Phillyo

13 minutes ago, AstroRuz said:

Thanks mate. Yeah I'm interested to see how it turns out also! Haha  

Yeah the 071 was messing about. Not sure as to why but instead of wasting more time I just put the Canon on and got busy. Oh another 5 hours? What's the total at now? Yeah the weather has been downright appalling this year hasn't it 

Ah man that sucks. Lucky you have a back up you can use! 

I have 6 hours total now and I'm probably leaving it there for this year. I'll move onto a new target whenever it's next clear. Either M45 or M42 I think. The classics!

I've updated my post on here (1 hour of NGC7000) with the 6 hour version if you wanted to take a look. And yeah, the weather is garbage. I need to move to Spain I think.

Absolutely stunning work. Love the processing!

10 minutes ago, valleyman said:

 

There's no such thing as an ASI833? Do you mean the ASI183MC? If so then I'm not sure why your image is black and white. Did you debayer the image during preprocessing?

Was this taken with a one shot colour camera? It looks black and white?

Love this Ruz! Lots of whispy stuff captured there. Look forward to seeing your updated version.

How come you resorted to the Canon? Issues with the astrocam? I was out last night as it was clear over lincoln too. Added another 5 hours to my NGC7000. Clouded over for another week now 

Added another 5 hours of data last night and reprocessed it (without drizzle this time Vlaiv ;)) so this is now 6 hours with a slightly different process. I've done stars and starless as I really like seeing both? 

I think the actual focal lengh is closer to 129mm as calculated by plate solving etc but i'll have a look at the step down rings and see which is closest

Hi all, if I want to use this lens at f4 using step down rings am I right in thinking i'll need to step down to approx 32.5mm? I don't want to use the internal aperture ring as it gives diffraction spikes that I don't really like. 

Thanks.

5 minutes ago, vlaiv said:

We probably need someone with more CCDInspector experience to explain what is going on.

I do know that software is sensitive to what type of star field you select, and it can interpret issues what come from lens being wide open as curvature (at least I think so since I have some idea of how it works).

For tilt and other issues - best to use it stopped down to say F/4 - that should give you proper stars all over, so there will be less chance to confuse the software.

Thanks Vlaiv. I'll give F4 a shot, although it'll mean more integration time it will also (hopefully) mean a bette final image. I have some step down rings I can use too so that should help also.

On 16/11/2020 at 19:06, vlaiv said:

That looks rather nice. Maybe something is tightened too much and creates pressure on optical train (are these rings height adjustable?).

There actually is a way to check for tilt in software. There is piece of software that is called CCD inspector.

You take one calibrated linear sub of star field (relatively uniform star field) and you analyze it in this software and it will produce diagram of field curvature, collimation and possilbe tilt.

It looks like this:

Above image shows a bit of curvature and some tilt / possibly slight collimation issue if scope is newtonian.

It will show both height diagram and 3d representation of focal plain. Again - corner affected will be lighter in color.

Software needs to be purchased but I've seen some members here offer to analyze subs with their copies if you upload them in these kind of situations when troubleshooting.

 

So you can get a trial version so I'm giving that a go. I uploaded all the images I took to create the image of this post and both curvature and tilt vary on each image, the worst being 18.1% curvature and 15% tilt. The best being 14.6% curvature and 5% tilt. Why does it vary so much image to image? Is there anything I can do about that?

I ended up removing the spacers this evening and reattaching it without doing it up super tight. I only took 2 images before clouds blocked the stars out but they were better, with curvature being about 10-12% and tilt being either 5% or 1%. 

So now I'm confused. I did shoot the first image (with 1% tilt and 10.3% curvature) at a narrower aperture of like f4 maybe? Just to see if it made much difference. The second image was shot wide open at f2, but it's still only 5% and 12.3%.

I'm rather confused now! Maybe I'll just take as many photo's as a can then just crop in a slightly to remove the very nasty stars

Thanks,

Phil. 

@vlaiv this is how it's all connected (Sorry for bad picture, cold and dark!) so I'm not sure where the tilt is coming from. I'll need to do some investigations me thinks! I don't suppose there's a way of checking for tilt using software is there? I hate to waste clear nights.

18 minutes ago, kirkster501 said:

You posted a wonderful NAN and Pelican for us to view and enjoy.  My counsel is not to be obsessive about it Phil with this guidance.

