alacant

Yes, well done. That's exactly it.

€silly, agreed. I haven't witnessed the Baader but this one I can recommend from hands on. If you've struggled with the basic 2 speed, this one you can fit and forget. It just works.

Maybe that now we know what it is, there will be other outlets.

10 minutes ago, Mandy D said:

hijacked

No, no. OTC. I'm sure that if we hang around long enough, someone somewhere will have found a source.

17 minutes ago, Mandy D said:

I'll give that one a miss

Hi

If anyone knows the answer to one of my original questions concerning the availability of the Quattro focuser, that would almost certainly represent a -drop-in- upgrade.

Anyone?

1 hour ago, Elp said:

interesting challenge

I once witnessed a side by side with an 80ed and a similar fl Newtonian. 150mm I think. DSLRs. For me at least there was a clear winner.

But that was five years ago.

1 hour ago, ollypenrice said:

imaging quickly

Not imaging. Processing.

If it's not working out, it's only because you have poor or not enough data. Best to go and get more frames the next night than sit in front of a screen over processing data which will never yield.

No theory in support of my claims. Just lots of wasted time!

On 06/12/2023 at 18:51, Elp said:

do this with a refractor

Hi

I had a go with a refractor but it takes ages; 6 hours. I don't think an hour or so would get much detail. Do post your image and prove me wrong though!

23 hours ago, ollypenrice said:

if the data are properly respected.

I think that's important. Even with just 72 minutes, it's tempting to push beyond what's really there.

When to stop? Having to continue processing to combat artefacts -not just noise- you've introduced is perhaps a good time to decide where processing ends and over-processing begins.

2 hours ago, Mandy D said:

one on the right

That's the Crayford-friction model as fitted to the Quattro range. It works without introducing tilt and holds the position at which it is locked. Out of the box, usually.

HTH

2 hours ago, Backyardscope said:

rack and pinion

Neither focuser is of rack and pinion design.

21 minutes ago, Whistlin Bob said:

there isn't consistency because it's a terrific scope

Thanks. Indeed it is such a pity. It seems to be down to luck as to which focuser is supplied. 

JTOL...
The closest we got from our local dealer was the distinction between Quattro and Black Diamond. Evidently, SW Europe carry both. Here for example is a black diamond. You can see that it has the inferior quality focuser. I wonder if that's it?

Still thinking....

Hi everyone
Upon our recommendation, a visitor brought over their newly acquired Quattro 150p. One of the main recommendations for it was that it had the excellent Quattro monorail focuser. Alas, this example had the awful sw ds focuser.

SW can't/don't know or help, Does anyone know the policy for what is supplied to where? It seems that Spain sourced models have the proper monorail focuser whereas (guessing non EU?) countries have the cheap ds model. Is it possible to convert between focusers? Is the Quattro focuser available separately anywhere?

Hi everyone

Trying to decide if loadsa short frames are better than fewer longer frames. Any ideas/examples most welcome.

m45 en tauro, 72 x 1 min ISO800. Looks quite promising. The noise seems to be under control, even for a short exposure time.

Cheers and thanks for looking.

Hi everyone

Anyone ever forgotten the moon may rise close to the target whilst asleep? I thought that Ursa Major would be relatively safe, but what a mess. Lesson learned.

What I anticipated to be an interesting and unusual galaxy, became a rescue mission. Big call out to StarTools' wonderful Wipe module  for getting us anywhere near.

Thanks for looking and please do post your -hopefully moonless- images of this. It seems impossibly faint.

nt150s ~5h, ISO800

11 hours ago, GeoAmy said:

The ones I’m considering

Hi

Unless you really do want to do wide sky shots, there's one on your list which stands out several kilometers above the rest;)

From the end of the FF closest to the camera to the plane of the sensor. The latter is marked on top of the camera: ø

What adapter do you have to attach the FF to the camera bayonet? How thick is it?

Which FF is it and how far is it from the sensor of the camera?

The image suggests it's too close.

14 hours ago, Tim Jennings said:

. If you look at the  corners you can see, that the stars are funny 

Hi

If you're using a telescope, fit a field flattener (FF) and ensure that the camera and FF assembly are held fair and square to the focuser. 
We don't know which telescope or lens you are using (or maybe it's in the signature which I can't see)  so it's difficult to offer specific help. But hey, well done. A worthwhile image no matter what.

