Saw Mars! But it was small.

The weather finally cleared and I could get my new toy out (a Meade
ETX-70AT) and look at Mars. I keep reading that Mars is currently something
like 1/70 or 1/75 the size of the full moon. The ETX-70AT has a 350 mm
focal length, I put a 4 mm (Plossl) eyepiece on it with a 2x Barlow, that
should give me 2 x (350 / 4) = 175x, right?

It was definitely round, and had a white blob in the lower left, and it kept
wandering from lower right to upper left in the view finder, but shouldn't
it have been something 2.5x the size of the moon? I realize I'm a couple
days past the *best* viewing, but the clouds weren't cooperating - is Mars
already that much further away, that it's that much smaller already?

Thanks!
C

p.s. As a newcomer to astronomy, what would you recommend would be my next
target? Will I be able to see the rings of Saturn with this telescope?
When would be the best time of year? Thanks!

"Chris Cooper" wrote:

The weather finally cleared and I could get my new toy out (a Meade
ETX-70AT) and look at Mars. I keep reading that Mars is currently something
like 1/70 or 1/75 the size of the full moon. The ETX-70AT has a 350 mm
focal length, I put a 4 mm (Plossl) eyepiece on it with a 2x Barlow, that
should give me 2 x (350 / 4) = 175x, right?

It was definitely round, and had a white blob in the lower left, and it kept
wandering from lower right to upper left in the view finder, but shouldn't
it have been something 2.5x the size of the moon? I realize I'm a couple
days past the *best* viewing, but the clouds weren't cooperating - is Mars
already that much further away, that it's that much smaller already?

Thanks!
C

p.s. As a newcomer to astronomy, what would you recommend would be my next
target? Will I be able to see the rings of Saturn with this telescope?
When would be the best time of year? Thanks!



Chris:

I am glad to hear that you got yourself a telescope and wandered out
to explore the skies I would just make a few observations:

1. Mars is always a difficult object to observe and it is usually
disappointing (dust storms, low in the horizon, few distinct surface
features, and it is just pretty far away)

2. Unfortunately (or fortunately) a lot of people got all excited
about Mars being so close this time around. However, people expect
Hubble telescope-like images when they try to observe it with their
modest telescopes. While this is great since it has gotten people out
to explore the skies, it is bad in the sense of the raised
expectations put forth by the media. There is simply no way you'll be
able to see Mars as clear as some of the photos you've seen. The white
blob that you saw was probably the polar cap and perhaps you were able
to see some surface features (usually looks like a dark X about the
Mars' surface). In order to see some color you would have to take a
long exposure photograph with a camera or a good CCD (and even then
you would have to do some correction in Photoshop or similar).
However, think about what you saw, you were able to discern the polar
cap of an object that is 35 million miles away!!

3. As to having missed the big event of Mars opposition, don't worry.
Mars was in fact further away when you saw it, but the distances are
so great that it would not have made any discernable difference if you
had been the first one to see it on Wednesday.

4. As to your question about Saturn, yes you WILL be able to see its
rings (in varying degrees of detail). Certainly, with an instrument
like yours, you will be able to see the Cassini Division and maybe the
rings' shadow on the face of Saturn. It will be a more satisfying
object to see if you are a beginner, and you will never forget your
first sight of it. Many professional astronomers, turn their scopes to
Saturn simply because of the thrill of the view. I know that I use it
as the first object to show people the first time they are out with a
telescope

5. Saturn right now, assuming you are in the US, is about 20 degrees
(pretty low in the horizon) with about .07 magnitude, which is pretty
bright. It rises at about 1:30 AM ET and sets at about 4:30 AM ET you
can find it in the Gemini constellation. As to the best time to view,
well, winter is usually best seeing, since warm air currents are at a
minimum.

Hope you enjoy your telescope, but don't limit yourself to planets!
There are some awesome sights out there. My recommendation is that you
get yourself a field/star manual or software (i.e. Deepsky) and set
yourself some goals/targets every time you go out. You will appreciate
the skies more that way.

Happy to have you join us amateur astronomers!

Don

Thanks for the info and advice!

I was aware of the issues with the terrestrial air currents etc. that would
greatly limit the detail I would be able to see - but I'm still not sure why
the image I saw was so _small_ in the viewfinder. It was definitely not
just a point, and as I increased magnification (with the different
eyepieces) it definitely got bigger, but it was never 2.5x the size of the
moon, which is what I expected.

Or was it? Did it just _seem_ smaller because of the lack of detail?

This was just a quick visit to a nearby dark street - so I fully expected
the city lights and pollution to decrease the amount of detail I would be
able to see. And yes, it was pretty cool to see the polar ice caps!

Chris

"Don" wrote in message
...
"Chris Cooper" wrote:

The weather finally cleared and I could get my new toy out (a Meade
ETX-70AT) and look at Mars. I keep reading that Mars is currently
something
like 1/70 or 1/75 the size of the full moon. The ETX-70AT has a 350 mm
focal length, I put a 4 mm (Plossl) eyepiece on it with a 2x Barlow, that
should give me 2 x (350 / 4) = 175x, right?

