Question on Planetary Magnification Increments

Here's my situation:

I'm using a 6" f/5 and eliminating some short focal length eyepieces with longer eye-relief options. My Ultimas (12.5mm and 7.5mm) and 9mm UO Ortho eyepiece/barlow configurations give me planetary magnifications of 160x, 180x 200x, 250x and 300x for exceptional nights. My urban conditions generally limit good seeing nights to 250x max, with 300x possible only on rare occasions.

Here's my question for die hard planetary observers (particularly Jupiter, Saturn an Mars) - do I need to fill in with something that will give me 225x, or is this redundant with the 200x and 250x I currently have?

Thanks for any guidance you can provide.

Thanks Mike, that is very helpful. I am contemplating replacing my 9mm UO ortho (yielding 166x, 180x, 200x and 250x in my current set) with a 10mm Ultrascopic to create a parfocal set with my Ultimas. This would change my spacing to 150x, 180x, 200x and 225x). I'm trying to figure our if the 225x might be better than the 250x as a realistic increment for planets. What do you think?

I can't see that you'd need the 225X.

That said, if you're achieving 200X with an eyepiece/barlow combination you can get higher power easily - just don't push the eyepiece all the way into the Barlow. Or use an extension tube in the Barlow (if you have a filter adapter, you're in luck, as it's an extension tube).

The further the eyepiece from the Barlows lens, the greater the magnification.
Renato
P.S. - But then again, an eyepiece giving 225X AND a Wideangle may be nice.

Hi, First Im curious, what scope do you have? I have a 6 inch F5 also, Discovery brand. I haven't "met" any other 6 inch F5 scope owners out there. Second, I do the "pull the eyepeice out" deal for small increases, seems to be about all the range I've need for the last few years. I have 4 eyepeices and a barlow. Usually it seems like I have more range than I need as I hate to be changing and refocusing all the time haha. Without barlow I can hit, 18x, 3Ox, 75x, and 136x and with barlow 36x, 6Ox, 15Ox, and 272x. and with a pull about 3OOx. So I have a big gap from 15Ox to 272x. Man, I never noticed that till now haha. Take care, Ron