Sunday, March 16, 2014
ISAN 2014 and How Do You Video II
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| Boomer on her AZ-4 |
This is
actually a semi-twofer, muchachos, since before I get to the main topic, Part Two
of the Getting Started in Deep Sky Video article,
I’d like to talk a little about ISAN 2014. International Sidewalk Astronomy Night, that is. The
evening when amateur astronomers all over the world set up their telescopes in
public areas to show off the night sky. ISAN is different from normal public
outreach in that we go to the people on this evening rather than having
them come to us.
ISAN has
become more and more popular over the last few years, but this year’s
edition, scheduled for Saturday evening, March 8, would be extra special. The
San Francisco Sidewalk Astronomers, the originators of ISAN, wanted it to be in
part a memorial for one of their departed members, famous telescope maker and
astronomy popularizer John Dobson, who died on January 15 at age 98.
The Possum
Swamp Astronomical Society has been participating in ISAN for five years now, and sure didn't want to miss this one. Not
only was this to be a remembrance for a man we revered, ISAN is fun. Being freed from the logistics of
setting up a public outreach event allows us to focus on enjoying showing the
sky to the public. We just take our scopes to where the public will be and have
a good old-fashioned “happening.”
The place for
our 2014 ISAN would be the same as in previous years, the Eastern Shore Centre,
an open air shopping mall across Mobile Bay from the Swamp. The Centre has a nice central
square/fountain area perfect for setting up scopes. There are lights
aplenty, sure, but when you’re doing sidewalk astronomy you don’t let light
pollution get in the way; you go after the bright stuff. We got the go-ahead from Centre management for this
year’s ISAN edition, and kept our fingers and toes crossed regarding the weather
forecasts, which were mostly of the “partly cloudy” variety.
Saturday
afternoon, the sky was, surprisingly enough, almost solid blue. Time to get the
public outreach rig loaded. If you’ve followed this blog long, you know I’ve
struggled with “Which scope for the public?” for many a long year. I’ve finally
settled (for now) on two. The RV-6 Newtonian for my students/older kids/adults,
and a C8 for younguns/general audiences.
The C8 OTA
in question, "Boomer," a 1984 model that began life as a Super Polaris C8, rides on
the simplest mount I could find for her, a Synta AZ-4. That’s a one-armed,
non-computerized, uber-manual fork.
No batteries, no cables, no alignments. Yeah, no goto either, but I’ve found I don’t need that for public outreach. What Mom and Pop and Bud and Sis,
want to see is the Moon, a planet or two, and maybe a bright star. At some
public events, I’ll show off a bright deep sky object or three, but at the
heavily light polluted Eastern Shore Centre, that is purty much a waste of
time.
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| iPhone Moon... |
I was
feeling right good about our prospects for doing some sidewalk astronomy till
the phone rang Saturday afternoon. It was my old buddy Pat Rochford wondering
whether I was still planning to do ISAN. “Huh?” said I. “Cloudy over here,” said Pat.
Since it looked so good in the Swamp, I just couldn’t believe we wouldn’t get a
few sucker holes, so, come five, Dorothy and I hopped in the 4Runner and made the
half-hour trip east to the mall.
Since we
were onsite a little early, we spent a few minutes browsing the Barnes and
Noble bookstore. Unk admired a couple of graphic novels, but since the suckers
didn't have the one I wanted, Batman:
Night of Owls, I left empty-handed. It was now time to get set up, and D.
and I got everything from the truck to the fountain (which was shut down and
dry; apparently, they don’t turn it on till spring) in just two trips: scope,
dew shield, mount, tripod, eyepieces, etc., etc.
Looking up,
the sky certainly wasn’t pristine, but it was more than good enough to show off
Luna, who was shining bravely through a thin veil of clouds. As we were getting
Boomer ready to go, we were joined by fellow PSAS member, Taras, and his
10-inch discovery Dobsonian. Not long after, Pat and his 8-inch Dobbie and PSAS
President Martin and his Meade LX90 SCT showed up.
How’d it go?
Purty smooth. We didn't get many takers at first, but as early diners
began leaving the nearby Wintzell’s (local seafood) and California Dreaming (nice
chain eatery) restaurants, we were able to give lots of little families looks
at the Moon. Did we do anything different this time? Not really. As usual, I
operated the scope (“Hold on a second, Coach; let me make sure the Moon is
still in there.”) while Dorothy gave out kid-centric literature and stickers
courtesy of NASA/JPL.
