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Re: [APML] Re: [Astrophotography] Auto Guiders
Hello Mike,
thanks for your reply.
The webcam I own is a Philips Vesta Pro, which is now discontinued but is
thought to be one of the best and more "tweakable" around. Original
quickcams, however, are at present too difficult to find. I know about
Marty Niemi's software from an Internet search: I also heard that good
results are obtained with COAA's AstroVideo. Trouble is, since I don't have
a terrace of mine, I have to lug my whole equipment away, so I don't have
many chances (and therefore much time) even to try. I also asked about the
guidescope because I had a hunch that the off-axis guider stars wouldn't be
bright and point-like enough, on average, to allow for autoguiding with a
webcam.
I also built a relay box (Kitsrus DIY kit) to be connected to a PC via the
parallel port, and the first tests are good. But I will have to fit it into
a nice box instead of using a wire tangle! :-))
Thanks for your info: I hope I will come up with some good results.
Emmanuele
At 06.51 11/09/2002 -0400, you wrote:
>Hi Emmanuele,
>
>For the last 3 years I have autoguided with an original greyscale Connectix
>B&W quick cam running Marty Niemi's guider software. Marty is a personal
>friend and fellow club member, so I got to work with him on the intial
>development and functionality on his software. If you can find a good
>working quickcam, his software is freeware, but good working ones are
>becoming difficult to find. I have since given up the quick cam for an STV
>due to recent problems with the quick cam camera heads. I have gone through
>4 in the last 9 months that dont work right anymore. Marty has said that
>others are starting to go bad as well, but his still works fine. I also know
>he's got a pile of spare parts for them, I know, I gave him all mine.<BG>!
>When the system works, they are absolutly a breeze to use and guided my G-11
>excellant. It was not uncommon once a guide star was found to be autoguiding
>within 5 minutes after learning the software. A good working cam with a 4"
>refractor guidescope can guide on a mag 9 star.
>Heres a link to Martys quick cam page, how to modify it, and download
>guider.zip
>http://www.ameritech.net/users/mniemi000/auto.html
>
>Hope this helps and good luck
>Mike Leitch
>galaxy@ncweb.com
>Astrophotography website
>www.ncweb.com/~galaxy/home/astropho.htm
>----- Original Message -----
>From: Emmanuele Sordini <vega@ulisse.it>
>To: <astro-photo@seds.org>
>Sent: Wednesday, September 11, 2002 7:01 PM
>Subject: Re: [APML] Re: [Astrophotography] Auto Guiders
>
>
> > Hello everybody,
> > I too missed the original post, but since this subject has come out, I
>take
> > a chance to pose some questions:
> >
> > 1) I was looking into a webcam autoguiding system (partly
> > do-it-yourself-made) with a guidescope: I would need a laptop, of course,
> > but it would be a very cheap way of getting started witha autoguiding. I
> > only have doubts as to how the faintest usable stars. Anybody have any
> > experience/pointers/opinions on this?
> >
> > 2) As a matter of fact, I have an SCT OTA, which I read is a pain the neck
> > to guide with a separate guidescope. Do I have to give up my hopes and
> > stick with an off-axis guider?
> >
> > Thanks
> > Emmanuele
> >
> > At 10.11 11/09/2002 -0700, you wrote:
> > >Hi Nelson,
> > >
> > >I missed the original post, so I'm sorry this is late.
> > >The 201s chip is not cooled, this is why it's not as
> > >sensitive as the ST-4. I have used both of these and I
> > >liked the 201 better. Here's why:
> > >
> > >1. The 201 is completely self contained. The ST unit
> > >has a separate control box that I found to be a pain
> > >to deal with in the dark.
> > >
> > >2. The 201 retains its settings from night to night.
> > >The ST-4s settings need to be re-entered after every
> > >power up.
> > >
> > >3. The 201 is operated by a single button on the back
> > >of the unit. I found this much more convenient than
> > >having to locate buttons on a separate control box.
