Quote:
Originally Posted by TwistedRider
Thanks Renato,
That was a really good into to eyepieces.
From what you have written, I think I'll look at trying some orthos and naglers.
Will have to ask nicely at the next Star party. 
Was some impressive hand grenades at the last one. 
Cheers,
Drew |
Hi Drew,
To be honest, I have Orthos - they are good - but I rarely use them. The narrow field annoys me. And way back then I later bought Meade 5-element Series 4000 Superplossls, which gave me sharp images across the entire field (not just in the centre) and I used them a lot. Unfortunately, Meade then changed their series 4000 SuperPlossls to lesser 4-element ones, and one can't tell them apart.
My high power Orthos, plossls and Ultrawides all have shallow eye relief, but at high power it doesn't really matter much whether you use eyeglasses of not. If you are long or short sighted, you adjust the focus. If you have astigmatism, it doesn't show up much at all with 1mm or smaller exit pupils (I start seeing the astigmatism at around 2.5mm exit pupil). I did find that buying even cheap GSO very low power eyepiece (26, 32, 40, 50mm) were useful in my dob when I put them in a Barlow, as I could then wear eyeglasses, since their long eye relief remained the same.
The hand grenade eyepieces are good, but weigh a lot. I had to figure out a way to add lead pieces to the back of my dob to balance them.
If you have a computerised dob that tracks objects, then an UltraWide (82 degree) or Megawide (100degree) eyepiece is certainly nice to have - but not really essential, as your eye can only ever see 65 or 70 degrees in it without moving your eye around. Superwide eyepieces with 65 to 70 degrees will give a pleasant view.
Before buying a coma corrector, see if you can borrow one and check it out. I wasn't overly impressed with my TeleVue Parracor Type 1 - the improvement at the edges wasn't all that great, and it added weight and 1.15X magnification.
Basically there are two types of amateurs - those who hate distortion at the edges of the field of view, and those who don't mind some because they focus on the central area most of the time. I'm the latter type, but you need to find out what type you are - which will determine whether you aim for very expensive premium eyepieces, or whether they are overkill for you and cheaper ones would have been very satisfactory.
Regards,
Renato