1 more Q on eyepieces...

[Steve Swancott]

After reading the advice for a 4mm eyepiece and that it may be too powerfull for the scope, would it be better to opt for a 17mm (as i currently have a super 10 and 25) so that would be 'in the middle' ???

[Aronnax]

Hi there, might be a good reminder to tell us what scope you've got?

[Mattscar]

What scope do you have? Theres theres a way of working out what EP lengths will best complement your scope.

[Mattscar]

You have the skywatcher 200 Newt I think? Which is an f/5 scope the same as mine. If you read this thread it explains the maths behind what Im about to say

http://stargazerslounge.com/topic/43171-eyepieces-the-very-least-you-need/

The upshot is, if your after a good 'in the middle' EP for an f/5 scope, go for an 18mm. Iv just bought an 18mm BST and couldn't be happier.

[ronin]

He says elsewhere the 200P but could be f/5 or f/6. So the high end would mean a 5mm, although the amount of use is questionable as conditions simply would not allow it all that often. Real question is the budget per eyepiece.

The BST's are considered good however selection at the low end is either a 5mm and then an 8mm.

I would suggest the 8mm if you want reasonable power. The 5mm is likely to be used only rarely.

The X-Cels are the next and they are offered in 7mm and 9mm, to an extent better for the scope as if the 7mm is too much the 9mm should be fine. Catch is they are £69 each, the BST's are £47 each. So 3 BST's for much the same as 2 X-Cels. Performance is pretty much identical from the various reports made.

Mid power 12mm or 15mm and a low power one at 25mm.

I have ignored the supplied eyepieces as I don't think they are even plossl's.

Mentioning plossl's there are the Vixen plossl's at £30 each from FLO, think they start at 8mm. If you wear glasses then plossl's may not be a good choice. As said it all depends on the budget and also how many you intend to get.

The parfocal aspect - have found that even ones of the same family are not parfocal but reasonable enough that there is not too much adjustment needed. 2 different eyepiece makes usually results in quite a bit of refocusing. So not ideal but what there is is useful.

[Mattscar]

If it is the scope we've guessed at, this recent thread pretty much covers it from start to finish

http://stargazerslounge.com/topic/183626-recommended-eyepieces-for-skywatcher-explorer-200p/#entry1906872

[Steve Swancott]

Yeah sorry abut that, i have the SW 200 so you did pretty well guessing!

Budget wise 20-60 £ ?

And also ive just forgotten what do the 'f/5 or f/6 mean?

Cheers

Steve

[Mattscar]

For around £40 you can pick up one of the BST Explorer EP's from http://www.ebay.co.uk/itm/1-25-18mm-BST-Explorer-Dual-ED-eyepiece-Branded-Starguider-/380521268257?_trksid=p5197.m1992&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14%26meid%3D7066883854865456168%26pid%3D100015%26prg%3D1006%26rk%3D1%26sd%3D380521268257%26 after tomorrow. f/5 and f/6 are the 'speeds' of your telescope. Rather than me trying to butcher the explanation, check the thread I posted a link to above which should give you all you need to know.

Matt

[Aronnax]

Yeah sorry abut that, i have the SW 200 so you did pretty well guessing!

...

Just to be sure, is it the 1000mm focal length Explorer, or the 1200mm focal length Skyliner?

The first is the equatorial mounted, the second dobsonian mounted (as standard).

Clear skies

[faulksy]

better than the bst,s in my opinion and the same price are the t.s. hr,s from modern astronomy, i find the bst,s add a yellow tint to bright objects, other than that there fine

http://www.modernastronomy.com/eyepieces.html

[ronl]

I find this site very helpful, giving explanations to eyepieces, it's worth a read

http://www.swindonstargazers.com/beginners/eyepieces.htm

Good Luck and Clear Sky's

[Steve Swancott]

Explorer