ollypenrice

That's a great result. The band of dust is much in favour at the moment and is superb in this rendition.

Olly

Magentas arise from too little green. Did you use a green noise remover, perhaps?

Whatever, your results are excellent.

Olly

I'm five years older than you and am no longer feel comfortable with 10x, unstabilized. This applies to a lovely little pair of Leica 10x25s as well, unfortunately. I see more, and more enjoyably, with 7x or 8x. I've settled on 8x42 but would urge you not to be talked into 10x, especially with an eye on the future.

Standard wisdom says porros are cheaper to make so you get more optical quality for your buck. However, I think individual deals will possibly outweigh that.

My Leica 8x42 came second hand from Clifton Cameras, who described them as 'good for their age' (8 years.)  In truth they were indistinguishable from new, some of the accessories never having been opened at all. They are just lovely to use, in the hand and at the eye.

Olly

3 hours ago, tomato said:

Great mosaic! The starless mono image could almost be a terrestrial cloudscape.

Exactly what struck me.

This is top quality, seamless, precise, clean.

Olly

This makes sense.

I only tried my 100-400L once on the moon but I was pretty impressed. This was hand held, braced against the side of the house.

Olly

Wouldn't your Sigma telephoto beat this easily? Not as portable, though.

Olly

That's a glorious image! 'Sharp and smooth' has to be the holy grail of narrowband imaging, not that I know anything about it.

Olly

If you can't tell the software which calibration files go with which lights, I think you'll have to make two stacks and stack those.

Olly

This thread covers the issue of small scopes on Star Adventurers. It will address most of your questions. 

When focusing a camera lens on stars, try concentrating on stars at the intersection of the 1/3 lines, imaginary lines parallel with the chip sides but a third of the way over to the other side. These 4 points will give you the best compromise for the chip as a whole.

If you zoom in at this point, critical focus can often be found by looking at the faintest stars which only appear when focus is right.

Starnett++ and StarXterminator: these modern star removal/replacement software tools work well on all kinds of astrophoto but are particularly effective on camera lens images because smaller apertures always produce larger stars. Some might say, 'Learn about this later,' but I'm not so sure. Being able to stretch the nebulae and the stars differently makes processing so much easier.

The Samyang 135 is a stunning astro lens, as Carole says.

Olly

On 15/01/2024 at 16:22, bosun21 said:

A sack barrow makes moving a 12” a piece of cake even over a distance. As long as you don’t encounter any considerable obstacles.

They also exist with stair-climbing wheels which work astonishingly well. https://www.amazon.fr/Juskys-Diable-descalier-Pliable-Monte-escalier/dp/B07Z7R4CMY/ref=asc_df_B07Z7R4CMY/?tag=googshopfr-21&linkCode=df0&hvadid=649021427975&hvpos=&hvnetw=g&hvrand=13307743385287580903&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9109705&hvtargid=pla-834757222970&psc=1&mcid=bf1bb220886b3c24abf8ccf5663884be

Olly

40 minutes ago, Elp said:

Not so sure on that calculator. I've imaged with my WO Z61 fine with an azgti in EQ mode. No way does that mount do half of the image pixel scale ratio, it typically guides around 1-1.2 RMS, the best I've got is around 0.6-0.8 with an OAG but that was a one off. The images however come out fine, loss of images due to guiding errors maybe 5-10 percent, but my rig is 6.5Kg so overloaded on it. My hem15 is more reliable in terms of little to no loss of subs.

For the OP, maybe you could adapt an azgti into EQ mode, but if you've got the funds a ZWO AM3 or Ioptron hem15 will be better, the lack of need for counterweights make them more portable, paired with a good carbon fibre tripod and even lighter transportation setup. They'll also be more future proof for larger setups, I've imaged with my C6 and Starfield 102 with the hem fine.

But yes, in general you want a mounts max payload capacity to be a significant percentage higher (think near 25-50 pc more) than your actual, especially for imaging, and for per sub reliability.

We can't argue with the facts, though.  If your RMS is 1-1.2 arcseconds your captured resolution will be about twice that. (This is only a rule of thumb.) That doesn't mean your images won't be good because an image with a resolution of 2 arcsecs can be great. I spent many years using a rig that worked at 3.5 arcsecs per pixel. What it does mean, though, is that you could have a much wider field of view from a shorter focal length and capture with just the same real resolution.

When you reject an image because the stars are elongated you are seeing a difference in the guiding precision of one axis against the other, hence elongation. If your guide errors are equal on both axes you will still get round stars but potential detail is still being blurred out.

This is important for the OP to understand because he might be tempted by a larger, costlier, longer FL scope in search of more resolution when, in fact,  a smaller, cheaper, lighter scope might give the win-win benefits of better stability, no loss of resolution and a wider FOV. A region of interest can also be cropped from the widefield with no loss of detail.

Olly

22 hours ago, RJC said:

Thanks for the advice everyone.
I'd roughly calculated the weight of everything and it should fall within the 6KG payload limit, I know you ideally don't want to get too close to that.

@Elp I would like to image DSOs, not interested in planetary/lunar particularly.
I ideally want to keep the rig as light weight as possible so I can take it on holidays around the UK etc. and also get from my house to some nearby dark sky sites.

I should also point out, I already have the Evolux 82, hence that scope is in the list.

