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Which two BST explorers?

Davie

By Davie
in Discussions - Eyepieces

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Davie

Davie

Posted
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Evening all,

I got some cash for Christmas to spend on some astronomy gear and I've decided to go for a couple of BST explorers but as the title says, which two?

At the minute ive pretty much only got the bog standard 10 & 25mm skywatcher ones and a 6mm which until i know better is pretty good when the seeing is spot on.

the two I was thinking on were the 8mm and probably the 18mm

any advice will be welcomed :)

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wookie1965

wookie1965

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Depends what you want to look at but for planetary you cant go wrong with the 8mm and the 15mm was voted best in class in Sky at night magazine. Thats two good choices there you could go for the 8 and the 18 but which ever you decide you wont be disappointed i have the 5,8.15.18 i bought the 8 and 18 first but since getting the 15 i have had some amazing views with that, hope i have helped and not confused you. 

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YKSE

YKSE

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If you're thinking of 8mm and 18mm EP, I would like to take a serious look at Baader Classic Ortho 18mm and Baader2.25x Q-T barlow instead. BST are good EPs, but BCO are better in contrast and scatter to my eyes, optical quality are among the best according to these reviews:

http://stargazerslou...e-story-so-far/

http://www.cloudynig...ll/fpart/2/vc/1

Combined with the 2.25x barlow, you get both the 8mm and 12mm.

If you can live with short eye relief of 5mm, I would highly recommend this set

http://www.firstligh...ith-turret.html

you get a decent finder eyepeice (32mm), then all the needed focal length with the other BCOs in combination with the barlow, with optical quality in par with EPs cost many times more.

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Erekose

Erekose

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I bought the 8mm and the 12mm. They compliment each other very well with the 8mm giving reasonable magnification and the 12mm a slightly bigger overall view more in the medium magnification group. It will depend on what it is that you want the eyepieces for: wider views, magnification or general medium usage.

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Stargazer_00

Stargazer_00

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Given than you you have a 3x and a 2x barlow I'd go for a 25mm giving you a 12.5mm and an 8.333mm with the barlows. 

Get just that to start with and then see if you want to put actual dedicated eyepieces at any of those point.

The 18mm would give 9mm and 6mm.  You have a 10mm and a 6mm already. 

If, like me, you prefer not using a barlow then I'd say go for the 18mm and the 12mm first.  Then put in an 8mm, then a 15mm then a 5mm and then replace the 25mm.  You can get the 25mm earlier than the lower end if you prefer the lower magnification.

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AlexB67

AlexB67

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The only thing I would say about the 25mm is that it shows a fair bit of astigmatism in a faster scopes.  While I've never tried with that eyepiece, sticking in the barlow could help reduce that.  Given it has been stated the 25mm is a bit of the weaker one in the range, I'd have to agree after having used the BSTs a lot out of the 3 that I own. I don't want too sound to harsh it is still very good though, so I'll say, relatively speaking.

An alternative would be a Vixen NPL with smaller FOV and larger exit pupil, but will likely be a bit sharper form what I've read, and less likely to suffer form aberrations across the FOV and bag about the same amount of sky. 

It has been  while since I compared them, but as far as the 25mm goes against the skywatcher plossl, apart from the bigger FOV and certainly noticeable improvement in contrast, which is nice in any case, star sharpness I did not find to be a noticeable step up, compare that to the Maxvisions for example ( a little bit more expensive ) off axis and sharpness are a step up.

Of course it is always possible I got one of the lesser ones  out of a BST batch, that I'll never know, it was a second hand 25mm.

If you want to go the barlow route, and if you spend 10 pounds or so on top, you could order the 24mm Maxvision since they barlow well apparently, you'd have 68 degree FOV for a bargain that holds up well at f/5. 

If FOV is less of a consideration but quality optics over the FOV high on the list at a lesser price, If I were in the same situation now buying in this range starting again, I'd also consider the higher quality plossls and orthos, eye relief wil not be a problem in the longer focal length in any case.

Good luck with whatever you go for  :smiley:

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YKSE

YKSE

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 I too owned the mv 24mm , albeit briefly . I can honestly say its the best eyepiece ive  used.

I agree that MVs are better than BSTs, but, BCOs are just a little step sharper and better scatter controll on axis than MV, to my eyes at least.

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rory

rory

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I agree that MVs are better than BSTs, but, BCOs are just a little step sharper and better scatter controll on axis than MV, to my eyes at least.

  ive not owned or looked through any ortho's , but I know the reputation that goes before them . 

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Davie

Davie

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Thanks for all the replies!

Never really considered the BCOs before but did look at the Baader plossls but decided id rather limit the spending to around about £50 each.

A few more options now so I'll have to do some more reading.

And thats not including second hand gear ....... the mind boggles when im actually trying to make a decision on what to actually buy rather than just browsing

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AlexB67

AlexB67

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I agree that MVs are better than BSTs, but, BCOs are just a little step sharper and better scatter controll on axis than MV, to my eyes at least.

