Astrophotography & Lenses

[MadMesh]

I want to shoot Mars on the 27th of Aug. This is going to be the closes mars has been to earth. This isnt gona happen for another 60,000 years. WHAT LENS DO I USE!!!

Prime or Zoom, 400mm cut it? sigma 500mm Prime. Will a 100-400 IS with a tripod work?


HELP!!!


and i dont want a telescope.

[Tom W]

I hope you don't mean this:

http://urbanlegends.about.com/library/bl_mars_encounter.htm

[MadMesh]

I do mean this.... Whats going on?>!?! I was gona buy a 400mm prime and go camp out on the mountains to shoot that. Am i waisting my time?!?!

HEELPPPP =)

[lomond]

I think you might be wasting your time with a 400 for Mars even at its closest approach.
You really need to be using your camera mounted on a telescope to get anything other than a whitish/redish dot. :(

[MadMesh]

Mars is supposed to be the size of the MOON on Aug 27th. From what I understand. Visible with the naked eye. I shot the moon with a 300mm and got good results.

[lomond]

Mars is supposed to be the size of the MOON on Aug 27th. From what I understand. Visible with the naked eye. I shot the moon with a 300mm and got good results.


Whoever said Mars will be the size of the Moon had too much to drink or was on a rocket to Mars.

[Nabil-A]

Did you read the update at the bottom of the page???

Ive included it below.

ANOTHER Close Encounter with Mars?
According to a forwarded email circulating for the past month or so, the planet Mars is due for an unprecedented close encounter with Earth this August when a wobble in its orbit brings the two planets closer together than they have been for thousands of years. "No one alive today will ever see this again," says the email — which is odd, considering that exactly the same thing happened two years ago (http://space.about.com/cs/mars/a/marsclose.htm).

Turns out, the email is a recycled message (http://urbanlegends.about.com/library/bl_mars_encounter.htm) from 2003. Even so, it's not entirely false. Earth and Mars will pass very close to one another again in October (not August) 2005, astronomers say (http://urbanlegends.about.com/gi/dynamic/offsite.htm?site=http://www.rednova.com/news/space/152719/a%5Fbreathtaking%5Fclose%5Fencounter%5Fwith%5Fmars/), at which time their orbits will be a mere 43 million miles apart (slightly more than the 35 million miles separating them in 2003). It won't quite equal the once-in-a-lifetime show of two years ago, but the enounter will be "breathtaking" nonetheless, scientists predict, with the red planet outshining every object in the night sky save Venus and the Moon. More from Space Guide Nick Greene... (http://space.about.com/od/astronomynews/a/marsclose2005.htm)

[lomond]

Bottom line is Madmesh will be wasting his money buying a 400 mm lens to shoot Mars. All he'll get is a white fuzzy dot.

Sorry Madmesh.

[MadMesh]

no problem guys... i wasnt worried about the lens, i was more worried about the time im gona spend driving to the mountains to WAIST MY TIME =)

Thanks Tho!

[duncanc]

Mars is supposed to be the size of the MOON on Aug 27th. From what I understand. Visible with the naked eye. I shot the moon with a 300mm and got good results.

If you visit the recomended link you can read:
"...At a modest 75-power magnification Mars will look as large as the full moon to the naked eye..."

AT A MODEST 75-POWER MAGNIFICATION ...

[sdommin]

All he'll get is a white fuzzy dot.

Not true. He'll get a fuzzy orange dot.

[Tom W]

Bottom line is Madmesh will be wasting his money buying a 400 mm lens to shoot Mars. All he'll get is a white fuzzy dot.

Sorry Madmesh.

Actually, if the atmosphere is relatively clear that night, he'll have a sharp dot, not a fuzzy one. :)

[rent]

didn't this happen back in 2003? buy a lens and a time machine. :p

-alex

[robertwgross]

Just to shoot a good image of the Moon, you need a lens up around 1000mm to 2000mm. The planet Mars is much smaller in apparent size, so what do you think?

I don't know! You send them to school, and you give them books, but still they don't learn anything.

---Bob Gross---

[Wazza]

You'd be wasting your time looking at Mars with only a 400mm. It's going to change from ant size, to queen ant size. :p

I shot this recently with a 2500mm telescope, and my 20D.

http://wazz*****scity.com/20d/jupiter_2500_01.jpg

(This IS a 100% crop. You won't get much bigger with any lens. :()

And just for comparison purposes. Check out this:

http://wazz*****scity.com/20d/moon_jupiter_50pc.jpg

Mars will probably look fairly similar size to the moon, and as you can see, it appears several hundred times smaller, due to our position in the Solar System.

[lomond]

Wazza, that's an impressive shot of Jupiter but to see the whole image in its full context is (forgive me :o) Stellar.

Truly wonderful, I'm in awe.

Regards,

[GyRob]

doesent a 400mm give about 8 times mag way short of 75.
Rob

[who me?]

Wazza, nice shot of Jupiter. Was that a direct projection or a eyepiece projection?
As for decent magnification to see Mars, back in 2003 with really steady skies, Mars was beautiful at 200X with my 13" dobsonian. I could see the southern polar cap and some darker features of some of the plains. Normally to get anything decent and see more than just an orange ball, you need more like 125-150X. Even though it is quite a bit closer, Mars is really a SMALL planet compared to Jupiter.

[FScott]

Wazza, nice shot of Jupiter. Was that a direct projection or a eyepiece projection?
As for decent magnification to see Mars, back in 2003 with really steady skies, Mars was beautiful at 200X with my 13" dobsonian. I could see the southern polar cap and some darker features of some of the plains. Normally to get anything decent and see more than just an orange ball, you need more like 125-150X. Even though it is quite a bit closer, Mars is really a SMALL planet compared to Jupiter.

Mars compared to Jupiter isn't quite that bad, although I agree with everything you've said. The closest approach of mars in 2003 was 55e6 km. Mars has a diameter of about 6800 km. Closest approach to jupiter is about 630e6 km and jupiter has a diameter of about 143000 km. Thus at one of these "special" times for mars it subtends about 1/2 the angle as Jupiter at Jupiter's closest approach or almost the same as jupiter when jupiter is farthest away.

Back to the topic at hand... I agree if you want to actually view the Disk of Mars and not just a colored dot, you are wasting your time with a 400mm lens which gives you about 13x magnification on a 20D/300D/350D.

To be explicit, for a 400mm lens, the field of view on a 350D is 3.2 degrees horizontal. Mars at its closest approach subtends 0.007 degrees or 0.22% of the field horizontally. The 8 MP CMOS is 3500 pixels horizontal which means that mars will be 7.7 pixels in diameter in your image. Short answer: get a telescope.

-- Scott.