CraigT82

56 minutes ago, Tommohawk said:

Quick follow on - if I set FC to debayer when capturing, the grid disappears

Ok that’s good, so FC does know what the debayer pattern is then, is the FC preview the correct colour and not odd looking?
 

56 minutes ago, Tommohawk said:

My understanding its best not to debayer when capturing, although not everyone seems to agree. Even if it did it makes focussing really tricky.

Yes I always focus using the debayered colour preview but then switch it off for capture. If I remember correctly I got significantly slower frame rates when FC was debayering each frame and so I always have it switched off (I think that was with a 224mc) but never tried it with my 462 or 485, just always switch it off now out of habit. 

56 minutes ago, Tommohawk said:

but in the end if you have the wrong pattern that will simply affect the colour - it should cause a grid pattern surely?

No actually you still get the grid pattern if the wrong debayer is used, it’s to do with the demosaicing (interpolation between the pixels) being incorrect too. 

I think Firecapture might be writing the wrong bayer pattern into the SER header and that is being picked up by AS3 making it debayer the video frames incorrectly, but you can force it to use the correct pattern so if you run it through AS3 and force the correct bayer pattern you should be good I think. 

My advice is to always do your debayering in AS3 as it uses a much more sophisticated algorithm for interpolation called bayer drizzle, this can overcome the resolutions disadvantage of OSC cameras compared to mono. 

Just found this on the IMX385 data sheet... GBRG

When you tick the debayer option in FC does it debayer correctly on the preview or does it still have the weird pattern? 
 

The Jupiter image looks like it’s been debayered with the wrong pattern in AS3, not sure what the actual patttern is but you can force AS3 to use a user specified pattern rather than autodetecting, you can just try each one until it looks right. I wonder if FC is reporting the wrong bayer pattern in the SER header which is causing AS3 to trip up? 

1 hour ago, newbie alert said:

What is it 7/10 or 9/10

Well, both. Seeing varies throughout a session and even within a single capture. 
 

As you say we’re veering off topic. 

I think the standard skywatcher motor focuser unit will probably go on there, might require a bit of bodging to get it to fit but will be worth it, motor focusing is great.

5 minutes ago, vlaiv said:

This is in fact very interesting comparison as we have 12", 14" and 16" scopes and images produced with them.

Images are all of the same size - so we can compare who is sampling properly and who is not.

Here it is - from left to right, 12", 14" (Damien's EdgeHD) and finally 16" - these are frequency spectrums - log version, maximally stretched.

Properly sampled image will have circle touching edges of image - so all frequencies from center to the edge are used. When image is over sampled - frequencies towards the edge will be missing - there won't be signal at those high frequencies and there will be "dark" region towards the edge.

We can clearly see following from above spectra:

- each larger aperture has a bit more resolving power than the last as each spectra is larger in extent of frequencies

- all images are over sampled by at least factor of x2

- Mewlon is best planetary scope / sharpest optics (or weather conditions were the best) - as image could be sharpened the best - most rapid transition from region of signal to region without signal (best defined circle)

- other two scopes have softer outer edge of the circle - meaning they were not sharpened as well as they could have been (or maybe noise won't allow it) - signaling either inferior optics or poorer conditions.

Very interesting, thanks for that. So no it’s not Mr Go’s oversampling then as they’re all at it! 

1 minute ago, newbie alert said:

Or could be just the weather, which if it isn't in your favour there's not much you can do about it

Well for that particular image he rates his seeing as 7-9/10, so no, not the weather.

44 minutes ago, newbie alert said:

He's using a x2 Barlow, so he's nowhere near f11.6 or f14.6

Might explain why his images aren't as good as they perhaps should be.

Here is a comparison of recent images from Chris Go and a few northern Europe planetary imagers.  Chris should be doing better than the rest due to the planet elevation advantage he enjoys in the Philipines (Jupiter at 80 degrees alt), but he isn't, in fact I'd say he's doing worse which is an arguable opinion I know, could just be his processing technique.

Nice shots! Jupiter looks good with some nice sharp detail but the Saturn might be a touch out of focus? It’s tough to get focus when they’re low down in the murk. Might just be fuzziness due to the relatively long exposures.  Don’t worry too much about the histogram it can be really quite low and dim raw frame and still result in a nice bright final image after processing. Faster exposures are more important and that will also lead to faster frame rates.
 

Very nice image. You might get more interaction if you attach the image directly to the post instead of requiring readers to click away from the site.

58 minutes ago, Mr Spock said:

I'd like someone to demonstrate how you use a Cheshire, in the dark, from the bottom of 12" Newt... 

