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Date: 24 Aug 2006 23:44:14
From: Steve & Lizzie
Subject: How can I find what I'm looking for?
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I am a struggling amateur trying to find my way around the night skies.
I have a Skywatcher 130P (130mm reflector) and a reasonable pair of 10x50
binoculars. My recognition of objects and constellations is improving but I
am finding it hard to recognise things in my scope.
For instance, I am pretty confident that I can locate M81 and M82 with the
binoculars (I can't see any details - just two points of light where I would
expect them to be), I use the plough to help me locate these. When using the
scope however I can't find them! Because of the equatorial mount I can't
follow the alignment of certain stars to point me in the right direction.
Am I doing something wrong here or is it just the matter of experience?
Also I've recently attempted to collimate the scope - previously when I've
de-focused on stars the surrounding rings were greatly to one side - these
are now central. However the number of rings varies greatly depending on
over focus / under focus - I'm not sure the rings are perfectly round
either! Have I collimated incorrectly?
Any help is greatly appreciated.
Many thanks
Steve
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Date: 24 Aug 2006 21:56:28
From: Willie R. Meghar
Subject: Re: How can I find what I'm looking for?
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"Steve & Lizzie" wrote:
>I have a Skywatcher 130P (130mm reflector) and a reasonable pair of 10x50
>binoculars. My recognition of objects and constellations is improving but I
>am finding it hard to recognise things in my scope.
>
>For instance, I am pretty confident that I can locate M81 and M82 with the
>binoculars (I can't see any details - just two points of light where I would
>expect them to be), I use the plough to help me locate these. When using the
>scope however I can't find them! Because of the equatorial mount I can't
>follow the alignment of certain stars to point me in the right direction.
>
>Am I doing something wrong here or is it just the matter of experience?
Hi Steve,
M81 and M82 should not look like "just two points of light" (like
stars) with 10x50 binoculars. They should look like small, nebulous,
oval, extended objects. An experienced observer under a dark sky
might call them "bright." Under poorer skies the same observer might
call them "faint" or "extremely faint" -- depending on just how poor
the sky is.
There's more than one way of finding celestial objects:
A 1x finder such as a Telrad or one of the many variations of red-dot
finders, if you don't already have one, ought to make it easier to
point your telescope at celestial objects. Some observers use these
finders in addition to a magnifying finder (such as a 9x50 finder).
It helps to use star atlase(s) that show the same stars that are
visible in your finder(s) -- (atlas and finder having a similar
limiting magnitude). Being able to successfully point a telescope is
easier with these basic tools (finder(s) + matching star charts).
You could also make use of your equatorial mount to help you find
objects: If your mount is properly polar aligned you could point the
scope at a star that's at the same RA (or Dec) as the object, then,
while looking in a low powered eyepiece, sweep in RA (or Dec) toward
the object.
After a little practice, and knowing the true fields of view of your
finder(s) -- as well as your eyepieces as used with your telescope,
you could make use of stars that are 'reasonably close' to the same RA
(or Dec) and use the same procedure outlined in the previous
paragraph.
After a bit of experience (stars can sometimes be better than deep sky
objects to practice finding techniques on) you'll discover one or more
finding technique that works well for you.
>Also I've recently attempted to collimate the scope - previously when I've
>de-focused on stars the surrounding rings were greatly to one side - these
>are now central. However the number of rings varies greatly depending on
>over focus / under focus - I'm not sure the rings are perfectly round
>either! Have I collimated incorrectly?
It sounds like you've collimated correctly. Eventually, especially
for high powered planetary work, you'll want to make sure the rings
*are* perfectly round; but for now it sounds like you're close enough
for the kind of observing you're doing.
Willie R. Meghar
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Date: 25 Aug 2006 12:13:36
From: Llanzlan Klazmon
Subject: Re: How can I find what I'm looking for?
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"Steve & Lizzie" <steveandlizzie@blueyonder.co.uk > wrote in
news:iRqHg.158765$F8.119056@fe3.news.blueyonder.co.uk:
> I am a struggling amateur trying to find my way around the night skies.
>
> I have a Skywatcher 130P (130mm reflector) and a reasonable pair of
> 10x50 binoculars. My recognition of objects and constellations is
> improving but I am finding it hard to recognise things in my scope.
>
> For instance, I am pretty confident that I can locate M81 and M82 with
> the binoculars (I can't see any details - just two points of light where
> I would expect them to be), I use the plough to help me locate these.
> When using the scope however I can't find them! Because of the
> equatorial mount I can't follow the alignment of certain stars to point
> me in the right direction.
>
> Am I doing something wrong here or is it just the matter of experience?
Equatorial mounts to take a bit of getting used to. It is a good idea with
an equatorial mount to make sure that it is at least roughly polar aligned
before you start. Some info:
http://www.astronomy.net/articles/25/
Klazmon.
>
> Also I've recently attempted to collimate the scope - previously when
> I've de-focused on stars the surrounding rings were greatly to one side
> - these are now central. However the number of rings varies greatly
> depending on over focus / under focus - I'm not sure the rings are
> perfectly round either! Have I collimated incorrectly?
>
> Any help is greatly appreciated.
>
> Many thanks
>
> Steve
>
>
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Date: 24 Aug 2006 23:57:26
From: Sam Wormley
Subject: Re: How can I find what I'm looking for?
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Steve & Lizzie wrote:
> I am a struggling amateur trying to find my way around the night skies.
>
> I have a Skywatcher 130P (130mm reflector) and a reasonable pair of 10x50
> binoculars. My recognition of objects and constellations is improving but I
> am finding it hard to recognise things in my scope.