Cheers

On 01/12/2023 at 03:01, Elp said:

never refocused during an imaging run

We neither. 

3 hours ago, Ouroboros said:

I thought it was just me!

LOL.  At the risk of putting Optolong out of business, I'm sure the craze will pass.
Take butter for example. Next year, it's bad for you.

Cheers and with my sincerest apologies to the OP, but please keep the reds coming, do.

39 minutes ago, Simone_DB said:

I don't know what the offset is, in this case) and I don't know what WHY is.

Hi. Sorry. English isn't my first language and I've learned how to write the technical form of it on this forum, so that's me just attempting to be pompous. And failing!
offset: a number derived from the bias which prevents negative cold pixel values. But please see below.
WHY: What Have You

39 minutes ago, Simone_DB said:

Wouldn't noise be produced anyway, just elsewhere?

It isn't, or at least there's less of it and other artefacts, but I've no idea why. Everything we post is from hands on experience. We gave up on trying to explain anything to do with astrophotography many moons ago!
HTH

5 minutes ago, Mr Green said:

I don't have a UHC

Well worth a go. The 2" version is around €30. Not sure where you are but they also have a European warehouse. e.g. ~5 days to Spain.

42 minutes ago, Mr Green said:

feel free to share a link to a video guide

Hi
I don't much care for false colour, but if you want to have a go with osc data, this Siril video makes it easy.
If you're into this on a regular basis, you may wish to consider StarTools which has a dedicated composition module.

BTW, you'll probably find that a UHC filter gives better results than a duo band; prominent colours, you get to keep the blue and far gentler on the finances!
Here is some UHC HOO stuff we did.
Cheers and HTH

22 hours ago, Simone_DB said:

what I did right and wrong

I'm guessing the darkest oif the frames is the bias, the next lightest the dark... (?).
Here is the calibration using only the bias and the flat. Gradient notwithstanding, relatively clean.

Now with -what I guess is- the dark. Much noisier.

I next try to find the offset from -what I guess is- the bias, so as to obviate the need for in-camera bias frames. It seems very low. 

Thoughts

I don't know where the noise in your -what I think are- stacked images (this post) originates. So...
Keep`it simple:

• Take a bias frame at 1/4000s in total darkness.
• Use Siril or WHY to find the offset as in the example above.
• Lose the dark and in-camera bias frames
• Calibrate the flat and light frames by subtracting the offset you found above.
• Clean the sensor
• Remoive any sd card from the camera.
• Download directly to your 'phone or a computer.

I've lifted this mostly from our dslr guru's recommendations: ,https://linuxcb.blogspot.com/2023/09/siril-dslr-processing.html

Cheers and HTH

On 22/11/2023 at 07:14, Simone_DB said:

I uploaded the .tif instead of the .fit

Hi

The files don't seem to be equivalent or linear. 
Originals:

Anyway, there is an almost impossible gradient and a noise pattern which suggests lack of correctly exposed flat frames, circular pattern walking noise or electrical noise; the sort you get when recording to in-camera sd with a mains fed dummy battery. Perhaps send more details of the image acquisition at the telescope and what you did to process up to the point of posting the frames here? Otherwise, we can only guess the cause. Here for example is the red:

I don't feel confident pushing any further than this:

But hey, there is some nice detail emerging.

Cheers and HTH

**EDIT... Ah... Just seen. DSLR? So best without dark frames of any kind. Simply subtract the bias from each frame you take. Siril makes this easy.
That may well explain the noise artefacts.

8 minutes ago, Alexp said:

higher guide speed, between 1 and 2 seconds.

What you are quoting there is the guide camera exposure. 

It was the guide rate -as a function of sidereal- which I thought may need attention.

11 minutes ago, Alexp said:

quality of the focuser

Before substituting the focuser, (expense!) dismantle it and remove any rubbish along with flexible components . That should help.

Cheers 

Hi

Small sensor notwithsatnding, to get stars that consistent under poor seeing using the sw ds focuser and a budget cc is pretty good.

If you want to take it further without upgrading the cc, maybe have a look at the (7 off) rubber rings in the focuser. They distort and perish easily giving rise to wobble, tilt and slip. Increase the guide speed. This may help the PE blip at around 12s although I doubt this can be removed by guiding.

Otherwise, perhaps simply stay as you are and hope for better atmospheric conditions.

Full sized .jpg of the images attached.

Cheers and HTH