Laptop vs. Charts

I would like to hear from folks who use a laptop when observing, as opposed
to charts. General impressions appreciated, as well as specifically
addressing how this works in terms of 1) dark adaption, 2) dew, 3)
cold/winter, 4) software. Thanks.

Dennis

On Mon, 3 Dec 2007 12:31:41 -0500, "Dennis Woos"
wrote:

I would like to hear from folks who use a laptop when observing, as opposed
to charts. General impressions appreciated, as well as specifically
addressing how this works in terms of 1) dark adaption, 2) dew, 3)
cold/winter, 4) software. Thanks.

A laptop has the advantage of giving you a very deep, customized chart
on demand. But if you are a critical visual observer, it is very hard to
use without some significant impact on dark adaptation. I prefer to
print out custom charts in advance (white stars on black, uses a lot of
toner but is necessary to preserve dark adaptation). The downside, of
course, is that this locks you into an observing program.

I use TheSky, and with several different laptop models have never had a
problem with even extreme cold. A box over the laptop with one side cut
off is generally sufficient to prevent dewing. Planetarium programs
aren't very demanding on computers; IMO it's best to use an old or cheap
laptop in the field. The sort of thing you can pick up for a couple
hundred dollars if you don't already have something collecting dust.

When using a laptop in the field, you'll need to add a screen filter to
reduce the brightness. Some people like using red filter material, such
as Rubylith. I don't think this works very well, however, and prefer to
use neutral density material (auto window tinting film) combined with a
carefully chosen color scheme.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Dennis Woos wrote:

I would like to hear from folks who use a laptop when observing, as opposed
to charts. General impressions appreciated, as well as specifically
addressing how this works in terms of 1) dark adaption, 2) dew, 3)
cold/winter, 4) software. Thanks.

1) Red displays aside, you can forget about dark adaptation when using
a laptop at the telescope. This may not matter; I, for example, am
using astrographs that have no eyepieces attached. I dim or cover the
screen while making camera exposures against the off chance that a
diffuse glow reflected from the dome might get into the telescope and
reduce image contrast.

2) Yes, your laptop can get dew on it. It depends largely on how warm
your laptop runs. Covering it with a towel when it is not needed may
help. This is not an issue if the laptop is in an observatory.

3) Laptops have LCD displays. The "L" stands for "liquid," and liquid
can freeze if it's cold enough. If the "L" freezes it will expand and
destroy your display. In use, Cold-Cathode Flourescent Lamp (CCFL)
backlights on older laptops generate a small amount of heat in spite of
their name; I don't know if this is the case with the latest models,
which have LED backlights. In any case, if it's cold enough to freeze
your "L", it's cold enough to freeze your "A," so quit for the night,
and take your laptop in with you.

4) I love my sky atlases for the same reasons I love books in general.
The look, the feel, the smell. Although I have observation planning
software, I prefer to plan my sessions with a large-format atlas such
as theSky Atlas 2000 (by Wil Tirion & Roger Sinnott.)

At the telescope, however, it's a different matter. An astrophotography
session is not the time to show your deep knowledge of the sky. Point,
click, goto.

As for the actual software, these are my favorites (alphabetically):

€ Cartes du Ciel is very popular because a) it's pretty good, and b)
it's free. It's for Windows, with Linux and Mac versions on the way.
Interfaces with Astroplanner.

€ Equinox 6 is excellent and interfaces with AstroPlanner. Equinox is
Mac-only.

€ StarryNight is very nice. Mac and Windows.

€ TheSky 6 is the gold standard, though it's showing its age. Relief is
on the way, however: all-new versions (complete re-write) are in the
works for Linux, Mac OS X, and Windows. The Mac version will be
released at MacWorld Expo in January, 2008.

Davoud

--
usenet *at* davidillig dawt com

On 2007-12-03, Davoud wrote:

3) Laptops have LCD displays. The "L" stands for "liquid," and liquid
can freeze if it's cold enough. If the "L" freezes it will expand and
destroy your display. In use, Cold-Cathode Flourescent Lamp (CCFL)
backlights on older laptops generate a small amount of heat in spite of
their name; I don't know if this is the case with the latest models,
which have LED backlights. In any case, if it's cold enough to freeze
your "L", it's cold enough to freeze your "A," so quit for the night,
and take your laptop in with you.

Two points. Firstly an LCD is a (Liquid Crystal) Display and not
a Liquid (Crystal Display). That is the technology uses liquid
crystals rather than actual liquids. Liquid crystals are a curious
state of matter that falls inbetween conventional liquid and solid
states. Having said that, they could still freeze solid although
I am not sure how far the temperature needs to drop for that to
happen - it isn't water after all.

Secondly, although it pains me to say it (sometimes literally!)
the coldest nights are often extrememely useful for astronomy since
in my experience at least, they tend to have the best transparency.
My (suburban) back yard has a typical NELM of 2.8-3.2 under normal
weather conditions. If the temperature drops to 0C or thereabouts
it isn't unusal for it to hit 4.0, perhaps better. Seeing isn't
always up to much in these conditions but at times there simply
isn't any substitute for darker than normal skies.

