Sun 4-3-17 First light

[tich]

Finally I managed a bit of an astro fix yesterday as it's been way to long so I gave the DMK41 camera (Thanks Helen) a first light on my Lunt 35 basic scope as I've read I can get the full disc using this set up.
I hastily set up although conditions weren't great due to haze & incoming clouds, focus was pretty tight with approx a quarter of a turn left although I was struggling to see the screen so it may have been a little off.
I've noticed its brighter one side of the disc & someone has mentioned its due to alignment of the imaging train, although I've no idea on how it can be adjusted. Unless its capture settings processing or errors on my part causing it. I did have an annoying dust bunny too which didn't want to shift but apart from the niggles I'm sure with more practice.

Processed using Autostakkert, wavelets adjusted with Registax & finished off with PS.
 

 

 

 

[xtreemchaos]

great firstlight mate, sols very quite at the moment, hopefully we will get some action soon. well done.  charl. 

[Macavity]

37 minutes ago, tich said:

Finally I managed a bit of an astro fix yesterday as it's been way to long so I gave the DMK41 camera (Thanks Helen)
a first light on my Lunt 35 basic scope as I've read I can get the full disc using this set up.

That's good news, since I have one of those (DMK41) "in the post" (sometime).

Quote

I've noticed its brighter one side of the disc & someone has mentioned its due to alignment of the imaging train,
although I've no idea on how it can be adjusted.  

As a first effort, I suggest Rotating the Diagonal + Camera relative to the scope!
Ninety degree increments for a start? One position may well be much better? To
recover the "aesthetics",  rotate the OTA in the tube rings(?) to compensate! 
(Proper e.g. T2-thread "rotators" are also available to do this job as well...)

FWIW, it's a GOOD, rather a *uniform* image! Compared to many 1st efforts.
 

[Davey-T]

Well done Tich, good to see another solar imager, uneven illumination is a pain, I've spent ages fiddling with my LS60DS, usually have to resort to some cheating in P'Shop to even it up.

You can try flats which sometimes help and sometimes hinder 

Dave

[Tony G]

 I want to get shots like that so bad with my l60.

[Pete Presland]

Great 1st light, you could always try a "synthetic" flat during processing.

[tich]

Thanks for the comments, I can't see me doing any more imaging until next weekend clear skies permitting, although I will be helping out at an outreach event on Saturday in Daventry so hoping to be able to show the public & have another go at imaging the Sun while I'm there.

As for flats I tried when I were suffering with newtons rings using my ASI120 MM but never had no joy so I'd rather get the sensor clean rather than faff around with those if possible.

[Merlin66]

Unfortunately in Ha imaging you may need flats not just for the "usual" dust bunnies but to provide some correction/ relief from Newton Rings.

These come from a different source - the interference pattern generated by very narrow band light (typically Ha solar) within the glass cover of the CCD chip.

Some chips are worse for NR than others. One solution is to use a tilter mechanism to apply a very small but effective "tilt" to the CCD - effectively changing the optical thickness and suppressing the NR.

ZWO do a neat version....

https://astronomy-imaging-camera.com/products/accessories/t2-tilter/

 

[tich]

Fortunately it doesn't seem to suffer with Newtons rings using the DMK41 on the Lunt35 but the ASI120MM was pretty horrendous for them. I did look at tilt adapters but unfortunately it would bring the focus point out further & this scope suffers with not having enough inward focus, the ASI wouldn't come into focus at all unless I were using a 2X Barlow on the nosepiece, the DMK does using the short nosepiece with the added benefit of getting the full disc too.
After hearing & seeing some good reports & images with this set up it seemed the way to go, although I know I've got a long way to go yet.

[Merlin66]

Yeah,

I haven't had any NR issues with any of my DMK cameras....

But with the new USB3 computer the DMK51 only runs at half frame rate (!!) - a known issue - bumma!

I need higher frame rates (>400 fps) so went for the ASI 174MM which unfortunately with any barlow/ powermate shows NR.

The tilter adds about 11mm to the backfocus.....

 

[tich]

Thank goodness I'm using an old Dell 630 with mine, sounds like if I updated the laptop I'd have to update everything else too including the scope, something I could not afford to do.

[johnfosteruk]

Great first light Tich. Looking forward to seeing many more.