Reflections in Images


Steve Reilly
 

Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 


Joel Short
 

Steve,
I've seen this kind of reflection caused by a bright object just off the field of view.  If your date is correct then NGC3521 was very close to Jupiter and Sh2-263 was rather close to Bellatrix.  The reason the reflection seems to change is because as time goes on the relative position of your camera orientation and slight differences in the camera sky position can change how intense the reflection is.  I've had cases where I moved the scope just a tiny distance away from the bright star or object and the reflection went away.  Yours is pretty extreme though.  I don't know if I've seen one quite that bright.

But that may only be half the problem.  I suspect your scope may have something shiny in it that is reflecting.  Is there any silver metal somewhere in the tube?  Is it baffled well?  Is it painted black?  
joel

On Tue, Feb 2, 2016 at 10:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 

Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 



stefan@...
 

Steve,

I have seen some strange artifacts on GSO RC's that came from "false" light directly hitting the chip because either primary and/or seconday baffles were a bit to short. This risk for this increases with chip size. The artifacts have been linear and not circular as in your case, though.

Stefan


Ron Wodaski <rwodaski@...>
 

It can also be an external, off-axis source of light, even something nearby, that just happens to reflect off of a surface. It can be difficult to track that kind of reflection down, but it typically occurs when the telescope tracks into an alignment that allows the light either to get inside the camera, or to reflect off some structure in the scope. It can be a strut, a baffle, a spider leg, secondary holder — anything, really.

Ron Wodaski



On Feb 2, 2016, at 8:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:



Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.
 
Thanks,
 
Steve
 




Joe Zeglinski
 

Steve,
 
    Just a guess, but maybe one of your filters is bouncing light back from the CCD window?  Has this always happened after installing filters?
 
    I think the direction of filters is NOT supposed to matter, most are supposed to be coated on “both sides”. But if one or more were anti-reflection coated ONLY on the sky side, then light bouncing off the CCD cover glass, would reflect back again to the sensor, producing a halo. If true, reverse the filter.
 
As I say, just my W.A.G.
 
Joe


Christopher Erickson
 

Sure looks like a metallic reflection to me.  Sort of like what I would get from a bright star reflecting off of a hex head stainless steel bolt near the optical path.
 
Just a guess.
 
 
Christopher Erickson
Consulting Engineer
Summit Kinetics
Waikoloa, HI 96738
www.summitkinetics.com
 


From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 6:12 PM
To: ap-gto@...; SBIG@...
Subject: [ap-gto] Reflections in Images

Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 


Steve Reilly
 

Joel,

 

The ota tube is carbon fiber and a dull black interior. There are two small dovetail bars mounted near the end of the ota for additional counter weights if needed. I guess I could remove them and see if that makes a difference. Other than that there is just the spider vane holding the secondary and its stepper motor. It is baffled well. I’ll try this and see if that make a difference. I have a 3-pound weight that I can find another way to attach for balance.

 

Thanks,

 

Steve

 

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 11:49 PM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images

 

 

Steve,

I've seen this kind of reflection caused by a bright object just off the field of view.  If your date is correct then NGC3521 was very close to Jupiter and Sh2-263 was rather close to Bellatrix.  The reason the reflection seems to change is because as time goes on the relative position of your camera orientation and slight differences in the camera sky position can change how intense the reflection is.  I've had cases where I moved the scope just a tiny distance away from the bright star or object and the reflection went away.  Yours is pretty extreme though.  I don't know if I've seen one quite that bright.

 

But that may only be half the problem.  I suspect your scope may have something shiny in it that is reflecting.  Is there any silver metal somewhere in the tube?  Is it baffled well?  Is it painted black?  

joel

 

On Tue, Feb 2, 2016 at 10:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:

 

Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 

 


Steve Reilly
 

Thanks Stefan. I will be looking closer at the ota for anything that might help.

