Short-sightedness and eyepieces

[darkskybondi]

I posted this question under equipment but I'm hoping there's an eyepiece buff or two out there who can help me out here.

I am sure everyone has a different opinion, particularly on eyepieces, but I'd like to know how much I should be spending on them with my purchase (I'll be buying a 10 or 12" dob) - how many, Barlow, what types, what brands, etc. Particularly given my vision:

I don't know if it is relevant, but I am very short-sighted (-12) and have poor night vision with quite a bit of fuzz/static in my visual field (hence the desire for a larger aperture - even with a 12" I won't see quite the dazzling view that some of you blokes do - the static "interference" in my visual field means that stars that are less bright are very difficult to distinguish from the static.) The reason I mention this is particularly because the shortsightedness means I am unable to, for example, use my binoculars without glasses on - it won't turn enough to focus clearly for me. Will this be a problem with eyepieces on the scope? http://www.iceinspace.com.au/forum/../vbiis/images/smilies/confused24.gif

Obviously I'd like to observe without my glasses, so it'd be ideal if I could focus the eyepiece to my level of shortsightedness. Will this be possible at my extreme myopia?

Thanks guys and clear skies!
- darkskybondi :newbie:

[PhilW]

DSB,

Do you suffer from myopia only, or astigmatism as well?

[darkskybondi]

Ha - I forgot about this. I am astigmatic but could not tell you the level of astigmatism. Does that change things significantly? I thought there might be a chance for blind bats like me! Observing with glasses... not such a pleasure..

[erick]

DSB

Suggest you read up on what Televue has to say:-

http://www.televue.com/engine/page.asp?cat=2 :)

[darkskybondi]

AWESOME. Thank you very much! :)

[ausastronomer]

Hi,

I posted a lot of information in this previous post on this topic, based on 30 years experience of observing with glasses on off sideways and every which way.

http://www.iceinspace.com.au/forum/showthread.php?t=34789

What I can also tell you is that Televue's Dioptrix is the answer for only some people and not the answer for a lot of people, me included.

Cheers,
John B

[darkskybondi]

Thanks John. I read through your suggestions, but I gotta tell you, it is so much more comfortable looking through eyepieces without glasses (for me!).

I am pretty intent on observing without glasses, so aside from the astigmatism issue which can in theory be corrected using Dioptrix, my question really is whether it is possible for an ordinary focuser to correct for my level of extreme myopia - minus 12. Or will I have to purchase specialized equipment? As I may have mentioned, ordinary binoculars simply won't focus for my level of myopia.

Cheers
DSB

[Wavytone]

With myopia you can easily observe without your specs - on a telescope winding the focusser in will compensate for myopia, moving the eyepiece closer to the mirror. For -12 that will mean moving most eyepieces a few millimetres. From personal experience your biggest problem will be taking the the specs off and losing them, then stumbling around in the dark to find them. Having them tied on with a chain around the neck is a big help.

I am quite long sighted and I have astigmatism as well, if I observe without specs I need to wind the focusser out to compensate.

With bad astigmatism, that is harder and in that case its best wearing your specs and using eyepieces specifically designed for that - in particular the Vixen LV and LVW which all have massive eye-relief (20mm or more) meaning you can wear specs to look through these eyepieces. One of the reasons I own a set.