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RE: [APML] Re: [Astrophotography] Auto Guiders
Mike, don't you have to build a relay box to guide a mount that only
accepts autoguiders such a an st4, in order to use a quickcam and
guider.exe? I know that it can send LX200 commands thru the serial
port, but not the st4. Right?
I used my greyscale quickcam and Marty's software to autoguide at TSP.
I shot images piggybacked on an 10" LX200. Big guidescope :)
Here is one of the images:
http://groups.msn.com/LenCasady/astrophotos.msnw?action=ShowPhoto&PhotoI
D=13
Len
-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org] On
Behalf Of Mike & Dianna
Sent: Wednesday, September 11, 2002 5:51 AM
To: astro-photo@seds.org
Subject: Re: [APML] Re: [Astrophotography] Auto Guiders
Hi Emmanuele,
I cant answer your SCT question, but I think I may be able to help with
the webcam idea. 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
> > >
> > > -- APML Archives at
> > > <http://astro.umsystem.edu/apml/> ---
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> >
> >
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