>>The depiction of the sky they project is not bad. Not bad at all.
>>[...]
>
>
> Whew, that brings back memories. I recall seeing one in school
> circa early 1950s, and a Google search just found this:
>
> <http://www.antiqueradio.org/spitz01.htm>
>
For those with experience with the Spitz Junior projector, was the
projected image clear and detailed enough for you to identify the
constellations and learn the sky? To locate planets or Messier objects?
- Also, was there a "Spitz Senior" projector?
Jim
>
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Date: 06 Jul 2007 19:07:33
From: William Hamblen
Subject: Re: Inexpensive planetarium projector?
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On Fri, 06 Jul 2007 17:47:27 -0600, JimC <avocat5@sbcglobal.net >
wrote:
>- Also, was there a "Spitz Senior" projector?
Sort of. Spitz builds projectors for "real" planetariums:
http://www.spitzinc.com/
Bud
--
The night is just the shadow of the Earth.
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Date: 01 Jul 2007 17:25:43
From: RMOLLISE
Subject: Re: Inexpensive planetarium projector?
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On Jul 1, 7:20 pm, RMOLLISE <rmoll...@hotmail.com > wrote:
> On Jul 1, 6:55 pm, "Howard Lester" <heyles...@dakotacom.net> wrote:
>
> > "RMOLLISE" wrote
>
> > > I've got one now. Back when I was a kid, I never had one of my
> > > own...apparently too expensive. I was able to borrow one for a while,
> > > and was purty downcast when I had to give it back.
>
> > > Yeah, I've got one now thanks to Ebay...spent more on it than I should
> > > have, but...it was worth it. ;-)
>
> > Rod, I dare not ask how much... somewhere in my pea brained skull I recall
> > it cost maybe $30 or less new back then... got it from Edmund. Makes me
> > wonder if my old tripod mounted black Palomar, Jr. is still alive... ;-)
>
> Ha! Try about 75 bucks. But getting that little toy and the Gilbert 2-
> inch refractor I also pined for so much seemed to finally close a long-
> open circle, and it was worth it at any price. Down here back in the
> early 60s? Might as well have asked for the Moon as for 30 bucks. ;-)
>
> I won't tell you how many lawns I had to mow to finance a (used)
> Palomar Jr. ;-)
>
> Unk Rod
"Gilbert 2-inch _reflector_" ;-)
And, I might add, I've seen the Spitz Jr. go for considerably more
than 75 bucks.
Unk Rod
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Date: 01 Jul 2007 17:20:01
From: RMOLLISE
Subject: Re: Inexpensive planetarium projector?
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On Jul 1, 6:55 pm, "Howard Lester" <heyles...@dakotacom.net > wrote:
> "RMOLLISE" wrote
>
> > I've got one now. Back when I was a kid, I never had one of my
> > own...apparently too expensive. I was able to borrow one for a while,
> > and was purty downcast when I had to give it back.
>
> > Yeah, I've got one now thanks to Ebay...spent more on it than I should
> > have, but...it was worth it. ;-)
>
> Rod, I dare not ask how much... somewhere in my pea brained skull I recall
> it cost maybe $30 or less new back then... got it from Edmund. Makes me
> wonder if my old tripod mounted black Palomar, Jr. is still alive... ;-)
Ha! Try about 75 bucks. But getting that little toy and the Gilbert 2-
inch refractor I also pined for so much seemed to finally close a long-
open circle, and it was worth it at any price. Down here back in the
early 60s? Might as well have asked for the Moon as for 30 bucks. ;-)
I won't tell you how many lawns I had to mow to finance a (used)
Palomar Jr. ;-)
Unk Rod
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Date: 01 Jul 2007 21:17:03
From: JimC
Subject: Re: Inexpensive planetarium projector?
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RMOLLISE wrote:
> On Jul 1, 6:55 pm, "Howard Lester" <heyles...@dakotacom.net> wrote:
>
>>"RMOLLISE" wrote
>>
>>
>>>I've got one now. Back when I was a kid, I never had one of my
>>>own...apparently too expensive. I was able to borrow one for a while,
>>>and was purty downcast when I had to give it back.
