ASTRO: First Light Tests of FLI Dream Machine on Stinger 450 classical cassegrain at f/7.1

there was a Dream Machine up on Astromart two weeks ago and I bought it.
Yesterday it arrived and I was fortunate enough to have clear skies for the
testing. But first light tests are never made under good conditions and last
night had its downside: it was terrible seeing out he really bad, in the
range of 6 to 7 arc-sec in my focus shot measurements. No matter how hard I
tried I simply could not get tight stars last night. Additionally the
guiding was jumpy too: all hallmarks of poor seeing. A quick look at the Jet
steam map showed it to be the source of the problem: it was headed straight
down the west coast, never good for seeing.

Still with clear skies that wasn't going to stop me from making a few test
exposures.

I had a Dream Machine from 2002 until late 2004 and liked many things about
it. The key thing is the QE and sensitivity of the TK1024 imager with those
24 x 24 micron pixels.

It is a reasonable sized sensor at nearly 1 inch per side but has only 1
megapixel of really large light-sucking pixels.

I recently completed a marathon 34 hour exposure set for Jones 1 and using
exactly the same equipment but changing only the camera I took three half
hour shots of Jones 1 in Halpha. I compared that to the most recent Halpha
shots I took using the CM10 Maxcam on the same optical system including 3nm
Cust Sci filters (my favorite Halpha filter by far). It is hard to compare
the two cameras this way, what with the radically different image scales
(0.42 versus 1.47 arc-sec/pixel), still it was useful to try the DM in the
socket where the CM10 was residing until last night.

Additionally I took a single 30 minute exposure in the Crab and finshed off
the evening with a set of four exposures of a half hour in IC410

The camera is really nice in that it develops a lot of signal fast. The
image scale with the 24x24 micron pixels used at f/7.1 in the 18" classical
cassegrain worked out to be 1.47 arc-sec/pixel which is a bit coarse in my
thinking but perhaps is a good match my bad seeing last night.

other than a colum defect on the right hand side of the array the sensor is
a really good one.

here are the first light tests including the jones 1 exposure comparison

http://www.narrowbandimaging.com/dre...light_page.htm

Easy to see why they call it a Dream Machine. Nice shots. That crab was
especially cool. Clear Skyz, LA

"Richard Crisp" wrote in message
. ..
there was a Dream Machine up on Astromart two weeks ago and I bought it.
Yesterday it arrived and I was fortunate enough to have clear skies for
the
testing. But first light tests are never made under good conditions and
last
night had its downside: it was terrible seeing out he really bad, in
the
range of 6 to 7 arc-sec in my focus shot measurements. No matter how hard
I
tried I simply could not get tight stars last night. Additionally the
guiding was jumpy too: all hallmarks of poor seeing. A quick look at the
Jet
steam map showed it to be the source of the problem: it was headed
straight
down the west coast, never good for seeing.

Still with clear skies that wasn't going to stop me from making a few test
exposures.

I had a Dream Machine from 2002 until late 2004 and liked many things
about
it. The key thing is the QE and sensitivity of the TK1024 imager with
those
24 x 24 micron pixels.

It is a reasonable sized sensor at nearly 1 inch per side but has only 1
megapixel of really large light-sucking pixels.

I recently completed a marathon 34 hour exposure set for Jones 1 and using
exactly the same equipment but changing only the camera I took three half
hour shots of Jones 1 in Halpha. I compared that to the most recent Halpha
shots I took using the CM10 Maxcam on the same optical system including
3nm
Cust Sci filters (my favorite Halpha filter by far). It is hard to compare
the two cameras this way, what with the radically different image scales
(0.42 versus 1.47 arc-sec/pixel), still it was useful to try the DM in the
socket where the CM10 was residing until last night.

Additionally I took a single 30 minute exposure in the Crab and finshed
off
the evening with a set of four exposures of a half hour in IC410

The camera is really nice in that it develops a lot of signal fast. The
image scale with the 24x24 micron pixels used at f/7.1 in the 18"
classical
cassegrain worked out to be 1.47 arc-sec/pixel which is a bit coarse in my
thinking but perhaps is a good match my bad seeing last night.

other than a colum defect on the right hand side of the array the sensor
is
a really good one.

