Good wide-angle EP for 200mm F5 1000mm OTA

[LouisJB]

I'm likely to upgrade from 130P to a GSO 200mm F5 1000mm focal length OTA shortly, which means all my existing eyepieces will change purpose a little (650mm focal length going to 1000mm focal length).

For wide I only have the standard kit SW 25mm Plossl at the moment, so thinking I'll need something wider to serve that purpose on the new tube.

Would I be right in thinking a BST eyepiece of around 32mm would be a good choice. Will there be much difference if it's 1.25" or 2", and if so is it worth it for a 2"when including accounting for the cost difference?

Also, related secondary questions:

At the other end, I have a 7mm Celestron excel LX, so that should give 140x on the new tube. What magnification realistically could I go to on that size tube, up to say 200x? That would suggest getting a ~5mm eyepiece for say planetary, would that be a good choice?

Finally, I only have a standard 2x SW barlow. For planetary with my camera I'd like more magnification, is there a good, reasonably priced say 3x barlow that would also be useful for use with eyepieces (on planets I'm thinking here, where max magnification will be needed the most).

[Rihard]

Hi LouisJB,

for the eyepieces choice, I recommend you take a look at this post from TheWarthog, It explains some useful maths to understand which type of eyepieces are useful depending on the telescope type / size.

Eyepieces: The Very Least You Need

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

I believe a 8" F/5 reflector can go much higher then 200X, depending on the weather conditions, for instance my Skywatcher 200P is advisertised as having an highest practical power of 400X. When the weather is good (not very common in Ireland), I'm able to use a Vixen 8mm eyepiece with my Antares 3X barlow, that should give something like 375X.

A good 3X barlow: if you are into planetary imaging, I recommend the Antares 3X. If I'm not wrong, many barlows are coated to block UV, while the Antares is not coated to block UV. This can be useful for imaging atmospheric features of Venus using the appropriate filters. I own the aforementioned Antares 3X, it's fairly inexpensive, it looks nice and solid and it does the job very well!

Hope this helps

Clear Skies

[rwilkey]

Hi, I would recommend not going more than a 6mm (166x) as this will hit the sweet spot between detail and clarity, as it's quality that counts in my view.

[LouisJB]

hi, thanks - I'll have a read of that link.

I'll try my 7mm out probably before getting anything with an even shorter focal length.

I expect I will need a wider angle eyepiece, I've come to appreciate wide-angle views visually and the 3x barlow sounds good for planetary with the video camera, planets are so small!