>>
>>>Yeah, I've got one now thanks to Ebay...spent more on it than I should
>>>have, but...it was worth it. ;-)
>>
>>Rod, I dare not ask how much... somewhere in my pea brained skull I recall
>>it cost maybe $30 or less new back then... got it from Edmund. Makes me
>>wonder if my old tripod mounted black Palomar, Jr. is still alive... ;-)
>
>
> Ha! Try about 75 bucks. But getting that little toy and the Gilbert 2-
> inch refractor I also pined for so much seemed to finally close a long-
> open circle, and it was worth it at any price. Down here back in the
> early 60s? Might as well have asked for the Moon as for 30 bucks. ;-)
>
> I won't tell you how many lawns I had to mow to finance a (used)
> Palomar Jr. ;-)
>
> Unk Rod
>
There is a used Spitz Junior planetarium offered on Ebay. Also, the
Sega Home Star Pro planetarium, for around $250, looks interesting. It
is claimed to project 10,000 stars and planets, uses six LEDs, but it
must be shipped from Japan.
Jim
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Date: 01 Jul 2007 16:34:20
From: RMOLLISE
Subject: Re: Inexpensive planetarium projector?
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On Jul 1, 6:23 pm, "Howard Lester" <heyles...@dakotacom.net > wrote:
> "RMOLLISE" wrote
>
> > It depends on what you want. Quite a few of us still hold onto and
> > love our old Spitz Junior Planetariums, even though they are "toys."
> > The depiction of the sky they project is not bad. Not bad at all.
>
> I figured YOU would have one of those... :-) I did, too, but threw it out
> long ago. It didn't have enough stars, so I started adding my own with a
> pin....
>
> oops
Hi Howard:
I've got one now. Back when I was a kid, I never had one of my
own...apparently too expensive. I was able to borrow one for a while,
and was purty downcast when I had to give it back.
Yeah, I've got one now thanks to Ebay...spent more on it than I should
have, but...it was worth it. ;-)
Unk Rod
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Date: 01 Jul 2007 16:55:41
From: Howard Lester
Subject: Re: Inexpensive planetarium projector?
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"RMOLLISE" wrote
> I've got one now. Back when I was a kid, I never had one of my
> own...apparently too expensive. I was able to borrow one for a while,
> and was purty downcast when I had to give it back.
>
> Yeah, I've got one now thanks to Ebay...spent more on it than I should
> have, but...it was worth it. ;-)
Rod, I dare not ask how much... somewhere in my pea brained skull I recall
it cost maybe $30 or less new back then... got it from Edmund. Makes me
wonder if my old tripod mounted black Palomar, Jr. is still alive... ;-)
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Date: 01 Jul 2007 16:21:37
From: RMOLLISE
Subject: Re: Inexpensive planetarium projector?
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On Jul 1, 6:13 pm, RMOLLISE <rmoll...@hotmail.com > wrote:
> On Jul 1, 2:18 pm, JimC <avoc...@sbcglobal.net> wrote:
>
>
>
>
>
> > At TSP this year one of the interesting new "toys" demonstrated by one
> > of the vendors was an inexpensive (around $250) "star projector" that
> > projected a moving pattern of stars on the ceiling, producing a quite
> > spectacular display. As understood, this particular unit is, in fact, a
> > toy, since the pattern of stars it produces isn't at all accurate or
> > representative of an area of the night sky. However, it suggested to me
> > that such a projector could be useful and educational, particularly for
> > demos for novices, etc. Particularly in areas such as ours (near
> > Houston), in which overcast skies and hot, humid weather have been the
> > rule for many weeks, good viewing nights are few and far between,
> > limiting observing time and making scheduling difficult. (Also, I have
> > to take time to refresh my own memory of the sky on each rare observing
> > session.)
>
> > I suspect that there are sophisticated professional and
> > semi-professional projection systems (sorry I forgot the correct
> > technical term) available at substantial prices, but does anyone know of
> > any relatively crude but less expensive instruments intended for home
> > use or for small groups? - For example, I'm thinking of a basic,
> > relatively unsophisticated unit that would project the constellations,
> > Messier objects, and perhaps a few hundred stars with moderate accuracy,
> > and perhaps with some form of adjustment for time, seasons, etc. - Some
> > sort of slide projector, or perhaps a wide-angle video projector with
> > DVD or software input?
>
> > Jim
>
> Hi:
>
> It depends on what you want. Quite a few of us still hold onto and
> love our old Spitz Junior Planetariums, even though they are "toys."
> The depiction of the sky they project is not bad. Not bad at all.
>
> The problem with most of the home planetariums that have been sold
> over the last decade or two is that they project black stars on a
> white background. Not as aesthetically pleasing as the old Spitz Jr.
> None have the wonderful Spitz "Sky Zoo," either.
>
> There have been a couple of promising home planetariums over the last
> year or two. One from Vixen, one from Sega (the game people). To my
> knowledge, neither has been sold in the U.S. yet. The Sega also
> apparently has quality problems as well.
>
> Step up from the home/toy planetariums? That demands an investment of
> about 10k, usually--more than most of us want to spend on such an
> endeavor.
