Jupiter & Mars 7/8/2020

[mikeDnight]

Jupiter was in turbulent air but a couple of nice shadow transits stood out like dots of Indian ink.

 

Meanwhile Mars was rising behind a low bank of haze and cloud, and so i made three seperate sketches as the planet rose above the murk on the horizon. Each sketch was made using a different magnification and each has its own merits. The same 100mm refractor was used for each. My personal favourite is the high power view given by the 2mm Vixen HR at 400X for which I've also included a labelled diagram of the features shown. As a diagonal prism was used the sketches show north top, east west reversed. Preceding is left.

Edited August 10, 2020 by mikeDnight

[John]

Wonderful observation and sketching skills Mike

You must be one of the foremost planetary observers and recorders in the UK currently I would think.

(that's a sincere remark)

 

[mikeDnight]

1 hour ago, John said:

Wonderful observation and sketching skills Mike

You must be one of the foremost planetary observers and recorders in the UK currently I would think.

(that's a sincere remark)

 

Thankyou John. I'm genuinely struggling to know what to say after such a compliment. It is nice to know my sketches are enjoyed by others. 

[JeremyS]

Lovely drawings Mike and so full of detail.

[BRADLEY 1953]

I agree, great sketches and so much detail on show. Also, surprisingly early in the night for mikeDknight !  I did a sketch myself (not posted yet) but so much later, 3.15 -5.00  BST.  

[mikeDnight]

25 minutes ago, BRADLEY 1953 said:

I agree, great sketches and so much detail on show. Also, surprisingly early in the night for mikeDknight !  I did a sketch myself (not posted yet) but so much later, 3.15 -5.00  BST.  

I look forward to seeing your sketch Chris!

As for my observations being early on, I try to catch the Planets before they reach the meridian because the nearer to the south they get, they also become affected by poorer seeing. I have a high south southwest tree line that hinders observations when the planet's are low like Jupiter and Saturn currently are. Most of my sketches are made while the planet is either in the east or high in the sky. I do seem to have consistently good seeing in the east so I shouldn't grumble.

[laudropb]

Your sketches are certainly enjoyed by all here Mike.

[dweller25]

Great sketches @mikeDnight

How do you calculate the magnification you have with the Binoviewers in your Jupiter drawing ?

[mikeDnight]

45 minutes ago, dweller25 said:

Great sketches @mikeDnight

How do you calculate the magnification you have with the Binoviewers in your Jupiter drawing ?

Hi David,

I follow Peter Drew's view, that there's an approximate 4X amplification due to the extended light path of the binoviewer after the 2X barlow. So simply multiply the magnification af the eyepiece by 4X. So with the Jupiter sketch the 18mm Ultima's giving me 44.44X were multiplied by 4 as I was using a 2X Ultima barlow giving 177.7X, rounded up to 178X. ☺

[dweller25]

2 hours ago, mikeDnight said:

Hi David,

I follow Peter Drew's view, that there's an approximate 4X amplification due to the extended light path of the binoviewer after the 2X barlow. So simply multiply the magnification af the eyepiece by 4X. So with the Jupiter sketch the 18mm Ultima's giving me 44.44X were multiplied by 4 as I was using a 2X Ultima barlow giving 177.7X, rounded up to 178X. ☺

Thanks - I will try that calculation the next time out.......

[andrew s]

You can easily measure the magnification. Measure the size of the exit pupil when scope is pointing at day time sky. Calipers or a ruler will do. Just look down the eyepiece from 50 or so cm back. Divide this into the aperture of the scope gives the magnification

This assumes the binoviewer does not vignette the scope

Regards Andrew 

[dweller25]

10 minutes ago, andrew s said:

You can easily measure the magnification. Measure the size of the exit pupil when scope is pointing at day time sky. Calipers or a ruler will do. Just look down the eyepiece from 50 or so cm back. Divide this into the aperture of the scope gives the magnification

This assumes the binoviewer does not vignette the scope

Regards Andrew 

👍