jetstream

Qualia,thank you for taking the time to put this together,it is fantastic.

I have at least a dozen refractors including a 102mm flourite, 127mm F15 triplet and a 220mm F 12.5 achromat, I still prefer the detail in my 16" SCT on a good night though a younger observer may well do better with the others.

Now that,Sir,is a telescope!(16" SCT) Mighty impressive looking,I can only imagine!

Very nice Rik,now we know who to ask about the Pentax's!Obviously they are excellent if they are in this case

I'm not one for excuses, but ....I've been suffering from chronic back ache this last week or so, a harsh case of sciatica. Refusing to take any time off work (exam time and slow but very worried children need to pass or they're put back a year!) mixed in with a little pain and a mighty cocktail of medicine is knocking me out a little. As soon as I get back on the mend, I'll tidy the OP and include a part III.

I am sorry and do apologise to everyone. Thank you all for your kind words and support, seriously, from the bottom of my heart, thank you to everyone

Your students are very fortunate to have you as their teacher Rob.Thanks again for all the work on this

Well done Qualia,can't wait for the DSO work!Thanks

For me "light tresspass" into my viewing area from local lighting messes up my night vision,so I take the steps to block that light,but actual skyglow problems are harder to combat. If the lights nearby are messing up nightvision and the sky is bright that is a real problem.I like umadogs reply!

There is also another thing that may help and it is the subject of exit pupil.As other posters have said as exit pupil decreases it dims the view.Mel Bartles assembled,came up with an interesting obsevation/conclusion.From the page Visual Astronomy at the Telescpoes Eyepiece:"Magnifying the image results in smaller exit pupils,the useful maximum magnification or smallest exit pupil being close to 1mm.The sky glow brightness drops more than 4 magnitudes to close to 26 magnitude as exit pupil shrinks to 1mm."This was from a reference of 21.5mag.The main issue for us (I think) is the 4 magnitude difference at the 1mm exit pupil.So thing is at the 2mm-1mm exit pupil will this provide an appropriate magnification for the existing sky (seeing ) conditions?I have personally obseved this from my light polluted house area.At 27x my scope illuminates the skyglow badly(3.28mm exit pupil),at 63x the skyglow is dimmed quite a bit(1.42mm exit pupil).This also answers my question of my Delos...Why at times did it do better on DSO's from my house?I thought just because it is a premium eyepiece,but at .86mm exit pupil the glow is dimmed to the limit.I can see bright DSO's from my yard-though not great-using the smaller exit pupils.So bascially if going to 1mm-2mm exit pupil puts you in a reasonable magnification range,try it.Along with the other suggestions this may help.