>
> If you'd like to keep up with home planetariums, you might want to
> join my Spitz Junior Yahoogroup. Not much traffic, usually, but when a
> new projector comes out, you'll hear about it.
>
> http://tech.groups.yahoo.com/group/spitz-jr/
>
> Unk Rod- Hide quoted text -
>
> - Show quoted text -
Looking back at my notes, I see that it was not the Sega that had
problems, but a unit Discovery Stores were selling during the
holidays. The Sega looks pretty good--if you can get one and don't
mind spending 200 bucks or so.
Unk Rod
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Date: 01 Jul 2007 16:13:52
From: RMOLLISE
Subject: Re: Inexpensive planetarium projector?
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On Jul 1, 2:18 pm, JimC <avoc...@sbcglobal.net > wrote:
> At TSP this year one of the interesting new "toys" demonstrated by one
> of the vendors was an inexpensive (around $250) "star projector" that
> projected a moving pattern of stars on the ceiling, producing a quite
> spectacular display. As understood, this particular unit is, in fact, a
> toy, since the pattern of stars it produces isn't at all accurate or
> representative of an area of the night sky. However, it suggested to me
> that such a projector could be useful and educational, particularly for
> demos for novices, etc. Particularly in areas such as ours (near
> Houston), in which overcast skies and hot, humid weather have been the
> rule for many weeks, good viewing nights are few and far between,
> limiting observing time and making scheduling difficult. (Also, I have
> to take time to refresh my own memory of the sky on each rare observing
> session.)
>
> I suspect that there are sophisticated professional and
> semi-professional projection systems (sorry I forgot the correct
> technical term) available at substantial prices, but does anyone know of
> any relatively crude but less expensive instruments intended for home
> use or for small groups? - For example, I'm thinking of a basic,
> relatively unsophisticated unit that would project the constellations,
> Messier objects, and perhaps a few hundred stars with moderate accuracy,
> and perhaps with some form of adjustment for time, seasons, etc. - Some
> sort of slide projector, or perhaps a wide-angle video projector with
> DVD or software input?
>
> Jim
Hi:
It depends on what you want. Quite a few of us still hold onto and
love our old Spitz Junior Planetariums, even though they are "toys."
The depiction of the sky they project is not bad. Not bad at all.
The problem with most of the home planetariums that have been sold
over the last decade or two is that they project black stars on a
white background. Not as aesthetically pleasing as the old Spitz Jr.
None have the wonderful Spitz "Sky Zoo," either.
There have been a couple of promising home planetariums over the last
year or two. One from Vixen, one from Sega (the game people). To my
knowledge, neither has been sold in the U.S. yet. The Sega also
apparently has quality problems as well.
Step up from the home/toy planetariums? That demands an investment of
about 10k, usually--more than most of us want to spend on such an
endeavor.
If you'd like to keep up with home planetariums, you might want to
join my Spitz Junior Yahoogroup. Not much traffic, usually, but when a
new projector comes out, you'll hear about it.
http://tech.groups.yahoo.com/group/spitz-jr/
Unk Rod
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Date: 01 Jul 2007 16:23:52
From: Howard Lester
Subject: Re: Inexpensive planetarium projector?
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"RMOLLISE" wrote
> It depends on what you want. Quite a few of us still hold onto and
> love our old Spitz Junior Planetariums, even though they are "toys."
> The depiction of the sky they project is not bad. Not bad at all.
I figured YOU would have one of those... :-) I did, too, but threw it out
long ago. It didn't have enough stars, so I started adding my own with a
pin....
oops
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Date: 01 Jul 2007 14:31:45
From: thad@thadlabs.com
Subject: Re: Inexpensive planetarium projector?
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On Jul 1, 12:18 pm, JimC <avoc...@sbcglobal.net > wrote:
> [...]
> but does anyone know of
> any relatively crude but less expensive instruments intended for home
> use or for small groups? - For example, I'm thinking of a basic,
> relatively unsophisticated unit that would project the constellations,
> Messier objects, and perhaps a few hundred stars with moderate accuracy,
> and perhaps with some form of adjustment for time, seasons, etc. - Some
> sort of slide projector, or perhaps a wide-angle video projector with
> DVD or software input?
Accurate placement would require a domed ceiling as found in a real
planetarium; most homes, businesses, warehouses, etc. have "boxes"
for rooms, so I'm curious how you'd expect such a projector to
function
correctly.
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Date: 01 Jul 2007 17:20:31
From: JimC
Subject: Re: Inexpensive planetarium projector?
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thad@thadlabs.com wrote:
> On Jul 1, 12:18 pm, JimC <avoc...@sbcglobal.net> wrote:
>
>
>>[...]
