david_taurus83

If you measure from the lens elements 480mm down the tube to the sensor mark on the camera it should give you an idea of where infinity focus is. You shouldn't need to use a diagonal as you'll be limited by the quality and condition of the mirror. Try to focus on a distant tree or landmark during the day to get you somewhere near.

As others have said, full frame is difficult to correct for but can be done if your willing to accept some mis-shappen stars at the edges. I bought an Altair 70mm quad and it was very good at correcting, not perfect at the edges but acceptable imo.. You could probably pick up a used 5D/6D for not much more than £300, add another £200 to mod it and you've got a very capable camera. Yes, a cooled astro cam would be better with less noise but then you need a PC of some sort, 12v power source etc and portability becomes a question if you want to travel.

I love my 6D. I have it paired on a star tracker with a Samyang 135mm. At f4 it's still nice and sharp in the corners. Great camera imo. Below is around 5 hours worth with just an L-Pro clip filter. That's another issue in itself, choices of filter a very limited.

The M48 adapters for the Samyang 135 are back in stock at FLO. They've been out of stock for ages but I ordered one yesterday and was quite happy to wait a few months if needed. As luck would have it, I received a notification that they were back in stock today! Not many left! 

https://www.firstlightoptics.com/adapters/astro-essentials-samyang-lens-to-m48-adapter.html

DBE can be a mare sometimes. If your struggling just place 4 markers in the corners and experiment with the tolerance. Another idea could be to find a really good image on Astrobin with a similar FOV, plenty of IFN and clear background. Register the image with yours, and use it to place markers over the background. Make a new instance and then apply to your image. I had to do this on an Orion and Horsehead image I done last year.

11 minutes ago, Occy said:

What is the black device you used to attach the EdgeHD to the AZ-EQ6 in the dual setup above?

Looks like the Skywatcher guidescope mount. Can make fine adjustments to alignment.

https://www.firstlightoptics.com/guide-cameras/skywatcher-guidescope-mount.html

I don't use the DSLR histogram as I usually use a PC for imaging but if I aim for a third to halfway on the PC histogram (based on actual ADU values) then the DSLR histogram is touching the right hand side. 

It entirely depends on what target you are shooting and how bad your LP is. For Orion the short exposures are OK but lots of them. It's low down and probably more affected by LP etc. For M81 say, it's up higher and not as bright so you could get away with going longer.

1 minute ago, LeeHore7 said:

Hi David.

The .png file is just to upload on here.  I always shoot in raw mode .cr2.  Then stack in dss.  Regarding the histogram on my dslr, am I right in thinking that it uses a scaled down jpeg and I'm not seeing the true raw histogram?  So saying if it shows the peak 1 third along then the raw version will be further to the left Sorry if I'm being silly here 

Yes.

23 minutes ago, LeeHore7 said:

After taking my first test image with my canon 450d unmodded dslr I check the histogram and try to get it as far away from the left as I can, I believe that as long as your at least a third of the way away from the left hand edge your ok as it doesn't clip any data. I think that you need to play around with iso and aperture to move the histogram around, the higher the iso the more noisy an image gets. But I could be wrong as I'm very green on this still.  The histogram on my ps screenshot doesn't seem to replicate what i saw on my dslr as this was stretched in processing. Here is a single sub from the said Orion image.

 

Is that a png file? You should be working with raw cr2 files for preprocessing and then a stacked tiff file after stacking. Also, the camera histogram uses a scaled down jpeg for display purposes so the actual histogram in the raw file will be much lower. 

Larger FOV yes, but your pixel scale will increase also. So you will have more photons (in theory) falling on individual pixels which will add to its charge. This is why people say it is 'faster but not in the same sense as a camera lens.

Thankfully I have all the astro equipment I should ever need with no intention of spending another penny! Yep, that's me sorted!! 🤣🤣🤣

Why not use Sharpcap for DSO if your already familiar with it? It can control the mount, platesolve etc?

4 minutes ago, Shimrod said:

It's certainly quite different to the 300s sample image on the camera page at FLO - scroll down to the bottom of the page  ASI533 Sample 300s image

The FLO image is still in raw format while the above has been debayered. Above looks just like a raw DSLR dark that has been debayered. 

@Moodtastic are you saying that after calibrating your lights the brighter pixels are still present in your lights?

The PDS scope is designed to enable focus with a DSLR with 44mm depth to sensor. You may need to fit an extension to the nosepiece to move the camera back out. 

Will be fine as long as camera orientation stays relatively the same.

Hi Craig,

Id really take the camera off the scope and do your darks library with the cap on the camera sensor, metal preferably or tin foil lined plastic cap. Dont want to spend hours doing darks to find a small light leak has crept in. Of course it might be absolutely fine the way your doing it but its just a thought

If you've got Pixinsight, you could also shoot 1 set of long dark frames and use dark scaling to calibrate your flats and lights. I have the Atik 460 and I have a pair of master darks captured at 30 minutes each, 1x1 and 2x2. As long as the lights are shot at the same temperature and binning as the darks, you could use the 1 master dark for all exposures,  up to 30 minutes in my case.

I had a go in Pixinsight. Its always difficult to remove gradients with DBE on a DSLR image I find as it always seems too aggressive and leaves the background rather noisy. Still if you got up to 4 or 5 hours with no moon around you'd have a really nice image. I'm impressed by how flat the field is on such a big sensor!

@Andrew INTCan you post the image up here and we'll see what ASPS does with the same settings?

Darks have no effect on artifacts in the image. I have a 6D and I don't bother with darks as the dark current is so low anyway. I just use a master bias to calibrate the flats and lights.

Meridian flip also has no bearing on the flats. If you have dust bunny in the top right of your image it will still be in the top right of the image after the flip. What can happen is the dust can move between images. I'm guessing the shutter action doesn't help. Are those dust bunnies in the individual subs? Try stacking the lights without calibrating with flats and see if they match the master flat.

That lens looks nice and sharp!

3 hours ago, Skipper Billy said:

I too had setup issues with the Meridian flip. It seems I was asking NINA and SiTech to do the same thing and as a result neither did it. Once that was resolved it has performed flawlessly. (I am using 1.10 Beta 3). IE NOT the nightly updates!

I'm on one of the nightlies. The last couple of occasions it slew to target, centred via platesolving, autofocused and for some bizarre reason then initiated the meridian flip routine even though I was aiming at M81 at about 9pm, a good 3 or 4 hours before its transit! I might join you back on 1.10 as I don't use the advanced sequencer anyway.

+1 for NINA. Doesn't take long at all to get used to it. Though its not perfect and you need to babysit sometimes. I struggle with meridian flips sometimes.

11 hours ago, wormix said:

Interested in this too - did you find an answer @david_taurus83?

Nope! Maybe @FLO can clarify?

I love Stellarmate and I have an RPi 4 with SM loaded onto it for my mobile setup but I wouldn't exactly call it easy to setup for a beginner. If you can receive wifi signal on your laptop outdoors on your home WiFi, if you had a spare laptop/pc you can access the one outside and control it from indoors. There are a few methods available like remote desktop or VNC Viewer etc

Does a OSC astro cam not output a raw bayered file? Like a DSLR? I always calibrate all my DSLR light frames with raw darks and flats before debayering prior to stacking. I thought the process was the same for astro OSC.