Xplode

46 minutes ago, vlaiv said:

That is about right. In fact, if you want to be precise, you should count in if it is a doublet or triplet and count each air/glass surface (4 for doublet, 6 for tripled - air spaced of course) and put something like 99.7% for each. But x2 0.99 is good approximation. Those numbers are there because my RC8" has dielectric mirrors that allegedly have 99% reflectivity.

There's a lot more losses than just from the mirrors/lenses, don't forget to take into account flattener/coma corrector, filter and the cover glass on the sensor.

Taking a peek at one of the guidelogs i can see some oscillation in there too.
Sometimes it seems to overcorrect so i would like you to set the RA aggressivenes to 75% of the current value.

I also think you should change to a longer guiding exposure, looking at the unguided graph during the guiding assistant i can see there is a lot of jumping up and down which is an effect from bad seeing either high up, but more likely local.
You might want to think a little about the thermals for your observatory and scope, it's incredibly important the both reach the same temp as ambient, an observatory should have some flow off air and the same would be great for the newtonian.

15 minutes ago, SlimPaling said:

Hi again Ole ..

I have a batch of LRGB images that I am hoping to find time to process soon .... I can see that at least 30%+ have got satellite trails.

I am a bit of a novice with PixInsight ( at the minute) ..... so can I ask if PI will remove all ( or much reduce ) all of these trails using the " Image_Integration" process in PI??? Or are there more processes that I need to consider along the way???

If the "Image_Integration" process is the main option in PI to remove the rails ... what settings do I need to look out for to give me the best results?

Cheers Mike

Yes they will normally be gone if you have enough images and use the right settings, you will want to change the rejection algorithm to this.

8 images is minimum for this algorithm, but it's best with 20+

If some trails are still left you can try to change Sigma low/high, don't remember which one does what, but you'll figure it out.



 

2 minutes ago, tooth_dr said:

Makes sense. I have a lot of short exposures I took one night. I’ll trawl through them tomorrow and see if I can find one suitable. What do you think is happening here?

It's hard to say since it's so regular.
It's either something creating vibration or it's the mounts RA motor tracking with a varying speed.

Maybe post some images of your setup too

Next time you are out imaging i suggest you take som shorter images, it would help find the frequency of the oscillations.
What you need is a satellite trail that starts and stops within your FOV, counting the oscillations would make it possible to calculate the frequency.

A lot can be learned from satelitte trails, i often use them to judge the seeing
Could you post your guidelogs, pre/postflip, would be interesting if anything can be learned from them?

It's better to go with a 12V usb hub because it's easier to power as you don't need an extra 5v power adaptor, but can instead use the same power supply as the mount, camera etc.
Most USB 2 hubs are 5v while most USB 3.0 hubs are 12v.

This is caused by the dec axis and the dec gear tooth not being machined cocentric, it's standard on cheaper mounts and there's really nothing you can do about it unless a spring loaded worm drive were mounted.
The groaning sound you hear is bad, it means there is high strain on gears and bearings.
You should loosen it a little so it can run free and easy the whole 360 degrees, that's the best you can do.
Something that will help you is to move the loose spot to the position where the scope is pointing downwards, move the scope with the motor, loosen the clutch and move the scope by hand.

6 hours ago, DaveS said:

One last (!) question then I'll let the thread back on track. Am I understanding correctly that if I want to bin, eg the whole frame, then I have to download the full size, 124 MB files and downsample after stacking? Or is there a more efficient way.

Sorry to hijack the thread.

If you want to bin "the right way" that's how you need to do it.
You can of course downsample the image before stacking, but i bet the image would end up better if downsampling after stacking/processing.

8 minutes ago, ollypenrice said:

Whenever the performance on paper of the KAI 11002 comes up it looks awful.

But whenever I process data from my 11002 it is just so gorgeous to work on. The stars are right. The colour is right. There's no fighting, just happy, happy processing.

Olly

You would be amazed at the low noise the IMX455 sensor has, i've compared the KAF 16200 sensor and the IMX455 sensor and the read noise is so low that images get deeper in a shorter time.
The downside is some stars have haloes, but the stars on the KAF 16200 isn't perfect either.

4 minutes ago, DaveS said:

 

I was seeing this on the FLO site

And assumed that it applied to the mono version. Are ZWO selling porkies?

I would say it's kinda a grey area around the binning of these sensors.
Like mentioned earlier it's meant for color cameras so it bins several R, G, B pixels together.

There's also the thing with the ZWO Ascom driver only supporting software binning, for hardware binning the software has to connect in native mode like what Sharpcap and other planetary imaging softwares can do.
I haven't really tested the hardware binning on the ASI6200 mono camera i have access to.

Just now, newbie alert said:

ASI  camera's are cmos so they can only do software binning, for hardware binning choose a ccd

Wrong, CMOS can do hardware binning too, but so far i know of only the IMX455(ASI6200) and IMX571 (ASI2600) sensor that can do it.
The minus is that the binning is meant for color cameras, CMOS mono hardware binning would have been cool to try.

10 minutes ago, DaveS said:

If you really *must* have an ASI camera (And after my experiences with a 1600 I would be dubious) then the ASI 6200 will give you 135 format and with that number of pixels could certainly be binned 2x2 or even 3x3.

Else a 16200 based camera from Atik or Moravian. SX are expensive, and FLI rouinous.

Binning doesn't really do anything for the IMX455 in the ASI6200, there's hardware binning, but it's meant for color cameras so it's not a 2x2 binning with adjecant pixels like for CCD.
Software binning is kinda pointless, it's better to downscale after stacking the image.

The 16200 sensor is really great, seems like the best largish CCD sensor out there at the moment that normal people can afford.
It also does great hardware binning.

