[Chaos-l] Astrophotography start up?

Sun Mar 17 09:58:38 EDT 2013

The second video is the process I'm more familiar with. It's a good video
to get started with, and it's essentially what I did to get going with
astrophotography. Keep your expectations realistic, though. The smaller
Messier objects the first guy imaged may only constitute 50x50 or 100x100
pixels on the camera sensor.

I would like to clarify a point or two that the second video wasn't clear
about. Generally speaking, integrated exposure is not the same as actual
exposure (i.e., 50 6-second exposures is not equivalent to 1 5 minute
exposure.) The additional images help to reduce noise which will allow you
to post process more aggressively. I had to prove this to myself by taking
61 images of M27 and then creating a sequence of stacks, from 1 to 32 (and
then 61.) Same post processing applied to each. It quite illustrative of
what stacking accomplishes:

http://www.astrobin.com/32323/

He also misspoke about bias frames. Bias frames are used to reduce readout
noise and really aren't necessary in DSLR's. As it happens dark frames also
contain readout noise and when you create your master dark, you are
implicitly creating a master bias. Bias frames are generally used for
scaling dark frames.

My point being, start off by taking 30 light frames and 25 dark frames and
work with those. Stacking and post processing can be an intimidating and
frustrating process. Spending 5 hours stacking 400 frames when you will
only gain a modest improvement in noise reduction, will only amplify the
frustrations when something goes wrong.

I don't have a tripod recommendation, as that would be heavily dependent on
the lenses you'll be shooting with. It should be sturdy and not shake
around in the wind though.

Mark

On Sun, Mar 17, 2013 at 1:24 AM, Steven Christensen <steve at smc.vnet.net>wrote:

> Thanks for the quick response Mark.   I was inspired by these two
> youtube videos.
>
> http://www.youtube.com/watch?v=11d-JbxXGAA
>
> http://www.youtube.com/watch?v=e0JSTF8SGi4
>
> as something to try before I get into tracking and telescopes.   In
> the videos, they are able to image most interesting objects from
> constellations to Messier objects etc.  Not to the level of a
> telescope, but pretty interesting for someone like me who wants to
> learn the sky and record what I have learned.
>
> I will go with the 60Da.   Any tripod recommendations?
>
> I also got the Regim software that was discussed a bit in the first
> video.   I use Macs but have both running.
>
> I will also get the BackyardEOS.  I don't run Windows, but that is
> simple to fix.  I can run it on a Mac if I have to.
>
> I will look around about the Canon lens issue on the web and see what
> I can find out.
>
> Steve C.
>
>
> On Sat, Mar 16, 2013 at 11:25 PM, Mark Montazer <mark at montazer.org> wrote:
> >>  I want to do things without telescope or clock drive for now until I
> >> learn more.
> >
> > Without a motor drive/tracking mount, your maximum exposure with no star
> > trails will be severely limited. There's a web based calculator that'll
> help
> > you estimate exposures: http://www.sceneplanner.com/tool3.php
> >
> >> So, I am considering
> >
> > The equipment looks good.
> >
> >> Does it make sense to use a Telrad or something similar to aim the
> camera
> >> to interesting objects?
> >
> > You can, but I find that at the shorter focal lengths it's not
> necessary. At
> > focal lengths above 400mm a finder becomes very useful.
> >
> >> What lenses are useful?
> >
> > Depends on what your goal is. I have no experience with Canon lenses,
> but be
> > keep in mind (for future reference) that all camera lenses and almost all
> > refractors, even APO's, fail to focus infrared light properly. This will
> > result in star 'bloat' on the more IR intense objects.
> >
> >> If I decide to add a telescope later, is this camera useful for that?
> >
> > Most definitely. You'll need a t-ring specific to your camera and
> possibly a
> > t-adapter depending on the focuser of the scope you end up getting.
> >
> >> What about external connections to a laptop or iPad etc?
> >
> > I'm not familiar with Canon PC connections but you should check out
> Backyard
> > EOS which is a Canon specific astronomy software. There's a big community
> > surrounding it and at least one fellow at the recent star party was using
> > it.
> >
> > So the bigger question is what are you hoping to image?
> >
> > Mark
> >
> >
> >
> > On Sat, Mar 16, 2013 at 10:20 PM, Steve Christensen <steve at smc.vnet.net>
> > wrote:
> >>
> >> Hi all,
> >>
> >> I hope it is OK to ask this here.  I am really enjoying starting some
> >> astrophotography and want to move up a little.  I want to do things
> without
> >> telescope or clock drive for now until I learn more.   So, I am
> considering
> >>
> >> Canon 60Da  (I have some Canon lenses already)
> >> Canon TC803N Remote Timer
> >> A new Tripod - suggestions?
> >> Maybe an IR filter for non astro things
> >>
> >> Use the Deep Sky Stacker software and Photoshop which I have already.
> Does
> >> it make sense to use a Telrad or something similar to aim the camera to
> >> interesting objects?  What lenses are useful?  If I decide to add a
> >> telescope later, is this camera useful for that?
> >>
> >> What do you folks suggest about this or other options?  I have learned
> >> that a number of you are extreme experts at this, so I hope you will be
> >> patient with a real newbie.  What about external connections to a
> laptop or
> >> iPad etc?
> >>
> >> Right now, I am getting what little I know from YouTube videos and
> Google
> >> searches.
> >>
> >> Thanks,
> >>
> >> Steve C.
> >> _______________________________________________
> >> Chaos-l mailing list
> >> Chaos-l at rtpnet.org
> >> http://rtpnet.org/mailman/listinfo/chaos-l
> >
> >
>
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