don4l

6 hours ago, wimvb said:

Starnet++ is your friend for this job. It's available as a standalone program as well as a script for PixInsight. Just google it. Process one copy of the image for stars, and one for maximum impact for the nebula. Remove stars in the latter and replace with those of the former. 

Btw, you got more colour variation in the nebula. It looks better, imo. 

Thanks, Wim.  I've downloaded it and I'll have a play tonight.

I said that I would have another go - and I almost wish that I hadn't! 

I've reprocessed the image, but I don't think that it is any better.  I've added in some of last year's SII data to the green channel, using layer masks to keep the halos at bay.

I need to do some research on star removal, and replacement.

36 minutes ago, wimvb said:

Thst's s very nice image of an unusual object. As the astrophotographer Metsavainio wrote, it's reminiscent of a wide screen version of the Rosetta nebula. I just wonder what happened to the small stars in your image? The star field reminds me of too aggressive star reduction in Pixinsight. But you used Gimp. 

Thank you.

You are absolutely right about the  stars.   The image was almost nothing but stars when I did the first colour combine.  So, your comment about aggressive star reduction makes complete sense.   I used two different methods at different stages, which won't have helped.  I didn't notice the issue until I did some final touch ups.

I'll have another go at this tonight to see if I can improve things.

1 hour ago, alan potts said:

Lovely shot of another I haven't seen before. I must find this catalogue in C-du-C to be able to locate these lovely areas of sky, feel it would be one for Borg 77mm wide area to cover.

Alan

The Sharpless catalogue is full of slightly unusual Ha objects.  I get the feeling that these are ignored because people used to think that Ha imaging was a bit difficult.  For whatever reason (Light pollution, optics, camera????) I find Ha much easier than RGB, so these objects are much easier for me than Galaxies.

The Sharpless catalogue  is part of the "LBN" catalogue on this page :-

https://www.ap-i.net/skychart/en/documentation/installation_of_extra_catalogs

Deal Salman maintains a very good website, which is a very good reference for the Sharpless imager:-

http://www.sharplesscatalog.com/sharpless.aspx

This is SH2-119 in Cygnus.  It sits just under the North American Nebula.  I tried to image this last year, but I couldn't get a result that was at all acceptable.  I was using old Astronomik filters which had appalling halos.  This was taken with Chroma Ha and OIII filters.   Unfortunately, there is very little OIII in this, (but there is loads of SII). 

Hopefully, I will have a decent SII filter next year, and I will come back to this.   The Blue data was almost identical to the OIII as far as I can see, and only takes a fraction of the time.

Camera STL6303,  OTA  FSQ106 @ F3.6, Mount:  EQ6.

120m Ha,  110m OIII, 12m Green, 12m Blue.

CCDCiel, CCDStack, Gimp.

Any advice would be very welcome.

Lovely image. 

Should it be in the "Getting started" forum?

This is a simple 2 panel mosaic of a part of Cygnus.  There are three Sharpless objects in the left hand pane, and these would be very suitable targets for a longer focal length than I have used.  SH2-112 has plenty of OIII, so could make a very nice target.  It is also fairly bright.  The field of view is about 7 x 2.75 degrees.

Each pane is 60m mins Ha - Chroma 3nm filter.

Moravian G3-16200 MKII, Tak FSQ106 (F3.6) on EQ6.

1 hour ago, Aramcheck said:

Hi,

We've recently upgraded from an EQ2 to an EQ6 with GOTO & have bought our first DLSR. So far we've only used the new scope for visual observation, but I'm hoping to have a first go tonight with the DLSR.

Should I set attach the DLSR to the OTA straight away, or do I need to do the 3-star alignment process first with an eye-piece & then replace/fit the DLSR and re-balance?

I'm guessing it would be best to have the DLSR already fitted, before doing the alignment & to use the live view to fine-tune the 3-star alignment?

Many thanks

Ivor

I wouldn't worry about rebalancing at this stage.   My EQ6 isn't half as sensitive to balance as many other  mounts.

If you are happy doing the alignment using an eyepiece, then do it that way first.

The first problem with the camera will be finding focus.  To get the camera into focus you will probably need to move inwards from where the eyepiece was.  However, if you are removing a diagonal to fit the camera, then you will probably have already moved in too far.

The first time that I tried to find focus, I was so far off that I had no idea if there were any stars in the field at all.  For me, the thing that helped was to make absolutely certain that I could trust the finder scope.  Before putting the camera on, I would align the finder so that I could use it to put a bright star in the centre of a high powered eyepiece.