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 1:00 AM
To: ap-gto@...
Subject: [ap-gto] Re: Reflections in Images

 

 

Steve,

I have seen some strange artifacts on GSO RC's that came from "false" light directly hitting the chip because either primary and/or seconday baffles were a bit to short. This risk for this increases with chip size. The artifacts have been linear and not circular as in your case, though.

Stefan


Joel Short
 

Do the dovetail bars extend past the front of the OTA?  If so that could be a contributing factor.
joel

On Wed, Feb 3, 2016 at 9:10 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 

Thanks Stefan. I will be looking closer at the ota for anything that might help.

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 1:00 AM
To: ap-gto@...
Subject: [ap-gto] Re: Reflections in Images

 

 

Steve,

I have seen some strange artifacts on GSO RC's that came from "false" light directly hitting the chip because either primary and/or seconday baffles were a bit to short. This risk for this increases with chip size. The artifacts have been linear and not circular as in your case, though.

Stefan



Stuart
 

Steve, the reflection could be from inside your filter wheel or adapters for connecting it. Or from an OAG. I recall years ago that some people complained of flaring and odd artifacts that were traced to the fact that their filters' uncoated, unblackened edges were exposed and the solution was to take a thick sharpie and colour in the sides of the glass filters.

Stuart

On Wed, Feb 3, 2016 at 10:09 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 

Joel,

 

The ota tube is carbon fiber and a dull black interior. There are two small dovetail bars mounted near the end of the ota for additional counter weights if needed. I guess I could remove them and see if that makes a difference. Other than that there is just the spider vane holding the secondary and its stepper motor. It is baffled well. I’ll try this and see if that make a difference. I have a 3-pound weight that I can find another way to attach for balance.

 

Thanks,

 

Steve

 

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 11:49 PM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images

 

 

Steve,

I've seen this kind of reflection caused by a bright object just off the field of view.  If your date is correct then NGC3521 was very close to Jupiter and Sh2-263 was rather close to Bellatrix.  The reason the reflection seems to change is because as time goes on the relative position of your camera orientation and slight differences in the camera sky position can change how intense the reflection is.  I've had cases where I moved the scope just a tiny distance away from the bright star or object and the reflection went away.  Yours is pretty extreme though.  I don't know if I've seen one quite that bright.

 

But that may only be half the problem.  I suspect your scope may have something shiny in it that is reflecting.  Is there any silver metal somewhere in the tube?  Is it baffled well?  Is it painted black?  

joel

 

On Tue, Feb 2, 2016 at 10:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:

 

Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 

 





Steve Reilly
 

Well that’s certainly encouraging Ron. The scope is due for mirror recoating this April when I go to NEAIC/NEAF so maybe a bit more maintenance will need to be done. I don’t expect this to be easy especially when it only happens on a select few objects.

 

Thanks Again,

 

Steve

 

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 1:21 AM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images

 

 

It can also be an external, off-axis source of light, even something nearby, that just happens to reflect off of a surface. It can be difficult to track that kind of reflection down, but it typically occurs when the telescope tracks into an alignment that allows the light either to get inside the camera, or to reflect off some structure in the scope. It can be a strut, a baffle, a spider leg, secondary holder — anything, really.


Ron Wodaski

 

 

 

On Feb 2, 2016, at 8:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:

 



Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 



 


Steve Reilly
 

Joe,

 

With the lens in place I did get reflections regardless of position of the filters. Due to pre-lens, lens, flipped filters, and so on I’ve been taking a ton of flats as some of these projects have been going on for 6-9 months thanks to ACP Expert’s ability to continue based on availability of targets. The FlatMan XL has saved my life on this although I’ve got ½ a 1TB hard drive full of flats. The best example of the reflections I have of these reflections is seen in my Cone Nebula image. Looking at the brightest stars you can draw an imaginary line to the center of the image from each reflection. The reflections are shaped like small Ring Nebulas and flipping the filters made little if no real difference. You can see the image here http://www.astral-imaging.com/NGC%202264-RC2_1600a.htm

 

Thanks for the suggestion, I’ve been down that road already but it was a good guess.

