What medium magnification would you choose for DSO's

[Rogering1]

Hi guys,

I have the following magnification in my F5 newt:

42x (30mm) 139x (9mm) 179x (7mm) & 250x (5mm)

I would like to use a medium ep for DSO's. From your experiences what has been most useful, 72x (17mm) or a 89x (14mm)?

Many Thanks

[Moonshane]

my favourite eyepiece in my 16" dob is my 26mm Nagler. this gives 71x. therefore I'd suggest that the 17mm in your scope would provide an equivalent magnification and also be a nice stepping stone to your 9mm.

[swamp thing]

Hi

In my 10" f4.5 Dob. I find my most used eyepiece (by a huge margin) is a 20mm. I also use this with a Barlow lens.

The magnification this gives me is around 60x and 120x This I find covers most DSO,s

[cs1cjc]

31mm to 9mm is a huge step, as you note from 42x to 179xin magnificaton, but also an exit pupil from just over 5mm to under 2mm. I would be tempted to look to cover this by 2 eyepieces in the long term, each with a step of about 1.5x to give focal lengths of around 14mm and 20mm. For DSO, I suggest an eyepiece of around 14mm first, in your case giving a good 2.8mm exit pupil.

[crazyjedi]

I use my 24mm ES to find them and have had some fine views through my 12mm Radian. The ring nebula looks fab through it. I'm dead keen to get a 15-16mm EP and a good 20mm SWA EP too

[crazyjedi]

Pentax do a very fine 14mm XW that would give you fab views. the light transmission is superlative on these EP's making them ideal DSO EP's and the 14mm will give fairly good magnifications.

[alan potts]

I would go for an eyepiece in the range from 14-18mm, there is a great deal of choice in this area but at F5 you should be looking for something of decent quality. If you want sharp to the edge you should look at higher end models but they have higher end prices. I would try for a second hand Nagler 16mm, pricey but almost impossible to better.

The other point made by Chris is also very true and his idea of 20 and 14 is a fine one too.

Alan.

[Luke]

For medium power, I like one EP at about 80x and one at about 120x. For me, out of the two, I'd choose 89x to narrow the gap to the 139x.

Good luck with your choice!