OR: Eyepieces, filters, and Mars

Last night I observed Mars using a variety of magnifications and filters on
my 12.5 newtonian. Skies were fairly unsteady but seemed to settle down
with the arrival of a very thin layer of fog.

The observing session spanned perhaps 45 minutes to an hour. Much of this
time was spent going back and forth to the accessory case and matching up a
new EP and filter.

Here's what I used:

3.8mm Orthoscopic
6mm Expanse from Orion
9mm MA from Meade
7.5mm Sirius Plossl
12.5mm Sirius Plossl
18mm Orthoscopic

25% Neutral Density Filter
#80A Blue Filter
#58 Green Filter


The Results:

In moments of good seeing, the 6mm and the 9mm offered the best image of all
the eyepieces. Both performed very well outfitted with the ND Filter. This
filter reduced the planets glare just the right amount
through my scope to reveal fine planetary detail. The Eye of Mars was
pronounced as were the regions to its immediate east and west. The South
Polar Cap was very distinct when the planet was viewed using the 7.5mm EP
fitted with the #80A Blue Filter.

The eastern edge of the planet had a curious white tint to it. Not being an
experienced planetary observer, I wasn't sure what I was seeing. I thought
at first it was something the eyepiece was "adding" something to the image
but the effect was present through all the eyepieces. Clouds? A storm of
some type on the surface? I tried different filters to see how or if they
altered this whitening of the edge. It shown through them all with pretty
much the same relative intensity.

Cartes du Ciel revealed Deimos 49" away from the planets disk in
approximately the 2 o'clock position (taking in account the image flipping
inherent in astronomical scopes). This seemed a respectable distace so I
decided to concentrate on seeing the little moon. No luck. My inability to
observe the Martian moons is a major disappointment.

At 11:00 p.m., Lake Stevens time, I called it a night and brought the
telescope in the house. I seemed to be slightly frustrated with the
evening. Perhaps this is because of my relative inexperience in observing
planets.
Then again, maybe I'm realizing that Phobos and Deimos will always escape my
detection with the present telescope at my present location.


Martin

In article .net,
"Starstuffed" wrote:

The eastern edge of the planet had a curious white tint to it. Not being an
experienced planetary observer, I wasn't sure what I was seeing. I thought
at first it was something the eyepiece was "adding" something to the image
but the effect was present through all the eyepieces. Clouds? A storm of
some type on the surface? I tried different filters to see how or if they
altered this whitening of the edge. It shown through them all with pretty
much the same relative intensity.


In the last three nights, I have also noted (6" APO, 287X) the Amazonis
covered with cloud when on the limb. But for me, it is most visible
with a blue filter.



Cartes du Ciel revealed Deimos 49" away from the planets disk in
approximately the 2 o'clock position (taking in account the image flipping
inherent in astronomical scopes). This seemed a respectable distace so I
decided to concentrate on seeing the little moon. No luck. My inability to
observe the Martian moons is a major disappointment.

At 11:00 p.m., Lake Stevens time, I called it a night and brought the
telescope in the house. I seemed to be slightly frustrated with the
evening. Perhaps this is because of my relative inexperience in observing
planets.
Then again, maybe I'm realizing that Phobos and Deimos will always escape my
detection with the present telescope at my present location.



I assume you are doing all the things that will increase your chances of
success? There are so many variables when looking for Deimos & Phobos
that it is best to just keep trying. They (especially Deimos) are still
possible during this opposition with 12" of aperture. The answer is
patience. BTW, I think you packed up your gear before Mars reached the
meridian- that doesn't help your odds.

Starry Skies,
Rich

In article .net,
"Starstuffed" wrote:

SNIP

The observing session spanned perhaps 45 minutes to an hour. Much of this
time was spent going back and forth to the accessory case and matching up a
new EP and filter.



At 11:00 p.m., Lake Stevens time, I called it a night and brought the
telescope in the house. I seemed to be slightly frustrated with the
evening. Perhaps this is because of my relative inexperience in observing
planets.
Then again, maybe I'm realizing that Phobos and Deimos will always escape my
detection with the present telescope at my present location.




Martin,

One other comment. You admit that 'the (total) session lasted perhaps
45 minutes to an hour' and 'Much of this time was spent going back and
forth to the accessory case and matching up a new eyepiece and filter.'

I suggest that if you are really serious about finding Mars' moons, you
need to spend at least that amount of time and concentration on just
that one task. I've seen them both with a 6" APO. Deimos several
times, and Phobos just once, but they are obviously extremely difficult.
Get Mars out of the field or use a simple occulting device. Good luck-
you have the necessary aperture.

Someone else here had an excellent web page on finding the moons, but I
cannot find it again. Perhaps the author is reading this?