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 2:38 AM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images

 

 

Steve,

 

    Just a guess, but maybe one of your filters is bouncing light back from the CCD window?  Has this always happened after installing filters?

 

    I think the direction of filters is NOT supposed to matter, most are supposed to be coated on “both sides”. But if one or more were anti-reflection coated ONLY on the sky side, then light bouncing off the CCD cover glass, would reflect back again to the sensor, producing a halo. If true, reverse the filter.

 

As I say, just my W.A.G.

 

Joe


Steve Reilly
 

Christopher,

 

I’ll have to take a very hard look at this but I have not seen anything that would suggest this. I’ll take my telescoping inspection mirror out there and give it a very hard look. It’d be sweet if it is that simple.

 

Thanks,

 

Steve

 

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 5:03 AM
To: ap-gto@...
Subject: RE: [ap-gto] Reflections in Images

 

 

Sure looks like a metallic reflection to me.  Sort of like what I would get from a bright star reflecting off of a hex head stainless steel bolt near the optical path.

 

Just a guess.

 

 

Christopher Erickson
Consulting Engineer
Summit Kinetics
Waikoloa, HI 96738
www.summitkinetics.com

 

 


From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 6:12 PM
To: ap-gto@...; SBIG@...
Subject: [ap-gto] Reflections in Images

Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 


Mike Mulcahy
 

Steve,

I had a strange muted reflection in my C9.25 which I looked for for a month.  I cannot tell you exactly how the reflection was produced but the solution was to move the filter wheel farther away from the sensor.  I inserted a t-thread extender and was lucky to be able to maintain the spacing from my reducer.

Good luck,

Mike Mulcahy 


Steve Reilly
 

At this point there is no OAG in place. I had one when I had the flattener in place though but removed and tried with the same results. I guess I could remove the filter carousel and see if that makes a difference. I’m using Baader 50mm unmounted filters in my FW8.

 

Thanks,

 

Steve

 

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 10:13 AM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images

 

 

Steve, the reflection could be from inside your filter wheel or adapters for connecting it. Or from an OAG. I recall years ago that some people complained of flaring and odd artifacts that were traced to the fact that their filters' uncoated, unblackened edges were exposed and the solution was to take a thick sharpie and colour in the sides of the glass filters.

 

Stuart

 

On Wed, Feb 3, 2016 at 10:09 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:

 

Joel,

 

The ota tube is carbon fiber and a dull black interior. There are two small dovetail bars mounted near the end of the ota for additional counter weights if needed. I guess I could remove them and see if that makes a difference. Other than that there is just the spider vane holding the secondary and its stepper motor. It is baffled well. I’ll try this and see if that make a difference. I have a 3-pound weight that I can find another way to attach for balance.

 

Thanks,

 

Steve

 

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 11:49 PM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images

 

 

Steve,

I've seen this kind of reflection caused by a bright object just off the field of view.  If your date is correct then NGC3521 was very close to Jupiter and Sh2-263 was rather close to Bellatrix.  The reason the reflection seems to change is because as time goes on the relative position of your camera orientation and slight differences in the camera sky position can change how intense the reflection is.  I've had cases where I moved the scope just a tiny distance away from the bright star or object and the reflection went away.  Yours is pretty extreme though.  I don't know if I've seen one quite that bright.

 

But that may only be half the problem.  I suspect your scope may have something shiny in it that is reflecting.  Is there any silver metal somewhere in the tube?  Is it baffled well?  Is it painted black?  

joel

 

On Tue, Feb 2, 2016 at 10:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:

 

Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.

 

Thanks,

 

Steve

 

 



 

--


Steve Reilly
 

Joel,

 

Have to run the dog to the groomer but when I return I’ll post a few pictures of the imaging train as it is now and the inside/outside of the ota. But no, the dovetail bar does not extend past the end of the ota.