here are the first light tests including the jones 1 exposure comparison

http://www.narrowbandimaging.com/dre...light_page.htm

I owned one before back in 2002 to 2004

here are various emission line images I took with my old one used on various
scopes

here are a number of early eline shots I took starting in 2002 using the DM
on various scopes:

http://www.narrowbandimaging.com/ngc...ssion_page.htm

http://www.narrowbandimaging.com/ngc...color_page.htm

http://www.narrowbandimaging.com/ngc...la_bw_page.htm

http://www.narrowbandimaging.com/B33_ha_page.htm

http://antwrp.gsfc.nasa.gov/apod/ap030908.html

http://www.narrowbandimaging.com/m27...la_ha_page.htm

http://www.narrowbandimaging.com/m27...hao3b_page.htm

http://www.narrowbandimaging.com/ngc...close_page.htm

http://www.narrowbandimaging.com/trapezium_sii_page.htm

http://www.narrowbandimaging.com/ngc...2hao3_page.htm

http://www.narrowbandimaging.com/ngc...lican_page.htm

http://www.narrowbandimaging.com/ngc...ornia_page.htm

http://www.narrowbandimaging.com/vei...field_page.htm

http://www.narrowbandimaging.com/ic1805_s2hao3_page.htm

http://www.narrowbandimaging.com/ic1396_S2HaO3_page.htm

http://www.narrowbandimaging.com/ic405_Ha_page.htm

http://www.narrowbandimaging.com/ngc...sette_page.htm

http://www.narrowbandimaging.com/ic434_flame_page.htm

http://www.narrowbandimaging.com/gum1_HaS2_page.htm

http://www.narrowbandimaging.com/ngc...ssion_page.htm

http://www.narrowbandimaging.com/ngc...c5068_page.htm

http://www.narrowbandimaging.com/m1_...ha_n2_page.htm

http://www.narrowbandimaging.com/m1_...2HaO3_page.htm

http://www.narrowbandimaging.com/m1_...N2_ha_page.htm

http://www.narrowbandimaging.com/ngc...la_ha_page.htm

http://www.narrowbandimaging.com/ngc2359_thor_page.htm

http://www.narrowbandimaging.com/ngc...2hao3_page.htm

http://www.narrowbandimaging.com/pickering1_page.htm

http://www.narrowbandimaging.com/van...g_142_page.htm

http://www.narrowbandimaging.com/sha...2_101_page.htm

http://www.narrowbandimaging.com/ic5..._neck_page.htm

http://www.narrowbandimaging.com/ic5...color_page.htm



"LA" wrote in message
news:ZFKbh.25329$oP6.13545@trnddc03...
Easy to see why they call it a Dream Machine. Nice shots. That crab was
especially cool. Clear Skyz, LA

"Richard Crisp" wrote in message
. ..
there was a Dream Machine up on Astromart two weeks ago and I bought it.
Yesterday it arrived and I was fortunate enough to have clear skies for
the
testing. But first light tests are never made under good conditions and
last
night had its downside: it was terrible seeing out he really bad, in
the
range of 6 to 7 arc-sec in my focus shot measurements. No matter how hard
I
tried I simply could not get tight stars last night. Additionally the
guiding was jumpy too: all hallmarks of poor seeing. A quick look at the
Jet
steam map showed it to be the source of the problem: it was headed
straight
down the west coast, never good for seeing.

Still with clear skies that wasn't going to stop me from making a few
test
exposures.

I had a Dream Machine from 2002 until late 2004 and liked many things
about
it. The key thing is the QE and sensitivity of the TK1024 imager with
those
24 x 24 micron pixels.

It is a reasonable sized sensor at nearly 1 inch per side but has only 1
megapixel of really large light-sucking pixels.

I recently completed a marathon 34 hour exposure set for Jones 1 and
using
exactly the same equipment but changing only the camera I took three half
hour shots of Jones 1 in Halpha. I compared that to the most recent
Halpha
shots I took using the CM10 Maxcam on the same optical system including
3nm
Cust Sci filters (my favorite Halpha filter by far). It is hard to
compare
the two cameras this way, what with the radically different image scales
(0.42 versus 1.47 arc-sec/pixel), still it was useful to try the DM in
the
socket where the CM10 was residing until last night.

Additionally I took a single 30 minute exposure in the Crab and finshed
off
the evening with a set of four exposures of a half hour in IC410

The camera is really nice in that it develops a lot of signal fast. The
image scale with the 24x24 micron pixels used at f/7.1 in the 18"
classical
cassegrain worked out to be 1.47 arc-sec/pixel which is a bit coarse in
my
thinking but perhaps is a good match my bad seeing last night.

other than a colum defect on the right hand side of the array the sensor
is
a really good one.

here are the first light tests including the jones 1 exposure comparison

http://www.narrowbandimaging.com/dre...light_page.htm

When seeing settles down can't that 18" work at f/12.6 or something like
that? That would give you about a 0.8 arc second pixel, and longer
exposure times of course.

