Jjmorris90

Does anyone have an asi air ?

If so what does it mean by bin1 bin2 bin3 bin4? It appears on the right under the capture button.

Here is the final image

30 minutes ago, teoria_del_big_bang said:

When I first looked at my stretched flats I thought they were horrendous, several big donuts, some visible on all filters, some specific to each filter, and offset vignetting, just like yours.
But after the initial surprise when I started to look at them in Pixinsight I could see that the actual difference in ADU between the almost black after stretching in the corners of the frame and the light area in the middle was actually very small, and the difference between the donuts and the lighter areas even less. It is just the fact that flat frames when auto-stretched are actually stretched so much to differentiate between these areas.

As states in above replies the real test is whether the flats improve the final stacked image and removes the donuts and most of the vignetting. If it does then no t to worry, if it doesn't then more than more than likely either something has moved in the image train between the lights and flats, or the calibration of the lights or flats has not worked correctly.

Steve

Thanks for the reply. They did not calibrate out 

I just discovered my camera lens is covered with dust. I blew it off and took another flat and no sign of these donuts. Though I assume they will be present in every image taken up to this point ?

This is after stacking. They are very visible

So do I need to do anything about it being off centre?

2 minutes ago, Shimonu said:

This looks like a decemt flat frame to me, what are you expecting? It's showing the vignetting and dust particles causing the donuts.

I don't know what I was expecting lol. Shouldn't it be more centered? 

How can I get rid of the dust?

Using the white t-shirt method and the sky as a light source.

The light never seems to be directly in the centre.  No matter what I do. Perhaps a secondary mirror issue?

Also what are those donuts. The camera is in focus.

Lastly the image has been autostretched.

Asiair

Asi183mc pro

1 hour ago, michael8554 said:

You didn't mention Calibrating ?

And what Dec were you guiding at ?

Michael

I'm unsure. I'm new to the asiair

59 minutes ago, Budgie1 said:

You may need to increase the gain and the exposure. The stars in your screen shot are hard to see, which makes them hard for the software to follow. 

With 0.5s exposures, you stand the chance of following the seeing, where the software is reacting to movement in the atmosphere, rather than actually following the star movement. Increasing the exposure time to 1-2 seconds will eliminate this.  

I think my ASI120MM Mini normally guides with a gain of about 48 and 2 second exposure, but start by increasing the exposure and see if it makes a difference.

Ok will try it thanks

Last night i encountered the most bizarre issue. 

I was polar aligned and good to go so I started guiding on asiair. 

Within a few seconds the stars that it was tracking (with the little green circles) were out of line. It seemed the mount wasn't moving. 

Everything was connected as it should have been. 

I'm using a 60 mm 240 guidescope with asi120mm mini

I managed to capture a screen shot. 

The settings are 

Calibration 2000

Max durations 1000

1 hour ago, Stu said:

You should be able to make a near full aperture filter from an A4 sheet of film

https://www.firstlightoptics.com/solar-filters/baader-astrosolar-safety-film-nd-50.html

Or buy a ready made one

https://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html

Thank you

6 minutes ago, Stu said:

No, you still need protection for the scope otherwise you will damage your camera through the intense heat.

Which scope do you have? At minimum you need a full aperture filter on the front of the scope such as a Baader AstroSolar filter.

I have a 200p

Hey 

I've got a skywatcher and asi183mc pro 

At the minute the sun seems to be visible more than the stars at night  (bloody clouds). 

Now I won't be looking directly into the eyepiece as I have asiair. Does this mean I do not need a solar filter? 

Thanks

Okay thank you for your help. I tried that plug-in on adobe but it didn’t make much of a difference. 
 

il cover the dslr viewfinder and try again. 

4 minutes ago, ONIKKINEN said:

The gradient is blotchy and difficult to remove. I end up with a similar result as you with most methods. I could probably brute force this with GradientXterminator plugin in Photoshop, but it looks difficult to deal with. Looks a lot like a light leak to the sensor somehow IMO. Also since you are using a newtonian it is possible your collimation has changed since shooting the lights and taking the flats, which is why flats are best taken straight after the session.

