Stub Mandrel

If you use dust and scratches then the heal tool to get rid of the stars you could then add in the extra nebulosity as another layer

Me too, I look at the night sky and wonder what it would look at if all the faint nebulosity was visible to the naked eye.

is there a touch of uncorrected coma there? Stars near the corners seem to be 'stretched' outwards a bit.

Ah. the aim of flats is to correct for things like vignetting (dark corners) as well as dust on the sensor. You need to take them with the scope attached to do this, also this affects how dust throws a shadow so basically always take them before removing the camera from the scope, even if you leave it there until morning.

The pictures are good. I'm worried about pointing the scope at the sun, it doesn't take long to burn out a sensor or worse, plus you really want an image with no features in it at all. For easy flats, just either point the scope at a featureless sky or a flat plain surface or even a hanging sheet - it must be evenly illuminated with no marks that will come out on the image. I use a flat painted wall indoors and rotate the scope between shots - the wall is so close that any marks on it will be so out of focus they don't show.

I use this method a lot on the RGB version of my DSLR data, I've set it up as an 'action'. I find it works best if you tweak the saturation up very slightly in C,M,Y & B but not R or G first. You can repeat it but watch out for any colour channel that is getting ahead of the others - you can pull its saturation back a bit before repeating. Another 'trick' that works well for brining faint nebulosity out of data from a DSLR is described at length in a 1 1/32 hour tutorial somewhere but the basic technique (for photoshop) is: Create a copy of your image called 'LUM'. Set the black point as high as you can without clipping the black, then back off a smidgin. <option at this point you may want to run a make stars smaller routine a few times> <option it can also be worth using curves at this point to help emphasise any nebulosity> Duplicate as a new layer. Use dust and scratches filter with a radius of 10-15 to remove most stars Use the 'heal' or 'clone stamp' tools to remove any large stars that remain so you just have the 'background' with any nebulosity. Check the black point again and move if required <option at this point it can be worth blurring the image slightly or running noise reduction if required> Now set the mode for this star-free layer to 'screen' - the image will lighten considerably, but the stars won't blow out. Add a levels adjustment layer as you will now almost certainly need to adjust the black point Also add a curves layer and add a slight upwards curve, starting just above the black background level to help further emphasise the nebulosity. If you keep layers separate you can go back an do further noise reduction etc. as required. I also sharpen/contrast enhance and noise-reduce my 'LUM' version in Astra Image. My RGB version , I normally blur slightly to reduce colour noise and bring colour into brighter stars I combine teh RGB and LUM versions by dropping the LUM version onto the RGB one as a layer and setting its mode to luminosity.

Well done Bob, your stars are looking rounder with more data as well. One sneaky tip for folks like us who haven't got Ha filters: take a colour copy of your image to make a 'lum' image and play with lightening and darkening different colour channels in an extra layer, not worrying about the actual colour. I find that lightening the red channel can enhance the nebulosity quite a bit, especially if you slightly blur the layer before carefully mixing a percentage of it back with the original.

Since getting the 'new style' polarscope, I take 2-minute subs and tell DSS to stack 80 - 90% and let it decide which of them are the best. I only manually remove subs when cloud is passing through or they are obviously awful. Problems at low DEC suggest it may be that your scope is too well balanced, my subs improved a lot now I make sure the scope is biased one way or the other.

:-) That's pretty much where I thought it was. It's a bit like the tiny 'antenna' on the horsehead's nose, I was able to process it hard enough to get it to show, but the rest of the image was totally destroyed in the process! The rosette will be my next target.

About three pixels across!

It's interesting, my photo is obviously not in they same class, but if you look at the light clouds in it they are pretty well correlated to his red clouds, even if there is a lot less detail. I've redone the pic reversing the effort I put in to 'de-redding' the background.

That's chap's got an Ha filter and he's going to use it!

Saw your posts giving me special permission to sneak in an EQ rosette. it's widefield so much smaller and not particularly brilliant (bear in mid done with an ancient 10D that cost me £30 off ebay). I couldn't find a raw stack but I was able to salvage some not-too processed layers from unflattened tiffs and tried my 'new superpowers' on it. The Christmas Tree is here too, but the cone is invisible: It does suggest that the background of the Rosette isn't very 'black'

I see, the first one does feel more 'natural'. What I do when I have two images that both have good points, is put one as a layer on top of the other in Photoshop and use modes (e.g. luminosity if one is sharp and clear and the other is colourful) and/or use different percentage transparency to see if I can get the effect I like.

I like it, but I'm still not entirely sure what 'faults' I should be looking for sometimes :-)

I got the Rosette on my (modded) 10D last year using a 135mm lens. Bearing in mind that the 10D is only 10bit so I is much less sensitive than even an unmodded camera I would say. I can't post the pic as it's taken on an EQ tripod ;'-)

I've turned this off on my camera, as if it self-cleans between me taking photos and making my flats...

Just a thought, I use gradient exterminator in Photoshop as a 'first operation' it usually does a good job of balancing overall colour as well as removing gradients - certainly better than auto colour.

Great stuff folks, I've done some 135mm widefield too, not quite as spectacular as Wim's but surprising what you can find and an ideal way for beginner's to learn the ropes with everything being just a little less critical.

Excellent stuff! The myth you can't image with light kit is surely debunked?

The dynamic range of that image is TINY, what are using to stack? Also can you post a link to the unmodified DSS stack? I think you may either have far too much background light pollution or moonlight or something is not happening right. Look how much bigger my stars are than yours - the 150P-DS ought to be bringing in far more light at 80 seconds with such a high ISO. This is 21 60-second exposures at ISO1600, chosen as it doesn't show a lot of gas:

It would be a cool and possibly achievable project to expand that into a meandering mosaic that takes in the whole sky more or less on the ecliptic visiting all teh interesting patches. The leo galaxies aren't far away for you (Orion is just about in the best place for me ATM).

Not quite, I was a bit late for Eagle; I was Buster and Beano (never Dandy) followed by 2000AD and Starlord. Best Alien ever, Galaxus, the thing from outer space:

No way, that's the Mekon!

Hmm. Compared to other solar scopes in this thread, mine is 'entry level'! But my solar finder got featured in S@N