exposure

What kind of exposure time do I need for a F10 scope for Jupiter and Venus
in early morning with ISO 400?

According to Astphoto you need 1/125th for Jupiter, 1/2000 for Venus.

You might want to download Astphoto from the Astronomical Society of Southern
New England's website. It's free...

jon

Michael Covington's exposure calculator is a good start to figuring this
out. Grab it off his site, I don't have a link but do a search on his name
and you'll find it.

Second, you don't say "how" you're going to photograph? Cassegrain
focus (unlikely), Afocal, EP projection. With EP projection we would need
an EP FL and for Afocal we would need that and the camera lens information.

--
Michael A. Barlow
"moT" wrote in message
news:zDFhd.80333$9b.74449@edtnps84...
What kind of exposure time do I need for a F10 scope for Jupiter and Venus
in early morning with ISO 400?

Second, you don't say "how" you're going to photograph? Cassegrain
focus (unlikely), Afocal, EP projection. With EP projection we would need
an EP FL and for Afocal we would need that and the camera lens
information.

--

Thanks but I found the "starshot" planetary calculator. I am using EP
projection
w/ SLR camera. It appears that I am in the fraction of a second range.
I'll blow off a whole roll starting at 1/8 sec and move up in 1/4 sec
intervals to a maximum of
1.5 seconds.

Actually I'll have to start at about 1/60 sec. and move up. Since Jupiter
is about 2 mags dimmer or 100X's less bright than Venus (-1.7 and -4),
maybe I can take
separate shots and then merge them.

moT nous a écrit :

What kind of exposure time do I need for a F10 scope for Jupiter and
Venus in early morning with ISO 400?

Go here http://www.covingtoninnovations.com/...astrosoft.html and
download the "Astrophotography exposure calculator ". This small piece of
software will give you all the data that you need.

--
Norbert. (no X for the answer)
======================================
knowing the universe - stellar and galaxies evolution
http://nrumiano.free.fr
images of the sky http://images.ciel.free.fr
======================================

According to Astphoto you need 1/125th for Jupiter, 1/2000 for Venus.

jon

Sure seems rather fast. Starshot gives much different results. 1/125 or
1/60 for Venus
1/8 for Jupiter

Sure seems rather fast. Starshot gives much different results. 1/125 or
1/60 for Venus
1/8 for Jupiter

Since you are using eyepiece projection then you probably ought to run the
program with proper focal lengths and see what it says. I assumed you were
operating at the F10 you specificed, if so then I would figure Astrophoto would
be fairly close. I know when I shoot venus with my CP4500 I am at 1/1000th or
so when operating at F15 or so and ISO 100.

Its a pretty neat program, it has a database of planetary and deep sky objects
and will give exposures and a representation of the size of the target in the
FOV. There is also a companion program that is specifically designed for CCD
camera.

jon

It appears that I am in the fraction of a second range.
I'll blow off a whole roll starting at 1/8 sec and move up in 1/4 sec
intervals to a maximum of
1.5 seconds.

A better stradgey is to increas by a factor of 2 or 1.4. Thats the way f-stops
go.