Hi Guys,
It is well known (meaning I personally know more than ten imagers
that have had this problem and it is regularly discussed on several
imaging forums) that the blue and green filters cause halos in RGB
images. Many people believe that they are very bad in the AstronDon
filters. They definetly happen with the AstroDons. I don't have
enough data on non-AstroDon filters to do an objective comparison.
It is obviously more prevalent around bright stars and is worse the
more you stretch the image. I have not seen halos with narrow band
filters of any brand.
Thanks, Rick

--- In ap-gto@yahoogroups.com, chris1011@... wrote:

In a message dated 6/21/2007 12:38:25 PM Central Daylight Time,
kgkirkley@... writes:

you say the Baader filter(s?) do
not cause any halos.

I have been testing the Baader filters for the last week under all

kinds of

sky conditions. I do not see any halos around any bright stars. My

H-a images

are very sharp with no reflections or ghost images around any

stars. Maybe I am

mistaken about Astrodon filters (I have not tested them myself,

but go only

on what I have heard from others). I do know that several of my

RGB filters in

my ST10 camera cause multiple reflection ghosts near bright stars.

I don't

know who makes these filters for SBIG, but they are not of the

quality level of

the Baader series. In my STL11K camera I have installed 3 of the

narrow band 2"

Baader filters and the images they produce are super nice. All

Baader filters

have high grade multi-layer coatings on them to insure freedom

from

reflections.

It may also be that the original poster's reflections are coming

from his

cover glass and filter rear surface, something that can't be

avoided unless the

coverglass is coated with a multi-layer.

Rolando


**************************************
See what's free at
http://www.aol.com.

Roland, the SBIG filters are from Custom Scientific I believe. I get very strong halos from my green Astrodon. I had thought it was due to the fast f-ratio I was shooting with the scope I've had till now.

Stuart
============================================================
From: chris1011@aol.com
Date: 2007/06/21 Thu PM 02:37:23 EDT
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] Re: First images with AP1200 GTO

In a message dated 6/21/2007 12:38:25 PM Central Daylight Time,
kgkirkley@aol.com writes:

you say the Baader filter(s?) do
not cause any halos.

I have been testing the Baader filters for the last week under all kinds of
sky conditions. I do not see any halos around any bright stars. My H-a images
are very sharp with no reflections or ghost images around any stars. Maybe I am
mistaken about Astrodon filters (I have not tested them myself, but go only
on what I have heard from others). I do know that several of my RGB filters in
my ST10 camera cause multiple reflection ghosts near bright stars. I don't
know who makes these filters for SBIG, but they are not of the quality level of
the Baader series. In my STL11K camera I have installed 3 of the narrow band 2"
Baader filters and the images they produce are super nice. All Baader filters
have high grade multi-layer coatings on them to insure freedom from
reflections.

It may also be that the original poster's reflections are coming from his
cover glass and filter rear surface, something that can't be avoided unless the
coverglass is coated with a multi-layer.

Rolando


**************************************
See what's free at
http://www.aol.com.





============================================================

In a message dated 6/21/07 1:42:04 PM, chris1011@aol.com writes:

I have been testing the Baader filters for the last week under all kinds of
sky conditions. I do not see any halos around any bright stars. My H-a
images
are very sharp with no reflections or ghost images around any stars. Maybe I
am
mistaken about Astrodon filters (I have not tested them myself, but go only
on what I have heard from others). I do know that several of my RGB filters
in
my ST10 camera cause multiple reflection ghosts near bright stars. I don't
know who makes these filters for SBIG, but they are not of the quality level
of
the Baader series. In my STL11K camera I have installed 3 of the narrow band
2"
Baader filters and the images they produce are super nice. All Baader
filters
have high grade multi-layer coatings on them to insure freedom from
reflections.

It may also be that the original poster's reflections are coming from his
cover glass and filter rear surface, something that can't be avoided unless
the
coverglass is coated with a multi-layer.

Rolando

Roland:

Thanks for the clarification.

Kent


**************************************
See what's free at
http://www.aol.com.

In a message dated 6/21/2007 2:32:22 PM Central Daylight Time,
stuart.j.heggie@sympatico.ca writes:

Roland, the SBIG filters are from Custom Scientific I believe. I get very
strong halos from my green Astrodon. I had thought it was due to the fast
f-ratio I was shooting with the scope I've had till now.