Unlike all
too many Uncle Rod expeditions, there were neither minor hiccups nor major disasters
this time. The closest thing to a bummer was that Martin’s LX90’s electronics
had died the previous evening, but he was able to press on manually. All told, we probably showed
close to 100 folks the Moon and Jupiter on a night that was occasionally mostly
cloudy. Best of all? We had one hell of a lot of fun doing it.
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| Our set-ups with California Dreaming in the background... |
By 8 p.m.,
three things were evident: more clouds and thicker were on the way, it was
getting chilly, and most of our “customers,” the little families, were now beginning
to drift on home. Sounded like Big Switch time to Unk. I snapped a couple of
afocal shots of Luna with my iPhone and called it a night. Dorothy and I packed
up Boomer post haste and made a beeline for California Dreaming, where Unk
treated himself to a nice rib eye and multiple
pints of Blue Moon.
How Do You Video Redux…
Okay…where
was we? Oh, yeah…we’d mounted the Mallincam video camera on the telescope, hooked
the camera to the computer, and plugged the video output cable into the monitor
and DVR. What’s next? Getting goto aligned. I habitually do that with the
Xtreme, since the camera’s field is equivalent to that of a medium power eyepiece,
and is just about perfect for alignment accuracy. One super cool thing for
alignments? Most of the Mallincams will allow you to superimpose a set of
crosshairs on the screen. If you are controlling the camera with a computer,
that is as simple as checking a box in the control program.
To get
started, light off your monitor if you haven’t done so already and apply power
to the camera, plugging it into its battery or AC power source. It should be
obvious if the monitor is picking up video from the camera; it will go from
dark to a gray screen, maybe with a hot pixel or two in evidence. At any rate,
when you turn on the camera you should notice a change on the monitor.
If you are
using a PC, boot it now and light off the Mallincam control software before you
begin goto alignment. If this is the first time you’ve used the software, you
need to set it up, which involves telling it which serial com port you will be
using to communicate with the camera. To see the com port number the laptop’s USB
– serial cable has established, look in Windows Control Panel and Device
Manager. In the device “tree,” you will see an entry for “Com and LPT ports.”
Click that and the com port number will be revealed.
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| Original Mallincam software... |
When you’ve
got that number, go to the “Config” tab in the Mallincam program. If you are
not using the original M-cam software, but one of the newer softs like Miloslick,
the screen will be different from the one shown and talked about here, but you
should have a similar settings screen. If you are using the original software, please note that when you start it up for the first
time you will likely get an error telling you the program hasn't picked up a com port.
Just acknowledge that and go to Config.
Com port
entered in the Config screen, go to the “advanced” tab on the original Mallincam
software or a similar camera control screen on the newer program(s). One that
allows you to set exposure, gain, and other parameters.
When you first go to the Advanced tab, you'll see most items are grayed out and a yellow “light” in the upper left portion of the window is illuminated. There will also be a “safety” timer counting down from 3-minutes. This is to prevent crashes when some camera settings are changed. You can override this safety timer, but you should only do so if you really know what you are doing. Otherwise, wait 3- minutes.
After the timer has run out, you can change settings. At this time, all you will be interested in is short exposure and crosshairs. On the upper left, you’ll see a “Sense up” section. Set the pull-down menu there to 128x. That will give you exposures of approximately 2-seconds, which is enough to show plenty of stars, but not so long as to make star-centering and focusing a pain.
When you first go to the Advanced tab, you'll see most items are grayed out and a yellow “light” in the upper left portion of the window is illuminated. There will also be a “safety” timer counting down from 3-minutes. This is to prevent crashes when some camera settings are changed. You can override this safety timer, but you should only do so if you really know what you are doing. Otherwise, wait 3- minutes.
After the timer has run out, you can change settings. At this time, all you will be interested in is short exposure and crosshairs. On the upper left, you’ll see a “Sense up” section. Set the pull-down menu there to 128x. That will give you exposures of approximately 2-seconds, which is enough to show plenty of stars, but not so long as to make star-centering and focusing a pain.
At the
bottom left of the window is “Crosshairs.” Check the box there and, assuming the PC
is communicating properly with the camera, crosshairs will be drawn on the monitor.
You can also choose “crossbox” if you like—which puts a little box at the
junction of the crosshairs.
Once you’ve
got the above sussed, the rest of the goto alignment is purty much as per normal.
