Jump to content

1029298577_Perseidsmeteorshowerbanner.jpg.53d23dd4ee968237ee2a9ad589662db2.jpg

Langrenus 061106


lunator
 Share

Recommended Posts

As the moon and mist was stopping me completing my DS plan. I decided that I would have a go at some luna imaging.

This is the Crater Langrenus taken using the 8" scope and a 4mm otho giving me x300. I also had the fiji camera at 3x optical zoom as it was the only way to get the camera & eyepiece to work togther. I have no idea what this makes the actual mag :?

I have compressed the image to fit on SGL.

Cheers

Ian

Link to comment
Share on other sites

I did some checking on my compact camera and the 3x zoom is equivalent to a 114mm lens (for a standard 35mm camera).

Anyone know how to translate this into magnfication.

I know the human eye has a focal length of about 58mm so the 114 mm lens is roughly twice the mag.

Does this mean that the image is actually at x600 mag. based on the x300mag for the 4mm eyepiece.

Come on all you optical experts I am courious to know.

Cheers

ian

Link to comment
Share on other sites

well, if you say it's at 3x, then it's at 3x mag, isn't it? or maybe it's only 3x the lowest mag of the camera. Anyway, if the scope's mag was at 300x, and you had 3x on top of that, you're talking 900x!! :shock:

that's quite some magnification.

But that's the upper limit. It might be more like 800x, depending on what 3x optical zoom actually means.

AP

Link to comment
Share on other sites

Ian, that's an excellent image.

Based on my imaging of the moon at known magnifications, (and looking at a good moon map) it appears to me to be no more than 480x.

This is still pushing it with an 8 ins scope.

I've not attempted to fathom the maths out, but 900x would just not be possible - and get any image at all, never mind your good quality one !

MD

Link to comment
Share on other sites

Ian

If you are using the afocal system of imaging the type of eyeypiece makes a difference.

Your Ortho may only have 45 degree FOV, plossls have 50 deg and wideangle 1 1/4 ins EP's have 65 deg.

You would need to alter the zoom setting of your camera to get the crater to fill the frame with each different EP, but all would give the same 300x magnification.

How you could work out the exact magnification mathematically beats me !

MD

Link to comment
Share on other sites

MD

That is a good point.

With the Orthos I do not need to use the zoom on the 25,18,12.5 & 9mm

I have to use the zoom on the 6,5 & 4 mm.The Orthos have a claimed AFOV of 44 degrees I think it is closer to 42 :D

I know the 4mm eyepiece gives me x300 but am just couious to know how much more magnication was 'added' in the process of filling the CCD chip

Cheers

Ian

Link to comment
Share on other sites

Ian

Hope you don't mind me messing with your image.

Looked up the stats on Langrenus and cut it out of your

image to overlay it on a map of the UK, roughly in the same scale,

to put it's size into perspective.

These craters are huge...

Covers Norfolk/Suffolk and buried Arthur under miles of moon rock :D

langmap.jpg

Link to comment
Share on other sites

Phil

excellent :D :D :D

Arthur are you Ok :shock: :shock:

I did check the size of Langrenus in my Collins 'Stars & Planets' book and it says that it has a diameter of 133Km.

I equated this with covering London & the SE from the Docklands to beyond Reading!

Your pic shows the scale superbly

Cheers

Ian

Link to comment
Share on other sites

I love this kind of stuff. I have a scale model of the solar system in my yard, and the "tour" is always popular. The Sun is the ~10mm across, Mercury is about 750cm away, etc. Pluto is over 100m and the nearsest star is almost 1200km away- near Reno, Nevada!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.