 

Thanks Again,

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 10:12 AM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Reflections in Images

 

 

Do the dovetail bars extend past the front of the OTA?  If so that could be a contributing factor.

joel

 

On Wed, Feb 3, 2016 at 9:10 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:

 

Thanks Stefan. I will be looking closer at the ota for anything that might help.

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 1:00 AM
To: ap-gto@...
Subject: [ap-gto] Re: Reflections in Images

 

 

Steve,

I have seen some strange artifacts on GSO RC's that came from "false" light directly hitting the chip because either primary and/or seconday baffles were a bit to short. This risk for this increases with chip size. The artifacts have been linear and not circular as in your case, though.

Stefan

 


Joel Short
 

Steven,
Your cone nebula image is revealing.  Those little "ring nebula-like" donuts are internal glass reflections.  If you move the scope around a little bit those little donuts will change position relative to the star.  I've seen this as well.  Unfortunately I think these are two separate issues.  The little donuts could be caused by a flattener or reducer.  Was your flattener/reducer in place for the cone nebula shots?

I'm still fairly convinced that the very bright arcs are caused by a bright object just off of the FOV.  But, I also don't use an RC scope so it could be different from my experience
joel

On Wed, Feb 3, 2016 at 9:28 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 

Joel,

 

Have to run the dog to the groomer but when I return I’ll post a few pictures of the imaging train as it is now and the inside/outside of the ota. But no, the dovetail bar does not extend past the end of the ota.

 

Thanks Again,

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 10:12 AM
To: ap-gto@...
Subject: Re: [ap-gto] Re: Reflections in Images

 

 

Do the dovetail bars extend past the front of the OTA?  If so that could be a contributing factor.

joel

 

On Wed, Feb 3, 2016 at 9:10 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:

 

Thanks Stefan. I will be looking closer at the ota for anything that might help.

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 1:00 AM
To: ap-gto@...
Subject: [ap-gto] Re: Reflections in Images

 

 

Steve,

I have seen some strange artifacts on GSO RC's that came from "false" light directly hitting the chip because either primary and/or seconday baffles were a bit to short. This risk for this increases with chip size. The artifacts have been linear and not circular as in your case, though.

Stefan

 



Kent Kirkley
 

Steve:

How old are your filters?
Astro imaging filters have gone through two evolutions, hence in the case of Astrodon filters, Series 1 and Series 2. I believe Baader filters have also done this. The later series have much better anti reflection coatings and on both sides. Your reflections appear to be of your mirror and secondary....much like what you'd see with an eyepiece and an out of focus position. If your filters are before the improved coatings I would suspect them.

Kent Kirkley


-----Original Message-----
From: 'Steven Reilly' sreilly24590@... [ap-gto]
To: ap-gto
Sent: Wed, Feb 3, 2016 9:26 am
Subject: RE: [ap-gto] Reflections in Images



At this point there is no OAG in place. I had one when I had the flattener in place though but removed and tried with the same results. I guess I could remove the filter carousel and see if that makes a difference. I’m using Baader 50mm unmounted filters in my FW8.
 
Thanks,
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 10:13 AM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images
 
 
Steve, the reflection could be from inside your filter wheel or adapters for connecting it. Or from an OAG. I recall years ago that some people complained of flaring and odd artifacts that were traced to the fact that their filters' uncoated, unblackened edges were exposed and the solution was to take a thick sharpie and colour in the sides of the glass filters.
 
Stuart
 
On Wed, Feb 3, 2016 at 10:09 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 
Joel,
 
The ota tube is carbon fiber and a dull black interior. There are two small dovetail bars mounted near the end of the ota for additional counter weights if needed. I guess I could remove them and see if that makes a difference. Other than that there is just the spider vane holding the secondary and its stepper motor. It is baffled well. I’ll try this and see if that make a difference. I have a 3-pound weight that I can find another way to attach for balance.
 
