Friday feast!

[JB80]

Well I'm surprised I managed to capture and process all of this before 3pm today. Seeing was reasonably good this morning and my wife is home today so I could settle in to capture some decent data.
I used 3 different telescopes and 3 different cameras to capture all these.

Could of done with one more to pad out the bottom right corner.

The white light full disc was with a Canon 450D and 6" f/8 reflector.
The white light close ups were with the 6" reflector and ASI120mm.
The one shot Ha full disc was with a standard PST and DMK41.
And the Ha close ups were a 88mm PST mod and DMK41.

[DJD]

Jarrod,
the poster looks great. Sadly I must be missing something as when I follow the link to Flickr the separate images are a bit small to appreciate. Am I doing something wrong ?
Best wishes,
David

[JB80]

Hi David, thanks!

If you follow the link I think if you click on the right arrow on the flickr page you can see each individual photo that I have uploaded and they should be at their full size when clicked on.

[grimble_cornet]

Superb collection of images Jarrod.

I am currently using the same two cameras and find the ZWOASI120MM excellent for white light and CaK images but it produces the worst Newton's rings I have ever seen in Ha. I have been trying a tilt-mount with limited success - such a pity as the high frame rate and smaller pixels make it a better choice than the DMK41 (or DMK21 which I also have) for solar imaging.

[JB80]

Thank you!

I seem to be OK with newton rings the ASI on Ha as long as I don't use a barlow in the train, I can still see them at times but they never really show up unless I am trying a close up. The same happens with the DMK though, add a barlow and get the rings.

[Andy Devey]

Beautiful job there

I am about 2 hours south of your location

Regards

Andy

http://thesolarexplorer.net/

[marktownley]

An excellent montage there Jarrod!

[swisswalter]

Hi JArrod

a fine presentation of the wonderful results from your session

[grimble_cornet]

Thanks for the feedback Jarrod.

I agree that the DMK41 shows NRs once a x2 Barlow is added and it gets significantly worse for some reason when using a x2.5 Powermate. However, I can usually correct the problem by using a flat (clingfilm filter) unless seeing is very poor in which case, I am really just wasting my time!

The ZWO produces NRs even without a Barlow and they become horrendous once one is added. With my humble SolarMax40, a Barlow is essential to record detail so it is a real problem.
As the SM40 is the only Ha scope I have access to, I'm not sure if the problem is with the scope, the camera or both
I have just ordered a Lunt 100 so it will be interesting to see how the ZWO performs on that.

As an aside, I also see NRs when using the ZWO with CaK plus Barlow under poor conditions but they are fairly mild and easy to remove by using a flat.

[Derek Klepp]

A productive outing

[RobBower]

Lovely display! Great captures! Really great set to view!

[mattwastell]

Great compilation from your session - glad you had a long one!

[solar]

Nice feast.

[JB80]

Thank you everybody!

Andy, that's a nice website. Lots to browse around in there.
Nice to find somebody reasonably close by. Hope you are making the most of the summer as well!

grimble, I am currently processing today's session which I used the ZWO for with my PST stage 1 mod. I will post the results soon and a couple of observations I made regarding the set up.

[JB80]

OK here are a few from today using the ASI120mm.
By the time I got around to taking these it was past lunch and 35°c so seeing was pretty terrible and especially once adding the barlows it dropped off rapidly but still OK enough for the test. I have enough issues with sharpening as is so getting the detail was tough.

Using without a barlow I could at times see NRs on screen but only briefly and they don't turn out in processing.

No barlow

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The x2 barlow showed more on screen and occassionally showed up after processing but you could with framing crop it out if it was there. They are evident on the first pic bottom right but weren't on the second at all or if they are they a very faint.

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The x3, well that was a mess but all in all I think it would be possible to get rid of them. Never mind the dust bunnies.

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Two things I noted that may be why mine does not suffer as bad from NR's is firstly using the PST black box still with the mod means I am still using the original eyepiece holder which has a cheap looking plastic screw to hold the EP or camera in with. When I tighten this I noticed that it slightly tilted the camera in the holder as it's not a completely snug fit.
The second was my rough alignment, I noticed I only saw the NRs on screen when I was moving the disc of the Sun. Whilst my alignment is OK for the short captures it would eventually drift off screen if I left it and I have read that may help.

I'm not sure if that's helpful to anyone but just my observations.