> > >
> > >4. The 201 is extremely light, and requires little if
> > >any counter balancing.
> > >
> > >Having said that, you need to understand that focus
> > >issues are critical when dealing with the 201. You
> > >will need to be able to easily repeat your focus from
> > >night to night, and shot to shot. I use the Taurus
> > >Tracker III which does make it easy. I do guide
> > >off-axis with a LX200. It's easy once you have the
> > >proper tools and experience.
> > >
> > >Read what Herm says below and keep in mind that there
> > >may be some equipment issues depending on what you
> > >use. I would not recommend the 201 to you unless you
> > >will use a quality off axis guiding system. Through
> > >the TTIII, I do NOT see out of focus blobs. I can
> > >easily get in-focus stars. This is a BIG reason why I
> > >can use the 201 with my equipment.
> > >
> > >I do think part of the 201's bad reputation has to do
> > >with the fact that many tend to try it as their first
> > >autoguider. I could not use my 201 for the first 18
> > >months I had it because I did not know how critical
> > >the focus issue really is. Once that is dealt with
> > >it's a piece of cake.
> > >
> > >Good luck,
> > >Alan
> > >
> > >
> > >--- Herm <hermperez@worldnet.att.net> wrote:
> > > > Sensitivity can be dealt by using longer exposures,
> > > > probably safely up to
> > > > 10 seconds or so.. while an ST4 will easily guide
> > > > with 1 second exposures.
> > > > Longer exposures will allow your mount to drift too
> > > > much. Since sensitivity
> > > > is low, sharp focus is extremely critical.
> > > >
> > > > Simultaneous corrections can be a problem with
> > > > certain mounts.. usually not
> > > > an insurmountable problem if you do a careful polar
> > > > alignment. 99% of your
> > > > corrections will be in the RA axis anyways. Losmandy
> > > > mounts WILL work with
> > > > a 201XT as long as the x axis of the 201XT
> > > > corresponds to RA.. the losmandy
> > > > will just ignore DEC corrections until no correction
> > > > is issued on RA.
> > > > Obviously this is not a problem with Meade mounts.
> > > >
> > > > The st4 will compute the centroid position of a blob
> > > > of light.. thus it can
> > > > guide extremely accurately on a distorted star or
> > > > out-of-focus blob (even
> > > > guide on the head of a comet). This feature is what
> > > > really makes the ST4 so
> > > > well loved. To compensate for this, make sure the
> > > > 201xt is precisely
> > > > focused to make the star as small as possible on the
> > > > ccd chip.. avoid using
> > > > a 201XT with an off-axis guider and an sct..
> > > >
> > > > SCT off-axis stars are distorted blobs (usually
> > > > crescent moon shaped), the
> > > > 201xt has difficulty locking on these.
> > > >
> > > > I would recommend you use the 201xt with a refractor
> > > > guidescope, preferably
> > > > 80mm and up so it delivers sharp bright stars.. if
> > > > you carefully make a
> > > > mark on the focuser you may never have to refocus it
> > > > again for a 201xt. You
> > > > cant use a guidescope on an sct due to mirror flop
> > > > issues, so avoid an
> > > > 201xt for an sct.
> > > >
> > > > Also note that the command flowchart tree that meade
> > > > includes with the
> > > > 201xt is wrong, there are correct ones avaialble in
> > > > the web.
> > > >
> > > >
> > > > biggsnj@cs.com wrote:
> > > >
> > > > > Does anyone use an autoguider for their long
> > > > exposure photograhy? SBIG has discontinued their
> > > > >ST-4 Autoguider, the only other stand alone unit I
> > > > have found is Meade's Pictor 201XT. Has anyone >used
> > > > the Meade unit? Would you recommend it? I'm on a
> > > > budget.
> > > > >
> > > > >Nelson Biggs
> > > >
> > > > Herm
> > > > Astropics http://home.att.net/~hermperez
> > > >
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> > >
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