Mars Attacks

[GRAV888]

Just got this from an old school friend (yes, I did go occasionally ):

Interesting Astrological Fact:-
Mars will be the brightest planet in the night sky starting August. It will look as large as the full moon to the naked eye.
This will culminate on Aug. 27 when Mars comes within 34.65M miles of Earth.
Be sure to watch the sky on Aug. 27 at approx. 12:30 am. It will look like the Earth has 2 Moons. Don't Miss it.....
The next time Mars may come this close is in 2287.
Share this with your friends as NO ONE ALIVE TODAY will ever see it again...

 

[Satch]

Urban Myth I am afraid. That was true in August 2003 but not 2006

 

[GRAV888]

Oh well.
Guess I'll have to wait a few hundred years then

 

[glojo]

Urban Myth I am afraid. That was true in August 2003 but not 2006

You beat me to it.

Grav has been the victim of high school ma-larkies

John

 

[GRAV888]

Just done a bit of research on this.
According to This Site, on 24/8/03, it was 56 million km away.
Closest one I could find when I hope I will still be here is 30/7/2018 at a distance of 57 million km.

 

[esox]

As large as the moon to the naked eye!!!!

I dont think so....

 

[Satch]

As large as the moon to the naked eye!!!!

I dont think so....

True also. Full Moon covers about 1/2 of degree.

Angular size of Mars at closest point was 25 arc seconds: 25/3600 of a degree!

60/3600 is an Arc Minute or MOA, a concept well known to we target shooters. A MOA is for all intents and purposes 1" at 100 yards.

So the apparent size of Mars at that point can be approximated by a viewing 4/10 inch disc at 100 yards. Telescope time.

 

[blassberg]

I think the chocaholics have it right - Mars should be barred

 

[glojo]

60/3600 is an Arc Minute or MOA, a concept well known to we target shooters. A MOA is for all intents and purposes 1" at 100 yards.

Hi Satch,
You appear to be a bit of an authority on this subject. I am trying (but failing miserably) to swat up on this interesting hobby. I am English by birth and thought I had a reasonable grasp of my native language, but what on earth is going on??? I have joined a forum in the hope of better educating myself, fat chance

Re-collimation is recommended because you probably initially collimated by eyepiece with a Meade diagonal which was non-orthogonal -- tipped. Checking collimation with the camera is easy and just good practice.

Vignetting is normal with an SCT and easily dealt with – just take flats. My LX-90 had 22% fall-off center-to-corner and that was no problem. The vignetting just costs you more exposure time to bring up the signal on the periphery. Wider spacing means more reduction
means more vignetting and more coma.

Unlike vignetting, coma is fatal as there is no software fix. Often it goes unnoticed in nebulae but shows up in star fields.

I just know that you will understand what has been said why must folks use words that contain more than four letters?

 

[Satch]

Re-collimation simply means putting an optical device back into proper alignment.

Vignetting in an optical device is the darkening you get towards the edge of the image

Coma is an optical defect and gives rise to the tail or starring effect when a bright object is viewed through a telescope.

Beyond that, beats me. All specialist areas & subjects tend have their own arcane language and many TLA's (Three Letter Acronyms)

My eldest son went on a trekking holiday a few weeks ago and was told he must have an IFAK. A what?

Nobody knew but thanks to the wonders of the internet soon worked out it was probably not a membership of the Instituts für angewandte Kindermedienforschung but an Individual First Aid Kit.

 

[glojo]

Re-collimation simply means putting an optical device back into proper alignment.

Now why couldn't they say that I laughingly commented on this 'foreign language' and was told that when starting out in a new hobby I should learn the language!!! Certainly put me in my place. I wonder how many folks learn the language of a host country when they have holidays in a foreign land?

By the way I am slowly learning this 'foreign' language

Thanks for the translation.

John

 

[Howard]

I laughingly commented on this 'foreign language' and was told that when starting out in a new hobby I should learn the language!!!

Thanks for the translation.

John

Sound like a friendly bunch , was it the MBOA stargazing club John ?

 

[glojo]

Sound like a friendly bunch , was it the MBOA stargazing club John ?

You don't get me putting foot into mouth that easy

John