From: Mark Gaffney <markgaffney@mac.com>
Date: June 28, 2008 7:07:18 PM MDT
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Re: Flea 2 colour cameras..
Thanks for the insight Tim, I`m yet to try auto-guiding which I hope to do initially with a GPUSB device running through Astro IIDC & a Unibrain Fire-i webcam. Milton says I should be able to track stars down to magnitude 5 or 6. I plan to buy a small guidescope before the end of the year & use my IS 21A F04.AS camera to take photos. I did look at a Lumicon Easy Guider for my big scope, a C10-NGT but have decided to try a guide scope first. The interest in the Easy Guider was because of flexure worries. I`m still a bit unsure about the process, either with the guide star 180 degrees from the object of interest with the EG or in more direct line of sight with the guidescope. Polar alignment has been a problem for me too. I`m leaving the 10" out under a tarp at present hopefully P/aligned. I`ll have to check it by drift aligning when I have some sort of reticle(the one in Astro IIDC looks like the first candidate). My firewire port is in need of repairs at present probably due to not using a repeater on my long cable.I`m finding with the C10-NGT it`s rather difficult discerning alignment stars from the rich field of view( they`re only slightly brighter than the other stars around Crux for instance?)& I`ve lost the 2 most obvious alignment stars behind trees this time of year.(Canopus & Sirius) Buying the Flea 2 is an "if" I manage to get a credit advance on my main credit card early next year?! I seem to be able to find new Astronomy items to buy without any trouble at all, you seem to be in a similar situation! Mark.
On 29/06/2008, at 10:08 AM, Tim wrote:
Mark:
I sometimes use the guiding chip with the SBIG, but it's a real pain
to find guide stars, unless you're shooting at a pretty short f/ratio.
Rotators help, I suppose, but they're out of my budget. I have
TheSky6 on my HP laptop, and it displays the camera and guiding chip
field, which makes it easier to figure out which way to orient the
camera, but I seem to always rotate the wrong way searching! Once I
find the guide star, though, it tracks well. I find I have to start
with the densest filter I'm going to shoot with. It's no fun to take a
couple of exposures in Clear, and find the tracking fails with the
filter cutting the light.
I prefer a guide scope and one of the Fleas with Astro IIDC doing the
guiding. Very fast getting going. But flexure seems to pop up
everywhere! I can't believe how many screws I've tightened chasing
down culprits.
I also bought the AO-7 with my ST2000, and it works very well except
that you can't use a focal reducer and reach focus with it on an SCT,
and the image scale is too big without one.
The SBIG camera works very well, but it's one of the heavier ones
available now. I hate taking it in the field. I used to have a
Starlight Xpress HX516, and the only gripe I had about it was that the
cables were very stiff, especially if it was cold.
I'm getting really lazy - I just put a second Robofocus on my Megrez 80!
Equinox 6 doesn't control the cameras anymore. You need "Equinox
Image" for that. But it works very well for that.
-Tim.
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
Hi Tim, Milton`s already put me onto the Mogg website. I`ll have to
look into the focal reducer. Do you use the autoguide facility on your
SBIG camera at all & what do you use for processing with it? I priced
the ST 2000XCM some months ago (the colour version of yours) & it`s
well out of my price rang at $3825 Australian dollars. I understand
Equinox 6 can be used to control it? Mark.
On 29/06/2008, at 2:31 AM, Tim wrote:
Hi Mark:
Steve Mogg makes all kinds of adapters, and is in your neck of the
woods: http://webcaddy.com.au/astro/adapter.htm
I have one of his c-mount/1 1/4" adapters that I use on one of my
fleas, plus the focal reducer that screws into the filter threads.
His adapters are made of a black plastic material - forget what it is.
They work fine for these small, lightweight cameras. I also ordered
adapters for my Nikon lenses to mate up with my DSI, and these are too
easily deformed when you tighten them enough to keep things from
shifting under their own weight on the scope. And you also have to be
wary of the threads stripping.
But again, the webcam and c-mount adapters are fine.
-Tim.
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@>
wrote:
Hi Tim, That`s interesting, I`ll have to decide myself what I want to
use the camera for (planetary or DSO) when I`m able to afford one.
