Lacey, A quick run-thru, Collimate the finder to the t'scope. To do this, take the t'scope outside during the DAY, or somewhere you can see an object about 500/1000 mtrs away, say a tower or pole.
DO NOT POINT AT SUN OR LEAVE UNATTENDED.
Fit the larger E/Pc, 25 mm?, centre the top of the pole in the (F)ield (O)f (V)iew of the E/Pc. Adjust the finder to centre on the SAME pole.
When viewing at night, roughly align the t'scope to/at the object, & using the finder, centre the object. USE the 25 mm E/Pc, & with, say, JUPITER centred, slowly adj. the focus till it's a crisp DISK, & the bands stand out clearly. You should also see the moons as pinpoints of light.
NOW, change E/Pcs. You should only have to move the focus very slightly to get a crisp image. Pinpoint stars are what you're aiming for.
If you want to use a barlow, (an 'ORION' shorty seems the go here), which will effectively double the magnification, then start with the 25 mm E/Pc first. This gives you 12.5 mm E/Pc., with 80 x mag.
Guys, please correct here if nec. The 8"/200 mm is 1000 mm long is it not? This makes it an f8. The mags you get with your current E/Pcs are 25 mm = 40 x, 10 mm = 100 x.
1000 div by 25 = 40. etc etc.......
In reading your post, I can see that you're trying to magnify by adjusting the focus. THIS IS WRONG. To magnify, you change E/Pcs.
A good spread of E/Pcs is one where you DON'T DOUBLE UP too closely, so with a 25 & 10, I would suggest an 18 mm/15 mm/9 mm. But, buy good quality 'Plossl's'.
HTH. If you have any more questions, please ask. We are here to assist everyone in this great hobby.
Regards, L
ps. Apologies to Grant for this post. Good luck with your choice of DOB.
