gold price: [SBIG] Re: ST-7 disappointing

Minggu, 24 Februari 2008

[SBIG] Re: ST-7 disappointing

Hi Bill,

Your initial reaction to your new camera is similar to mine when I
received my ST-10 three months ago.

Let's put it straight, in my opinion this is not a camera for
planets or Lunar imaging. I tried it and discovered that you cannot
go to those .005 sec exposures which we use with the DSI. If I'm
wrong may someone correct me.

I suggest using your DSI for planetary and Lunar imaging, that is
what I intend to do.

If someone uses these cameras for planetary or lunar imaging, please
let us know how you do it!

Regarding the star-blooming while imaging, I suggest that you just
ignore it. When you will stack your subs, you will have a very
different picture. If blooming is still evident, there is software,
like ccdStack and others which eliminate it totally.

Bill, it is a matter of getting used to your new camera. It took me
some time to do it, but now that is history.

Just don't lose heart.

Regarding your question about photometry, I leave others to reply to
that.

Kind regards,

Leonard.

--- In SBIG@yahoogroups.com, "Bill Logan" <wb9sat@...> wrote:
>
> Hi group,
>
> I have spent the last two nights trying to image with my new ST-
> 7XME. I am very disappointed in its highly touted performance. I
> am using an NexStar11GPS with a f/6.3 focal reducer. I am using
> three different camera control software programs; CCDOps, CCDSoft
> and Nebulosity. All with the same results. I have LRGB and V
> filters loaded in the filter wheel. As with all new cameras and
> telescopes, I always try the easy objects first. After carefully
> focusing the camera on a dim star with my FeatherTouch
microfocuser,
> I cannot get an image of the moon. I've tried the lowest possible
> shutter speed of .001 second and all I get is black and white
> streaks. Ok, so it's too bright and the camera is too sensitive
so
> I moved on to another object. I tried Saturn and all I can get is
a
> white blob with ears and that was at the zenith. Seems I can't
get
> the exposure down far enough. Is there a gain adjustment
somewhere
> in the software?
>
> Tried to image M42; an easy object. Looking at the image, you
would
> think I was at f/10, but I have a .63 focal reducer on the rear
> cell After the focal reducer comes a short T-adapter and then the
> CWF9 and camera. I cannot physically get the camera any closure
to
> the C11 without removing the focal reducer. All I can get is the
> trapezium. If I lengthen the exposure to 30 seconds, I begin
seeing
> the some of the nebulous filaments, but now the stars start
blooming.
>
> How do you folks take those pretty pictures that I see everyday?
One
> final note. I bought the camera primarily for differential
> photometry, but for some reason, the FOV is less than 15'. Any
> suggestions and advice would be appreciated. The ST-7 cost too
much
> money to give up, but I am about ready to go back to my Canon
Rebel
> XT.
>
> Clear skies,
> Bill
>