In my experience star sharpness is not the strongest feature of the BST starguider design IMHO having compare it to an MV, still very good, but personally having compared them to SW super plossls as well, the main area where they win is contrast, a bit more FOV and some aberrations controlled better. 

I must say the one area where I prefer the BST over the two MVs is their tone, this is purely subjective of course as much as anything as to what one likes, but the star background is darker in my 25mm BST compared to  the 20mm MV, which you'd expect to be the other way round due to larger exit pupil.  I am not fussed about owning a series as such, but when I jump from my 25mm BST to 20mm MV to the 15m BST, sky background goes something like darker, little bit lighter, much darker.   Under better skies the MVs this effect is less noticeable. Overall transmission in the MV is still better slightly and star colour I feel.  it is not  reflection of the contrast I see in the MV is poorer, just an overall brighter rendition of what I see. 

Without having used them but listening carefully to those in the know that have used them, what I would expect to see when I buy a good ortho is that I'd be sacrificing in FOV obviously, but for a much lesser price you'd be getting an eyepiece that is very close in quality to a premium eyepiece for less cash. In the little FOV that is there you'll be minimising distortion, get excellent sharpness with very good light scatter control  and terrific transmission. Good at seeing planetary details, and also deep sky when detecting faint objects are on the edge, but possibly may find tricky to work with and not very relaxing on the eye.

Another thing I should mention on the good side of the BSTs, if it is eye comfort you are after, a relaxing view you can't do much better than the BSTs, ever so easy to use and relaxing on the eye. So are the MVs I find but their eye relief is that bit tighter when you wear glasses, the 20mm is  just on the limit for me for seeing the entire FOV without pushing my glasses against it whereas with a BST there is enough adjustable range left on the twist cup .. comfortably too.

Davie, hope that helps a bit in my limited insight having used some of these eyepieces with the disclaimer, a bit more experience than a beginner, but not a long term user like many members here that will provide better and more reliable info :smiley:

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YKSE

YKSE

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 Overall transmission in the MV is still better slightly and star colour I feel.   

Without having used them but listening carefully to those in the know that have used them, what I would expect to see when I buy a good ortho is that I'd be sacrificing in FOV obviously, but for a much lesser price you'd be getting an eyepiece that is very close in quality to a premium eyepiece for less cash. In the little FOV that is there you'll be minimising distortion, get excellent sharpness with very good light scatter control  and terrific transmission. Good at seeing planetary details, and also deep sky when detecting faint objects are on the edge,

Alex, I agree with your assessment here.

Eye relief for shorter focal ortho than 18mm is too short for htose who have to ware glasses obsering, while 18mm BCO's ER(14.7mm) feels like MV20mm's 16mm ER because of the plano eye lens. I find that it's all right not to wear glasses whith shorter ortho, since the astigmatism is very limited in high magnification, and BCO's volcano top for 10mm and 6mm make eye placement easier, to me at least.

I watched Jupiter the other night with all my EPs from 8mm to 20mm.  The seeing was very good, 200x with 10mm BCO showed all the four bands and polar cap most of the time, which can only be done with 16mm MV in more ordinary seeings. There's a white patch around Jupiter, which reduces the contrast of Jupiter's details, the brightness of this patch in decending order (not related to the focal lengths of the eyepieces) of the my EPs are: BST -> HR planetary -> MV -> BCO.

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Davie

Davie

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another option (option 473 :) ) would be that I could get a BST and a BCO to see which I like better for myself and would then maybe get the 8mm BST and the 18mm BCO.

It'll be summer before i make up my mind  :rolleyes:

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jetstream

jetstream

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Alex, I agree with your assessment here.

Eye relief for shorter focal ortho than 18mm is too short for htose who have to ware glasses obsering, while 18mm BCO's ER(14.7mm) feels like MV20mm's 16mm ER because of the plano eye lens. I find that it's all right not to wear glasses whith shorter ortho, since the astigmatism is very limited in high magnification, and BCO's volcano top for 10mm and 6mm make eye placement easier, to me at least.

I watched Jupiter the other night with all my EPs from 8mm to 20mm.  The seeing was very good, 200x with 10mm BCO showed all the four bands and polar cap most of the time, which can only be done with 16mm MV in more ordinary seeings. There's a white patch around Jupiter, which reduces the contrast of Jupiter's details, the brightness of this patch in decending order (not related to the focal lengths of the eyepieces) of the my EPs are: BST -> HR planetary -> MV -> BCO.

While I have not used a BST,they are highly a regarded EP.I do own an 18mm BCO - its optical quality is up there with Televue Ethos/Delos etc. and is very comfortable in use.Very little glare as YKSE states.

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rory

rory

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another option (option 473 :) ) would be that I could get a BST and a BCO to see which I like better for myself and would then maybe get the 8mm BST and the 18mm BCO.

It'll be summer before i make up my mind  :rolleyes:

  paralysis by analysis can be a terrible thing ,any of the eyepieces you choose between those options will not disappoint.

 I like the idea of the 18mm ortho and a 8mm bst.  

good luck with your choice .

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