I`ve ordered a Lumicon C-mount to 1.25 nosepiece at only $24.95 USD
from Telescopes.com, the postage turned out to be a bit of a problem
to Australia at $44.97 USD! I had a bit of a search & found 2 places
selling nosepieces without going too far into Google, the other was
in
England(haven`t heard back from them). I have Point Grey bookmarked &
I understand there`s a Sony 1/2" B/W or colour version of the Flea 2
at 1392x 1032 pixels (15fps) & a Sony 1/1.8" B/W or colour 1624x 1224
pixel job(15fps). They`re $995 USD & $1495 respectively plus $100 USD
each for the obligatory Development kit. Mark.
On 29/06/2008, at 12:35 AM, Tim wrote:
Hi Mark:
I have both the flea 640x480 color and the flea2 1032x776 color
camera. Depending on what I'm most interested in, I might guide
with
one and image with the other.
I think where the smaller-pixel camera shines is on planetary
imaging,
because the ROI feature allows you to crop around the planet an
get to
high frame rates while still giving you the chip real estate to
aid in
centering the planet. It also allows use of lower power barlows to
get the same pixel scales as cameras with larger chips. And of
course, for planetary imaging, the pixel size is less important than
the image scale.
So, neither of my Fleas can quite replace the other. Currently, I'm
fiddling with using the flea as a wide angle finder with an 11mm
c-mount lens on it, and the flea2 is on my C 9.25" with a meade f
6.3
FR for guiding, while my SBIG ST2000XM is on my Megrez 80 for
imaging.
I'm still fine tuning the polar alignment and have just eliminated
one
more source of flexure in the system, but following Milton's
suggestion for the Fleas, I have a 2" nebula filter in front of the
SBIG, and I'm imaging 13th magnitude galaxies from my home just 7
miles from downtown Los Angeles. ;oD
I haven't been to the Pt Grey website in a while. But I thought
they
added 1/2" ccd models to the Flea2 line? Mine both have 1/3" chips.
-Tim.
--- In Astro_IIDC@yahoogroups.com, Milton Aupperle <milton@> wrote:
Hi Mark;
On 22-Jun-08, at 1:03 PM, Mark Gaffney wrote:
Hi Milton, I was wondering if you`ve had a chance to use the 1032x
776 version of the
colour Flea 2 camera.
Yes. I have a picture I took of M67 with it
http://www.outcastsoft.com/AstroImages/M67_20080307_MJA.jpg
I still prefer a CCD with larger pixels though.
I was thinking of the possibility of buying one of these early
next
year. I
notice the pixel value on the higher resolution model drops to
4.65x 4.65 micron pixels
compared to 7.4x 7.4 on the 640x 480 model.
You lose a 250% of the light gathering sensitivity with the pixel
size decrease too. So with 4.65 micron pixels you need 2.5 minute
exposure times to capture what a 1 minute exposure with a 7.4
micron
pixels can capture.
It`s an extra $100 USD for this model & Point
Grey also tack on $100 for a Development kit which has a IEEE 1394
b-a cable amongst
other things. I understand they`re transitioning away from the
Flea
camera now?
Yes the Flea2 use somewhat different electronics and are support
FireWire 800. Physically they are the same size.
I`m told PG
don`t sell nosepieces so I`m hoping one from Imaging Source will
do
the job.
It will. The noise piece uses a standard C or CS mount thread and
you
can get them all over the place. It's just a "C mount to M1.25"
adapter.
With the
Unibrain Fire-i camera in the meantime, I was thinking of buying
one of these nosepieces &
widening the opening to accomodate the C-mount thread (as Jim
Chung
did with a penknife I
understand).
The problem there is making sure it's perpendicular to the CCD and
that the lens mount here is an M10x0.5 or M12x0.5.
I`m thinking at the moment I`ll go with a $215 Orion Short Tube 80
Guide
scope to begin with & leave the Lumicon Easy Guider OAG til later
perhaps.
Just make sure your not putting too much weight on your mount. As I
said in another thread, you should try to keep the weight of
Optical
Tubes, cameras, weights, finders, cables to around 50 to 80% of the
mounts rated capacity. Go over that and it won't track well at all.
HTH..
Milton J. Aupperle
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