Once you know where the focus is, then aligning with the camera is likely to be more accurate.

Excellent idea.

I've started a spreadsheet.

10 "man points" for using a 20 year old copy of Corel Draw.

14 minutes ago, knobby said:

Lovely image, especially the way you've captured the cloud of gas blown from the baby's bottom

I'll never be able to look at the Soul Nebula again without that image coming to mind.

I think that most people are not very familiar with this object.  I've just revisited my own version, and I agree that I was not able to supress the background noise.  However, I have that problem with all of my images (a combination of over stretching and a very noisy camera).

I'd also assume that it was temperature.  I often have to refocus every 30 minutes.

11 minutes ago, Adam J said:

I cant comment on those cameras, 

This is the manual for an ATIK one which shows the filters being screwed in from the scope side and the thread side facing the sensor. Hence you need to actually removed the wheel to screw the filters in from the scope side. 

https://nimax-img.de/Produktdownloads/46419_1_AtikOneManual.pdf

this is from baader:

https://www.baader-planetarium.com/en/blog/unmounted-filters-which-side-should-face-the-telescope/

I note that the reflective side of a mounted baader filter is the top and not the side with the threads on it which is less reflective.  Hence the threaded side of the filter should under normal conditions face the sensor. The only time you might have the thread face the scope is if the scope has really poor AR coating on its corrector. 

Now looking for images of the Moravian G2 i see examples in the manual with 31mm unmounted filters but not 1.25 ich filters.....

Hence if they are really that way on your camera, I have trouble with that design choice. 

Adam 

Thanks.

I found this in the Baader link that you provided :-

" All cell-mounted filters are already oriented in a way that the most appropriate filter face is facing the sky when the filter would be mounted directly onto the front end of the nosepiece of a camera. "

That actually sounds very sensible to me.

I'll check to see if the Moravian filter wheel will accept the screw in filters from the sky side - it is possible.  The Moravian manual doesn't give a definitive answer.  The unmounted filters definitely go in from the CCD side.

I need a new set of filters anyway, so I guess that I will have to get unmounted.

1 hour ago, Adam J said:

The anti-reflection coating is on the threaded side of the filter and is normally placed facing the sensor.

Adam

I wonder if I have read your post correctly.

The filters on my SBIG and Moravian cameras both screw in from the sensor side, so the threaded side faces away from the sensor.

I've done the exact opposite.  I have an image "M24.tif" that I took in 2009 but only managed to identify a few months ago.  It is  M25.  The whole area is full of fantastic stuff.

That's really quite beautiful.

17 minutes ago, Natty Bumpo said:

I am not sure of a trend, but I do see constant AP activity across the forums.

The following sums up for me my point if view on Visual Observation.

Visual astronomy is where you stick your eyeball on the opening of that little glass piece on the southern end of your telescope and soak up photons in your retina. You're just sitting there quiet but for the occasional gasp of delight.

It is an intimate activity. It is, on its face, a one way conversation wherein we allow a particular part of the universe to physically enter our body through our eye, or eyes, as the case may be. And for the earliest astronomers it was a profound intercourse with a vast mystery.

Today as we post ourselves in the dark behind our instrument we have the experience of "listening" with our eyes to the story written large in time and space of beginning, continuance, and ending. It is the grand metaphor of our tiny personal existance. It is a renaissance of the mind were we rediscover our humanity in the inanimate light.

These are my peculiar thoughts, as I sit in the dark and listen, unable to willfully respond, passively reflecting the tiniest fraction of this light from the surface of my glistening eye. But there is nothing original in that reflection. It is what has come to me from without.

In speaking to you of what I see I find a mere approximation of what has happened to me. If I describe to you the mechanics of the experience, the physicochemical activity of my eye, it would not do. So I speak in a crude translation of what has changed within me as a result.

There the motion and velocity of thought, which is another mechanism of organized chemistry and matter, cascades in symbols of sound. And this must again iterate in a further translation through ear and in your mind. And just so we convert light into thought.

It is always a pleasure to read here the observing accounts of data. But it is thrilling to read the account of one struggling to express the change that has occurred in ones self as a result of the seeing.

Ok. So where is the practical in all of this palaver?

With AP we have a product. It is now an image preserved, ready to share. After all a picture is worth a thousand words. And there it is. The seeing is worth a thousand words. The eye must engage. But here is the rub

We have not seen the thing. We have seen another kind of estimation of the thing perturbed by the biases of the camara. It is no longer intimate.

The product of observational astronomy is intimacy.

I haven't read the whole thread, but I agree with you completely.