I almost didn't recognize M1. That one filament really stands out from
the rest. I didn't expect that.

I have your same seeing here. Temp dropped from mid 30s to zero in a
few hours and seeing dropped just as far. I didn't even try last night
it was so bad. Normally my focus range is about 75 microsteps of the
robo focuser. But last night I could move 400 and not see any change.
I had to go out and be sure it was not slipping. It wasn't. So I
closed up shop and went to bed early.

After that long exposure time on Jones 1 I sort of expected a back lit
chip in your future. Unfortunately, my astro budget has been pretty
well blown for the next couple years just setting up what I have now. I
keep lusting after the newer stuff coming down the tech trail but I'll
have to settle for just looking and wishing for now! Still where I am
now is so far ahead of my old film setup I'll never run out of targets.

Have fun with your "new" toy.

Rick


Richard Crisp wrote:
there was a Dream Machine up on Astromart two weeks ago and I bought it.
Yesterday it arrived and I was fortunate enough to have clear skies for the
testing. But first light tests are never made under good conditions and last
night had its downside: it was terrible seeing out he really bad, in the
range of 6 to 7 arc-sec in my focus shot measurements. No matter how hard I
tried I simply could not get tight stars last night. Additionally the
guiding was jumpy too: all hallmarks of poor seeing. A quick look at the Jet
steam map showed it to be the source of the problem: it was headed straight
down the west coast, never good for seeing.

Still with clear skies that wasn't going to stop me from making a few test
exposures.

I had a Dream Machine from 2002 until late 2004 and liked many things about
it. The key thing is the QE and sensitivity of the TK1024 imager with those
24 x 24 micron pixels.

It is a reasonable sized sensor at nearly 1 inch per side but has only 1
megapixel of really large light-sucking pixels.

I recently completed a marathon 34 hour exposure set for Jones 1 and using
exactly the same equipment but changing only the camera I took three half
hour shots of Jones 1 in Halpha. I compared that to the most recent Halpha
shots I took using the CM10 Maxcam on the same optical system including 3nm
Cust Sci filters (my favorite Halpha filter by far). It is hard to compare
the two cameras this way, what with the radically different image scales
(0.42 versus 1.47 arc-sec/pixel), still it was useful to try the DM in the
socket where the CM10 was residing until last night.

Additionally I took a single 30 minute exposure in the Crab and finshed off
the evening with a set of four exposures of a half hour in IC410

The camera is really nice in that it develops a lot of signal fast. The
image scale with the 24x24 micron pixels used at f/7.1 in the 18" classical
cassegrain worked out to be 1.47 arc-sec/pixel which is a bit coarse in my
thinking but perhaps is a good match my bad seeing last night.

other than a colum defect on the right hand side of the array the sensor is
a really good one.

here are the first light tests including the jones 1 exposure comparison

http://www.narrowbandimaging.com/dre...light_page.htm

well Rick, I have had a back illuminated chip in my past too: this is the
third Dream Machine I have owned and I am going to try hard to not let this
one slip between my fingers like I did the other two :-)

When I first worked with Optical Mechanics to spec-out the mirror set, it
was done with the TK1024 sensor in mind. I had been using it successfully at
f/12.46 on my C14 so I wanted to goose it up a bit in focal length to get
into the 0.8 range as you suggested and we settled on f/12.6

I had an alternate configuration in mind which was an f/4.2 newtonian with
corrector using the KAF3200ME sensor in the Maxcam. That would give me 0.73
arc-sec/pixel versus the 0.86 ASP I get at 5760mm (f/12.6)

So in due time I plan to deploy it that way and will probably configure the
beam splitter/AO7 arrangement as I did earlier with the 6303 camera and have
done in the past on the C14 with the old Dream Machine.

http://www.narrowbandimaging.com/dic...itter_page.htm

http://www.narrowbandimaging.com/cam...r_c14_page.htm

http://www.narrowbandimaging.com/ima...nstruments.jpg

What I plan to do initially once I stop playing with it is to compare it
used at f/12.6 (0.86 ASP) to the Maxcam used at f/7.1 but binned 2x2 (0.84
ASP). I want to compare exposure times and depth of exposure to see if
there's a difference greater than the ratio of the pixel areas normalized to
image scale. That should be the difference in the Quantum Efficiencies of
the two detectors with the TK1024 at the wavelengths in question

In looking at the QE curves of the two sensors (attached) the key
differences are in favor of the TK1024 at the extreme ends of the spectrum:
the blue end and the NIR end. In the mid ranges the 3200me beats the TK1024.

