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Main
Date: 04 Jul 2007 15:21:48
From: pascal
Subject: autoguiding with DSI ii and ST4 compatible mount
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Hi,
Have an operational DSI ii. it takes wonderfil pics of remote
balconies... Now more seriously, have an Heq5 mount (st4 compatible),
i want use the autoguiding option of the envisage software, I am just
wondering if the DSI does the autoguiding at the same time as taking
pics or the option works only if you have one DSI that takes pics and
another one on a different telescope doing the autoguiding.
Or should I just buy a webcam and mount it on a different scope for
the autoguiding while the DSI takes pics on the main telescope?
Thanks.
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Date: 05 Jul 2007 09:08:19
From: pascal
Subject: Re: autoguiding with DSI ii and ST4 compatible mount
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On 5 juil, 15:35, RMOLLISE <rmoll...@hotmail.com > wrote:
> On Jul 4, 5:49 pm, pascal <pascal_minvie...@yahoo.com> wrote:
>
>
>
>
>
> > On Jul 5, 12:33 am, RMOLLISE <rmoll...@hotmail.com> wrote:
>
> > > On Jul 4, 5:21 pm, pascal <pascal_minvie...@yahoo.com> wrote:
>
> > > > Hi,
> > > > Have an operational DSI ii. it takes wonderfil pics of remote
> > > > balconies... Now more seriously, have an Heq5 mount (st4 compatible=
),
> > > > i want use the autoguiding option of the envisage software, I am ju=
st
> > > > wondering if the DSI does the autoguiding at the same time as taking
> > > > pics or the option works only if you have one DSI that takes pics a=
nd
> > > > another one on a different telescope doing the autoguiding.
>
> > > > Or should I just buy a webcam and mount it on a different scope for
> > > > the autoguiding while the DSI takes pics on the main telescope?
>
> > > > Thanks.
>
> > > HI:
>
> > > It doesn't guide and image at the same time. The only cameras that do
> > > that are the SBIGs (which have two sensors) and some Starlight Xpress
> > > cameras (which guide on alternate frames). A webcam will work, but a
> > > better choice is another DSI, perhaps the inexpensive original color
> > > version.
>
> > > Actually, I rarely guide with the DSI...I just take 30 second shots
> > > (with the mount decently polar aligned) and have the program stack
> > > 'em.
>
> > > Unk Rod
>
> > Thanks Rod, but don't you think that a single DSI can autoguide in
> > between shots, meaning after the 30s shot if the mount has gone out of
> > the guiding star, it will reajust automatically?
> > If there is only one sensor it means that even for LX200 mounts users,
> > autoguiding and taking long shots are not coupled.
> > Can you get good galaxy composite pics with tons of 30s shots? I
> > thought that 2 x30s shots composited have a lower amount of light
> > compared to a 1 mn shot.- Hide quoted text -
>
> > - Show quoted text -
>
> Yeah, it can guide between shots, but that won't help much. If you
> can't guide during the exposure, just go unguided and stack frames.
>
> Unk Rod- Masquer le texte des messages pr=E9c=E9dents -
>
> - Afficher le texte des messages pr=E9c=E9dents -
Thanks Rod, I understand now that the DSI is nice and easy to use for
beginners, autoguiding does not drastically improve the quality when
the camera is used as it should be which is to take bunches of 30s
shots (as shown in the promotional video) . The average quality is
good but at some stage an enthousiastic photographer may want to
invest in something more sophisticated (and exponentially more
expensive)
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Date: 05 Jul 2007 06:38:25
From: RMOLLISE
Subject: Re: autoguiding with DSI ii and ST4 compatible mount
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On Jul 4, 6:01 pm, Chris L Peterson <c...@alumni.caltech.edu > wrote:
> On Wed, 04 Jul 2007 15:49:20 -0700, pascal <pascal_minvie...@yahoo.com>
> wrote:
>
> >Thanks Rod, but don't you think that a single DSI can autoguide in
> >between shots, meaning after the 30s shot if the mount has gone out of
> >the guiding star, it will reajust automatically?
>
> Some software can do this sort of mount correction. You don't actually
> guide between shots, but look for a position error in each image, and
> send a mount correction if required. Of course, if your mount is
> drifting significantly in just 30 seconds, you aren't going to be able
> to image without full-time guiding.
>
> >Can you get good galaxy composite pics with tons of 30s shots? I
> >thought that 2 x30s shots composited have a lower amount of light
> >compared to a 1 mn shot.
>
> Depends on what you mean by "good". Readout noise is significant at 30
> seconds. You can certainly stack a bunch of 30 second exposures and get
> a reasonable image, but it won't be as good as starting with longer
> subexposures. You are correct that 2x30s is noisier than 1x60s.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatoryhttp://www.cloudbait.com
Yep. Don't expect Jack Newton quality shots, but you can get a nice
color snapshot of almost any galaxy with this method. I used the DSI
and a C8 to do Stephen's Quintet a while back, and the image not only
showed the whole bunch, but showed some detail. Noisy? Yeah. Pretty?
No....but not bad anyway, not bad at all.
Unk Rod
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Date: 05 Jul 2007 06:35:53
From: RMOLLISE
Subject: Re: autoguiding with DSI ii and ST4 compatible mount
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On Jul 4, 5:49 pm, pascal <pascal_minvie...@yahoo.com > wrote:
> On Jul 5, 12:33 am, RMOLLISE <rmoll...@hotmail.com> wrote:
>
>
>
>
>
> > On Jul 4, 5:21 pm, pascal <pascal_minvie...@yahoo.com> wrote:
>
> > > Hi,
> > > Have an operational DSI ii. it takes wonderfil pics of remote
> > > balconies... Now more seriously, have an Heq5 mount (st4 compatible),
> > > i want use the autoguiding option of the envisage software, I am just
> > > wondering if the DSI does the autoguiding at the same time as taking
> > > pics or the option works only if you have one DSI that takes pics and
> > > another one on a different telescope doing the autoguiding.
