BST Explorer/Starguider 15mm or 18mm

[t0ny]

Hi, is this a stupid question?

I don't know what to go for as they seem so similar to me, at least their numbers do! Lots of people seem to have the 18mm is there a reason for that?

I have an f/5 SW150p if that helps?

[rory]

well if your scope has a focal length of 750mm (if thats correct) then a 18mm wil give you x 41.6 magnification, a 15mm would give x50 , so not alot in it, perhaps slighly longer eye relief on the 18 mm . i cant cant comment on the 15 to much but i had the 18mm and used it alot ,giving me x66 worked well on alot of open clusters. the other reason could be down to barlowed e/p's with 18= 9 and the 15=7.5 . other than that its just personal choice of what mag youd preffer. unless im missing something obvious.

clear skies.

[nightfisher]

The 18mm is considered the best by some people, and might be a little better for DSO viewing, and if you have a barlow it will give you a nice 9mm in the barlow, but nothing wrong with the 15mm, maybe get the 18mm, then when funds allow, get another

[t0ny]

Thanks guys that's really helped.

8mm and 18mm it is!

The 25mm skywatcher that came with it seems OK, but many go for a 30mm. I've also seen people opt for a vixen NPL over the BST at 30mm, does this sound right?

[cotterless45]

I use a Bst 25 mm for general searching , it's sharp and worth having.

Nick.

[adrianelliott]

Out of the 25mm BST and the 30mm Vixen, I'd chose the BST.

• Wider apparant field of view will be more enjoyable to use.
  
• Provides a very similar actual field of view to the Vixen (2 vs 2.08) but with more magnification.
  
• Parfocal with other BSTs so less refocusing when you switch.
  

I'd recommend though that you try the 8mm and 18mm BSTs first. You may well find that 18mm frames everything you look at very well, and that you will use a 25mm as a finder only. The supplied Skywatcher 25mm isn't actually that bad for this purpose.

[Mark in Macc]

The 15 mm won a group test award last month in Sky at Night magazine. Either would be excellent choices.

[Mzungu]

I have both and use both all the time - they both barlow well if thats any help

[t0ny]

Just ordered the 8mm and 18mm.

I hate spending money!

[Naemeth]

Just ordered the 8mm and 18mm.

I hate spending money!

Hate to say it, but you're in the wrong hobby .

Good choices by the way .

[t0ny]

My other hobby is cycling which is worse!

At least so far!

[Obi Wan Ken00bi]

Congrats on your new BST ED's! I was also very much in doubt between the 15 and 18, good choice . I also just ordered the 12, 18 and 25 last weekend.

Let us know when you have them, mine will have to travel a bit longer.

Cycling should pay for itself after a while you'd guess with the fuel prices of today

[spektrumdx8]

Congrats on your new BST ED's! I was also very much in doubt between the 15 and 18, good choice . I also just ordered the 12, 18 and 25 last weekend.

Let us know when you have them, mine will have to travel a bit longer.

Cycling should pay for itself after a while you'd guess with the fuel prices of today

Let us know how you get on with the 25mm as I used my BST Starguider properly last night- only got them last week-the 18 and 8 eyepieces, the Jupiter/Moon event looked amazing with the clearest views I've had for a while !!

Plan to upgrade my lenses to the BST range.

[t0ny]

There is always a carbon upgrade to make to a cycle, it's never ending!

I'll report back when they arrive. They were dispatched on Monday so they might be here tomorrow although so will the cloud!

I do only have 2x20min sessions worth of experience so far, got my first ever telescope on my Birthday (12th) which was a clear night, then foggy next night then snow storms and cloud until now. Guess I should have expected it!

[alan potts]

I don't have any BST's but I do read most of the eyepiece threads and have done for some time. Many say the 18mm is pick of the crop, so something to think of if only for that. I don't really think there is enough in the magnification to worry about because yours is only a short foacl length. So I think I would go with the 18mm as it would Barlow to a nice Medium power 0f about X83. At a later date you could add the 12mm

Alan

[Obi Wan Ken00bi]

Sure will do! The 25 is supposed to be the 'worst' or least good. But i like to have one range of similar EP brand.

brw tony, surprise surprise,in astronomy there is also a carbon upgrade.... Haha