LX90 8" or 10"

I am in the UK living in central England, I currently use an Orion Europa
150 which I sometimes attach my 300D to and take shots of the Moon, as the
Europa does not have a drive of any kind, instead of looking for a mount
that is precise enough to take other shots, planets/ deep sky with the
Europa, I am looking at saving my pennies and getting a Meade LX90 but not
sure which to go for 8" or 10".

Is it worth the extra £££'s for the 10" ?

How portable are they as I would like to take it out in the car, have a Ford
Ka and a Mazda MX-5 ( so don't have loads of space), but saying that MX-5
may be changed for a Ford Focus hatch back next year (lot more room).

On average how easy and how long does it take to set an LX90 up?

What can I expect to 'see' on average with each and what type of shots could
I get (any links to photo's would be good)?

Would use the 300D with it at first but would then look at getting a Meade
DSI

Or are there any other scopes I should look at in the same price range ?

Thanks for any help or advice

Stu

On Thu, 3 Nov 2005 10:48:44 -0000, "@home"
wrote:

What can I expect to 'see' on average with each and what type of shots could
I get (any links to photo's would be good)?

Would use the 300D with it at first but would then look at getting a Meade
DSI

Or are there any other scopes I should look at in the same price range ?

Thanks for any help or advice

I've got a 10" LX200 (not sure how it compares to the LX90 in terms of
weight, but it's a heavy blighter. I can bodily lift it on my own -
just.

A few things to consider with the 300D (there are from my exerience
with my LX200 so I'm sure someone will correct me if the specs vary).

The mount is alt-az by default. This means that extended exposures
will suffer from field rotation. To cure this you'll need to polar
align the scope with some form of wedge. I bought a standard wedge for
my 10" and found it to be useless. I now have a mega-wedge which is
rock solid (on top of the standard field tripod).

You also need to consider balance with the scope. A 300D isn't
weightless and will cause a bit of strain on the telescope's drive. A
counterweight balance would be a good idea.

Finally, what's the focal ratio of the LX90? I guess it will be f/10
(but might be wrong). If it is, you may need to consider investing in
a focal reducer to give you a slightly more relaxed image scale when
imaging with the 300D.

--
Pete
http://www.digitalsky.org.uk

"@home" wrote in message
...

I am looking at saving my pennies and getting a Meade LX90 but not
sure which to go for 8" or 10".

On average how easy and how long does it take to set an LX90 up?

For the aperture you're looking at SCT's like the LX90, LX200 etc are going
to be the most portable option.

The LX90 shares the same optics as the LX200 range. The handset, drives and
focusser differ. As the LX90 10" is pretty new you'll be best seeking
guidance from someone who's familiar with the LX200 8 and 10 inchers for the
benefit of the increased aperture.

The LX90 (8 inch) on its own is pretty quick to set up. Say 5 minutes to
carry out and mount, and another couple of minutes to align.

Its when you start setting everything else up required for imaging that
takes time and effort. You may get away with multiple short duration
exposures (60 to 120s) on the existing mount but as Pete says, field
rotation becomes apparent with longer exposures.

The optional equatorial wedge takes time to align and a permanently aligned
pier seems a more sensible idea here.

You may also be lucky wth focussing the 300D directly but I found it
necessary to attach it to a PC while focussing. This needs the laptop and
associated power requirement (more to carry and set up). You may also find
it necessary at a later stage to add a guidescope to the top of the LX90.
Its here that the arrangement starts becoming cumbersome. I find that with
the wedge, guidescope, pc and associated setup it starts becoming an effort.
Not just in the setup but also the taking apart and packing away in the
cold, when you're tired at 3am.

All this isn't to put you off. Rather to point out that the 10" may be even
more of a pain in the butt to set up and pack away if you end up with the
bells and whistles; given the extra size and weight. The 8" being the easier
option. If its easier you'll tend to use it more often, to the point that
I'm foregoing the wedge and guidescope until a more permanent arrangement
can be worked out.

As Pete also points out, F/10 may leave you with a small FOV (about 30 x 35
arc seconds with the 350D). I understand that the F3.3 reducer sold by meade
was designed for smaller CCD chips (vignetting on the larger chips). The
larger chip on the Canon attached at F/10 should cover about the same FOV as
the DSI at anyway F/3 though. At F/10 longer exposures are requried
though...

If deep sky stuff is what you're primarily looking to capture you'd be
surprised to note that its focal ratio rather than aperture that matters
most. I ended up taking more shots through the F/5 guidescope than I did
using it to guide (using the LX90 for autoguiding). If deep sky objects are
your thing you might want to consider the tiny Evostar ED80 for a larger
field of view at around 90 x 120 arc seconds with the Canon. I've seen some
great shots coming from these.

Something to chew on anyway...

Regards


Chris

Stu,



I own a LX90 8" with UHTC coatings. All of what has already been said is
correct. You have asked the right questions but some of the answers are
unique to your circumstances i.e. How portable are they! The LX90 is easy
for an able bodied adult to lift and carry over short distances. Remember
though when transporting it, you may also require some form of padding or
box to store the scope. I have had a metal case made to carry mine although
this adds weight it also doubles as a seat whilst waiting for my exposures
(requires cushion or you get a numb bum!!)it is well worth the weight for
the protection of your investment.



How portable are they would they go in my car? Yes the scope would go
in the boot, I lay my tripod in a bag across the back seat. It's the extras
you have to think about (unless they all go in your box) i.e. camera,
eyepieces, diagonal, hand box, cables, laptop, power packs, focal reducer,
counter balance kit and wedge if required.



It all depends how much you want to do with the scope, if you just want
to set up for a quick visual session then this is quick easy and doesn't
require much kit to carry, and if you have difficulty getting time out then
it is a bonus to have an easy to set up scope with the go to working to
allow maximum viewing in the smallest time. In this case the LX 90 is a
tough scope to beat.



If you want to get in to photography the LX90 in alt az mode is very
good with a web camera for planets and moon shots. You can connect your 300d
at prime focus but even with the 6.3 focal reducer you would be limited to
around 30 second images. This is not a problem if you stack a number of
these although again you need software (some is free). There have been some
very good images taken the LX90 as short exposures. Take a look on the yahoo
lx90 user group (Good helpful bunch on there).



If you want to do longer exposures you will have to buy a good wedge
,again more money and space along with counter balance kit.



If you want to do piggyback with small lens then you can get some
good results again by stacking the pictures.



Re is it worth the extra for the 10" that is something that you will
have to judge for yourself by looking through a 8 and 10" SCT and decide,
perhaps local club or star party or if near Derbyshire drop me a line.



All in all Stu I hope that this has not put you off but make sure
it's what you want before you buy it!!



If you want to take wide field shots with little time setting up or
weight what about a second hand GPDX with sky sensor and a 80mm ed or
similar mounted on the top.(scour the astro adds for a good mount) the above
should cost less than the LX90 and will be more portable.



My imaging set up that is almost ready to go is a GPDX with canon 20D
intending to mount the LX90 optics on this with a TMB 80 at the side. I sue
a Mintron camera for the auto guiding with guidedog software running on the
lap top. This is a lot of kit to move around and it can get frustrating once
set up and the clouds roll in!!!!



Hope this helps,



Paul

How good it is for planet observations?
Mars, Jupiter and Saturn look crisp and good contrast?

thanks,

Paul