I have an older SBIG ST10E which has very strong multiple reflections form
the green filter and fainter ones from the blue. These filters have no coatings
on one side, so about 4% of the energy keeps bouncing between front and rear
surface. I do not know where SBIG got those filters. The STL11K camera that I
got from Ray Gralack have Custom Scientific RGB filters, he tells me. I have
not had any reflection problems with them.

Rolando


**************************************
See what's free at
http://www.aol.com.

In a message dated 6/21/2007 12:38:25 PM Central Daylight Time,
kgkirkley@aol.com writes:

you say the Baader filter(s?) do
not cause any halos.

I have been testing the Baader filters for the last week under all kinds of
sky conditions. I do not see any halos around any bright stars. My H-a images
are very sharp with no reflections or ghost images around any stars. Maybe I am
mistaken about Astrodon filters (I have not tested them myself, but go only
on what I have heard from others). I do know that several of my RGB filters in
my ST10 camera cause multiple reflection ghosts near bright stars. I don't
know who makes these filters for SBIG, but they are not of the quality level of
the Baader series. In my STL11K camera I have installed 3 of the narrow band 2"
Baader filters and the images they produce are super nice. All Baader filters
have high grade multi-layer coatings on them to insure freedom from
reflections.

It may also be that the original poster's reflections are coming from his
cover glass and filter rear surface, something that can't be avoided unless the
coverglass is coated with a multi-layer.

Rolando


**************************************
See what's free at
http://www.aol.com.

In a message dated 6/21/07 12:13:55 PM, chris1011@aol.com writes:

I use the Baader 2" filter now. It does not cause any halos.

Rolando

Roland:
I responded to your post, with wonderment, some days ago where you mentioned
that Astrodon filters caused halos. And, now you say the Baader filter(s?) do
not cause any halos.

This is the first I have heard of this 'situation', while halos have been
evident since the beginning of their use in ccd imaging, I thought all filters
produced some level of halos, especially with faster optical systems. I also
thought all filter manufacturers anti-reflection coated their filters.

So what is unique about the Baader's?
Is Baader producing only the Ha or a complete line of LRGB, Ha, etc. filters?

Kent Kirkley






**************************************
See what's free at http://www.aol.com.

In a message dated 6/20/2007 8:00:49 PM Central Daylight Time,
peturnielsen@yahoo.com writes:

do all H-alpha filters cause halo (i'm looking to buy one and was
thinking about getting the astrodon). what h-alpha filter would you
recommend ?

I use the Baader 2" filter now. It does not cause any halos.

Rolando


**************************************
See what's free at
http://www.aol.com.

Dear Group,

With Cygnus slowly getting into good position for imaging, there is a wide variety of goodies it provides for the interested observer and imager.

Given the plethora of Barnard dark nebulae it offers, I thought I would try my hand with one of the largest such objects just north of the bright star Sadr.

More specifically, I pursued B343 which lies within a couple of degrees just north of Sadr. For an image based on four hours total exposure, I kindly direct you to http://www.perseus.gr/Astro-DSO-Nebulae-Dark-B343.htm . This is my first attempt at a dark nebula and I would welcome all feedback. I have checked around and cannot find any reference images for comparison B343 ... if someone has pursued this particular object, I would love to see your results.

Clear skies!

Anthony.

Rick,

If you want a right-angle adapter try L-com #DG090MF1 or #DG090MF2.
See them at www.L-com.com.

Norm

--- In ap-gto@yahoogroups.com, "Rick K" <JunkMailGoesHere@...> wrote:

--- In ap-gto@yahoogroups.com, "David B. Toth" <ve3gyq@> wrote:

At 09:36 AM 6/19/2007, Rick K wrote:

And which batteryless Bluetooth adapter will do this job? AFAIK

the

serial port on the AP mounts have NO provision for supplying

power to

attached serial devices. As well any of those serial devices

are about

2 inches long and would stick up waiting to get ripped off the
controller as the scope or camera passed by. No thanks.

Integrated is

by far the best solution.

