4 inch reflector can't resolve Mars at all

On May 3, 10:12 am, Bullseye wrote:
[...]
When Mars does show up
higher in the sky in a few months what will we be able to see? You say
in the 2003 opposition you were able to see the polar caps and dark
markings. When it's not so close to Earth what do people usually see
in 4-8 inch scopes? I hope it's not just an orange ball

Should be able to discern polar cap(s) as (at least) a white spot(s),
but
IIRC Mars will only subtend 15 or 16 arcseconds max on Dec. 24.

On May 2, 7:36 pm, "Starlord" wrote:
I would go for a single high power EP, they do much better that the barlowed
ones do. I used my 4.8naggler EP during mars passing.


I tend to disagree. A good Barlow, such as a Televue, works very
well.. You also effectively double the number of eyepieces you have,
giving you more flexibility WRT magnification, longer FL eyepieces
tend to have better eye relief and eyepieces used alone just barely
get you into the magnfication range needed with the typical f/6 focal
ratio.

However, the real point is that if the OP isn't prepared for Mars'
upcoming apparition, about seven months away, he will have to wait
seven YEARS, or longer, for an apparition as good. It's better, I
think, that he try to hone his skills with a larger scope, rather than
try to figure out what's wrong with a much smaller scope that didn't
work well for him at the previous (and better) apparition.

On 3 May 2007 10:45:08 -0700, "
wrote:

On May 3, 10:12 am, Bullseye wrote:
[...]
When Mars does show up
higher in the sky in a few months what will we be able to see? You say
in the 2003 opposition you were able to see the polar caps and dark
markings. When it's not so close to Earth what do people usually see
in 4-8 inch scopes? I hope it's not just an orange ball

Should be able to discern polar cap(s) as (at least) a white spot(s),
but
IIRC Mars will only subtend 15 or 16 arcseconds max on Dec. 24.

So no markings on Mars? I've decided I'm gonna get an 8 inch dob. The
114GT I've been told has a short focal ratio and built-in barlow which
is known for producing poor images.

On Fri, 04 May 2007 05:24:58 GMT, Bullseye wrote:

So no markings on Mars? I've decided I'm gonna get an 8 inch dob. The
114GT I've been told has a short focal ratio and built-in barlow which
is known for producing poor images.

You've been told wrong.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Fri, 04 May 2007 05:32:08 GMT, Chris L Peterson
wrote:

On Fri, 04 May 2007 05:24:58 GMT, Bullseye wrote:

So no markings on Mars? I've decided I'm gonna get an 8 inch dob. The
114GT I've been told has a short focal ratio and built-in barlow which
is known for producing poor images.

You've been told wrong.

_______________________________________________ __

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Well this is someone from the more specific Nexstar Yahoo group who
might know a little more about the Nexstar line of scopes. Plus he has
an Observatory signature underneath his post just like you
No really I've tried with this scope, I'm not wasting another spring
and summer with it.

On May 4, 12:32 am, Chris L Peterson wrote:
On Fri, 04 May 2007 05:24:58 GMT, Bullseye wrote:
So no markings on Mars? I've decided I'm gonna get an 8 inch dob. The
114GT I've been told has a short focal ratio and built-in barlow which
is known for producing poor images.

You've been told wrong.

Yeah, give it a break. The rule of thumb regarding Mars is that
you can begin to resolve features when Mars reaches 10" in
diameter. That occurs on 6 Oct 07. Of course this requires
excellent conditions.

The opposition date is Dec 24.822213. However it is closest
(0.5893 au) on Dec 19.

Ben

On May 3, 10:32 pm, Chris L Peterson wrote:
On Fri, 04 May 2007 05:24:58 GMT, Bullseye wrote:
So no markings on Mars? I've decided I'm gonna get an 8 inch dob. The
114GT I've been told has a short focal ratio and built-in barlow which
is known for producing poor images.

You've been told wrong.

I disagree. I bought two 114GT systems at Costco about 2 months before
the 2003 Mars opposition to have additional scopes out for my Mars
party
and the OTA is the most difficult to collimate and use of any OTA I've
ever
used. Ever. I ended up with 10 other scopes/mounts out instead.

To be fair, in skilled hands (e.g., mine :-) a good view can be
achieved,
but I quickly decided that if anyone so much as looked crosseyed at
the focuser it'd be out of service for the evening. The two OTAs are
in
a box and their GOTO mounts are in service for binoculars and cameras.

Some pix he

http://thadlabs.com/ASTRO/Projects/#114GT

On 3 May 2007 23:56:07 -0700, "
wrote:

On May 3, 10:32 pm, Chris L Peterson wrote:
On Fri, 04 May 2007 05:24:58 GMT, Bullseye wrote:
So no markings on Mars? I've decided I'm gonna get an 8 inch dob. The
114GT I've been told has a short focal ratio and built-in barlow which
is known for producing poor images.

You've been told wrong.