>
> For instance, I am pretty confident that I can locate M81 and M82 with the
> binoculars (I can't see any details - just two points of light where I would
> expect them to be), I use the plough to help me locate these. When using the
> scope however I can't find them! Because of the equatorial mount I can't
> follow the alignment of certain stars to point me in the right direction.
>
You should be able to "scan" the right region with your 130mm and a 25mm
or longer focal length eyepiece and find M81 and M82 in the same field
of view. Are you sure you are finding the right location with the binocs?
http://edu-observatory.org/mcc/sky_charts/M81M82.pdf
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Date: 24 Aug 2006 23:55:00
From: Sam Wormley
Subject: Re: How can I find what I'm looking for?
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Steve & Lizzie wrote:
> I am a struggling amateur trying to find my way around the night skies.
>
> I have a Skywatcher 130P (130mm reflector) and a reasonable pair of 10x50
> binoculars. My recognition of objects and constellations is improving but I
> am finding it hard to recognise things in my scope.
>
> For instance, I am pretty confident that I can locate M81 and M82 with the
> binoculars (I can't see any details - just two points of light where I would
> expect them to be), I use the plough to help me locate these. When using the
> scope however I can't find them! Because of the equatorial mount I can't
> follow the alignment of certain stars to point me in the right direction.
You should be able to "scan" the right region with your 130mm and a 25mm
or longer focal length eyepiece and find M81 and M82 in the same field
of view. Are you sure you are finging the right location with the binocs?
http://edu-observatory.org/mcc/sky_charts/M81M82.pdf
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Date: 24 Aug 2006 23:54:52
From: Jim Klein
Subject: Re: How can I find what I'm looking for?
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"Steve & Lizzie" <steveandlizzie@blueyonder.co.uk > wrote:
>I am a struggling amateur trying to find my way around the night skies.
>
>I have a Skywatcher 130P (130mm reflector) and a reasonable pair of 10x50
>binoculars. My recognition of objects and constellations is improving but I
>am finding it hard to recognise things in my scope.
>
>For instance, I am pretty confident that I can locate M81 and M82 with the
>binoculars (I can't see any details - just two points of light where I would
>expect them to be), I use the plough to help me locate these. When using the
>scope however I can't find them! Because of the equatorial mount I can't
>follow the alignment of certain stars to point me in the right direction.
>
>Am I doing something wrong here or is it just the matter of experience?
>
>Also I've recently attempted to collimate the scope - previously when I've
>de-focused on stars the surrounding rings were greatly to one side - these
>are now central. However the number of rings varies greatly depending on
>over focus / under focus - I'm not sure the rings are perfectly round
>either! Have I collimated incorrectly?
>
>Any help is greatly appreciated.
>
>Many thanks
>
>Steve
>
When I started, a Nortor Star Atlas, a red flashlight and a
confortable pool-side type folding lounge helped. Going to a star
party with someone who knows the constellations helps a great deal.
Lots of practice helps you learn to "see" the patterns of the
constellations. Planetarium shows help if you have one near.
Spotting Scope
If the rings are not symmetric when the star is in the center of the
field of view, the collimation may be off. If recollimation does not
help, there may be a wedged element or airspace.
If the asymmetric rings only appear when the star is to one side of
the center of the field then it may be residual comma or other
off-axis aberrations.
Most spotting scopes work well during the day with bright scenes and
your eye's pupil stopped well down but show their residual aberrations
at night, looking a point sources when you eye's pupil is opened up to
5 or 6 mm.
When picking any spotting scope or binocular for astronomy, you really
must test them with stars. No other test outside the optics lab is as
critical.
Hope this helped,
James E. Klein
jameseklein@earthlink.net
Engineering Calculations
http://www.ecalculations.com
ecalculations@ecalculations.com
Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows and (soon) MAC OSX
Free KDP-2 (DEMO) downloadable!
1-818-507-5706 (Voice and Fax)
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Date: 25 Aug 2006 07:55:52
From: John Carruthers
Subject: Re: How can I find what I'm looking for?
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Steve & Lizzie wrote:
> I am a struggling amateur trying to find my way around the night skies.
>
> I have a Skywatcher 130P (130mm reflector) and a reasonable pair of 10x50
> binoculars. My recognition of objects and constellations is improving but I
> am finding it hard to recognise things in my scope.
>
> For instance, I am pretty confident that I can locate M81 and M82 with the
> binoculars (I can't see any details - just two points of light where I would
> expect them to be), I use the plough to help me locate these. When using the
> scope however I can't find them! Because of the equatorial mount I can't
> follow the alignment of certain stars to point me in the right direction.
>
> Am I doing something wrong here or is it just the matter of experience?
>
> Also I've recently attempted to collimate the scope - previously when I've
> de-focused on stars the surrounding rings were greatly to one side - these
> are now central. However the number of rings varies greatly depending on
> over focus / under focus - I'm not sure the rings are perfectly round
> either! Have I collimated incorrectly?
>
> Any help is greatly appreciated.
>
> Many thanks
>
> Steve
Hi Steve, get hold of a copy of "Turn Left at Orion", it will keep you
going for years :-)
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Date: 25 Aug 2006 06:46:44
From: William Hamblen
Subject: Re: How can I find what I'm looking for?
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On 2006-08-24, Steve & Lizzie <steveandlizzie@blueyonder.co.uk > wrote:
> I have a Skywatcher 130P (130mm reflector) and a reasonable pair of 10x50
> binoculars. My recognition of objects and constellations is improving but I
> am finding it hard to recognise things in my scope.
First, I would replace the red dot finder on the Skywatcher 130P
with a decent finder.
Second, I would look for M81 and M82 in March, when they are
high in the evening sky.
Bud
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