6 minutes ago, gorann said:

Yes, aperture rules - ESA do not put up 5" refractors on mountains in Chile.

Aperture rules, but there's a reason they put the telescopes on top of mountaines, better seeing...
There's also a reason professionals aren't using C14's, you might want to look at the RASA versions, the RASA14 was totally redesigned compared to EdgeHD/smaller RASA scopes because they have problems with mirror flop etc.
Please also compared the price for the Rasa 14 vs Rasa 11...

Check if long term noise reduction is set to on of off, it should be off.

Go for ONTC, it has a much better mirror cell and the same goes for the spider too

On 20/04/2020 at 20:40, DaveL59 said:

wait till they start failing and a new load get thrown up there, no doubt the old junk will be left floating around and still messing up the views. Surprised NASA and others haven't stepped in as they must reach a point where launching anything to head out of earth orbit will be running even more of a gauntlet of space garbage.

It's a kinda pointless thing to be doing really too. There's only so many areas where internet via satellite is really worth putting into place surely? Most developed regions already have infrastructure that would be far better and more reliable so it only really serves for really remote/under-developed regions. So why not just put a few geo-stationary units up there like they have for telecoms and TV rather than litter the entire sky?

Failed satellites will deorbit automatically.

It's not pointless, it will give people who either don't have internet or who has crappy internet service like from geostationary satellites the possibility to get fast internet with low ping times.
Internet from geostationary satellites usually has a ping of 500-1500ms, browsing on it is a bad experience because of the slow response, the slowness is caused by their large distance from the earth.
Starlink will have a low ping time of around 10-20ms from what i've read, this will of course rise with distance like with regular internet.

2 hours ago, Swoop1 said:

Comets are a mobile object but are they mobile enough that it would preclude stacking 30 second subs?

On my set up, each 30 second sub is a minutes worth of camera time- 30 seconds data capture and 30 seconds data writing.

If I took 10 minutes worth of data (10 subs) would there be enough movement in the target to have a noticeable effect on the finished stack?

Which camera do you have? 30 seconds for writing data sounds like a lot....sounds like you have a DSLR and have dark subraction enabled in the camera?

I'd say save your money, the Esprit with it's ease of use and a lack of all the problems that comes with an SCT i'd advice you to use the it instead of the C11.
Hyperstar is incredibly hard to get right, dealing with tilt, focus etc is a big problem and not for most people.

The Esprit 120 will most likely be just as sharp as the SCT during most nights and the stars will be tight instead of fuzzy looking

 

1 hour ago, Hallingskies said:

Ah, right, so me not liking to see a string of bright, man-made lights streaming across the sky every evening is down to my hysteria or lack of knowledge, rather than my respect for the sanctity of everyone's night sky and my wish to see it remain unspoiled.  Thanks for clarifying that.  I look forward to Coca Cola or McDonalds placing orbiting adverts around the world in low orbits.  It won't matter after all, you'll only be able to see them at dusk or dawn...

The only way Pixinsight could properly deal with Musk's satellites is to shoot them all down IMO.  I'll happily buy the first version that does that.

You might want to read again, my comment was on the effect on astrophotography because some people think it's the end of astrophotography, that's hysterical and saying so it really a lack of knowledge.

I'm not happy about the satellites being points of lights in the sky either, but i'm realistic and realizing there's nothing i can do about them being there so i'm trying to get people to realize it doesn't really affect astrophotography that much, and there's also the thing about more people getting faster internet and some people won't have a chance of getting internet without Starlite at all.
What's more of a problem for astronomy is the local light pollution and air pollution.

12 minutes ago, westmarch said:

To try to inject a note of hope into this, is it not likely that imaging software will evolve to remove the noise of satellites from images. Is it not just about software consulting a database of satellite position and time?

John

This has been possible for over 10 years so it's pretty funny to see people are still deleting images with satellites, the problem is a lack of knowledge, not satellites.

What most people don't think about is they won't see the Starlink satellites unless the sun is lighting them up, since they are so low they will be in the earth shadow most of the time except low towards the horizon or during dusk and dawn.
Still they don't really affect most people doing astrophotography, it's just hysteria because of a lack of knowledge.

You might want to take a look at my image here to see how well Pixinsigh deals with satellites

On 12/04/2020 at 21:14, Adreneline said:

I have wasted so much time trying to get autofocus to work (in SGPro) that in the end I spent one night just establishing the best focus position with a BM.

With my Baader filters and a ZWO-EAF I got these focus positions:

OIII 28302   -50

G    28312   -40

B    28312   -40

SII  28322   -30

L    28352   0

R    28372   +20

Ha  28382   +30

The mean position is 28342 so close to L but far enough away from G and B (and OIII) to give bloated stars.

Adrian

Setting up autofocus in SGP nowadays is usually pretty easy, i'd love to help if you'd like

Seeing the hysteria from a lot of people about satellite trails supposedly being the end of astrophotography i wonder if it would be a great idea to write a guide on how to remove them with different softwares and in different ways?
I'm thinking a combined thread for different softwares so it would be easy to find and easy to link to.
I'm certainly not the person do to it, but i can think of at least a couple guys that could help like @ollypenrice  and @vlaiv

Yes Pixinsight does a great job at removing satellite trails

All the complaining about satellites nowadays is mostly hysteria, it's nothing to worry about for regular astrophotographers.

Personally i never throw out images with satellites.

Here's a stack of Abell 1656 from the other day of a bunch of 120s images, this is stacked to show all the satellittes and other garbage.

Here is the same data stacked to remove satellite trails and other garbage, it's processed a little, but there's no trace of any satellites because they are rejected during stacking because their trails are seen as outlier pixels.