I disagree. I bought two 114GT systems at Costco about 2 months before
the 2003 Mars opposition to have additional scopes out for my Mars
party
and the OTA is the most difficult to collimate and use of any OTA I've
ever
used. Ever. I ended up with 10 other scopes/mounts out instead.

To be fair, in skilled hands (e.g., mine :-) a good view can be
achieved,
but I quickly decided that if anyone so much as looked crosseyed at
the focuser it'd be out of service for the evening. The two OTAs are
in
a box and their GOTO mounts are in service for binoculars and cameras.

Some pix he

http://thadlabs.com/ASTRO/Projects/#114GT


Hey I bought that 114GT at Costco about a week before the opposition
in 2003 That is very enlightening, cause I've heard from some
people you can collimate it, while others say it is not good cause it
has a built in barlow and short focal ratio. Someone in the Yahoo
group just pointed me to a LONG document on how to collimate it. I'm
gonna take your statement and agree that it can be collimated in
expert hands but it is more complicated than most other scopes, and
the best thing is just getting an 8" dob. Thanks.

"Bullseye" wrote in message
...
On 3 May 2007 23:56:07 -0700, "
wrote:

On May 3, 10:32 pm, Chris L Peterson wrote:
On Fri, 04 May 2007 05:24:58 GMT, Bullseye wrote:
So no markings on Mars? I've decided I'm gonna get an 8 inch dob. The
114GT I've been told has a short focal ratio and built-in barlow which
is known for producing poor images.

You've been told wrong.

I disagree. I bought two 114GT systems at Costco about 2 months before
the 2003 Mars opposition to have additional scopes out for my Mars
party
and the OTA is the most difficult to collimate and use of any OTA I've
ever
used. Ever. I ended up with 10 other scopes/mounts out instead.

To be fair, in skilled hands (e.g., mine :-) a good view can be
achieved,
but I quickly decided that if anyone so much as looked crosseyed at
the focuser it'd be out of service for the evening. The two OTAs are
in
a box and their GOTO mounts are in service for binoculars and cameras.

Some pix he

http://thadlabs.com/ASTRO/Projects/#114GT


Hey I bought that 114GT at Costco about a week before the opposition
in 2003 That is very enlightening, cause I've heard from some
people you can collimate it, while others say it is not good cause it
has a built in barlow and short focal ratio. Someone in the Yahoo
group just pointed me to a LONG document on how to collimate it. I'm
gonna take your statement and agree that it can be collimated in
expert hands but it is more complicated than most other scopes, and
the best thing is just getting an 8" dob. Thanks.

Collimating a Dob is easy. Here's my experiences with my XT-8:
http://www.schlatter.org/Dad/Astronomy/collimate.htm

Hope you find something useful.

Visit the Orion website and check out their Dobs -- I have an XT-12
Intelliscope. I use the handheld computer about 1/3 of the time, mostly
just starhop but the computer is nice to have.

When Mars does get into position for better viewing, you should be able to
make out the polar ice caps -- the planet will be a small orange ball but
you can see white on top and bottom -- not spectacular but clearly there.

On May 4, 1:09 am, Bullseye wrote:
On 3 May 2007 23:56:07 -0700, "
wrote:
[...]
I disagree. I bought two 114GT systems at Costco about 2 months before
the 2003 Mars opposition to have additional scopes out for my Mars
party
and the OTA is the most difficult to collimate and use of any OTA I've
ever
used. Ever. I ended up with 10 other scopes/mounts out instead.

To be fair, in skilled hands (e.g., mine :-) a good view can be
achieved,
but I quickly decided that if anyone so much as looked crosseyed at
the focuser it'd be out of service for the evening. The two OTAs are
in
a box and their GOTO mounts are in service for binoculars and cameras.

Some pix he

http://thadlabs.com/ASTRO/Projects/#114GT

Hey I bought that 114GT at Costco about a week before the opposition
in 2003

Ours are probably from the same batch! :-)

That is very enlightening, cause I've heard from some
people you can collimate it, while others say it is not good cause it
has a built in barlow and short focal ratio.

It can be collimated and I did it using every trick I've learned using
Newts since the 1950s, but it was tedious and the focuser leaves
a lot to be desired which is why I didn't bring them out for the Mars
party -- just touching the focuser with its builtin relay lens
(Barlow)
was inviting frustration for people inexperienced with it.

Someone in the Yahoo
group just pointed me to a LONG document on how to collimate it. I'm
gonna take your statement and agree that it can be collimated in
expert hands but it is more complicated than most other scopes,

Hmmm, assuming you mean Yahoo's "BabyNexstar" group, I'll take a
look there and see what's written. I wonder if any OTA changes have
occurred in the past 4 years?

and
the best thing is just getting an 8" dob. Thanks.

You're welcome! As others have written in this thread, the Orion
Newts (or Dobs if mounted on an alt/az rocker platform) are
extremely easy to collimate and use and they now come with a
really decent Crayford focuser, much better than the original
rack&pinion focuser (which I replaced on mine using the Orion
#13039 which is now standard on their Newts and Dobs). If
you get the Orion you'll be happy.