>
> > > Or should I just buy a webcam and mount it on a different scope for
> > > the autoguiding while the DSI takes pics on the main telescope?
>
> > > Thanks.
>
> > HI:
>
> > It doesn't guide and image at the same time. The only cameras that do
> > that are the SBIGs (which have two sensors) and some Starlight Xpress
> > cameras (which guide on alternate frames). A webcam will work, but a
> > better choice is another DSI, perhaps the inexpensive original color
> > version.
>
> > Actually, I rarely guide with the DSI...I just take 30 second shots
> > (with the mount decently polar aligned) and have the program stack
> > 'em.
>
> > Unk Rod
>
> Thanks Rod, but don't you think that a single DSI can autoguide in
> between shots, meaning after the 30s shot if the mount has gone out of
> the guiding star, it will reajust automatically?
> If there is only one sensor it means that even for LX200 mounts users,
> autoguiding and taking long shots are not coupled.
> Can you get good galaxy composite pics with tons of 30s shots? I
> thought that 2 x30s shots composited have a lower amount of light
> compared to a 1 mn shot.- Hide quoted text -
>
> - Show quoted text -
Yeah, it can guide between shots, but that won't help much. If you
can't guide during the exposure, just go unguided and stack frames.
Unk Rod
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Date: 04 Jul 2007 15:49:20
From: pascal
Subject: Re: autoguiding with DSI ii and ST4 compatible mount
|
On Jul 5, 12:33 am, RMOLLISE <rmoll...@hotmail.com > wrote:
> On Jul 4, 5:21 pm, pascal <pascal_minvie...@yahoo.com> wrote:
>
> > Hi,
> > Have an operational DSI ii. it takes wonderfil pics of remote
> > balconies... Now more seriously, have an Heq5 mount (st4 compatible),
> > i want use the autoguiding option of the envisage software, I am just
> > wondering if the DSI does the autoguiding at the same time as taking
> > pics or the option works only if you have one DSI that takes pics and
> > another one on a different telescope doing the autoguiding.
>
> > Or should I just buy a webcam and mount it on a different scope for
> > the autoguiding while the DSI takes pics on the main telescope?
>
> > Thanks.
>
> HI:
>
> It doesn't guide and image at the same time. The only cameras that do
> that are the SBIGs (which have two sensors) and some Starlight Xpress
> cameras (which guide on alternate frames). A webcam will work, but a
> better choice is another DSI, perhaps the inexpensive original color
> version.
>
> Actually, I rarely guide with the DSI...I just take 30 second shots
> (with the mount decently polar aligned) and have the program stack
> 'em.
>
> Unk Rod
Thanks Rod, but don't you think that a single DSI can autoguide in
between shots, meaning after the 30s shot if the mount has gone out of
the guiding star, it will reajust automatically?
If there is only one sensor it means that even for LX200 mounts users,
autoguiding and taking long shots are not coupled.
Can you get good galaxy composite pics with tons of 30s shots? I
thought that 2 x30s shots composited have a lower amount of light
compared to a 1 mn shot.
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Date: 04 Jul 2007 23:01:23
From: Chris L Peterson
Subject: Re: autoguiding with DSI ii and ST4 compatible mount
|
On Wed, 04 Jul 2007 15:49:20 -0700, pascal <pascal_minvielle@yahoo.com >
wrote:
>Thanks Rod, but don't you think that a single DSI can autoguide in
>between shots, meaning after the 30s shot if the mount has gone out of
>the guiding star, it will reajust automatically?
Some software can do this sort of mount correction. You don't actually
guide between shots, but look for a position error in each image, and
send a mount correction if required. Of course, if your mount is
drifting significantly in just 30 seconds, you aren't going to be able
to image without full-time guiding.
>Can you get good galaxy composite pics with tons of 30s shots? I
>thought that 2 x30s shots composited have a lower amount of light
>compared to a 1 mn shot.
Depends on what you mean by "good". Readout noise is significant at 30
seconds. You can certainly stack a bunch of 30 second exposures and get
a reasonable image, but it won't be as good as starting with longer
subexposures. You are correct that 2x30s is noisier than 1x60s.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 04 Jul 2007 15:33:18
From: RMOLLISE
Subject: Re: autoguiding with DSI ii and ST4 compatible mount
|
On Jul 4, 5:21 pm, pascal <pascal_minvie...@yahoo.com > wrote:
> Hi,
> Have an operational DSI ii. it takes wonderfil pics of remote
> balconies... Now more seriously, have an Heq5 mount (st4 compatible),
> i want use the autoguiding option of the envisage software, I am just
> wondering if the DSI does the autoguiding at the same time as taking
> pics or the option works only if you have one DSI that takes pics and
> another one on a different telescope doing the autoguiding.
>
> Or should I just buy a webcam and mount it on a different scope for
> the autoguiding while the DSI takes pics on the main telescope?
>
> Thanks.
HI:
It doesn't guide and image at the same time. The only cameras that do
that are the SBIGs (which have two sensors) and some Starlight Xpress
cameras (which guide on alternate frames). A webcam will work, but a
better choice is another DSI, perhaps the inexpensive original color
version.
Actually, I rarely guide with the DSI...I just take 30 second shots
(with the mount decently polar aligned) and have the program stack
'em.
Unk Rod
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