The Socket CSA is 2" or less in size, and can get its power from

Pin

9 ... you can wire pin 9 on your mount with 5 volts.
The adaptor doesn't seem to stick out any further than a DB9

would

.... I don't think it would be too vulnerable to "attack" if I

recall

where the connector is.

BTW, I think reworking the mount's electronics to add Bluetooth

would

very well require RECERTIFICATION by the FCC ...
If I recall correctly, that can cost upwards of $20k - Roland

could

comment as I am sure he knows the cost.

(The electronics have to be evaluated for the FCC to prove that

they

do not have significant RF radiation - I'm not sure if a simple

rework

would require this, but it would not surprise me)

Your mileage may vary.

Dave

Sorry, but I have looked into this and 2 inches is over a half

inch

too high. The clearance on the mount from both the big 900 and 1200
plates is inadequate to allow a 2" projection. It barely clears a
1.25" projection. I actually tie the serial cables down out of the

way

specifically so that they stay out of the way. I have been on the
lookout for right angle DB9 connectors but since RS232 is

essentially

obsolete, such items are virtually impossible to find. As it

stands,

for Bluetooth, I could wire up a short 'serial' extender cable and
modify the port to supply power but this is just a kludge. A proper
built-in Bluetooth implementation would be better. Of course, all

this

pales when compared to adding USB connectivity. THAT is way more
important. Shelve Bluetooth entirely if it is going to be a choice
between that and USB.

Although I would be completely at ease modifying the controller to
supply power to the Bluetooth adapter, I am wondering what Roland
would think about this. I expect that he might not be amused and

that

it would void the warranty.

do all H-alpha filters cause halo (i'm looking to buy one and was
thinking about getting the astrodon). what h-alpha filter would you
recommend ?

Peter


$--- In ap-gto@yahoogroups.com, chris1011@... wrote:

In a message dated 6/16/2007 8:54:07 AM Central Daylight Time,
dbcoote@... writes:

These show some halos around the stars in colour but at least I am

not

clipping the data (much) any more.
This is at:-
http://www.bcoote-astro.com/eta_tri_panel.htm

That is a pretty amazing image. By the way, it is well known that

Astrodon

filters do cause halos around bright stars. It's because of the type

of coatings

they use.

Rolando


**************************************
See what's free at
http://www.aol.com.


[Non-text portions of this message have been removed]

Bluetooth sounds good, too. What is the range for bluetooth? Will
it go thirty feet and through a window? Then I can keep the
computer inside.

Rick

Harold,
No, it's a program my friend wrote. I'll post more on it when I get
his permission.

My understanding is that it sends alt and az commands. Would it be
more accurate if it sent RA and DEC commands instead? Is it
essential that it wait for the reply after sending each command?

Sometimes the mount gets confused or loses calibration. We're
tracking that down now.

Rick

Hi,

I vote against WLAN in the mount. Users who want it can get 3rd party
serial bluetooth adapter. Let's not waste Roland's time and effort on
something that user can do themselves vs the stuff that only he on
this planet can do.

Clear Skeis,

Gert

Dear Group,

Thanks to pristine weather conditions on Monday, I had the privilege and thrill of observing and imaging my second occultation during the past three years involving two of the three brightest objects in the sky. In spite of the fact that the occultation of Venus by the 3.5-day old moon occured during the day (similar to the May/2004 event), these two bright celestial bodies were easily visible both naked-eye as well as through the telescope's humble finderscope.

Venus is currently at 26.39 arc-seconds and growing as it approaches opposition later this summer. With a magnitude of -4.4 and a phase of 44.1%, it is an easy target to locate during the day and, particularly, when the moon is nearby so that proper focusing by our eye against the blue sky (for true infinity) becomes feasible. Through a telescope, even the telescope's finderscope, Venus and its approximate first-quarter phase are easily discernible.

Similarly, the 3.5-day old waning moon was also a pleasant site through the telescope's finderscope with the thin crescent moon meticulously bathed against the rich blue sky. Its milky white surface allowed the identification of many major lunar features associated with the eastern quadrant including Mare Crisium being the most dominant due to its proximity to the lunar terminator.

