Image upside down.

Don't be shy! If you're just starting out, here's the place to ask that first question

Moderators: joe, Brian, Guy Fennimore

Post Reply
vauxhall
Posts: 1
Joined: Tue Feb 21, 2012 5:13 pm
Location: Scotland
Contact:

Image upside down.

Post by vauxhall »

From my question,you will realise that I'm an absolute beginner.My telescope is a Jessop reflector TA800-80.The image I see is upside down.Is this correct or have I assembled it wrongly?
David Frydman
Posts: 5363
Joined: Mon Jan 18, 2010 9:25 am
Contact:

Post by David Frydman »

That is correct.

Ordinary astro telescopes such as lens telescopes and mirror telescopes give upside down images.

This is historic because extra lenses are needed to give an upright image, and this was extra cost and degraded images.

Nowadays things are more complex, but a simple Newtonian gives upside down images although the image can move around at different telescope angles.

With a mirror diagonal on straight through scopes you can get a laterally reversed image.
And photographers also get different orientations.

With a DSLR camera a prism is used to get right way round images, some old ones gave upside down or reversed images.

So basically you can meet all sorts of orientations.

This why a binocular needs prisms to get upright images.
It would be much simpler without but the images would be upside down.

Old opera glasses and field glasses give upright images by using a negative eyepiece. The disadvantage is a very narrow field of view.

One quickly learns to move the scope correctly with a little practice.

Regards, David
Last edited by David Frydman on Tue Feb 21, 2012 9:45 pm, edited 1 time in total.
dazcaz
Posts: 236
Joined: Mon Mar 12, 2007 8:05 pm
Location: Cardiff
Contact:

Post by dazcaz »

This is normal on a reflector. You are doing nothing wrong.

http://www.spaceref.com/telescopes/Imag ... -Down.html
I once came last in an astronomy competition.
I was awarded a constellation prize


Skywatcher Explorer 200 HEQ5
Skywatcher Skymax 127 SupaTrak
Celestron C4-R CG-4 mount
Brian
Posts: 3725
Joined: Fri Dec 03, 2004 9:58 pm
Location: Wellingborough
Contact:

Post by Brian »

Welcome to the Forum! :)

Also, don't be tempted to try using the maximum claimed magnification of x399 with your telescope, the image just won't stand up to that power. The maximum useful magnification under good conditions will be nearer to x160, but you will probably find that x100 is a more practical value,

HTH,
Brian
52.3N 0.6W
Wellingborough UK.

254mm LX90 on Superwedge, WO ZS66SD, Helios 102mm f5 on EQ1, Hunter 11x80, Pentax 10x50
ASI120MC Toucam Pros 740k/840k/900nc mono, Pentax K110D
Ro-Ro roof shed
Post Reply