Mars, 2nd attempt

For a small disc you sure have captured lots of clear and well-defined detail there Frank. Seeing must have been pretty near perfect. The colour looks natural, and well balanced between features and terrain.

That's a fine image Frank.
Colour looks just like it appears when viewed through a scope.
Colour appears much more red when viewed without optical aid.
What f/ratio was that taken at Frank?

sorry doubled up on this

What f/ratio was that taken at Frank?

Sorry Mike I don't know.
All I do know is the ETX has an f/ratio of f/15, so with a 2xbarlow
what does that work out at?
Does the 2xbarlow double the f/ratio of the scope?
If so the f/15 then becomes f/30?

I must admit, working out f/ratios etc is an area I have neglected.
How does this effect webcam imaging?
(broad question I realize but what are the basics)


Cheers.

15 x 2 = 30
So, your image was taken at f/30.
Total focal length = 5 x 30 = 150inches.

The longer the f/ratio, the "slower" the scope, and the longer the exposure.

I have a 5.5" apo, so to get the same size image on my camera, I'd need to be operating at a similar f/ratio. (A slightly simplistic explanation as it ignores pixel size of the cameras).
As I have a 5.5" f/7, total focal length 5.5 x 7 = 38.5inches
So, I'd need a 3.89x barlow to get the same size image of Mars, assuming I use the same camera.
Obviously, such a barlow doesn't exist but it gives me some idea what I would need to do to get the same image.
Make sense?

Cheers,

Thanks Mike.
Makes perfect sense now!

Seeing must have been pretty near perfect.

Yip. Best I've seen in 2 years.
Lasted for around an hour.
The rain came just as I was getting good focus on Mars using the 5xpowermate.
I had to quickly dash back into the house as it lashed within a few min.


I really really need an observatory! :lol:


Just on the features,
I was looking at The Sky at Night mags online Mars tool and
starry night to see if I could work out the markings.
I'm baffeled!
Do any of you want to try and see can you work out the main features?
The shot was taken at 12:44 am 3rd Dec.

Cheers.