Starry Skies,
Rich

Richard wrote:


Martin,

One other comment. You admit that 'the (total) session lasted perhaps
45 minutes to an hour' and 'Much of this time was spent going back and
forth to the accessory case and matching up a new eyepiece and filter.'

I suggest that if you are really serious about finding Mars' moons, you
need to spend at least that amount of time and concentration on just
that one task. I've seen them both with a 6" APO. Deimos several
times, and Phobos just once, but they are obviously extremely difficult.
Get Mars out of the field or use a simple occulting device.


Thanks for offering this. You are right. I should spend at least that much
time and probably be prepared to do a couple of hours.

Last night, one of the diffraction spikes that arise from the vanes which
support the secondary mount was directly over that "2 o'clock" position I
referred to. However, it did not seem so bright that the little moon would
not penetrate it. Now I realize that it more than likely was and that I
don't need anything other than optimum conditions for snaring Deimos or
Phobos.

Cartes du Ciel gives Mars a cuImination time of 10:49 p.m. for tonight and a
separation 49" between it and Deimos. . .which will occupy the ten o'clock
position in an inverted and flipped FOV. I'm also going to prepare an
occulting bar for the 6mm eyepiece. This EP yields 254x with my telescope's
1525mm focal length which is in the ballpark of the 287x which you
successfully employed. Finally, I'll assume a comfortable seated position
and glue myself to the eyepiece; catching every fleeting instance of perfect
seeing as it comes along.

Thanks very much for your good advice. It is very much appreciated.


Regards,


Martin

In article .net,
"Starstuffed" wrote:


Thanks for offering this. You are right. I should spend at least that much
time and probably be prepared to do a couple of hours.

Last night, one of the diffraction spikes that arise from the vanes which
support the secondary mount was directly over that "2 o'clock" position I
referred to. However, it did not seem so bright that the little moon would
not penetrate it. Now I realize that it more than likely was and that I
don't need anything other than optimum conditions for snaring Deimos or
Phobos.

Cartes du Ciel gives Mars a cuImination time of 10:49 p.m. for tonight and a
separation 49" between it and Deimos. . .which will occupy the ten o'clock
position in an inverted and flipped FOV. I'm also going to prepare an
occulting bar for the 6mm eyepiece. This EP yields 254x with my telescope's
1525mm focal length which is in the ballpark of the 287x which you
successfully employed. Finally, I'll assume a comfortable seated position
and glue myself to the eyepiece; catching every fleeting instance of perfect
seeing as it comes along.

Thanks very much for your good advice. It is very much appreciated.



Martin,

I found the webpage. It is Greg Crinklaw's Skyhound pages. Go to the
following URL:

http://www.skyhound.com/sh/skyhound.html


Then click on 'Focus On...'
It will then take you to
'Focus on Observing the Moons of Mars.'

Great advice in this article, especially the following lines....

Focus on a nearby faint star rather than on Mars.* Try to relax your eye and
imagine that you are looking into the distance while focusing.* Most people
don't focus neutrally -- the eye isn't completely relaxed and focused at
infinity.* While looking for a moon you should relax your eye, yet this can
cause a small shift in focus unless you are careful.* Good focus is critical!

The above lines were a big help to me. Have fun!

Best Regards,
Rich

PS: You're correct- Mars culminates shortly before 11:00pm. I was in
error when I mentioned in my other post that you were looking at it
BEFORE it is on the meridian. And Deimos will be BARELY past elongation
at that time tonite- a good time to look. I hope you get transparent
and steady skies.....

Hi,

Richard DeLuca wrote:
Martin,

I found the webpage. It is Greg Crinklaw's Skyhound pages. Go to the
following URL:

http://www.skyhound.com/sh/skyhound.html

That article has been replaced with the October feature article on
Gyulbudaghian's Nebula. But I have made it available at the following
location:

http://www.skyhound.com/sh/mars_moons.html

Clear skies,
Greg

--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools Software for the Observer:
http://www.skyhound.com/cs.html

Skyhound Observing Pages:
http://www.skyhound.com/sh/skyhound.html

Greg Crinklaw wrote:
http://www.skyhound.com/sh/skyhound.html

That article has been replaced with the October feature article on
Gyulbudaghian's Nebula.

Great article, by the way. Nice job.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

Brian Tung wrote:
Greg Crinklaw wrote:

http://www.skyhound.com/sh/skyhound.html

That article has been replaced with the October feature article on
Gyulbudaghian's Nebula.


Great article, by the way. Nice job.

Thanks Brian.

--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools Software for the Observer:
http://www.skyhound.com/cs.html

Skyhound Observing Pages:
http://www.skyhound.com/sh/skyhound.html