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Finally on the BST firm

spaceboy

By spaceboy
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spaceboy

spaceboy

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I kind of knew this was one day going to happen http://stargazerslounge.com/members-equipment-gallery/117135-finally-tv-firm-7.html#post1752246 as I had always appreciated the views I'd got from my TMB clones. It wasn't until I decided to pursue imaging that it really made sense to let my set of Naglers go and seek a respectable budget alternative for the replacement. I have yet to see how they do perform under clear skies but at first impressions I'm happy with my choice. You really do seem to get a lot of eyepiece for your money. I have to say though that the eye lens caps resemble an after thought. Kind of the EP designer was so wrapped up in the idea of creating a smart looking EP that they totally forgot that a lens cap would be needed at one point. BUT smart they are. They have a nice weighty feel about them and a nice rubberized grip. Not too much they they will end up grimy with use but just enough to enable a comfortable grip when using in the cold. The focal lengths are all indicated largely on the sides of the EP so that they can be easily identified in the dark. No doubt due to keeping the cost down this is printed on as apposed to engraved so it will remain a test of time to determine the paints durability with regular handling. The only critique I would have if any is that the actual twist cup could be susceptible to malfunction over the TMB clones. The twist cup rotates upward to expose a gap between the main body and eye cup where as with the TMB clones the entire grip twists up. This means with the clones you grip the EP and no dust or other contaminates can get into the mechanism/thread where as handling the BST's with this exposed gap and some woolly gloves could be a recipe for disaster. This obviously only applies when using the twist cup and I doubt there would be any issue other wise. The eye lens is a good size so that the 60' FOV can be comfortably taken in. I think the eye relief is documented as being 16mm. Some may find this difficult to position the eye correctly but thankfully due to the twist up eye cups eye position shouldn't be an issue. This was a feature I really liked on my TMB clones and TV Radian but it's not to everyones taste.

The proof is in the pudding so to speak and I will have to await clear skies to really pic out the Pros & Cons of an eye piece but if they are anything like the TMB's I think I will be happy with the BST's for the amount of visual observing I will be doing in the future.

I have a 70' 30mm Revelation planned for my low power EP and my 3-6 zoom and BGO's are keepers for planetary observing so I think for visual observing this should have all the bases covered. There is no doubt the initial look through the BST's will have me chocked up at the sacrifices I made loosing the Nags but as I have said in previous threads, I feel the TMB's offered me more than there price point where as your paying for that level of quality Televue offer.

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John

John

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It will be very interesting to hear your impressions of how the BST's perform given your experience with premium eyepieces. I've not actually used a BST eyepiece but I've owned a few of the TMB Planetaries and their clones and enjoyed using those. The BST's are reputed to be at least as good as the TMB clones so should be pretty nice. On axis, you may not notice much difference at all in performance between the BST's and more expensive types.

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spaceboy

spaceboy

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Nice new set of ep`s were your tmb clones the same as sold at skys the limit?

Yes Jules. I had originally only purchased the clone to see if it was worth getting a TV in the focal length and ended up finding them to be great for the money. I did consider going with the clones again but coming from 82' to 60' is going to be painful enough as it is.

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spaceboy

spaceboy

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I thought I had best document my first light for those of you who had shown an interest.

All my observations were based on using the BST's in an 200mm F/5 Newtonian and results may differ in different styles of scope no matter what the focal ration.

