M31 & M45 w Evoguide50+Flattener

[vineyard]

Hello,

Here are a couple of images from my first spin with the new flattener for the Evo50 last week.  No filters (that's the biggest design fault w this - no natural place for a 1.25" filter vs the Starizona one, although I intend to test one way to see if it might work).  I've cropped it a bit (probably taken about 5-10% off on each side) b/c there is vignetting which causes some edge effects in stacking (see separate thread for that).  60lights of 60s, unguided, d, f & df applied.  All stacking & processing done in Pixinsight.  A little bit of star reduction in both images (& both downsampled for size).

All feedback on the processing v welcome pls (I know the camera - ASI294MCPro - has too big pixels for this little scope based on astronomy.tools, leading to under-sampling & a bit of softness; but I'm also pretty clumsy so feedback is the only way to improve!).

Overall I'm quite happy with this wee flattened scope (even with the cropped FOV) - if the filter adaptation works, then that'll be gravy.

Stay safe,

Vin

 

Edited October 14, 2020 by vineyard

[ollypenrice]

Surely those are encouraging results. An hour's integration isn't much and you'd be able to go deeper, and do more sharpening, if you upped that considerably.

There's something going on in the M45 image: there are some not-quite-vertical striations running down the middle part of the frame. They may go right across it but they only show where it's lighter. We don't see anything like this in M31 and that target is fainter, which is odd. Could these be stacking/calibrating artifacts? Try looking at some raw subs under a good screen stretch to see if they're present.

The other thing I'd be thinking about would be extracting more colour, particularly from the stars. I can't help on how to go about in PI since I do it in Photoshop but perhaps someone will come along with advice.

Olly

[Adreneline]

7 minutes ago, ollypenrice said:

extracting more colour, particularly from the stars ...... in PI

You could try making a duplicate of the image and stretching it using ArcsinhStretch to bring out the star colours. You could use HistogramTransformation on the original copy. You then have a number of options for combining/blending the two including the likes of PixelMath or another application like Photoshop, etc. Or you could use Starnet in PI and remove the coloured stars from ArcsinhStretch and replace the stars in the original image.

Lots of fun to be had!

Adrian

[vineyard]

Thanks both Olly @ollypenrice & Adrian @Adreneline.  Yes I noticed those striations too (reminded me a bit of stretch marks on skin!).  Definitely re more data, and ok will look at subs too.  And will tinker w ArcinhStretch & see what happens (I definitely want to explore what PixelMath allows a bit more - sadly no Photoshop).  The star-swapping sounds cool too - have not used Starnet yet.  Lots of cloudy days & nights had, so this gives me stuff to play with.

Cheers both!

Vin

[Adreneline]

4 minutes ago, vineyard said:

And will tinker w ArcinhStretch & see what happens

I would recommend lots of incremental stretches making constant small adjustments to both Stretch Factor and Black Point keeping a careful eye for the tell tale coloured pixels appearing when you've gone too far.

Not that I've used it much but GIMP will let you combine layers in just the same way as PS - and it's free!

Good luck!

[Neko]

very good results with the flattener! 

althought that pattern looks like walking noise. did you dither the frames? did it happen with other images ? 

[vineyard]

14 hours ago, Neko said:

very good results with the flattener! 

althought that pattern looks like walking noise. did you dither the frames? did it happen with other images ? 

Cheers!

Ah re walking noise (what is that?). No unfortunately I couldn't dither (haven't yet got a mini-guide cam for my guide cam 😂 but Christmas is approaching...).

[Neko]

2 hours ago, vineyard said:

Cheers!

Ah re walking noise (what is that?). No unfortunately I couldn't dither (haven't yet got a mini-guide cam for my guide cam 😂 but Christmas is approaching...).

Walking noise seems to be typical from One shot color cameras and DSLR. Also heard they call it "Correlated Noise" and I guess is same as "color mottle" that Tony Hallas was talking about here 

Once I tried  my Olympus ep-3 for wide field and saw a lot of those  I have a lot of it. In your M31 there is too, but in different direction as the M45. Was told, althought I couldn't see it that much, that in my qhy8L I also had some, so since I am dithering and indeed the images come out "cleaner" 

Patience till Christmas then! 😛 

[Taman]

Some very promising results!

I have the same as you, the Evoguide and ASI294MC Pro. Just wondering what you have planned for the filters? I have a ZWO filter drawer on order, which may or may not solve this.

Tony.

[vineyard]

On 06/11/2020 at 22:08, Taman said:

Some very promising results!

I have the same as you, the Evoguide and ASI294MC Pro. Just wondering what you have planned for the filters? I have a ZWO filter drawer on order, which may or may not solve this.

Tony.

Hi Tony, sorry for the v slow reply. There's a little T2-1.25" adapter that comes as standard with the ASI294MCPro.  If you buy it separately its this one.  I thread the 1.25 filter into that, and then thread the adapter into the camera.  There are still enough threads left in the camera to then attach the flattener.  I've tried that and found focus w v distant objects in daylight - haven't had a chance to use it at night yet though b/c some logistical reasons have meant I haven't been able to set up my AP rig at all for a few weeks.

I've never used a filter drawer but I don't think that will work b/c I think it will introduce too much distance into the path (the chip needs to be 17.5mm from the back of the flattener so unless you can remove the stubby 11mm T2 nose on the camera I think it'll be too far away w a filter drawer?).  Unless you're using the Starizona flattener which can work with more distance and does allow for filter wheels.

Cheers & good luck!

[Taman]

9 hours ago, vineyard said:

Hi Tony, sorry for the v slow reply. There's a little T2-1.25" adapter that comes as standard with the ASI294MCPro.  If you buy it separately its this one.  I thread the 1.25 filter into that, and then thread the adapter into the camera.  There are still enough threads left in the camera to then attach the flattener.  I've tried that and found focus w v distant objects in daylight - haven't had a chance to use it at night yet though b/c some logistical reasons have meant I haven't been able to set up my AP rig at all for a few weeks.

I've never used a filter drawer but I don't think that will work b/c I think it will introduce too much distance into the path (the chip needs to be 17.5mm from the back of the flattener so unless you can remove the stubby 11mm T2 nose on the camera I think it'll be too far away w a filter drawer?).  Unless you're using the Starizona flattener which can work with more distance and does allow for filter wheels.

Cheers & good luck!

Thanks for the info. I originally ordered the filter drawer to go with my SCT, so nothing lost! It should take up 20mm of space which is not far off the 17.5mm required, so may be worth experimenting with.

Hope you get up and running soon!

Clear skies! Tony.