Thank you. I don't obsess over it, but I like tinkering and making things 'better', it's one of the things I find most interesting in the hobby. Gotta strive to be better right? 

2 minutes ago, vlaiv said:

Indeed could be processing thing.

It is most likely tilt - as it affects only bottom part of the image - that is signature of the tilt - which is in reality - distance issue - one part of sensor having different distance then the rest of it. If it affects only one corner or two corners - it is likely tilt.

By the number of corners it affects - you can figure out direction of the tilt. If it's only one corner - it is "diagonal" to sensor, but if its two corners - it is parallel to sides of sensor.

Interesting! I'll need to take a look at that then. Thanks again.

Haha no that's fair. I did indeed do 2xdrizzle, I will do it again without the drizzle. However, the reason for the halos is due to the very fast processing I did. I removed the stars with Starnet to work on just the nebula on it's own, then I added them back in with pixelmath at like 0.8x maybe? Like I say, it was quick and dirty and if/when I come to do a 'final' edit (whenever I get more data) I'll not remove the stars and edit the same way. 

There is some tilt, though I don't know why. I'm supporting the lens, with 2 rings and the camera with a ring too so neither should be tilting/sagging. I'm wondering if it might be a distance thing? Is it definitely tilt? I'll upload a picture later of how it's all set up (I'm at work now). 

I have a friend-made bahtinov mask which work's 'okish' but I'm looking at getting a better one as it isn't great. That being said, I spent a good long while getting focus so I think focus is fine and I think it's more the processing that caused the slightly out of focus look at 100%.

Cheers Vlaiv.

Phil

Congratulations Spongey, a great process and fully deserved win!

2 hours ago, vlaiv said:

I do it every single time

It's not about pixel peeping, it's about appreciating the scale of things. I also like to sometimes spot very faint background galaxy or see something else that I would miss by looking at "larger picture".

 

Don't do it this time! Give me some more integration time first please 

2 hours ago, MartinB said:

That's a beauty, I love the colour.  I think the best processing tool for managing noise and lack of exposure time is to present the image at a smaller scale.  This image demonstrates this perfectly.  And how often do we ever look at images at full scale unless we are pixel peeping.

Thanks Martin, and yes you're right. I uploaded this at full res if you click on it and it definitely shows the noise. I'm not too concerned about it as it is definitely a work in progress! It looks fine on insta/facebook too :P

48 minutes ago, Stuf1978 said:

That's lovely for 1 hour, well done. If you persevere, another 19hours may take you to 2022 with the current weather 😂

Aint that the truth 🙄

14 minutes ago, tooth_dr said:

Very tasty for just one hour!  Unfortunately I can’t see you sig on the phone.  Was this with a lens?

Thank you, yes taken with the Samyang 135 @ f2.8. 4 min subs.

I let the dogs out earlier this evening and noticed that it was actually clear here in Lincoln for the first time in weeks! Decided to try and snatch an hour on NGC7000 and give it a gentle process. It's a bit grainy, a bit noisy and it's not my finest processing ever. However, it's nice to actually catch some photons for a change! I'd like to add a LOT more data on this area, like another 19 hours or so.

Kit as per sig with the IDAS NBX filter.

Thanks, Phil.

These are great first images, well done! You should be proud of them, it's onwards and upwards from here. This is often up for debate, but I personally wouldn't use dark frames for calibration with a DSLR due to the fact they need to be taken at the same exact temperature as the light frames. That's tough with an uncooled sensor as it will fluctuate noticeably throughout the night. 

This is beautiful, the whispy nebula at the bottom is gorgeous. I'm generally not a huge fan of blue for Ha though.

2 hours ago, KEJ said:

Really impressive.  I must admit I have recently ordered a ZWO to Nikon lens adapter, I assume you have used something similar ?

 

Great picture though.

Thank you, yes I have the ZWO to canon adapter with the filter 2" drawer in it. 

15 minutes ago, AbsolutelyN said:

Thanks. I think the detail is simply due to the 8" aperture. The detail here is far more than I got with my Esprit 80 / 1600MM. Just wish the stars were pinpoint across the frame. 

Haha yeah, there's always something that needs tweaking or tinkering. I think we're our own worst critics half the time!!

Absolutely stunning. I love M31 and this is top notch. The level of detail is phenomenal. I took a similar image recently with the 533 on a Samyang, slightly wider than this though. Didn't get this level of detail from it.