I think the BST Explorers are all good for the money and would most probably perform well in scopes F/7-8 and above in the longer focal lengths and F/5-6 in the shorter focal lengths. The shortest of which 5mm didn't really suffer being in an F/5 as a planet sits in the center FOV. The 18-24mm in the F/5 I would estimate the outer 30-40% edges shows signs of coma with the last 20% showing so much field curvature, coma and astigmatism that I'd consider it pointless being there. The 8-12mm (15mm not as good as the 12 but better than the 18) did show coma but it was of an acceptable level given the cost of the eye piece and the open clusters I was viewing at these magnifications M35,36,37. The 5mm was a very nice eyepiece only showing problems if Jupiter was on the outer FOV. The larger 60' FOV more than big enough to fit the Jovian moons. I only had a brief chance to try the BST's but if it's a good budget eyepiece your looking for then I doubt for the money you could go far wrong with the BST's in scopes F/6-7 and above. They are a nice eyepiece showing much brighter and cleaner stars than most budget EP's I have come across and even my Nags but I don't think the longer focal lengths 18-24 mm (depending how fussy you are the 15mm as well) work well in fast scopes. Others may disagree but we all have our likes and dislikes. I personally find CA distracting in achromatic refractors where others don't notice it. Some may find coma more distracting than others.

What I do know is that you really will not find a better person to do business with than Alan at sky's the limit. He goes above and beyond the standard of customer service that I have ever come across. If you are considering the BST's then I know Alan offers a try B4 you buy on some of the EP's so it may pay to put this into practice with the longer focal length EP's if you are like me and have fast scopes. As for the shorter focal lengths they will show a significant improvement over the SW plossls that come with the scope.

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spaceboy

spaceboy

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The 18-24mm in the F/5 I would estimate the outer 30-40% edges shows signs of coma with the last 20% showing so much field curvature, coma and astigmatism that I'd consider it pointless being there.

I just wanted to EDIT my original post regards the aberrations experienced in the 18 &25 mm BST's to something more accurate.

The 18-25mm in the F/5 I would estimate the outer 30-40% edges starts to show signs of coma, the last 20% showed significant pin cushion that I'd consider it pointless being there. While I was able to position my eye to reduce this effect non the less it was still an issue for me.

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spaceboy

spaceboy

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What I have found with cheaper eyepieces is that they work perfectly fine if you do not have over expectations. If £40 EP's were perfect then everyone would have them. As it is they aren't perfect so you have to make compromises when using them. In my F/5 I found the 8 & 15mm BST to be very good given the cost of the EP and the FOV you get. It depends on what objects you intend to use those magnifications on. The 8mm will give you x187 so your likely only to be looking at the centre of view, ie planets/ globulars and may not notice any issues regards edge correction. The 15mm at x100 will probably see use on some nebulas and tight clusters so surrounding stars will show signs of coma and distortion. What I do is drop the mag slightly so that the object sits within the centre of view. The stars around the object then make no difference to me if they do show aberrations as long as the object in the centre is well corrected. It might be considered pointless having the extra FOV in this case but the BST's are an improvement in more ways than just FOV. If you currently use these magnification in a cheap plossls and are looking to improve the views then you will benefit from the BST's but they will show aberrations at the edges due to the nature of wider field EP's. As said above for me I feel they did show more aberrations the longer the focal length but the 5-15mm coped with them well.

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todd8137

todd8137

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What I have found with cheaper eyepieces is that they work perfectly fine if you do not have over expectations. If £40 EP's were perfect then everyone would have t

cool might give them a go i do have a couple a decent eps, and i have a couple a skywatcher uw 66 ep now they show the smallest bit, and a mean smallest bit of curvature, but the have great contrast, and seem great so its either 2 of those,or two bst`s we shall see a mate might let me have the use of one no pay pal so i can not ask alan to do the deed but i reckon if i send him the cash he will send me a couple to try ,my fear is that if so many people have had the try before you try eps they may not be in the best condition no probs thanks for the reply

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spaceboy

spaceboy

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,my fear is that if so many people have had the try before you try eps they may not be in the best condition no probs thanks for the reply

I would not let this concern you. If an ep was returned to Alan in less than 100% mint condition I'm sure he would not accept it back and he certainly wouldn't pass it on to a buyer.

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todd8137

todd8137

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I would not let this concern you. If an ep was returned to Alan in less than 100% mint condition I'm sure he would not accept it back and he certainly wouldn't pass it on to a buyer.

I ment the ones they send out to try, of course he will send new ones out,have brought stuff before of him and it was a great service

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