I never realised how addictive that AP would become (or how expensive).

And yet, my best images are just in my memory.  I can clearly remember my first views of Saturn and Jupiter (and moons!!!)

My best memory is the view of the Perseus double cluster.  One of them struck me as a diamond ring.  I've never seen an image that had anywhere the colour and vibrancy that I thought that I saw.

This is a 6 pane mosaic with 60 min per pane.  It has been combined by hand in the Gimp.

I know that the joins are visible,  but I sort of enjoy seeing if I can put one of these together.

In the past, I've struggled with mosaics because I cannot really get my head around the rotation issues involved - and once I start rotating panes in the Gimp, the stars become visibly different from one pane to the next.  During this image I tried a completely new (to me anyway) method of aligning frames.  Each image was platesolved and put into Cartes du Ciel as a background image.  For the next frame I platesolved, and used CCDCiel's "Send frame to Planetarium" option.  This immediately showed if the camera need rotating or re-centering.  This sounds much more complicated than it is in practice.  Anyway, the result is that none of the panels needed to be rotated.  They aren't perfect, but they are close.

FSQ106ED at F3.6

G2-16200 MKII camera,  EQ6

EQ6

Acquired with CCDCiel, Calibrated and stacked in CCDStack, patched together in the Gimp.

Comments, suggestions and advice very welcome.

20 hours ago, Anthonyexmouth said:

is there an easy way to work out how much time you should spend on a target before you see diminishing returns?

just wondering as I think i had some good data from the pelican last night, 3.5 hours and wondering how much more time i should spend on it, if any. 

 

 

I think that you need to be a mathematical genius to get a proper answer to your question.

I've read that doubling your exposure time improves your signal to noise ratio by 1.4(ish).  If I combine 2 subs and compare the result to a stack of 4 subs, I can usually see what this difference looks like.

However, I recently had a go at the Squid in SH2-129, which is a notoriously weak OIII target.  After 2 hours of data I had a result which looked promising.  I then got another 6 hours of data before having another at processing.  I was horrified to see that the 8 hours showed absolutely no improvment at all over the 2 hours.

The subs in the extra 6 hours all looked to be of similar quality to the first two hours.

I don't understand what the problem is.  I think that it is either related to read noise, or sky background or something else.

I have just received a new camera which is much more sensitive to OIII and it has lower read noise.  If you see a post from me in the next few weeks about SH2-129, then have a look, because I will definitely comment on this issue.

3 minutes ago, Calzune said:

What do you mean? The light frames? 

 

Yes.  If you can look at one of the images as it came out of the camera, then you will have a better idea.

Perhaps deepskystacker allows you to look at the images before you process them???

If they are in Raw, then it should be possible to convert one to a jpg.  Depending on the settings in your camera, you might have the jpegs already.

If the moon caused the problem, then you should be able to see it in a single image.

To be honest,  the moon was quite bright two nights ago, so you wouldn't have been able to get anything great without narrowband filters.

How do the individual frames look before you calibrate them?

I spent last year playing with all this stuff.

I can image with a 3nm Ha filter almost anytime.  If the moon is too bright, I keep away from it.  Tonight I am imaging around the Crescent, and I cannot see any effect.  However, if I was a much better imager, then I might notice that the dimmer areas were not as good as they might be.  Maybe next year I won't bother on a night like tonight.  When I was using a 7nm filter, the moon had a much greater effect.  Even then, I could do stuff binned 2x2.

OIII is affected much more by the moonlight, even at 3nm.  At 12nm, I found the OIII almost unusable if there was any moonlight at all.  I think that is partly due to the fact that most OIII targets are much weaker than the Ha targets, so if there is any background light, then it will have a bigger impact.

I found that practising gave me a feel for what I can do.

I wouldn't bother imaging without narrowband tonight. 

That is an excellent result for just an hour's worth of data.  It is very satisfying to be able to produce an image in an evening.

Superb!

I looked at it in full resolution.  If you split that image into 9 panels, then 6 of them would make brilliant images in their own right.

On 12/09/2019 at 23:08, Kinch said:

The big one for me - and I hate to say it....because your eye will be drawn to it - M32 should not be so bright in comparison to the center of M31. To try bring detail as far in as I could in M31, the 'HDR Multiscale Transform' tool was used in PixInsight which reduces the galaxy core brightness......but I feel that the galaxy core should still be brighter than its small neighbour. This hits me everytime I look at it - but I don't know how to dim M32 on its own (....and perhaps M110 some also).

I would never have noticed it if you hadn't pointed it out.