You’ll just be observing stars on the monitor rather than in an eyepiece. If
this if the first time you’ve used the camera with the scope or scope/reducer
combination, your focus will likely be WAY off, but you should still be able to
detect a bright alignment star. When you’ve centered the star in the crosshairs
of the telescope’s finder, look for a big out of focus disk on the screen.
Increase the monitor’s brightness contrast if necessary till you see it. Then,
begin adjusting focus until star one is as small as you can get it. When it is,
center it in the crosshairs with the scope hand control.
Center
however many other alignment stars your scope/mount requires. When the last one
is done, take a critical look at focus. At 128x and the default gain of the
camera (which will be on the high side), you should see plenty of dimmer stars
onscreen. Are they pinpoints? If not, touch up focus. This will get your focus
close, but maybe not quite dead on. There are two ways to get precise focus.
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| Advanced tab... |
One is to
use an aid like a Bahtinov mask. These focus masks, which go over the front
aperture of the telescope, are inexpensive to buy and simple to make. One will
produce a series of spikes around a bright star. Adjust focus until these
spikes are arranged as per the instructions that came with the mask. When
that’s done, focus should be right on. Just remember to remove the mask when
you are finished. Don't be like Unk, who invariably forgets that step and starts
cussing M13 for looking so fraking funky.
If you don’t
want to use a focus mask, salvation comes in the form of a bright globular
cluster. Most of the year a good one will be somewhere in the sky, and a glob’s
tiny stars are perfect for focusing. Going to one also provides a quick check
of the quality of your alignment. When the scope stops and the camera’s
exposures “catch up,” center the glob with the hand control if it’s not in the middle
of the screen and have a look. A bright Messier should be visible and showing a
few stars at 128x, but if it’s on the dim side, up the exposure to 7-seconds.
How you do
that will depend on which Mallincam you own. If it is an Xtreme or one of the
other cameras that allow computer control of long integrations, just select
7-seconds on the integration control about halfway down the window on the right
side. Other cameras may require you to set longer exposures with a wireless
remote or via toggle switches on the camera itself. Once you’ve selected
7-seconds, the Mallincam should begin doing repeating 7-second exposures.
At
7-seconds, a good globular will be bursting with stars. What you’ll do is
observe those stars, especially the ones close in toward the center. Twitch the
focus control a small amount, and then wait for another exposure to complete.
Right direction? Need to go the other way? Adjust focus in this fashion until
the tiny stars are as sharp as you can get ‘em. Given the small chip/large
pixel nature of deep sky video cams, good focus is important for good-looking
pictures.
Focus attained,
let’s stay on the glob for a bit while we set the camera up. To start, we’ll
mess with three adjustments: gain, gamma, and color balance. “Gain” is much like the ISO setting on a DSLR
or other digital camera. It determines the sensitivity of the chip. The higher the gain, the more sensitive to
light the camera will become. Alas, there ain't no such thing as a free lunch (TANSTAAFL), and images will become noisier as
gain goes higher. In addition, any light pollution present will be more
noticeable as a bright background in the video with higher gain settings. So what
should gain be? I am mostly after lots of detail and dim objects, so I
habitually run at “6.” My buddies who are more interested in pretty video are
typically at 3 or 4.
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| The bridge of the starship U.S.S. Possum Swamp... |
Let’s set gain. In the AGC section on the Advanced tab screen, click “Manual.” Then, enter the gain setting you want. Type the number
in the box next to “Manual;” don’t use the up/down controls. When you change
gain, the camera’s safety timer will engage. If you use up/down, each click
will require a 3-minute wait. Just type in the gain (I suggest 4, 5, or 6 to begin)
and you’ll only have to endure one 3-minute time-out.
Next is “gamma,” which is sorta like a
brightness adjustment. The control near the top of the screen has two settings,
.45 and 1. 1 will give a darker picture, .45 a brighter one. The way I work,
with relatively short exposures (28 seconds or less) on dim objects, .45 is
best for me. With a brighter object/longer exposure, “1” can make pictures look
better. I recommend beginning with .45 until you have a feel for the camera’s
settings and how they interact.
Finally, there’s
white balance. It’s not overly
important except on brighter objects, and especially nebulae. I leave it on
“ATW,” automatic white balance. If white balance is “wrong,” pictures can have
a pink or blue cast. If colors do not look right, select “Manual” and adjust the
red/blue controls.
