Im confused - eyepieces

[Crash Nebula]

ok, i think is hould know what eyepieces do what, which are best for deep sky and which are best for imaging
cheers,
crash

[h0ughy (David)]

deepsky try eyepieces with a very large field of view I personally like my 40mm, 32mm 30mm and my 25mm 2" eyepieces. for imaging something clear, that could be anything from a 50mm through to a 12mm or 7mm, but depending on what you have as a camera will determin how much vigenetting you have (Afocal eyepiece projection). I have a maxview DSL 2" adapter so I can fit any eyepiece imaginable and use it to project. I will have it with me when I attend the Ice in Space Star party on the 7th. I also have a 40mm scopetronic eyepiece threaded with adapters to fit my Pentax digital SLR and also my minolta dimage 7.

checkout www.scopetronix.com

[mch62 (Mark)]

Small world.
Speaking of EP adapter for a D7.
Here is one i made about 4 years ago well before Scoptronixs came out with theres.
Interesting to note Scoptronixs uses the same designed 42mm eyepiece with the large objective lens to mate to the D7.
This is a cheapy Sysnta 3 element Kellner.
The brackets are my design to hold the camera weight.

For deep sky wide field it will depend on the F ratio if a reflector as to how low you can go.
You have to be aware of a thing called exit pupil.
If you have to low a power eyepiece it can be possible to see the central obstruction as a dark area in the eyepiece.

If the pupil on your dark adapted eye is 6mm then for an f5 scope you shouldn't go lower than a 30mm (6x5=30)
An f6 scope with a 7mm exit pupil then a 42mm eyepiece.
If your young you exit pupil will more than likely be around 7mm but for us older farts it could be only 5mm or 6mm.

If you have a reflecter try a low power eyepiece during the day and more than likely you will see this effect as you eye pupil will be a lot smaller.

A refractor won't suffer from this but going past your exit pupil will only result in light not entering your eye.Wasted light.

If doing afocal where you have the camera up against the eyepiece you will, need to have an eyepiece with a large enough lens to alow the samller camera lens to get the full field of view.
So chose an eyepiece with a larger top element .
This can be easier with a 2"eyepiece but will depend on design.
see my pic of the one I made.

Mark

[mch62 (Mark)]

in use