Thanks,
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 11:49 PM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images
 
 
Steve,
I've seen this kind of reflection caused by a bright object just off the field of view.  If your date is correct then NGC3521 was very close to Jupiter and Sh2-263 was rather close to Bellatrix.  The reason the reflection seems to change is because as time goes on the relative position of your camera orientation and slight differences in the camera sky position can change how intense the reflection is.  I've had cases where I moved the scope just a tiny distance away from the bright star or object and the reflection went away.  Yours is pretty extreme though.  I don't know if I've seen one quite that bright.
 
But that may only be half the problem.  I suspect your scope may have something shiny in it that is reflecting.  Is there any silver metal somewhere in the tube?  Is it baffled well?  Is it painted black?  
joel
 
On Tue, Feb 2, 2016 at 10:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 
Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.
 
Thanks,
 
Steve
 
 


 
--



Stuart
 

Kent, I too think it is his filters but the positioning of the flaring from the very edge of the field suggests to me it is the edge of the filters not the coatings (else this would be on all bright stars IN the field). There was a distinct debate about the filters not having blackened sides and later sets shipped with the sides of the filters blackened. 

I think that is the problem.

Stuart

On Wed, Feb 3, 2016 at 11:15 AM, Kent Kirkley kgkirkley@... [ap-gto] <ap-gto@...> wrote:
 

Steve:


How old are your filters?
Astro imaging filters have gone through two evolutions, hence in the case of Astrodon filters, Series 1 and Series 2. I believe Baader filters have also done this. The later series have much better anti reflection coatings and on both sides. Your reflections appear to be of your mirror and secondary....much like what you'd see with an eyepiece and an out of focus position. If your filters are before the improved coatings I would suspect them.

Kent Kirkley


-----Original Message-----
From: 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Wed, Feb 3, 2016 9:26 am
Subject: RE: [ap-gto] Reflections in Images



At this point there is no OAG in place. I had one when I had the flattener in place though but removed and tried with the same results. I guess I could remove the filter carousel and see if that makes a difference. I’m using Baader 50mm unmounted filters in my FW8.
 
Thanks,
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 10:13 AM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images
 
 
Steve, the reflection could be from inside your filter wheel or adapters for connecting it. Or from an OAG. I recall years ago that some people complained of flaring and odd artifacts that were traced to the fact that their filters' uncoated, unblackened edges were exposed and the solution was to take a thick sharpie and colour in the sides of the glass filters.
 
Stuart
 
On Wed, Feb 3, 2016 at 10:09 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 
Joel,
 
The ota tube is carbon fiber and a dull black interior. There are two small dovetail bars mounted near the end of the ota for additional counter weights if needed. I guess I could remove them and see if that makes a difference. Other than that there is just the spider vane holding the secondary and its stepper motor. It is baffled well. I’ll try this and see if that make a difference. I have a 3-pound weight that I can find another way to attach for balance.
 
Thanks,
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 11:49 PM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images
 
 
Steve,
I've seen this kind of reflection caused by a bright object just off the field of view.  If your date is correct then NGC3521 was very close to Jupiter and Sh2-263 was rather close to Bellatrix.  The reason the reflection seems to change is because as time goes on the relative position of your camera orientation and slight differences in the camera sky position can change how intense the reflection is.  I've had cases where I moved the scope just a tiny distance away from the bright star or object and the reflection went away.  Yours is pretty extreme though.  I don't know if I've seen one quite that bright.
 
But that may only be half the problem.  I suspect your scope may have something shiny in it that is reflecting.  Is there any silver metal somewhere in the tube?  Is it baffled well?  Is it painted black?  
joel
 
On Tue, Feb 2, 2016 at 10:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 
Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.
 
Thanks,
 
Steve
 
 


 
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topboxman
 

Best way to resolve the reflection issue is process of elimination starting with just the camera. If no reflections are shown, then add one piece of equipment (FW, then OAG, etc.) at a time until reflection shows up and that would be your culprit.