[grimble_cornet]

Excellent set of images Jarrod.

You seem to suffer far less with the dreaded Newton's rings than I do and your explanation about the layout of the pst optics could be the reason. I suspect that my SolarMax40 is particularly bad as it shows some NRs with all of my cameras. I understand that the new ZWO cameras have a window over the sensor which might be a response to the many complaints they have had?

[JB80]

Thank you!

Funny you should mention the window, it is postulated by people who have more of an idea than I do that the window is a likely cause of NRs.
It's even mentioned on one astro shops site here.
http://www.365telescopes.com/how-to-dea ... s-imaging/

[solar]

Hi Jarrod,
Think the ugly bits are from processing. What program did you use?

[JB80]

Yeah they are just stacking artifacts due to all the dust bunnies on the barlow, it was in AS!2. I need to give them a good clean but rarely use them because of the NRs.

[grimble_cornet]

Hi Jarrod.
I'm far from being convinced about many of the points being made on the 365 website:
I've never seen NRs in white light so I don't understand the comments about planetary imaging. The ZWO camera produces brilliant results on Jupiter, the moon and WL solar with not a hint of NRs. They only happen in narrow band - Ha is the most obvious but I also get them in CaK to some extent when using Barlows/Powermates.
Drift imaging is not really a viable method for high res Ha unless you are using a very large chip and are happy with a tiny section of the fov being recorded!
I don't understand the reference to using usb2 rather than usb3 to prevent Newton's Rings which, as far as I understand, are a purely OPTICAL phenomenon. I have heard this suggestion about it being essential to use usb2 sockets only for the ZWO but I have two laptops each with a mix of usb2 and usb3 sockets and IT MAKES NO DIFFERENCE WHATSOEVER which socket I use; the results are identical.

The link in this article to David Cortner's Slowblog is however very interesting.
I have just downloaded the Fourier Transform plugin for Photoshop which he talks about and the initial results are quite promising. He says that it removes NRs from flats but he has had less success with real images. I had a quick play (instructions are very, very basic so its really just a matter of trying various things):

This is a ZWOASI120mm + x2 Barlow image and the NR are pretty obvious

This is the same image after playing with the Fourier Transform plug-in

Certainly going to explore this further

Mike

[JB80]

I do agree with you about the rings only appearing in narrowband so it won't be a problem in white light, etc... The only thing I can think of in regards to planetary is the camera will produce a ring rind effect if the settings are pushed too far, again though it's not to do with newton rings.

It was more to highlight that the belief is the small glass window is one of the causes of the bad NR's in some ASIs which it mentions, there is plenty of posts about it here too.

I see your point about drift imaging too and I'm not certain just how much drift you would need, I don't think it would be lot and it's possible that even a slight bounce from the wind in the avi may help. It's not something I have experimented with but it is often windy.

The camera also is well known for not liking any usb hub but especially the usb3 ports, it's even recommended on the ZWO site not to use USB3 as some ports it's just not compatible with.
There was even mention that cameras had issues with AMD processors and they recommended using intel. Whether or not that has been fixed I don't know and it was only happening to some users not all. Plus now they have the mm-s which is a usb3 camera.

It looks though as if that Slowblog solution is quite promising on your images, flats seem to be the way to go. Definitely worth looking into.

http://www.schursastrophotography.com/s ... icle5.html

[grimble_cornet]

I do normally use flats and they work very well most of the time with the Imaging Source cameras but with the ZWO the NRs are often too severe for a flat to remove them completely.

With the 'window' I'm never sure whether people are talking about the protective glass covering/in contact with/bonded to the sensor which all cameras have or the additional glass cover that prevents dust entry and is placed several mm above the sensor (as with my Atik ccd camera). My ZWO is one of the very early models and just has the usual protective sensor cover but I understand the new ones have an additional coverglass? They are for sale as after-market 'upgrades' on the site. Also, a couple of the pre-release testers report that the new usb3 version has no issues with NR!

I bought the tilt adapter which David Cortner talks about on his blog BUT, like him, I found the amount of tilt was not great enough to completely remove NRs. I have just changed the bolts to give more tilt (as he did) - just need some sun to try it out.

My ZWO is quite happy working through a 10 socket, usb3 powered hub connected to a usb3 socket on my new Win8.1 laptop so.......... maybe this is a driver/hub architecture issue only effecting some computers?