From: TerryMoselaol.com
Date: Thu, 9 Dec 2004 17:28:24 EST
Subject: Lidl Binocs, IAA lecture, Dunsink, Geminids
Hi all,
Some people have been asking me about the binoculars featured in the next
Lidl Special Offer, available from Monday 13 December.
These are 8-24 x 50 zoom, costing 19.99 pounds in N.I., and according to the
website euro 19.99 in ROI (not fair!).
I obviously haven't seen them yet, but I'm not sure that they would be
good for astronomy. For a start, zoom binocs are generally not ideal for
astronomy, as the extra zoom lens elements degrade the image by the extra internal
reflections and scatterings. Secondly, it costs more to produce the zoom elements
& mechanism, so if they are still keeping the price low, the quality must be
suffering somewhere! (Although I must say that the quality of all their other
optical items has always been quite good. I've had various good reports on
their two bargain telescopes, recently featured.) Third, the zoom mechanism is
one more part to go wrong, although they are of course covered by guarantee.
The glass type (I presume for the prisms) is quoted as BK7, which isn't
quite as good as the usual BAK4 (but it's still acceptable). It says that the
lenses are 'blue', which I presume is an anti-reflection coating, but it doesn't
indicate if it's multi-coating, or broadband, or full multi-coating, etc,
etc. You would need to read what's on the box to be sure.
But my most serious reservation is the small field of view, which is 78m
at 1000m, or just about 4.5 degrees, at 8x. Most 8x binocs would have a FOV of
about 8 degrees; my 10x50's have a 7 degree field. So 4.5 degrees is really
quite small, giving the impression of 'looking down a tunnel'. And the FOV will
decrease considerably with higher zoom magnification.
They do have a tripod socket at the front of the centre bar, but it
doesn't say whether a tripod adaptor is included.
They look well enough made from the photo, but it's impossible to say
until you actually see & hold & try them. A case, strap, & lens caps are included.
So my advice would be not to rush to buy them first thing on Monday - if I
get a chance I'll check out a pair 'in the flesh', and report further if I
think they're worth considering.
They might be OK for birdwatching, especially at the ROI price of euro 19,
but
you would need a tripod to use them at x15 or more.
Or at that price you might like to split them into two high-power finders
for your telescopes! If the zoom elements are not actually integral with the
eyepieces, you could dispense with them and probably get a larger FOV. But
attempt that at your own risk!
2. The next Irish Astronomical Association Public Lecture will be on Wed
December 15, when Dr John Butler of Armagh Observatory will give a talk entitled
"The 2003 Restoration of Armagh Observatory" (If you haven't visited the
Observatory recently, you should do so - quite a few changes, including one
completely new dome, a unique 'Human Orrery', and major refurbishments! But first,
come & hear this lecture, to get the full story.) It will be at 7.30 p.m.,
Lecture Room 5, Main Building, Stranmillis College, Belfast, with plenty of free
parking. Free admission as usual and there will be some free seasonal
refreshments as well!
3. I hope you've all replied to Brian McBreen as per the email letter to save
Dunsink, featured in my last email notice?
4. And don't forget the Geminids on Monday night! (details in last email)
Clear Skies,
Terry Moseley
aol.com Date: Thu, 9 Dec 2004 17:28:24 EST Subject: Lidl Binocs, IAA lecture, Dunsink, Geminids Hi all, Some people have been asking me about the binoculars featured in the next Lidl Special Offer, available from Monday 13 December. These are 8-24 x 50 zoom, costing 19.99 pounds in N.I., and according to the website euro 19.99 in ROI (not fair!). I obviously haven't seen them yet, but I'm not sure that they would be good for astronomy. For a start, zoom binocs are generally not ideal for astronomy, as the extra zoom lens elements degrade the image by the extra internal reflections and scatterings. Secondly, it costs more to produce the zoom elements & mechanism, so if they are still keeping the price low, the quality must be suffering somewhere! (Although I must say that the quality of all their other optical items has always been quite good. I've had various good reports on their two bargain telescopes, recently featured.) Third, the zoom mechanism is one more part to go wrong, although they are of course covered by guarantee. The glass type (I presume for the prisms) is quoted as BK7, which isn't quite as good as the usual BAK4 (but it's still acceptable). It says that the lenses are 'blue', which I presume is an anti-reflection coating, but it doesn't indicate if it's multi-coating, or broadband, or full multi-coating, etc, etc. You would need to read what's on the box to be sure. But my most serious reservation is the small field of view, which is 78m at 1000m, or just about 4.5 degrees, at 8x. Most 8x binocs would have a FOV of about 8 degrees; my 10x50's have a 7 degree field. So 4.5 degrees is really quite small, giving the impression of 'looking down a tunnel'. And the FOV will decrease considerably with higher zoom magnification. They do have a tripod socket at the front of the centre bar, but it doesn't say whether a tripod adaptor is included. They look well enough made from the photo, but it's impossible to say until you actually see & hold & try them. A case, strap, & lens caps are included. So my advice would be not to rush to buy them first thing on Monday - if I get a chance I'll check out a pair 'in the flesh', and report further if I think they're worth considering. They might be OK for birdwatching, especially at the ROI price of euro 19, but you would need a tripod to use them at x15 or more. Or at that price you might like to split them into two high-power finders for your telescopes! If the zoom elements are not actually integral with the eyepieces, you could dispense with them and probably get a larger FOV. But attempt that at your own risk! 2. The next Irish Astronomical Association Public Lecture will be on Wed December 15, when Dr John Butler of Armagh Observatory will give a talk entitled "The 2003 Restoration of Armagh Observatory" (If you haven't visited the Observatory recently, you should do so - quite a few changes, including one completely new dome, a unique 'Human Orrery', and major refurbishments! But first, come & hear this lecture, to get the full story.) It will be at 7.30 p.m., Lecture Room 5, Main Building, Stranmillis College, Belfast, with plenty of free parking. Free admission as usual and there will be some free seasonal refreshments as well! 3. I hope you've all replied to Brian McBreen as per the email letter to save Dunsink, featured in my last email notice? 4. And don't forget the Geminids on Monday night! (details in last email) Clear Skies, Terry Moseley
