Re: [William-Optics] Re: Megrez 80ED: Nice January Full Moon
- Hey Timm,
Thanks for all the good info.
Yup, that's what I thought the setup was/is. I don't
think I'll try the ep projection at this point. As is
your case, I too have a lighter mount and without
going to a dove tail mount with rings I think balance
would be very difficult. It may even stress the L
bracket or the 1/4 20 thread.
I have done ep projection with a smaller camera (canon
A75)and an adapter I built out of plumbing pipe. So
far it has worked well for the moon. I have actually
used this on my ETX-60 and then proccessed the shot in
Registax. If I go this way I'll just shoot straight
through the tube with the SD it will give me just over
500mm of clear color free shots.
Thanks again Timm, you seem to be a bottomless fount
of information. Where do you find the time?
--- Timm Bottoni <t.bottoni@...> wrote:
> Hi Rick,http://www.covingtoninnovations.com/dslr/EOS300Dastro.html
> Before you start - a word of warning... This gobbles
> up loads of
> time, but is really rewarding when you get some good
> I highly advise a book by Mike Covington,
> "Astrophotography for the
> Amateur" (I think I am the only one to have ever
> checked out the copy
> from our library) if you are getting started. Here
> is a link you
> might find useful as well.
> I have a Celestron Canon EOS T-Ring - which goes
> onto the camera in
> place of a lens, it locks in place onto the camer
> just like a lens,
> and has standard threading on the end away from the
> They run about $15-20, and I have no idea if some
> brands are better
> in quality than others, but they should all work.
> I also have 2 T-adapters, which the T-Ring screws
> onto in both
> WO 2" photo adapter - which goes directly into the
> telescope (no
> diagonal) and it gives me the extra distance I need
> to reach focus,
> does not vignette any light, and screws directly to
> the T-ring. The
> telescope becomes a big, fixed aperture, manually
> focusing lens.
> Remember that the focal length determines the
> magnification here, so
> a 500mm focal length telescope = 10X on an SLR, but
> on a DSLR like
> the Canon 20D or Rebel XT, it has a sensor smaller
> than a 35mm film
> negative, which crops the image, so it makes the
> lens act as if it
> were multiplied 1.6X the actual focal length. Most
> of my shots are
> using this setup, so no eyepiece is used, and the
> camera lens is
> taken off, with the telescope in its place.
> The second adapter I have is an Orion variable
> adapter (#05262 1.25"
> Variable Universal Camera Adapter). This is a 1.25"
> T-Adapter, that
> is screwed into a variable eyepiece projection
> adapter. You can read
> about it on the Orion web site, but Meade, and
> others make the same
> thing, more or less. The quality is OK on my Orion
> one, but its not
> as nice as the WO fit and finish, and the threads
> squeak like nails
> on a chaulkboard when I screw it on and off. The
> idea is that it can
> be used as a T-Adapter in prime focus mode,
> unscrewed from the
> variable tube (but its hard to reach focus, because
> its just barely
> enough travel for infinity focus, and not really
> enough for closer
> objects), and with the tube you can put an eyepiece
> inside (something
> like a plossl, nothing oversized) in the 15mm-25mm
> range, and get
> more magnification for planets, and other objects.
> You also use the
> the diagonal in this setup, so this thing really
> starts looking like
> a monster at this point. In theory it works well,
> but in practice I
> have not had any luck doing this. I don't have a
> steady enough mount
> to really pull this off, and it adds a bunch of
> weight and extends
> the tube out and really makes balancing and focusing
> a challenge.
> Also, the 1.25" T-Adapter vignettes light noticabley
> on a short
> refractor, which I didn't know until I got it, but
> you can see from
> the pictures in my review, the effect.
> I also have a Celestron Ultima barlow, which could
> be used in Barlow
> projection photography, with the 1.25" T-adapter,
> but I haven't had
> much luck trying that either, to be honest. I would
> love to try a WO
> 2" 2.5X barlow to see how it would work for this
> sort of thing.
> Hope that helps,
> --- In William-Optics@yahoogroups.com, Rick Yent
> <gdy3@...> wrote:
> > Hi timm,
> > I forgot to ask. Looking at the adapters I noticed
> > some have a screw to hold an eyepiece. Is your set
> > going though the "eyepiece" ? What I thought I was
> > trying to do was set the SD up as though it were a
> > telephoto lens, which I would also like to try.
> > Thanks
> > Rick
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