Peter


---In ap-gto@..., <stuart.j.heggie@...> wrote :

Kent, I too think it is his filters but the positioning of the flaring from the very edge of the field suggests to me it is the edge of the filters not the coatings (else this would be on all bright stars IN the field). There was a distinct debate about the filters not having blackened sides and later sets shipped with the sides of the filters blackened. 

I think that is the problem.

Stuart

On Wed, Feb 3, 2016 at 11:15 AM, Kent Kirkley kgkirkley@... [ap-gto] <ap-gto@...> wrote:
 

Steve:


How old are your filters?
Astro imaging filters have gone through two evolutions, hence in the case of Astrodon filters, Series 1 and Series 2. I believe Baader filters have also done this. The later series have much better anti reflection coatings and on both sides. Your reflections appear to be of your mirror and secondary....much like what you'd see with an eyepiece and an out of focus position. If your filters are before the improved coatings I would suspect them.

Kent Kirkley


-----Original Message-----
From: 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Wed, Feb 3, 2016 9:26 am
Subject: RE: [ap-gto] Reflections in Images



At this point there is no OAG in place. I had one when I had the flattener in place though but removed and tried with the same results. I guess I could remove the filter carousel and see if that makes a difference. I’m using Baader 50mm unmounted filters in my FW8.
 
Thanks,
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Wednesday, February 03, 2016 10:13 AM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images
 
 
Steve, the reflection could be from inside your filter wheel or adapters for connecting it. Or from an OAG. I recall years ago that some people complained of flaring and odd artifacts that were traced to the fact that their filters' uncoated, unblackened edges were exposed and the solution was to take a thick sharpie and colour in the sides of the glass filters.
 
Stuart
 
On Wed, Feb 3, 2016 at 10:09 AM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 
Joel,
 
The ota tube is carbon fiber and a dull black interior. There are two small dovetail bars mounted near the end of the ota for additional counter weights if needed. I guess I could remove them and see if that makes a difference. Other than that there is just the spider vane holding the secondary and its stepper motor. It is baffled well. I’ll try this and see if that make a difference. I have a 3-pound weight that I can find another way to attach for balance.
 
Thanks,
 
Steve
 
 
From: ap-gto@... [mailto:ap-gto@...]
Sent: Tuesday, February 02, 2016 11:49 PM
To: ap-gto@...
Subject: Re: [ap-gto] Reflections in Images
 
 
Steve,
I've seen this kind of reflection caused by a bright object just off the field of view.  If your date is correct then NGC3521 was very close to Jupiter and Sh2-263 was rather close to Bellatrix.  The reason the reflection seems to change is because as time goes on the relative position of your camera orientation and slight differences in the camera sky position can change how intense the reflection is.  I've had cases where I moved the scope just a tiny distance away from the bright star or object and the reflection went away.  Yours is pretty extreme though.  I don't know if I've seen one quite that bright.
 
But that may only be half the problem.  I suspect your scope may have something shiny in it that is reflecting.  Is there any silver metal somewhere in the tube?  Is it baffled well?  Is it painted black?  
joel
 
On Tue, Feb 2, 2016 at 10:12 PM, 'Steven Reilly' sreilly24590@... [ap-gto] <ap-gto@...> wrote:
 
Back a few months ago I posted a webpage with some reflections I was getting in some images. The link to that page is http://www.astral-imaging.com/reflection.html Since then I have removed the flattener lens from the RC and am again seeing some reflections I had thought were from the lens. The latest images to show this strongly are of NGC3521 and seen here  http://www.astral-imaging.com/reflections.html Any ideas how to track down the source of these reflections would be great. The telescope is a OGS 12.5” RC with a Pyxis 3” rotator, STL-11002M w/fw8.
 
Thanks,
 
Steve
 
 


 
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