Any ideas what this is caused by

[alan potts]

Had this on a few images last night and the night before, does anyone know why it happens from time to time. looks like light from somewhere, also had it on 2 images from NGC 7000 which I was just looking at to see how doable it was.

No bright stars that near and no lights, focus could be better but I don't feel that is issue though guiding was very up and down from time to time. This is a 4 minute sub at 800iso

 

 

 

 

Alan

[david_taurus83]

Does look like some sort of reflection. Is it there in all images over different targets?

[alan potts]

2 hours ago, david_taurus83 said:

Does look like some sort of reflection. Is it there in all images over different targets?

It was in images where the telescope was pointing almost upright to the east and not quite so much to the west as int he M13

What ever caused this added one was in a different direction to the first one, this was the area of the Pelican and facing east but fairly high.

I have image the exact same place many times this month and have not seen it before, the dew shield is fully extended and lights are few here. Note there are 3 on this  shot which was from the night before.

 

Alan

[Laurin Dave]

Hi Alan

Some thoughts ..  Maybe an internal reflection ..  to check take the camera off, aim the scope at the sky and look through to see if there’s any unblackened bits showing.... maybe unlikely if it hasn’t happened before..  have you got the viewfinder cap on to prevent stray light getting in..  try taking a shot in daylight with the lens cap on and see whether you get the same pattern showing if so then figure out which bit is leaking light..  my filter wheel did from leds on the mount until I taped it all up ..  so are there any leds that come close to the scope/ camera when it’s pointing straight up ...

Dave

 

[alan potts]

37 minutes ago, Laurin Dave said:

Hi Alan

Some thoughts ..  Maybe an internal reflection ..  to check take the camera off, aim the scope at the sky and look through to see if there’s any unblackened bits showing.... maybe unlikely if it hasn’t happened before..  have you got the viewfinder cap on to prevent stray light getting in..  try taking a shot in daylight with the lens cap on and see whether you get the same pattern showing if so then figure out which bit is leaking light..  my filter wheel did from leds on the mount until I taped it all up ..  so are there any leds that come close to the scope/ camera when it’s pointing straight up ...

Dave

 

There is the screen of the laptop but I stuck a piece of gaffer tape across the viewfinder, I wonder if a corner has worked loose. That though would not account for the M13 shot when the camera is on the other side but there are 3 LED's on the floor for cigar lighter plugs for mount camera etc. It could be them. It looks clear tonight I will turn everything away to ground, turn the laptop and check the gaffer tape, it will be the tape. Let you know.

When the scope is up the LED's are at there closest to the camera.

Alan

[alan potts]

Thought I had found what this problem was for about the length of a sub, I thought it was the laptop reflecting off the top front of the observatory roof which is white. So moved it back out the way and it was exactly the same as the picture directly above in the exact same part of the sky.

Moved the telescope a fairly short distance, only about 5 degrees and nothing. All lights, dim as they are covered and laptop top covered too. There is not a light of any type for for a fair distance, even street lamps which are orange are shielded by trees and a good distance away from me. Pointing at the Pelican Nebular there is only stars above and the odd aircraft, can't work this out at all, never saw it before this TS .79 reducer was put in place.

Alan

[Laurin Dave]

Maybe an internal reflection then from within the TS reducer from a nearby bright star (looks like Deneb is the culprit on your image of the Pelican particularly as the arc is so much brighter than in your M13 image) ..  take the camera off and have a look through against a bright sky and see if there are any reflections from it.. are all surfaces Matt black or is it anodised black? (Which can reflect certain wavelengths)  . what do your flats look like with the reducer on..  and also with it off..  when I had an internal reflection recently the flats showed a concentric ring..  a bit of black flocking sorted it out 

Dave

Edited September 4, 2019 by Laurin Dave

[alan potts]

Flats look fine as far as I can see they look, well, flat. I thought Deneb, it is near and nothing change from one night to the next, can't say I am impressed with this TS reducer at all, about 350e new I believe, so not exactly cheap but if it does this not exactly good either. Checked everything else and basically seen nothing. I have taken it of and gone back to 805mm with the Hutech flattener, which in my books is better.