Don’t have a
computer to control your Mallincam? Don’t want one? You can set all these
things (except long exposure integrations) with the buttons on the back of the Mallincam
or with a wired remote. Mashing the buttons causes menus to appear on the
monitor. I don’t like to work without a computer, so I am not an expert on these
“OSD” menus, but they've been easy enough for me to use the couple of times
I’ve resorted to them. You can find a good description of these menus in this .pdf document from U.S. Mallincam distributor
Jack Huerkamp’s website.
You’ll likely
find, as I did, that learning to use the Mallincam is a little like learning a
musical instrument. There are many settings and they can affect each other. It will
take some practice before you begin getting the images you want—but, believe me,
you will.
Next? You
get to work on the deep sky, of course. You start having fun. You’ll develop your own procedures, but this is how Unk does
it. After I am aligned and the basic camera settings are laid in, I fire up SkyTools or Deep Sky Planner on the laptop and have a look at my observing
list. I tend to work one constellation at a time rather than jumping around the
sky. Once I’ve identified the first object, I’ll look out of the EZ-up to make
sure the telescope is clear—of wandering people or other obstructions—and issue
the first goto command.
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| Focus target... |
When the scope
stops, I’ll usually up the long integration duration to either 14 or
28-seconds. Given my other settings, 14-seconds yields good images even under
less than perfect skies, and I will often leave the gain there all night. If I
am after the very faintest details and the sky will permit it, I might go to
28-seconds. I will usually only go longer than that if I am after a pretty a picture
and need good color saturation and image smoothness.
“How about
filters, Unk?” I used to preach against them, since most light pollution
reduction filters make longer exposures necessary and shift color balance.
Lately, though, I’ve been using a mild filter an Orion Skyglow Astrophotography Filter. It lets me do good work in bright skies
and doesn't change the color balance much. I frequently use it when I have to image
an object down in the Possum Swamp light dome. The Orion has worked well for
me, but it’s a wee bit expensive, and I suspect any mild filter—like a Lumicon Deep Sky, for example—would do as
well.
What else?
As I mentioned in the previous installment, I record my video on a DVR since I
like to view my results on the big screen TV, and sometimes process video in
the computer. The Orion StarShoot DVR’s screen is way small, so I use both a monitor and the recorder. I soon
discovered the Mallincams don’t have enough “drive” feed both a monitor and a recorder
at the same time using a splitter, however. Video quality suffers. I could use
a video amplifier, I reckon, but I owned a cheap solution already, an old
composite video switcher left over from the analog video/cable/TV days.
I center the
object on screen with the HC if necessary and evaluate it on the monitor. If it
doesn't require any changes to exposure or gain or somesuch, I mash the
switcher to send video to the DVR. I then push the button on the Orion DVR’s
wired remote, which turns on the recorder and begins recording. The StarShoot will
record an audio track from its built-in microphone, so I speak my notes into
the DVR as I “tape” the video. The Orion also records a time/date
display in the upper right hand corner, which often comes in handy. Pretty
dadgum slick, all said.
One question
I’m sometimes asked has to do with the Mallincams’ ability to output S-VHS
video, Super VHS video, which is somewhat higher in quality than normal
composite video. My experience is that if you are focused on broadcasting on
Night Skies Network or doing heavy computer processing of images, S-VHS can
help a little. For just
viewing/recording video? Not so much. I never use it.
And then? On
to the nextun. If I am moving to a radically different part of the sky, I shine
a red light on the scope and watch for cable wrap. With all them wires going to
the mount and camera, that is always a distinct possibility. Anyhoo, I just
keep going, as I did back in the days of The Herschel Project, recording 50 or
100 or more objects over the course of an evening. That is not too many objects
by any means, not when you have the ability to give each one all the time it
needs at home on the TV or computer.
What else is
there to the video game? You may occasionally want to improve your videos by
processing them with a computer program. Or you may want to make still pictures
from ‘em. All that is another long story for another Sunday, muchachos. Now?
The night is old, the video is in the can, and Chaos Manor South’s warm den and
omnipresent bottle of Rebel Yell are calling.
Nota Bene: I’m sure all y'all have been watching the big show, but remember to let your non-astronomer friends know
about the new Cosmos series hosted by
Dr. Neil deGrasse Tyson. Dorothy and I loved it; it was clear Tyson’s heart was really in
it and he did a superb job. Good stuff.
Next Time: Unk and the BCH...