It was definitely round, and had a white blob in the lower left, and it
kept
wandering from lower right to upper left in the view finder, but
shouldn't
it have been something 2.5x the size of the moon? I realize I'm a couple
days past the *best* viewing, but the clouds weren't cooperating - is
Mars
already that much further away, that it's that much smaller already?

Thanks!
C

p.s. As a newcomer to astronomy, what would you recommend would be my
next
target? Will I be able to see the rings of Saturn with this telescope?
When would be the best time of year? Thanks!



Chris:

I am glad to hear that you got yourself a telescope and wandered out
to explore the skies I would just make a few observations:

1. Mars is always a difficult object to observe and it is usually
disappointing (dust storms, low in the horizon, few distinct surface
features, and it is just pretty far away)

2. Unfortunately (or fortunately) a lot of people got all excited
about Mars being so close this time around. However, people expect
Hubble telescope-like images when they try to observe it with their
modest telescopes. While this is great since it has gotten people out
to explore the skies, it is bad in the sense of the raised
expectations put forth by the media. There is simply no way you'll be
able to see Mars as clear as some of the photos you've seen. The white
blob that you saw was probably the polar cap and perhaps you were able
to see some surface features (usually looks like a dark X about the
Mars' surface). In order to see some color you would have to take a
long exposure photograph with a camera or a good CCD (and even then
you would have to do some correction in Photoshop or similar).
However, think about what you saw, you were able to discern the polar
cap of an object that is 35 million miles away!!

3. As to having missed the big event of Mars opposition, don't worry.
Mars was in fact further away when you saw it, but the distances are
so great that it would not have made any discernable difference if you
had been the first one to see it on Wednesday.

4. As to your question about Saturn, yes you WILL be able to see its
rings (in varying degrees of detail). Certainly, with an instrument
like yours, you will be able to see the Cassini Division and maybe the
rings' shadow on the face of Saturn. It will be a more satisfying
object to see if you are a beginner, and you will never forget your
first sight of it. Many professional astronomers, turn their scopes to
Saturn simply because of the thrill of the view. I know that I use it
as the first object to show people the first time they are out with a
telescope

5. Saturn right now, assuming you are in the US, is about 20 degrees
(pretty low in the horizon) with about .07 magnitude, which is pretty
bright. It rises at about 1:30 AM ET and sets at about 4:30 AM ET you
can find it in the Gemini constellation. As to the best time to view,
well, winter is usually best seeing, since warm air currents are at a
minimum.

Hope you enjoy your telescope, but don't limit yourself to planets!
There are some awesome sights out there. My recommendation is that you
get yourself a field/star manual or software (i.e. Deepsky) and set
yourself some goals/targets every time you go out. You will appreciate
the skies more that way.

Happy to have you join us amateur astronomers!

Don

I am at 45 deg North and 93 deg West, so I thought midnight would be
tolerable okay for seeing Mars. I wasn't able to find it (but my
optical tools are very primitive) and suspected Mars was hanging too
close to the horizon (any old tree or haze would block).

I have been told that the planets precess in their appearance near the
zodiacle constellations. I suppose there are tables somewhere but
might there be some fairly simple algorithms for reckoning?

Thanks,

but shouldn't it have been something 2.5x the size of the moon?

Mars may be 2.5X the moon's diameter but it's a lot further away. If
you could see it as an 1/8 inch blob with a bright cap you're doing
well. A larger instrument might show more surface detail but not a
much bigger image. In my 10" F6 I can push it up to about a 1/4
"diameter but it's blurred out and not very steady.
Keep doing what you're doing, and if you're not sure; ask :-))
jc


---
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Checked by AVG anti-virus system (http://www.grisoft.com).
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I'm glad you explained this. People watch the evening news and get the
impression that they will see what the reporter is seeing at the local
observatory! I think the news reporters do a disservice by not making it
clear that you will not see what they are seeing unless you go where they
are and use the equipment they are using.
Phyloe


"Don" wrote in message
...
"Chris Cooper" wrote:

The weather finally cleared and I could get my new toy out (a Meade
ETX-70AT) and look at Mars. I keep reading that Mars is currently
something
like 1/70 or 1/75 the size of the full moon. The ETX-70AT has a 350 mm
focal length, I put a 4 mm (Plossl) eyepiece on it with a 2x Barlow, that
should give me 2 x (350 / 4) = 175x, right?

It was definitely round, and had a white blob in the lower left, and it
kept
wandering from lower right to upper left in the view finder, but
shouldn't
it have been something 2.5x the size of the moon? I realize I'm a couple
days past the *best* viewing, but the clouds weren't cooperating - is
Mars
already that much further away, that it's that much smaller already?

Thanks!
C

p.s. As a newcomer to astronomy, what would you recommend would be my
next
target? Will I be able to see the rings of Saturn with this telescope?
When would be the best time of year? Thanks!