>> but does anyone know of
>>any relatively crude but less expensive instruments intended for home
>>use or for small groups? - For example, I'm thinking of a basic,
>>relatively unsophisticated unit that would project the constellations,
>>Messier objects, and perhaps a few hundred stars with moderate accuracy,
>>and perhaps with some form of adjustment for time, seasons, etc. - Some
>>sort of slide projector, or perhaps a wide-angle video projector with
>>DVD or software input?
>
>
> Accurate placement would require a domed ceiling as found in a real
> planetarium; most homes, businesses, warehouses, etc. have "boxes"
> for rooms, so I'm curious how you'd expect such a projector to
> function
> correctly.
A further option for reducing the distortion you mention came to mind. -
On our patio we have a large (nine-foot diameter) patio umbrella that
can be deployed over the patio by turning a small crank. - The
deployment mechanism and struts are on top, supported by a stand with
vertical standard on the side, so that there is little obstruction and
no inner, central rod under the dome. - Seems to me that an "umbrella"
of this type could be made in a substantially semispherical shape and
provided with a stand permitting it to be deployed over the projector
when in use, either inside or outside. - They are relatively inexpensive
(ours cost less than $100), so it shouldn't add too much to the cost.
Actually, I think the one we have would work fairly well, although
it is probably built more heavily than would be needed for indoor use.
Jim
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Date: 01 Jul 2007 22:52:29
From: JimC
Subject: Re: Inexpensive planetarium projector?
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thad@thadlabs.com wrote:
> On Jul 1, 12:18 pm, JimC <avoc...@sbcglobal.net> wrote:
>
>
>>[...]
>> but does anyone know of
>>any relatively crude but less expensive instruments intended for home
>>use or for small groups? - For example, I'm thinking of a basic,
>>relatively unsophisticated unit that would project the constellations,
>>Messier objects, and perhaps a few hundred stars with moderate accuracy,
>>and perhaps with some form of adjustment for time, seasons, etc. - Some
>>sort of slide projector, or perhaps a wide-angle video projector with
>>DVD or software input?
>
>
> Accurate placement would require a domed ceiling as found in a real
> planetarium; most homes, businesses, warehouses, etc. have "boxes"
> for rooms, so I'm curious how you'd expect such a projector to
> function
> correctly.
>
The short answer to your question is that I don't expect such a
projector to function "correctly." I thought I had made it clear that I
was speaking of a crude, relatively unsophisticated unit that would
project star patterns with only moderate accuracy.
Nevertheless, if it were fed with a software program incorporating
appropriate image processing, it could be designed to compensate
somewhat for the distortion you mention. In practice, it might be
limited to showing less than an entire horizon-to-horizon view.
Consider also that the charts and planispheres we routinely use show
star patterns on a flat surface, with some distortion, but we are still
able to use them to learn the shapes and orientations of the
constellations, to find objects, and to recognize various asterisms,
etc.
Jim
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Date: 02 Jul 2007 00:03:03
From: OG
Subject: Re: Inexpensive planetarium projector?
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"JimC" <avocat5@sbcglobal.net > wrote in message
news:NeWhi.893$eY.798@newssvr13.news.prodigy.net...
>
>
> thad@thadlabs.com wrote:
>
>> On Jul 1, 12:18 pm, JimC <avoc...@sbcglobal.net> wrote:
>>
>>
>>>[...]
>>> but does anyone know of
>>>any relatively crude but less expensive instruments intended for home
>>>use or for small groups? - For example, I'm thinking of a basic,
>>>relatively unsophisticated unit that would project the constellations,
>>>Messier objects, and perhaps a few hundred stars with moderate accuracy,
>>>and perhaps with some form of adjustment for time, seasons, etc. - Some
>>>sort of slide projector, or perhaps a wide-angle video projector with
>>>DVD or software input?
>>
>>
>> Accurate placement would require a domed ceiling as found in a real
>> planetarium; most homes, businesses, warehouses, etc. have "boxes"
>> for rooms, so I'm curious how you'd expect such a projector to
>> function
>> correctly.
>>
>
> The short answer to your question is that I don't expect such a projector
> to function "correctly." I thought I had made it clear that I was
> speaking of a crude, relatively unsophisticated unit that would project
> star patterns with only moderate accuracy.
>
I have thought about plotting star images onto thin card gores that could be
assembled into a celestial sphere. Pierce the card with holes sized
appropriately for the stars' magnitude. For a light source, use a maglite in
'candle' mode, where you take the reflector/lens assembly off to get close
to a point source of light. Put the maglite into the sphere through the
southern celestial pole.
Not got much further than thinking about it.
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