It’s actually quite easy, but only if you swap your donut centre spot for a triangle one, and apply the triangle so that each point is pointing at a collimation bolt. That way just by looking through the Cheshire you can see which bolt to turn and which way to turn it. Granted there is still a little bit of back and forth between eyepiece and mirror end to get perfectly collimated so not quite what you asked, but much easier than turning the bolts randomly and seeing what happens.
 

5 hours ago, PeterC65 said:

As I understand it, the LCG / HCG switching point is not set by Sony or by the sensor, but buy the camera designer. You can see this with the IMX585 where the switching point is different for the ASI585MC and the Uranus-C. It is very unlikely that ZWO would design a camera with a 252 switching point and then publish a spec curve that shows at at 150. Much more likely that the camera design has changed.

Well there is two possibilities the way I see it:

A) ZWO released the camera with the old specs however those charts were wrong (maybe this “incorrect testing” they mentioned?) and they have quietly corrected and updated the specs and the camera hasn’t changed at all and always switched to HGC at 252. 

B ) ZWO released the camera with the HCG set at 152, then decided at some point to change this on the cameras to the new HCG point and released those into the wild, again quietly.
 

Either way what I find fishy is how quietly they changed the specs… not even FLO knew about it! They didn’t tell their customers or dealers?! You’d think that if it was scenario B and this change made the camera better in some way they’d be making a song a dance about how it’s better than their competitors models, but I haven’t seen anything like that.
 

This makes me think it might be scenario A and the lack of announcements are because they are keen to avoid a rush of complaints/returns from people who are miffed that their camera didn’t work as it was advertised. 
 

I will accept they ZWO may have made announcements/explanations as to the change of specs somewhere and I just haven’t come across them. I’m all ears if so. 

1 minute ago, gorann said:

Obviously this shows that Olly has a particularly young and open mind, which does not listen to outdated advice from old and grumpy men😄

Indeed… it’s nice to hear praise and acceptance of something new rather than the usual “new stuff is rubbish - everything was better in my day” attitude that we see daily for a certain member demographic (not Olly!) 

Nice! 

Wouldn’t you need to test one of the early cameras with HGC at 150 against one of the newer cameras with the HGC at 252? 
 

Or is it the case that the cameras themselves haven’t changed it was just the specs on paper that were wrong initially? 
 

ZWOs answer about the change is vague doesn’t really clarify anything, which makes me think they really messed up! 

Very nice work, the Jupiter is good but the Mars is a belter, well done 👍🏼 

You don’t need that much distance just for collimation, I’ve done it with about 30m I think, if you were planning on star testing with it it would need to be further to be viewed as a genuine point source. 
One problem I experienced (I used the Hubble optics star) was that I collimated nicely on the star with the scope pointing nearly horizontal, but when pointing the scope upwards to the sky the collimation shifts slightly. 

This is the kind of thing you want for that purpose:

https://www.screwfix.com/p/rawlplug-r-kem-ii-styrene-free-polyester-resin-300ml/32863?kpid=32863&ds_kid=92700048793290424&ds_rl=1249413&gclid=Cj0KCQjw1bqZBhDXARIsANTjCPKfz2W-3koY6YC1IY0bZhlaj8puhwvqOLLauMQz3fGvja7XrYNR6D0aAvt6EALw_wcB&gclsrc=aw.ds#product_additional_details_container

edit: just browsed through this thread and the Google book linked and I also spotted the gate brace the wrong way round, wonder if it’s sagged and been fixed in the last ten years?! 

I also turn fan down to minimum just before observing/imaging, so that it’s just enough to break up the primary boundary layer. I also have it pulling air down the tube rather than pushing air up, I find the airflow within the tube is a bit more orderly that way. 

Yes that is odd, I get 250fps maximum speed at smallest ROI with my ASI485mc

Having a well baffled fan like the one above is a great way to increase the efficiency of the fan which lets you run it at lower speeds to minimises vibration. Saying that though I don’t think I’ve ever seen the vibration effects of a fan running visually, but when hi-res imaging it is very visible, so I make sure to mechanically decouple the fan from the scope on my OTA. 

Well that’s CN for you! I personally like it, I can zoom in if I want to get close but I do enjoy the open space feeling the full frame gives. Lovely stuff. Would be very boring if everyone did the same thing. 

Space bar to deselect in AS3

The auto detection only works for the overall size of the planets disk and the rough alignment of the equator with the cloud belts… you have to check yourself if the north and preceding are set correctly.

As Neil says the bright limb is very common and can be mitigated by adjusting the LD value when you do the derotation. Can also be sorted in post process too to a certain extent. 
 

Nice image btw lots of detail 👍🏼

It won’t be dusty or dirty glass so don’t worry about cleaning them. Most likely poor seeing and thermals in the scope. Possible collimation too but you say it was ok?  Big cat like that needs good thermal management. 
Try a longer eyepiece, even a 20mm will give you 195x in a C14  which is probably too much for poor seeing.