--
Andrew Smallshaw

On Mon, 3 Dec 2007 23:27:50 +0100 (CET), Andrew Smallshaw
wrote:

Two points. Firstly an LCD is a (Liquid Crystal) Display and not
a Liquid (Crystal Display). That is the technology uses liquid
crystals rather than actual liquids. Liquid crystals are a curious
state of matter that falls inbetween conventional liquid and solid
states. Having said that, they could still freeze solid although
I am not sure how far the temperature needs to drop for that to
happen - it isn't water after all.

I've used laptops when it was below -10°C. The screens get a little
sluggish, but work fine and don't seem to be harmed. Davoud's
observation about new units with LED backlights is a good one, however,
as there is less waste heat to help keep the LCD happy.

I've had LCD displays stored outside with temperatures down around -20°C
and they suffered no apparent damage.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Dennis Woos wrote:
I would like to hear from folks who use a laptop when observing, as opposed
to charts. General impressions appreciated, as well as specifically
addressing how this works in terms of 1) dark adaption, 2) dew, 3)
cold/winter, 4) software. Thanks.

Dennis



I've used both. The laptop pluses relate mostly to the way the database
is handled. Easy upgrade to charts, easy to move around to any part of
the sky, easy to flip and mirror image the charts to match views,
plotting of planets is done automatically, as well as comets and
asteroids, et al. Minuses include need for electrical power, brightness
of the screen, and what to do if moisture develops.

Chart pluses are no need for any power other than a red light, which you
need anyways, ease of use, ease of writing notes and corrections.
Minuses are not as easy to move around and find the chart you need,
sometimes you need to use more than one chart for those incidents are on
the borders, upgrades are not as easy to "download", planets, asteroids,
and comets are not plotted automatically.

Which do I prefer? Each has its place. Computers are fine where power
is available, preferably AC power, but don't mitigate the brightness of
some screens. I found the only reliable filter was a cellophane-like
substance called Rubellite (spelling?), while others have reported
success with screen dimmers. However, where I've been able to observe
screen dimmers at work, they still cast around the observing area a lot
of light, light that apparently the user is unaware of.

Charts are easy to use, and have more immediacy to me than a laptop.
But then you have to do your own plotting for solar system objects. I
do prefer them.

--- DiN

On Tue, 04 Dec 2007 04:10:52 GMT, David Nakamoto
wrote:

Chart pluses are no need for any power other than a red light, which you
need anyways, ease of use, ease of writing notes and corrections.

Or a dim white light g.

Minuses are not as easy to move around and find the chart you need,
sometimes you need to use more than one chart for those incidents are on
the borders, upgrades are not as easy to "download", planets, asteroids,
and comets are not plotted automatically.

It seems to me that you overlook an intermediate solution: using a
charting program to produce custom maps. This minimizes organizational
problems and eliminates the problem with borders, and automatically
plots dynamic objects as well. And, of course, the charts are
sacrificeable to the elements, unlike those in a printed atlas.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

I use a laptop to control my CCD camera (of course), but for charts I use
the laminated Sky Atlas 2000.0. If I need something more detailed, I step
indoors where Millennium and Herald-Bobroff are available. I use a red film
over the computer screen, which helps to keep dark adaptation, but the
cursor can be very hard to see. Like one of the other posters, I like
physical star atlases. This whole subject is one of personal preferences.
I don't propose my approach as being "best." It's just what works for me.
--
Curtis Croulet
Temecula, California
33°27'59"N, 117°05'53"W

To address specifically address some of the questions:

(1) Dark adaptation: already addressed with the red film on the computer
screen.

(2) If dew starts to be a real problem, I usually pack up. I don't want to
fight it all night. Where I observe it's usually pretty dry. Increased
humidity is usually related to a deepening marine layer coming in from the
coast (50-60 miles away), and transparency is likely going to take a
nose-dive.

(3) Extreme cold is not a problem in my situation. I regularly
observe/image from a site at about 4500 ft elevation, where winter temps may
occasionally drop to 10 F (-12 C), but if it's that cold, I'm probably
indoors. More typical would be temps in the upper 20s F.

(4) For software I use SkyMap Pro, but I don't have it on my field laptop.
--
Curtis Croulet
Temecula, California
33°27'59"N, 117°05'53"W

"Dennis Woos" wrote
....
I would like to hear from folks who use a laptop when observing, as opposed
to charts. General impressions appreciated, as well as specifically
addressing how this works in terms of 1) dark adaption, 2) dew, 3)
cold/winter, 4) software. Thanks.


I use a laptop (or PC) when imaging, but I prefer charts when visual
observing. I've observed with other people's GoTo Dob's with an attached
laptop to control the scope, but I find the display too bright and the
computer too much effort to fool around with compared to just going with a
chart and a list of targets. It is nice however, when at home to have access
to the web with my wifi equipped laptop.

Please check out this website (http://www.uv.es/jrtorres/index.html) where
the author has a pretty good and free planetarium program and some of the
best "charts" I've seen (pdf files). I've printed out his low rez charts on
tabloid 11x17 paper and they are quite nice. The full rez charts would take
hundreds of pages to print but might be worth it.

George N