Overall the area under the curve is a reasonable indicator for the overall
sensitivity of the sensor over the wavelength ranges of interest.




"Rick Johnson" wrote in message
...
When seeing settles down can't that 18" work at f/12.6 or something like
that? That would give you about a 0.8 arc second pixel, and longer
exposure times of course.

I almost didn't recognize M1. That one filament really stands out from
the rest. I didn't expect that.

I have your same seeing here. Temp dropped from mid 30s to zero in a
few hours and seeing dropped just as far. I didn't even try last night
it was so bad. Normally my focus range is about 75 microsteps of the
robo focuser. But last night I could move 400 and not see any change.
I had to go out and be sure it was not slipping. It wasn't. So I
closed up shop and went to bed early.

After that long exposure time on Jones 1 I sort of expected a back lit
chip in your future. Unfortunately, my astro budget has been pretty
well blown for the next couple years just setting up what I have now. I
keep lusting after the newer stuff coming down the tech trail but I'll
have to settle for just looking and wishing for now! Still where I am
now is so far ahead of my old film setup I'll never run out of targets.

Have fun with your "new" toy.

Rick


Richard Crisp wrote:
there was a Dream Machine up on Astromart two weeks ago and I bought it.
Yesterday it arrived and I was fortunate enough to have clear skies for
the
testing. But first light tests are never made under good conditions and
last
night had its downside: it was terrible seeing out he really bad, in
the
range of 6 to 7 arc-sec in my focus shot measurements. No matter how hard
I
tried I simply could not get tight stars last night. Additionally the
guiding was jumpy too: all hallmarks of poor seeing. A quick look at the
Jet
steam map showed it to be the source of the problem: it was headed
straight
down the west coast, never good for seeing.

Still with clear skies that wasn't going to stop me from making a few
test
exposures.

I had a Dream Machine from 2002 until late 2004 and liked many things
about
it. The key thing is the QE and sensitivity of the TK1024 imager with
those
24 x 24 micron pixels.

It is a reasonable sized sensor at nearly 1 inch per side but has only 1
megapixel of really large light-sucking pixels.

I recently completed a marathon 34 hour exposure set for Jones 1 and
using
exactly the same equipment but changing only the camera I took three half
hour shots of Jones 1 in Halpha. I compared that to the most recent
Halpha
shots I took using the CM10 Maxcam on the same optical system including
3nm
Cust Sci filters (my favorite Halpha filter by far). It is hard to
compare
the two cameras this way, what with the radically different image scales
(0.42 versus 1.47 arc-sec/pixel), still it was useful to try the DM in
the
socket where the CM10 was residing until last night.

Additionally I took a single 30 minute exposure in the Crab and finshed
off
the evening with a set of four exposures of a half hour in IC410

The camera is really nice in that it develops a lot of signal fast. The
image scale with the 24x24 micron pixels used at f/7.1 in the 18"
classical
cassegrain worked out to be 1.47 arc-sec/pixel which is a bit coarse in
my
thinking but perhaps is a good match my bad seeing last night.

other than a colum defect on the right hand side of the array the sensor
is
a really good one.

here are the first light tests including the jones 1 exposure comparison

http://www.narrowbandimaging.com/dre...light_page.htm

there's also another point that is actually the most important one: the main
reason for the DM camera is to get the 24x24 micron pixels. that's just a
better match to my seeing at the two focal lengths I have available with the
18": 3366mm (f/7.1, 1.41ASP) and 5760mm (f/12.6, 0.86 ASP)

Being a thinned back illluminated type helps the QE due to fill factor
considerations across the board, the thinning really pays off on the blue
end. The red end can actually be hurt by it.