Please find listed below three links which depict Monday's celestial waltz. The first link is with Venus just to the east of the transparent lunar limb seconds before first contact and disappearance. Similarly, the second link is with Venus just past the western lunar limb seconds after reappearance 80 minutes later. The third and final link is a collage of the first two images which beautifully illustrates yesterday's disappearance and reappearance.

http://www.perseus.gr/Astro-Lunar-Occult-2007-06-18.htm
http://www.perseus.gr/Astro-Lunar-Occult-2007-06-18b.htm
http://www.perseus.gr/Astro-Lunar-Occult-2007-06-18c.htm

http://www.perseus.gr/Astro-Lunar-Occult-2004-05-21D.htm (same event also during the day in May/2004)

Imaging during the day is somewhat challenging and requires careful processing due to the low inherent contrast.

Clear skies.

Anthony.

--- In ap-gto@yahoogroups.com, Rick Thurmond <yahoogroups@...> wrote:

My 1200's serial port connectors have gotten a little rusty. Does
anyone know where one can get those plastic caps to cover them

with?

I've not used them up until now, my friend has a program we plan

to

use to track satellites and the ISS, and we're going to try it

out.

And here I am with embarrassing rusty serial ports on an otherwise
beautiful mount!

I'd vote for 802.11 wireless LAN to replace the serial ports.

Then

I wouldn't have to take my computer outside.

Generally, though, I'm happy to get away from the computer for a
change, and just use the fine hand controller. In addition to the
great mechanicals of the mount, the fact that I can run it without
being disturbed by a computer is its greatest feature.

Rick

Rick are you planning to use Satellite Tracker or some other program
and please post the results when you try it out.

Hi Steve,

Just got off the phone with L-com. I was hoping for solderable
connectors so that I could modify my cables but these should work out ok.

Rick.


--- In ap-gto@yahoogroups.com, "Steve Reilly" <sreilly@...> wrote:

Here's a fast two links...





http://www.blackbox.com/Catalog/Detail.aspx?cid=45,659,875
<http://www.blackbox.com/Catalog/Detail.aspx?cid=45,659,875&mid=4304>
&mid=4304



http://www.l-com.com/item.aspx?id=8656



Steve





From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] On

Behalf Of

Rick K
Sent: Wednesday, June 20, 2007 2:02 AM
To: ap-gto@yahoogroups.com
Subject: [ap-gto] Re: New features



--- In ap-gto@yahoogroups.com <mailto:ap-gto%40yahoogroups.com> ,

"David B.

Toth" <ve3gyq@> wrote:

At 09:36 AM 6/19/2007, Rick K wrote:

And which batteryless Bluetooth adapter will do this job? AFAIK the
serial port on the AP mounts have NO provision for supplying power to
attached serial devices. As well any of those serial devices are

about

2 inches long and would stick up waiting to get ripped off the
controller as the scope or camera passed by. No thanks. Integrated is
by far the best solution.

The Socket CSA is 2" or less in size, and can get its power from Pin
9 ... you can wire pin 9 on your mount with 5 volts.
The adaptor doesn't seem to stick out any further than a DB9 would
.... I don't think it would be too vulnerable to "attack" if I recall
where the connector is.

BTW, I think reworking the mount's electronics to add Bluetooth would
very well require RECERTIFICATION by the FCC ...
If I recall correctly, that can cost upwards of $20k - Roland could
comment as I am sure he knows the cost.

(The electronics have to be evaluated for the FCC to prove that they
do not have significant RF radiation - I'm not sure if a simple rework
would require this, but it would not surprise me)

Your mileage may vary.

Dave

Sorry, but I have looked into this and 2 inches is over a half inch
too high. The clearance on the mount from both the big 900 and 1200
plates is inadequate to allow a 2" projection. It barely clears a
1.25" projection. I actually tie the serial cables down out of the way
specifically so that they stay out of the way. I have been on the
lookout for right angle DB9 connectors but since RS232 is essentially
obsolete, such items are virtually impossible to find. As it stands,
for Bluetooth, I could wire up a short 'serial' extender cable and
modify the port to supply power but this is just a kludge. A proper
built-in Bluetooth implementation would be better. Of course, all this
pales when compared to adding USB connectivity. THAT is way more
important. Shelve Bluetooth entirely if it is going to be a choice
between that and USB.