The TS Reducer/ flat does not give round stars at the corners in my scope and it is set at 55mm, it is recommended by them I understand but that doesn't cut the mustard with me, I got this fairly cheap fortunately.

Alan 

[Laurin Dave]

If the Hutech works use it! Shame about the TS one.. maybe some Matt black paint will sort it..  

Dave

[alan potts]

1 hour ago, Laurin Dave said:

If the Hutech works use it! Shame about the TS one.. maybe some Matt black paint will sort it..  

Dave

Just the sort of thing that one should do to an item that will cost you close to 300 quid if bought new. It may be interesting to see if placed in the sky in the same place, I synced it, whether the Hutech causes issues, I rather think it will not as I have use this now for a fair while and never seen anything.

Alan

[wesdon1]

21 hours ago, alan potts said:

It was in images where the telescope was pointing almost upright to the east and not quite so much to the west as int he M13

What ever caused this added one was in a different direction to the first one, this was the area of the Pelican and facing east but fairly high.

I have image the exact same place many times this month and have not seen it before, the dew shield is fully extended and lights are few here. Note there are 3 on this  shot which was from the night before.

 

Alan

Hi. It looks like diffracted light coming at you telescope from an angle, hence the diffracted colours of light showing. Has to be a source of light from somewhere? Unless your telescope needs blackening on inside in case it's reflected/diffracted light bouncing around inside telescope? Hope you resolve the issue sir. beautiful image by the way! 

Wes, Liverpool, UK.

[alan potts]

1 hour ago, wesdon1 said:

Hi. It looks like diffracted light coming at you telescope from an angle, hence the diffracted colours of light showing. Has to be a source of light from somewhere? Unless your telescope needs blackening on inside in case it's reflected/diffracted light bouncing around inside telescope? Hope you resolve the issue sir. beautiful image by the way! 

Wes, Liverpool, UK.

I am beginning to feel it is something to do with the reducer, it I don't believe is the telescope as this is an expensive scope and never causes a problem with the other flattener, I also cannot see a problem with the camera albeit at 10 years old. Even light, what light as it is in my case there isn't any, lets see if the same happens tonight now I have removed the reducer.

Alan 

[Ibbo!]

As a test can you rotate

just the camera

camera and flattener.

 

 

I had to flock a very shiny extension tube many years ago that caused problems.

[alan potts]

51 minutes ago, Ibbo! said:

As a test can you rotate

just the camera

camera and flattener.

 

 

I had to flock a very shiny extension tube many years ago that caused problems.

Steve, I have taken it off now, the reducer that is. I will run the test in the next couple of days weather permitting and message you, I will have to do new flats now😀. It was not new but this was a pricey bit of kit at near 300 quid if new, the camera is the same one as the last 2 years.

Alan

[alan potts]

Well again thank-you to all that tried to help, I removed this Reducer earlier and about 2 hours ago put it back, in doing so I saw something I had missed but then wasn't looking for it. There were a couple of areas, not large, but areas as opposed to scratches where the black was missing and the shinny metal was visible underneath. Who knows what been going on here.

That said I could not make it repeat the arc lighting effect from other nights, so I covered them up with Matt black paint, one assumes job done, its a good job it was cheap, would have been well angry at 345 euros.

Have to say though the corner are not good and the spacing for a Canon at 55mm is difficult to get wrong, and my scope is only 5mm F/L longer than the 800 they state which I would have though negligible.

Alan

[Ibbo!]

The shiy bits more than likey produced the arcs in your image.

The t adaptors can vary in length esp the cheap ones have you any very thin spacers to slighty increase the distance and see if that makes a difference.

 

Apart from that I am out of ideas.

[alan potts]

15 hours ago, Ibbo! said:

The shiy bits more than likey produced the arcs in your image.

The t adaptors can vary in length esp the cheap ones have you any very thin spacers to slighty increase the distance and see if that makes a difference.

 

Apart from that I am out of ideas.