This needs to be blocked so that no light can enter during shooting. It could be the culprit here.

But one more thing you can try other than re-shoot the frames is to do the background extraction per sub. This works well for linear gradients, but if each sub has a nonlinear gradient due to light leaks it may not work that well.

To do this you should use the "seqsubsky" command in Siril before stacking. After pre-processing you can run this command by inputting "seqsubsky pp_light 1" to the console. In here seqsubsky is the command, pp_light is the sequence name in question and 1 is the degree order of the extraction. 1 is linear 2 is less linear etc, usually only the first order extraction works well for individual subs.

If you used one of the scripts built in to Siril to do the whole process you can add the command line in to the script you used. You can open the .SSF files with Windows word pad.

I am not quite sure to which point the command goes, but it might be the one i marked.

An easier way (which i use) would be to use Sirilic, a software that uses Siril for stacking but makes all the data usage much simpler with a drag and drop interface. No need to manually faff with folders with Sirilic.

Here: https://siril.org/docs/sirilic/#download

 

In Sirilic the "subsky" command does the background extraction per sub. Set to 0 for no extraction, 1 for linear extraction. Higher than 1 will probably not work well but you could always try.

Its a lot to think about, sorry if it sounds like im rambling 😅

Aha i will give it a Go. Thanks for looking. 
 

il block the viewfinder next time. And how can I take flats at night? 
 

thanks 

3 minutes ago, ONIKKINEN said:

Difficult to tell from the screenshot if something is wrong, can you post the raw stack?

Im banking towards background extraction going wrong. I use Siril a lot and sometimes its just difficult to use and should be done on the individual subs before stacking. There is a method to do this in Siril with the seqsubsky console command but i would like to try on the stack first if thats ok.

sure, here. 

thank you  

result.fit

this is the stack before any processing. 

uncropped

I've selected RGB and autostretch only

sure. here is one of the flats. 

IMG_2741.CR2

8 minutes ago, ONIKKINEN said:

Looks a bit like light leak from the viewfinder if you used a DSLR. The viewfinder is a light pathway to the sensor and some light will leak there if its not blocked.

On my first session out with a DSLR i had a red light headlamp on pretty much the whole night and occasionally i would point it towards the camera. It left a red blotch on all the frames that looks a lot like what you have here. This would not be removable with flats and would conveniently explain why the weird shape remains after taking flats. Or could just be that the flats you took were not that great, so how did you take the flats?

I took the flats by pointing the scope at the sky and covering it with a white T-shirt. I used AV mode. Same iso. Camera determined shutter speed 

19 minutes ago, Iem1 said:

That is much better, but still not ideal. You could probably crop that and use the "eye dropper tool" in levels in PS to even out the background well enough.

Perhaps try without any flats at all, might give you a better start to work with.

Also, Im not a pro with the background extraction in Siril, but I do find it can be very harsh I think..The default is set to 4 and that will do all kinds of weird to my images usually, try 1-2, these tend to be a bit more subtle if I remember correctly. Good luck

I didn’t know I could do it without flat frames in siril?

48 minutes ago, barbulo said:

Flat frames must be taken maintaining the very same optical path as the light frames: same camera position, same filters, same focus position...  Otherwise, they are useless. Normally are taken at the end of the imaging session.

Oh. I’ve read that you can take flat frames by pointing the telescope at the sky and covering the scope with a T-shirt ?

This is what I got after taking new frames 

Thanks for the reply. 
 

the flats I have just look like a white blank light. No difference throughout. 
 

il take new ones as I think they are over exposed. 

28 minutes ago, barbulo said:

I'm far from being an expert but, are you using flat frames for image calibration? Surely they will help. 

Before background and green removal I crop the image and do a photometric color calibration. After that, do the background and green noise removal and then I move to Photoshop for the non-linear post processing. 

Ah that must be it! Lol. The flat frames I took are just pure light. Is that incorrect ?