david_taurus83

I'm currently using it for my mobile setup (OS on an RPi4) and I can't figure out how to use the app. I only use the app to connect to the device on startup so it updates the time and location, then it's VNC for everything after that.

1 hour ago, ollypenrice said:

It's best to measure the vignetting rather than eyeball a very posterized stretch. Just take the linear master flat and open it in software which lets you measure individual pixel values. I use my stacking/calibrating software, AstroArt, for this but lots of pre-processing packages let you do it. I get considerable vignetting in my Tak 106/2inch mounted filter/full frame CCD setup. The corners will give around 19,000 ADU when the centre is at around 23,500. That's a big difference but it calibrates out fine.

Olly

Hi Olly. The corners of the master flat are around 4600 ADU and the centre is 6300 ADU but camera is 14 bit so only goes up to 16k.

9 hours ago, vlaiv said:

That is rather interesting. Stddev (avgdev) value shows significant distinction.

Stddev is mix of bias (read noise + read signal) and dark current noise. It shows 8.6ADU in first case and 10.7ADU in second case.

That would make dark current expressed in ADU around 6.366.

Can you read off FITS header information? It should show black level automatically removed from raw file when converted into fits - at least FitsWork creates that Fits header - here is example of one raw file converted to FITS:

No, FITS header doesn't show anything like that.

Basically identical. 0.001s bias and 20s dark frame. Mean value of 2047.

I've also realized that it was an error on my behalf that the frame size was incorrect. I reset everything and upon restarting, Ekos asks the user to input the sensor resolution. I must have read an incorrect size off the web when I first set up the profile.

So some experimenting today.

Below single 20s image and calibrated image.

Its correcting the dust spots but looks to be over correcting the right side.

See below stack of 15 images or so and the master flat.

Normally I shoot from my back garden so I would have just assumed this gradient was a result of the local streetlights. But I have found a "dark" site not far from where I live (literally 5 minute drive!) and there is no local LP whatsoever from streetlights etc so this gradient is definitely the flats.

Perhaps the vignetting is simply too much?

All images were taken with my 6D on a Redcat 51 and captured via Ekos/Kstars. What bugs me a little is that Ekos doesnt like Canons CR2 files so converts everything to FITS. In doing so, it also alters the size of the image frames from the standard CR2 size of 5496x3670 to 5472x3648. So I also had to shoot a new set of Bias images to match.

Thanks vlaiv. So I should shoot a set of flats, subtract bias, create master flat. Then, perhaps dim the light source even more and try a 10s exposure. Check if I can calibrate that with the master flat.

Question on flats. Should a master flat correctly calibrate and remove dust artifacts and vignetting from the same flat frames themselves?

The flats would have the bias removed prior to integration. Camera is Canon 6D and ISO will be 1600, same as my lights.

I want to experiment indoors in a dark room to get good usable flats for my lights. If I can get flats to work on the individual flat frames them they should also work with the lights, right?

It's up on their Facebook page. They are saying they will be available once all the early backers have received theirs.

That looks great! Will definitely be looking to this thread if I get the chance to do it for myself! I like the heavy duty runners idea! Will you need to keep them regularly greased due to outdoor conditions?

I don't think it works in Kstars. I've had issues in NINA and Kstars if I try to enable the MLU function on my 6D.

Nice! It's a pity you can't buy these anymore! I'm sure another member on here bought the last one a while ago.

So, there's an area of gain that's effectively unusable? Can't use unity gain?

It's obviously not recovering quick enough before the next exposure starts. When APT sends a dither command, PHD picks a random position for the crosshair and selects a new pixel, for example. Then PHD moves the mount so the star lands on the new crosshair position. It can take a while depending on how big a shift in position it is. If there's excessive backlash in the gears it can take even longer. Try upping your settle time to 60s and see how you get on. Also, make sure the timeout time is longer than the settle time. This should cancel the dither operation and continue with the next frame. If its shorter than your settle time this could be why it's starting exposures too early as well.

What size of a dither are you using? What does the graph look like when the exposure starts?

Very nice! Unfortunately far to bright in my back garden. I have tried a number of times to get a pleasing image of this but its so faint and LP extraction leaves it very noisy. I am going camping next month to a dark site and this is on the shortlist for the Redcat/6D combo, weather permitting! 

What mount are you using? It sounds like the settle time is too short and the capture starts before the mount has recentred on the star. This can happen if there's lots of backlash, especially in the Dec axis. 

10 minutes ago, newbie alert said:

100mm has a 40mm imaging circle

120 has a 44mm

Yes and the sensor diagonal is 43mm so the 120 just about covers it. The 80 won't. Then there's the consideration of correction at the edges. Even the quads I've used don't fully correct for round stars but I think you need to be pragmatic with expectations with full frame sensors, especially at the budget end of the hobby most of us work with.

18 minutes ago, newbie alert said:

The esprit has a 33mm imaging circle.. not sure what the 6d sensor size is..

Fantastic scope..I use one myself

6D is full frame 36mm x 24mm. I've only had 2 scopes that pair well with mine. Altair 70EDQR (same as Star 71 etc) and my recently purchased Redcat 51. Petzval designs that quote a full frame imaging circle. 

I think you'd need an Esprit 120 or 150 to cover a full frame chip. 

If your using a decent LP filter (IDAS D2, Astronomik etc) then it has IR/UV cut out anyway.

Check out AstroBackyard on YouTube. He done a video on this.

Will the Esprit 80 cover the sensor of the 6D? Or will you be happy to crop?

I don't bother with my Atik 460. No issues with walking noise etc. Different sensor tech though.

Fightin' talk!

I wonder then if the issue exists if used with EQMod. Have you tried via a laptop?

2 hours ago, rorymultistorey said:

I just like to say to other readers unsure about whether lucky imaging works or not to check galaxies on astrobin and see how the sharpest ones had exposure lengths of just a few seconds.  The proof is in the pudding.

Vlaiv seem to be very keen to pick holes in everything I or anyone else says. I don't claim to know everything but i'm not sure you know everything either.  If I had to guess I'd say you were an armchair astronomer who hasn't actually been out their and taken photos. I could be wrong but that is what I'm thinking. In the case of the read noise have you considered  the beautiful and powerful noise reduction that comes from stacking thousands of subs. Whatever your answer I will simply come back and say that I've done it and it works. And I did it with a £700 set up.  Lucky imaging is not easy, lucky imaging relies on lots of other things being set up correctly, lucky imaging is continually fighting the fact that we're not catching many photons but it works. Its the theory of proof and pudding. So please if someone else is keen to join the BAT please don't be put off by negativity. We're a lovely bunch and if your set up isn't quite up to lucky imaging standard then we will ask you to help us get the dim bits of whatever we're shooting bc the faint bits is where lucky imaging really struggles.

 

Hi Rory. I think your being a bit harsh on vlaiv. This is an open forum and he's well entitled to contribute. He hasn't said the project can't be done as far as I can see and he has highlighted some obstacles to overcome. 

Ps. Looking forward to the next videos and to see how this project is coming along.