No I don't have such but thought of it, the matt black paint didn't help either, it is still there when very close to Deneb, but not the same,  internal reflection of some sort for sure. Maybe just have to put up with it, turn the camera a tad and run new flats. Not the end of the world but very poor for a piece of kit costing almost 300 quid, and I'm sure it is the reducer.

Alan

[wesdon1]

On 04/09/2019 at 12:38, alan potts said:

I am beginning to feel it is something to do with the reducer, it I don't believe is the telescope as this is an expensive scope and never causes a problem with the other flattener, I also cannot see a problem with the camera albeit at 10 years old. Even light, what light as it is in my case there isn't any, lets see if the same happens tonight now I have removed the reducer.

Alan 

That sounds a very plausible scenario with the flattener? You could try a process of elimination, and when/if it is the flattener, try contacting manufacturer for advice? From my experience with photography, it's often a whole host of different reasons why an image can have imperfections/distortions etc. Light can do strange things when we play around with it! lol How did your Wednesday session turn out? did you get to the bottom of it? 

Wes.

[alan potts]

1 hour ago, wesdon1 said:

That sounds a very plausible scenario with the flattener? You could try a process of elimination, and when/if it is the flattener, try contacting manufacturer for advice? From my experience with photography, it's often a whole host of different reasons why an image can have imperfections/distortions etc. Light can do strange things when we play around with it! lol How did your Wednesday session turn out? did you get to the bottom of it? 

Wes.

No sort of got nowhere fast, thought it was some marks inside the sleeves caused by something, covered them with matt black paint and still the same but not as bad, the smallest movement seems to make it go away so it's internal reflections of some type, poor for what this would cost new.

Alan

[wesdon1]

8 minutes ago, alan potts said:

No sort of got nowhere fast, thought it was some marks inside the sleeves caused by something, covered them with matt black paint and still the same but not as bad, the smallest movement seems to make it go away so it's internal reflections of some type, poor for what this would cost new.

Alan

Awww i'm sorry you haven't quite gotten to root cause of it. I suppose you will just have to bear with the situation and hopefully in time you will find the cause and rectify it. Yes very true, if the 'scope is a good one with a price tag to match, then these anomalies shouldn't be happening? Which makes me think if it isn't stray light, it has to be something in the image train? a flattener, corrector, filter, barlow, eyepiece etc etc etc? Surely a quality 'scope wouldn't be so easily affected by stray light, if indeed thats what is causing said issues? I'm confident you'll find the cause soon enough sir! Best of luck to you! Please let me know when you solve the problem what it was. 

Wes.

[Ruud]

No Idea what's going on, but you have triple arcs. I traced them and tried to determine their relative radii. The arcs  look like reflections of each other. That they're not the same size would indicate reflections off curved surfaces. 

For a moment I thought the centres of the circles formed a right angle, but they do not.

I hope you can sort this out soon.

[rockinrome]

Is this a slight imperfection/crack in the glass that the eye cannot see ...??
 

[Stargazer33]

Is there something loose in the TS reducer/flattener that possibly causes slop when you're imaging near the zenith? 

[alan potts]

1 hour ago, Ruud said:

No Idea what's going on, but you have triple arcs. I traced them and tried to determine their relative radii. The arcs  look like reflections of each other. That they're not the same size would indicate reflections off curved surfaces. 

For a moment I thought the centres of the circles formed a right angle, but they do not.

I hope you can sort this out soon.

Interesting piece of work there and thank-you for taking the time, I personally feel this reducer is a piece of junk, best not put stronger. Dave has google this and it would appear I am not on my own but I will just have to lump it. Here is another shot not as bad from last night, withing a tad the same place, glutton for punishment, I am sure you can see from this the corners are rubbish too, near 300 pound new this, and as poor as I am at this AP game, Canon camera and 55mm back space with only one fitting for the camera and threads all around, difficult to get wrong. BTW guide was decent.

 

Alan

[alan potts]

1 hour ago, Stargazer33 said:

Is there something loose in the TS reducer/flattener that possibly causes slop when you're imaging near the zenith? 

I will check but I do not believe this to be the case, but no harm looking.

Alan