New kit new problems.

[alan potts]

I am guessing it is me doing something wrong on this one or does data have to be proceeded differently. I have just received an Optolong L Enhance filter from FLO and I tried it out two nights back. At first glance using the area around Sadr I thought I was getting more signal through on a 4 minute sub. I only used darks and dithered between shots. All in all there is 1 hour 30minute and I limited the selection to 80% as I had a feeling there was hazy cloud in at least 3 of the captures. Now because of the data I have only streched it very lightly due to the faults in it, there are Red and Green streaks here and there.  I cannot see this fault on any single shot at all.

I am aware of slight icing at the bottom edge, this was a mistake by me in cooling.

 

Is this me or is it the way the filter works, or has something else happened I am unaware of.

Any advise gratefully received,

Alan

[TerryMcK]

Hmm quite odd artefacts and I can see them in blue too towards the bottom left of the picture. I'm not familiar with that filter.

What did you use to register/stack? 

[wxsatuser]

The red and green streaks look like hot pixels.

[tomato]

+1 for hot pixels being the cause of coloured streaks. I regularly encountered this effect on stretched images taken with an Atik 314 OSC. Have you used calibration frames?

[alan potts]

3 hours ago, tomato said:

+1 for hot pixels being the cause of coloured streaks. I regularly encountered this effect on stretched images taken with an Atik 314 OSC. Have you used calibration frames?

Only darks, I never use calibration as I move the cameras about too much, I dither between each shot and have never seen anything on the 100 or so images I have taken since I bought the two ZWO cameras. I tend to agree with you but why should you see them just because of the filter which this was first light.  Same night same set-up without filter different target nothing, just a decent image of the Pelican.

It has only had the smallest of stretches.

Alan

[alan potts]

3 hours ago, TerryMcK said:

Hmm quite odd artefacts and I can see them in blue too towards the bottom left of the picture. I'm not familiar with that filter.

What did you use to register/stack? 

I use DSS and it has never done this before, no settings were changed at all, the same evening I took an hour on the Pelican without filter and it's fine.

Alan

[wxsatuser]

What stacking method are you using?

Median or sigma clip should shift the outliers as I can see satellites trails as well., average will not shift them.

Edited August 16, 2020 by wxsatuser

[steppenwolf]

Definitely hot pixels and not something to do with the filter. I agree with Mike, these should have been removed if you used sigma clip during the stacking process, especially as the images were dithered.

[alan potts]

1 hour ago, wxsatuser said:

What stacking method are you using?

Median or sigma clip should shift the outliers as I can see satellites trails as well., average will not shift them.

Median with sigma clipping, this puzzled me the satellite has not been removed, I have double checked and the settings are correct, satellites always come out and even aircraft, don't understand this. If it doesn't remove them the filter is of no use to me, under normal condition I have 8 aircraft overhead at any time and rarely do not get one through a frame or two most nights.

Alan

 

[alan potts]

1 hour ago, steppenwolf said:

Definitely hot pixels and not something to do with the filter. I agree with Mike, these should have been removed if you used sigma clip during the stacking process, especially as the images were dithered.

Steve, without doubt I used Sigma clipping and dither, tried it a second time in DSS and got the same result. 3rd time I check ticked a box in the advanced section for removing hot and cold pixels which has never been ticked. This solves the problem but I am interested as to why my settings that I have used for over 2 years didn't work. Not sure I like the results of this filter, maybe my choice of target was poor. I may try and do a mix of normal OSC with IR/UV filter and some with this L Enhance.

Alan

[TerryMcK]

I would try stacking without darks just to see if the problem goes away and eliminate that. Then remove the bias from the integration etc.

I had a problem with darks the other day that I couldn’t track down. Then it was staring me right in the face. Temp was ok, gain was ok, duration was 240 seconds instead of 180 seconds that the lights were taken at. A simple oversight. I did some more darks at the right duration and it was cured.

Edited August 16, 2020 by TerryMcK
Lights was flats

[alan potts]

2 hours ago, TerryMcK said:

I would try stacking without darks just to see if the problem goes away and eliminate that. Then remove the bias from the integration etc.

I had a problem with darks the other day that I couldn’t track down. Then it was staring me right in the face. Temp was ok, gain was ok, duration was 240 seconds instead of 180 seconds that the flats were taken at. A simple oversight. I did some more darks at the right duration and it was cured.

The darks Terry are only one length, 240secs, I have never used this camera at any other length, it's an 071. The 183mc I only use that at 180secs. As I don't really understand what the gain does I never touch it after making a mess in the first week, now stick to only one. I don't have LP out here which sort of makes me ask why I bought this filter, I guess just to see if it would help. Well like it or not I am stuck with it as i do not believe in this returning things if you don't like them.

Alan

[alan potts]

2 hours ago, TerryMcK said:

I would try stacking without darks just to see if the problem goes away and eliminate that. Then remove the bias from the integration etc.

I had a problem with darks the other day that I couldn’t track down. Then it was staring me right in the face. Temp was ok, gain was ok, duration was 240 seconds instead of 180 seconds that the flats were taken at. A simple oversight. I did some more darks at the right duration and it was cured.

Actually Terry I have just tried what you suggested and forgot to re-set the setting to where I always had them but I have to say without darks added (which were correct) the image is much much more pleasing to my eye. My messing with setting to some something I had never used before got rid of the colourful lines but this without darks is for me nice, I like what i see. The other image was so noisy and looked awful.

Alan

 

[TerryMcK]

Nice one Alan. Hopefully the filter is ok.

On my ZWO ASI183MC I use the IDAS D2 as we have light pollution from LED street lights here. I've just ordered the ZWO ASI183MM as I like the images the MC does but want to do some narrowband with the mono camera. Maybe even use the colour images from the MC and add HA from the MM as Lum channel.

Edited August 16, 2020 by TerryMcK

[alan potts]

8 hours ago, TerryMcK said:

Nice one Alan. Hopefully the filter is ok.

On my ZWO ASI183MC I use the IDAS D2 as we have light pollution from LED street lights here. I've just ordered the ZWO ASI183MM as I like the images the MC does but want to do some narrowband with the mono camera. Maybe even use the colour images from the MC and add HA from the MM as Lum channel.

I did consider this filter as I do have a bit of a glow to the south east from the town which is 5 miles away. I also just have a issue with a lamp about 100m away to the south which was well covered by a walnut tree, this has now been removed by the owners. It is causing me a few problems in the shape of lens flare when pointing to the south, the south of course being an interesting area. Over all though I am in a much better situation than many of our members but in the last 12 years my sky has without doubt become brighter.

Alan