Chris:

I am glad to hear that you got yourself a telescope and wandered out
to explore the skies I would just make a few observations:

1. Mars is always a difficult object to observe and it is usually
disappointing (dust storms, low in the horizon, few distinct surface
features, and it is just pretty far away)

2. Unfortunately (or fortunately) a lot of people got all excited
about Mars being so close this time around. However, people expect
Hubble telescope-like images when they try to observe it with their
modest telescopes. While this is great since it has gotten people out
to explore the skies, it is bad in the sense of the raised
expectations put forth by the media. There is simply no way you'll be
able to see Mars as clear as some of the photos you've seen. The white
blob that you saw was probably the polar cap and perhaps you were able
to see some surface features (usually looks like a dark X about the
Mars' surface). In order to see some color you would have to take a
long exposure photograph with a camera or a good CCD (and even then
you would have to do some correction in Photoshop or similar).
However, think about what you saw, you were able to discern the polar
cap of an object that is 35 million miles away!!

3. As to having missed the big event of Mars opposition, don't worry.
Mars was in fact further away when you saw it, but the distances are
so great that it would not have made any discernable difference if you
had been the first one to see it on Wednesday.

4. As to your question about Saturn, yes you WILL be able to see its
rings (in varying degrees of detail). Certainly, with an instrument
like yours, you will be able to see the Cassini Division and maybe the
rings' shadow on the face of Saturn. It will be a more satisfying
object to see if you are a beginner, and you will never forget your
first sight of it. Many professional astronomers, turn their scopes to
Saturn simply because of the thrill of the view. I know that I use it
as the first object to show people the first time they are out with a
telescope

5. Saturn right now, assuming you are in the US, is about 20 degrees
(pretty low in the horizon) with about .07 magnitude, which is pretty
bright. It rises at about 1:30 AM ET and sets at about 4:30 AM ET you
can find it in the Gemini constellation. As to the best time to view,
well, winter is usually best seeing, since warm air currents are at a
minimum.

Hope you enjoy your telescope, but don't limit yourself to planets!
There are some awesome sights out there. My recommendation is that you
get yourself a field/star manual or software (i.e. Deepsky) and set
yourself some goals/targets every time you go out. You will appreciate
the skies more that way.

Happy to have you join us amateur astronomers!

Don

It was definitely round, and had a white blob in the lower left

That is the polar cap.

Vince
10" LX200 GPSw/UHTC

John Ferman wrote:

I am at 45 deg North and 93 deg West, so I thought midnight would be
tolerable okay for seeing Mars. I wasn't able to find it (but my
optical tools are very primitive) and suspected Mars was hanging too
close to the horizon (any old tree or haze would block).

Perhaps you just didn't stay out late enough. You shouldn't need any
optical aid at all to find Mars, assuming it wasn't behind clouds.
Could you see any stars near the horizon? My horizon is eight or nine
degrees higher than yours, but even from here the planet has been
unmistakably obvious for several weeks -- whenever weather and
forest-fires haven't conspired to hide the sky.

I have been told that the planets precess in their appearance near the
zodiacle constellations. I suppose there are tables somewhere but
might there be some fairly simple algorithms for reckoning?

Precession is too slow to make any noticeable difference to an
observer. Over the course of a lifetime the heavens appear to shift
by only about a degree. All the planets move against the background
of the stars very much faster than that; even Pluto covers over 100°
of ecliptic longitude in a lifetime. Around now Mars is retrograde
(because the earth is passing it), seeming to move backward about a
quarter of a degree per day and slowing; it will appear to be
stationary near the end of the month.

--
Odysseus

"Chris Cooper" wrote in
:

Thanks for the info and advice!

I was aware of the issues with the terrestrial air currents etc. that
would greatly limit the detail I would be able to see - but I'm still
not sure why the image I saw was so _small_ in the viewfinder. It was
definitely not just a point, and as I increased magnification (with
the different eyepieces) it definitely got bigger, but it was never
2.5x the size of the moon, which is what I expected.

You might be surprised. The Moon is actually quite small to the unaided
eye ~ 0.5 degrees. BTW you are already over the maximum useful
magnification of your scope. 70mm aperture gives a rule of thumb maximum
useful magnification of about (2 x aperture in mm) 140 X for your scope.

Or was it? Did it just _seem_ smaller because of the lack of detail?

I think so. The effect may have something to do with the overall apparent
field of view as well


This was just a quick visit to a nearby dark street - so I fully
expected the city lights and pollution to decrease the amount of
detail I would be able to see. And yes, it was pretty cool to see the
polar ice caps!

Light pollution isn't too much of a problem for viewing the planets as
they are bright anyway. Some people find Mars too bright near opposition
and use various filters for viewing. One thing is to make sure that you
are not viewing directly over the roof of a building, as the warm air
rising off the building (or a large concrete area) can play havoc with
the quality of the view.

Llanzlan.


SNIP