Although I would be completely at ease modifying the controller to
supply power to the Bluetooth adapter, I am wondering what Roland
would think about this. I expect that he might not be amused and that
it would void the warranty.





[Non-text portions of this message have been removed]

You don't mention if this is for visual or astrophotography.
If its for visual the Losmandy DC11 that Gilles recommended will be
fine. I had one mounted on a 600GTO and it was very stable.
Dan

If the error is consistent as you indicate, then it's probably
misalignment of the optical and mechanical axes of the C-14. An
alternative approach is to use adjustable tube rings (the kind with
the three adjustment screws) for the AP160. Then you adjust the 160 so
that it's pointing where the C-14 is.

Eric,

Thanks for the reply. I think you're right. I haven't quantified
the amount of error but, since shimming, it's small. When the object
is centered in the C-14 FOV (narrow) it is in the outer 1/4 of the
AP160's FOV (wider). It also occurs in all parts of the sky, so it's
not mirror flop related. I was thinking that it could be mechanical
misalignment in the C-14, being a mass produced scope etc. I'll
probably use your solution #2 and live with it. It's more anoying
than anything else.

Thanks,
Mark

--- In ap-gto@yahoogroups.com, "ebuehrens" <ebuehrens@...> wrote:

Hi Mark,

It would be good to know how much misalignment you're seeing, but my
guess is that the issue is not with the mounting hardware, it's in

the

C-14 - either you are seeing mirror flop (which would produce
inconsistent pointing errors depending on what part of the sky the
scope was pointing to - or (just as likely, I think) the optical and
mechanical axes of the C-14 are not aligned. All it takes for that

to

happen is for the central pipe on which the moving primary slides to
be slightly out of alignment with the mechanical axis of the OTA. In
that instance the "wedge" you're chasing is actually in the scope.

My advice: determine whether the error is reproducible over all

areas

of the sky, which would favor my hypothesis #2, and then either
machine some clearance in the bolt holes so the cradle can be moved
slightly side-to-side, or (my favorite) just live with it. If you

get

it sorted out once, I guaranteee that it will go out of whack in the
future. There are just too many sources of mechanical error in the
C-14. Good scope and good value but IMHO the design and mechanicals
are overtaxed at this aperture.

good luck,

Eric
www.taconicobservatory.com

--- In ap-gto@yahoogroups.com, "Mark Squicquero" <docsquic@>

wrote:

I mistakenly posted this in the AP-UG group.

Hi all,

I have a general question regarding my current setup:

Ap1200GTO, AP 160, C-14, Robin Casaday tandem mounting system,
Homeyer Cradle on the C-14.

I've just begun to refine this setup and have found that there

are

slight alignment issues ie the two scopes don't exactly align on

the

same target. When I calibrate the mount using the Ap 160,

pointing is

superb. I shimmed the C-14 between the Homeyer Cradle and the
mounting plate and it improved the alignment somewhat. ( I

figured

that the AP scope/rings/ Casaday plate were probably pretty

accurate

so I focused on the C-14/custom SS plate/Homeyer system). The
shimming consisted of "raising" the back of the cradle. I also

found

that I had to slightly shim more one side of both the front and

back

of the cradle. As I mentioned the alignment is improved but not
perfect. If I move the scopes so that one is above the other on

one

side of the mount, I can move the tandem arrangement in pure dec

very

slightly to bring the C-14 to target. So it appears the necessary
correction is to diverge the back of the OTA's very slightly by
shimming one side of the C-14.

My question is, how do I accomplish this? The C-14 fits very

snugly

in the cradle and there doesn't appear to be any room to shim.

I've

tried loosening the mounting bolts and applying pressure to one

side

of the cradle and then re-tightening to no avail. My guess is

that

the custom SS mounting plate, although very sturdy and cool

looking,

has some wedge in it. I've read nothing but praise for the

Homeyer

cradle as far as its accuracy and rigidy (which is why I

purchased

it), so I don't think that is the source. Any suggestions would

be

appreciated. If shimming won't work maybe I can try a different
mounting plate.

Thanks,
Mark Squicquero

Joe,
Wow, that's exactly the answer I was looking for. Where else can one
get such good advice? I'll get some of those covers.

Thanks,
Rick