The problem is a balancing act: make the chip thin enough so that the blue
light makes it deep enough into the silicon to be converted and collected
with high efficiency, but not be too thin so that the red light passes all
the way through the silicon without interacting with the lattice:

I have attached a curve that shows the photon absorption depth into silicon
as a function of wavelength tha shows the absorbption coefficient as a
function of wavelength. That shows the problem pretty well.

the second illustration attached shows how the fill factor is improved by
using backside illumination. Essentially the frontside wiring of the gates
no longer interferes with the light collection in the substrate. Kodak gets
around the problem by using Indium Tin Oxide (ITO) as the conductor on the
frontside to fabricate the gates from. That happens to be transparent to
visible light but is an exotic material and has incompatibilities with other
semiconductor fabrication processes. Butthe high voltages needed for clocks
are more or less incompatible with logic processes too. That's why CMOS
sensors make so much sense because you can integrate the analog and digital
signal processing right on the same chip as the image sensor function and
make it all very cheap that way.

it is all quite interesting to me but on the other hand all I have done in
the past 30 years is to work in the semiconductor industry :-)


"Rick Johnson" wrote in message
...
When seeing settles down can't that 18" work at f/12.6 or something like
that? That would give you about a 0.8 arc second pixel, and longer
exposure times of course.

I almost didn't recognize M1. That one filament really stands out from
the rest. I didn't expect that.

I have your same seeing here. Temp dropped from mid 30s to zero in a
few hours and seeing dropped just as far. I didn't even try last night
it was so bad. Normally my focus range is about 75 microsteps of the
robo focuser. But last night I could move 400 and not see any change.
I had to go out and be sure it was not slipping. It wasn't. So I
closed up shop and went to bed early.

After that long exposure time on Jones 1 I sort of expected a back lit
chip in your future. Unfortunately, my astro budget has been pretty
well blown for the next couple years just setting up what I have now. I
keep lusting after the newer stuff coming down the tech trail but I'll
have to settle for just looking and wishing for now! Still where I am
now is so far ahead of my old film setup I'll never run out of targets.

Have fun with your "new" toy.

Rick


Richard Crisp wrote:
there was a Dream Machine up on Astromart two weeks ago and I bought it.
Yesterday it arrived and I was fortunate enough to have clear skies for
the
testing. But first light tests are never made under good conditions and
last
night had its downside: it was terrible seeing out he really bad, in
the
range of 6 to 7 arc-sec in my focus shot measurements. No matter how hard
I
tried I simply could not get tight stars last night. Additionally the
guiding was jumpy too: all hallmarks of poor seeing. A quick look at the
Jet
steam map showed it to be the source of the problem: it was headed
straight
down the west coast, never good for seeing.

Still with clear skies that wasn't going to stop me from making a few
test
exposures.

I had a Dream Machine from 2002 until late 2004 and liked many things
about
it. The key thing is the QE and sensitivity of the TK1024 imager with
those
24 x 24 micron pixels.

It is a reasonable sized sensor at nearly 1 inch per side but has only 1
megapixel of really large light-sucking pixels.

I recently completed a marathon 34 hour exposure set for Jones 1 and
using
exactly the same equipment but changing only the camera I took three half
hour shots of Jones 1 in Halpha. I compared that to the most recent
Halpha
shots I took using the CM10 Maxcam on the same optical system including
3nm
Cust Sci filters (my favorite Halpha filter by far). It is hard to
compare
the two cameras this way, what with the radically different image scales
(0.42 versus 1.47 arc-sec/pixel), still it was useful to try the DM in
the
socket where the CM10 was residing until last night.

Additionally I took a single 30 minute exposure in the Crab and finshed
off
the evening with a set of four exposures of a half hour in IC410

The camera is really nice in that it develops a lot of signal fast. The
image scale with the 24x24 micron pixels used at f/7.1 in the 18"
classical
cassegrain worked out to be 1.47 arc-sec/pixel which is a bit coarse in
my
thinking but perhaps is a good match my bad seeing last night.

other than a colum defect on the right hand side of the array the sensor
is
a really good one.

here are the first light tests including the jones 1 exposure comparison

http://www.narrowbandimaging.com/dre...light_page.htm

I hadn't known about the Red problem with such chips but then I don't
work in the chip industry -- poker, potato, cow or silicon.

In any case, being retired, my budget for cameras is spent for a while.

Perfect night here, except for the moon, seeing is even great. One
minor problem. Two hours ago the power went out and I'm running on a
backup generator. Observatory isn't on it so if the power don't come on
I'll have to close up manually. At near zero that will be a cold job.
Seems a wide area outage. Not sure what happened. Anyway I was 28
minutes into an Halpha frame that would have gone only 2 longer and that
was the first frame of the night. So I got nothing for my efforts. Bummer.

