TAKO. INTERNET SEIT 1996.
Olympus-OM

RE: [OM] Taking pictures of Mars

Subject: RE: [OM] Taking pictures of Mars
From: "Olaf Greve" <o.greve@xxxxxxx>
Date: Tue, 26 Jun 2001 13:50:44 +0200
Hi Ralf and Rainer (and others),

Thanks a lot for your reply, I see a lot of my assumptions were correct.
Some feedback:

> Mars has a size less that 30" (if I remember correct) so with your 2800mm
> telescope mars will be probably less than 0.4 mm on the film... too less
> for viewing something (polar areas, color differences in different areas
> etc).

Yes, that would be roughly consistent with what I estimate from seeing
through the viewfinder: just a small dot, without any (in the viewfinder)
discernable details, hence not really worth wasting expensive film on.

> You should be able to have a good photo with a size of at least 1mm, so
you will need a
> focal of more than 7/8 metres!

Hehehe, or a LOT of teleconverters ;))) Perhaps stacking some 3 more TCs in
there would do the trick (if one forgets the fact that the resulting image
might than be completely useless due to image degradation, even when stopped
down to f22 on the lens, as well as the fact that the auto diaphragm lever
stacking might be too much to actually stop down the lens).

> The best method for taking a planet photo is to use a method called
"eyepiece projection"
> with a telescope but this is long story (briefly, a telescope, an eyepiece
as a magnifier
> and the camera). Second problem is the movement of mars in the sky:
depending on the
> coordinate of mars it can move up to 15 arcsec in a second, a distance
comparable on the
> diameter of mars itself! So you will need not only a very robust tripod,
but an equatorial
> mount with a motor in order to have mars not moving during the photo.

This is exactly what I was already afraid of. The economical expenses (as
well as the effort) required to take such pictures at present fall well out
of my range. This, for me, is the main reason to not have tried this type of
shot before. Perhaps someday I will try to acquire a decent telescopical
set-up (including rotating mounts), until then I'll just have to dream away
on our own Starmatt's page :)

> Ahh, what a long reply with my poor english, now is time for lunch...

Your English is not poor at all, and thanks a lot for taking the time to
answer, and I hope you enjoy your lunch.

Then Rainer Wagner added:

>Sorry that i have to discourage you a bit, but with your setup you will get
>a mars picture which will have less than half a millimeter  diameter on
your slide

I'm not discouraged by this, as it is consistent with what I already feared
would be the case. When mounting the set-up I never really expected to get
very good results anyway, but I tried it to see what it would look like :)

> So there is no chance of seeing details. You will only see a bright ,
perhaps somewhat
> orange spot which I would consider is not worth the effort.

Exactly!

> You would need a focal length of mor than 15 m to have a chance.

Hmmm, in terms of TCs that would be roughly between 5 and 6 2x TCs, when
starting out with a 300mm lens...:) Hehehe, has anyone actually (just out of
curiosity, or so) ever ried stacking _that_ many TCs??? :)))

>Perhaps it would be worthwhile to picture Mars with adjacent stars with a
50
>or 100 mm lens, but even this is not easy, because the brightness
difference
>is very high,

Yes, that's indeed something which may be doable.

>and you will either get a nicely exposed reddish mars with only a few (
Antares, or anti -
>mars just somewhat to the right of mars, and nearly the same colour),

Aha! So that's what the "other red star(?)" is. I was already wondering what
this one was, as I too noticed it. It shows up smaller than Mars, and the
light seems to flicker. I always thought that planets were the ones that
showed up flickering, but perhaps I'm wrong... What exactly is Antares then,
BTW?

>or there are more stars with severe overexposure of mars.

Bracketing would be key, I suppose. Perhaaps I'll try a roll of Provia F on
it. How would the reciprocity failure work out for Provia 100F when pushed
to 400 ASA? Note: I know virtually nothing about reciprocity failure, so
perhaps this is a silly question, but I wonder what the effect would be
during long exposures.

>So , if your southern horizon is really dark (it is not so nice here in
Juelich/ germany,
>perhaps not very far from you) try your 50/1,8 with 400 or even Kodak 1600
asa slide film ,
>start with 5 sec exposure and step up to 1 or two minutes. You will get
amazing results!

It sounds like a lot of fun, I might just try that with the 100/2 or the
50/1.8 (even though I live in the city and light pollution may be too much
of an issue), hmmmmm....

>I  have something like 200 pictures of this type.  I would prefer the OM1
because it has the
>mechanical shutter. I even tried to use the 55/1,2 at full speed, the
consequence was
>selling this and buying a 50/1,4 and a 24/2,8 instead.

Well, I also have the 24/2.8, but I guess that might get just a bit too much
sky (and city lights!) in the image... maybe not... I'll have a try with
some lenses to see which focal lengths seem to work best.

Then: I do remember having read something to the effect of that in this type
of photography the focal length of the lens is of hardly any influence to
the size of the stars as they show up in the pictures due to the enormous
distance there is between the earth and the stars, but how about stopping
down? What would be the most ideal apertures? Wide open? Stopped down 1
stop? f4/8/11? f16 perhaps?

Cheers and thanks for your answers!
Olafo


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