Looking at the payload capacity is all very well but it is only half the story. The accuracy of your tracking also needs to support the image scale at which you are imaging. If it doesn't, you might as well image at a shorter focal length and get a wider field of view with no loss of real resolution. This calculator will give image scales. https://www.12dstring.me.uk/fovcalc.php

Whatever your image scale in arcseconds per pixel, your guide error RMS in arcseconds must be no more than half that. A good HEQ5/NEQ6 can manage about 0.5" RMS under guiding but beware, it might be twice that.

Your mount must track accurately enough to support your image scale. How accurate are the small Skywatcher mounts? I've no idea but don't buy one without finding out. Users on here who autoguide will know.

Olly

You could get even more out of this by using a star removal routine to process stars and nebula differently.

Olly

That's an exceptionally good Soul nebula. For me its most obvious shortcoming is in star colour, which you could easily catch in a short run without the filter.

Although the 4 pixel array of the Bayer Matrix captures less first hand resolution than mono, the de-bayering algorithms are so good that they restore it. In the real world you will notice no difference.

The advantages of mono are diminished 1) by the CMOS chips because CMOS OSC is, for some reason, far more convincing than CCD OSC. This is based on first hand experience of both. 2) by the arrival of the various NB filters for OSC.

However, mono can be used for fairly moonlit Ha sessions and will allow you to go deeper on faint signal by concentrating on luminance.

Olly

9 hours ago, Meluhanz said:

That would be amazing if anyone can show what I can do with the images. Here you go..... 

Light_Stack_8.zip 178.29 MB · 0 downloads

Here we are...

The Trapezium region is saturated on the linear stack so no detail can be recovered. This is normal and we all have to shoot short subs to fill it in. I'd learn more about basic processing before learning how to do that, I think. Mine has a smaller saturated region in the final image because I stretched so as to minimize the problem.

I did a so-so cosmetic repair of dark patches which should be dealt with by using flats. You do need flats!

I put it the northern hemisphere way up!  

Nutshell: More subs. Flats. Tweak the guiding.

Olly

There is an awful lot more to processing than contrast and brightness. 'Stretching' is the most important of all.

You could post your linear (unprocessed) stack for members to try in their various workflows.

Olly

I share Michael's concerns. I tend to think of the star adventurer as a camera lens mount rather than a telescopic one, especially since the tiny pixels of modern cameras make an 80mm scope quite high resolution these days.

There is nothing worse than being under-mounted.

Olly

That's great. The X shaped composition of the full field works beautifully.

Olly

10 hours ago, WolfieGlos said:

Thanks Olly, it looks much better with the colour balance tweak by reducing the cyans - I think that that's done it.

Much better colour in the Ha, and also boosted the blue in the core of M78 as you described. Worked a charm 😁

Look forward to seeing how you get on with my stack 🙂

Now that's great. If I'd known you were going to get it as good as that I wouldn't have dared play with your data!   I certainly can't beat it and not for want of trying. 

Very good data and guests have brought much worse LP down here, I promise you.

Olly

13 minutes ago, WolfieGlos said:

Thanks Olly, I see what you mean in the Ha area. I’ll take a look later. Happy to share the linear stack if you wanted a go at the devil target 😉

Love to. The joys of our new fibre internet!!

Olly

6 hours ago, WolfieGlos said:

I can see myself re-visiting this one for processing again in the future. Whilst I feel I have a good image, I don't feel like it's quite there and I can't put my finger on why at the minute.

I think it's pretty damned close. I still think the blues would stand more saturation and, in Photoshop, I would use Selective Colour to lower the cyans in red. This is a demon tweak for anything Ha.

Olly

As others have said, this is a great start. You picked a popular but very difficult target, the only one on which I've found multiple exposure lengths to be unavoidable. Combining them is quite a complex process but can be done.

If you don't have any short exposures you can use a very soft stretch to replicate them. How blown is your core in the linear image? It cannot be 'de-blown' but there is no reason for the brightest parts to get any brighter. This is a good photoshop tutorial. https://www.astropix.com/html/processing/laymask.html  This is the method I always use on M42 to produce something like this: https://www.astrobin.com/321869/B/?nc=&nce=

Exposure time in One Shot Colour and Mono? There's no free lunch.  An OSC captures red on a quarter of its pixels, green on half its pixels and blue on a quarter of its pixels. It might be better to replace the term 'one shot colour' with the rather cumbersome, 'quarter of a shot red, half a shot green, quarter of a shot blue.' When a mono shoots through a colour filter it shoots that colour onto all pixels. There's not much overall difference in that respect. On faint targets, though, a mono can shoot luminance on all pixels and this picks up faint signal very fast. You don't actually need as much colour as luminance so mono starts to pull away. It's also much faster in narrowband.

In theory there is a slight resolution advantage in mono but, in reality, you will be very unlikely to be able to see it.

Olly

As a proof of concept it's a total success, no?

Olly

There are too many variables for a clean answer. How reflective are the curtains? How reflective is the window glass? How reflective are the surfaces newly illuminated outside and how much of that reflection is directed back into the room? If someone holds mirrors up outside the window, the room will surely get lighter. If the curtains are made of glitter and the window looks onto a mat black wall, it will get darker.

It would only need a  photographic light meter to get a good idea of the reality. Most cameras have them built in...

Olly

3 hours ago, ONIKKINEN said:

The credit for the tight stars in the cluster should go to BlurXterminator for sure. The data isn't at all special at roughly 3.6'' fwhm.

Pre and post BXT below:

Not used BXT for globulars before, but looks like the tool is perfect for them based on this short image.

Interesting. I'll have another look at my own raw Glob data if I can still find it.

Olly