Rick


Richard Crisp wrote:
there's also another point that is actually the most important one: the main
reason for the DM camera is to get the 24x24 micron pixels. that's just a
better match to my seeing at the two focal lengths I have available with the
18": 3366mm (f/7.1, 1.41ASP) and 5760mm (f/12.6, 0.86 ASP)

Being a thinned back illluminated type helps the QE due to fill factor
considerations across the board, the thinning really pays off on the blue
end. The red end can actually be hurt by it.

The problem is a balancing act: make the chip thin enough so that the blue
light makes it deep enough into the silicon to be converted and collected
with high efficiency, but not be too thin so that the red light passes all
the way through the silicon without interacting with the lattice:

I have attached a curve that shows the photon absorption depth into silicon
as a function of wavelength tha shows the absorbption coefficient as a
function of wavelength. That shows the problem pretty well.

the second illustration attached shows how the fill factor is improved by
using backside illumination. Essentially the frontside wiring of the gates
no longer interferes with the light collection in the substrate. Kodak gets
around the problem by using Indium Tin Oxide (ITO) as the conductor on the
frontside to fabricate the gates from. That happens to be transparent to
visible light but is an exotic material and has incompatibilities with other
semiconductor fabrication processes. Butthe high voltages needed for clocks
are more or less incompatible with logic processes too. That's why CMOS
sensors make so much sense because you can integrate the analog and digital
signal processing right on the same chip as the image sensor function and
make it all very cheap that way.

it is all quite interesting to me but on the other hand all I have done in
the past 30 years is to work in the semiconductor industry :-)


"Rick Johnson" wrote in message
...

When seeing settles down can't that 18" work at f/12.6 or something like
that? That would give you about a 0.8 arc second pixel, and longer
exposure times of course.

I almost didn't recognize M1. That one filament really stands out from
the rest. I didn't expect that.

I have your same seeing here. Temp dropped from mid 30s to zero in a
few hours and seeing dropped just as far. I didn't even try last night
it was so bad. Normally my focus range is about 75 microsteps of the
robo focuser. But last night I could move 400 and not see any change.
I had to go out and be sure it was not slipping. It wasn't. So I
closed up shop and went to bed early.

After that long exposure time on Jones 1 I sort of expected a back lit
chip in your future. Unfortunately, my astro budget has been pretty
well blown for the next couple years just setting up what I have now. I
keep lusting after the newer stuff coming down the tech trail but I'll
have to settle for just looking and wishing for now! Still where I am
now is so far ahead of my old film setup I'll never run out of targets.

Have fun with your "new" toy.

Rick


Richard Crisp wrote:

there was a Dream Machine up on Astromart two weeks ago and I bought it.
Yesterday it arrived and I was fortunate enough to have clear skies for
the
testing. But first light tests are never made under good conditions and
last
night had its downside: it was terrible seeing out he really bad, in
the
range of 6 to 7 arc-sec in my focus shot measurements. No matter how hard
I
tried I simply could not get tight stars last night. Additionally the
guiding was jumpy too: all hallmarks of poor seeing. A quick look at the
Jet
steam map showed it to be the source of the problem: it was headed
straight
down the west coast, never good for seeing.

Still with clear skies that wasn't going to stop me from making a few
test
exposures.

I had a Dream Machine from 2002 until late 2004 and liked many things
about
it. The key thing is the QE and sensitivity of the TK1024 imager with
those
24 x 24 micron pixels.

It is a reasonable sized sensor at nearly 1 inch per side but has only 1
megapixel of really large light-sucking pixels.

I recently completed a marathon 34 hour exposure set for Jones 1 and
using
exactly the same equipment but changing only the camera I took three half
hour shots of Jones 1 in Halpha. I compared that to the most recent
Halpha
shots I took using the CM10 Maxcam on the same optical system including
3nm
Cust Sci filters (my favorite Halpha filter by far). It is hard to
compare
the two cameras this way, what with the radically different image scales
(0.42 versus 1.47 arc-sec/pixel), still it was useful to try the DM in
the
socket where the CM10 was residing until last night.

Additionally I took a single 30 minute exposure in the Crab and finshed
off
the evening with a set of four exposures of a half hour in IC410

The camera is really nice in that it develops a lot of signal fast. The
image scale with the 24x24 micron pixels used at f/7.1 in the 18"
classical
cassegrain worked out to be 1.47 arc-sec/pixel which is a bit coarse in
my
thinking but perhaps is a good match my bad seeing last night.

other than a colum defect on the right hand side of the array the sensor
is
a really good one.

here are the first light tests including the jones 1 exposure comparison

http://www.narrowbandimaging.com/dre...light_page.htm