don4l

I use the Chroma filters at F3.6, F5 and F8.  I haven't seen any evidence that their performance is impaired at 3.6.

I had to make a choice between a Pi and a laptop to live beside the mount.  Initially, I was attracted to the Pi.  It would be neater, and cheaper.

In the end, I went with the laptop (and screen) for a few reasons.

1)  Rotating the camera.  I am not going to spend a small fortune on a rotator, but I do rotate to frame my images.

2) Focusing the autoguider.  (not really a big issue in practice)

3) Focusing my Tal.  I don't really need a motorised focuser for this F10 scope.

4) Anything that I hadn't thought about where a display would be useful.

I'm using a refurbished laptop that cost £200.00 - so it wasn't too expensive. 

A headless computer would be neater, but I'm happy with the way I've implemented it.  I like the idea that I can just sit down beside it if things go wrong.

On balance, I would suggest that you go with whatever you feel more comfortable with.

Try it and see.

The only thing that matters is the image that you get at the end.

Generally speaking, the more data that you collect the better.  If you see a problem with continuous imaging, they try leaving a gap to see if that fixes your problem.

6 hours ago, CraigT82 said:

https://www.stark-labs.com/help/blog/files/GainAndOffset.php

Thanks for posting that link.  I had to read parts of that twice, but it was well worth it. 

There's no Moon here tonight at all.

If the sky is clear tomorrow night then I'll probably image the Moon.

....sorry!

I am very happy with my Chroma filters.

They may seem a bit expensive, but they have upgraded the performance of my camera and scope.  I didn't really understand this properly until I saw the first 10m Ha sub appear on my laptop screen.

13 hours ago, geoflewis said:

Great job Donal,

You're definitely getting the process nailed down and the final result is excellent. Building the mosaic on the fly with quick screen captures is a great way to go. Interesting that you took Autostakkert out of the mix as in my experience that generally produces a better stack than Registax, so what was your thinking there?

At full resolution I can see one fairly long horizontal seam to the north of Mare Serenitatis heading towards Plato, i.e. towards the bottom of your image as you've presented it, so don't know if you had a small capture miss there, or whether it's a blending issue that you can fix. Other than that very minor blemish this is a superb image, very well done

I didn't consciously take AutoStakkert out.  I processed a single AVI in Registax and was impressed with the result, so I just carried on with the rest.  Tomorrow, I'll do some experiments to see what produces the best result.  I'm also going to play with the number of frames used in each panel.

I've cropped a frame to remove a horizantal line which was at the bottom edge of one of the frames.   (There isn't any "blending" as such. The layers are just on top of each other.)

I *think* that I've fixed it in this???

This is my third mosaic (5th attempt - first two had gaping holes), and things are definitely getting easier with practice.  I discovered the "take a snapshot" button in Sharpcap and thought that I could build up a quick mosaic as I went along.  This turned out to be much easier to do than I thought.  The workflow was 1) take snapshot, 2)start capture 3)Open snapshot as new layer in Gimp and quickly line it up, 4)move mount and repeat.

This resulted in a mosaic that needed 24 frames as opposed to the 32 that my last mosaic needed.  I think that I could get this down even further if I try.

One weird thing is that I had to refocus during the capture.  I prefer to leave everything the same because it greatly reduces the processing.  I haven't had to adjust the brightness .

The image was taken through a Tal200k, ASI120mc on an EQ6.  Acquisition was with Sharpcak.  Stacking and wavelets in Registax6.  Mosaic assembly in Gimp.

Comments and suggestions very welcome.  The suggestions that I got on the previous images have been brilliant and really helped. 

I still don't understand what the Gain and Brightness settings really do.  I think that it would be good to capture some of the "Earthshine", but I cannot see any hint of the unlit part of the Moon even when I change the settings.

Click the image for full size (18Mb).

That's a nice result.  I've just started to try to learn how to image the Moon and your questions are, more or less, the exact same questions that I was asking a week ago!  I haven't worked out proper answers yet.  Lunar rate tracking helps,  but I would say that exposure and focus are much more important.  At the moment, I start off by looking at a largish bright feature and adjusting the exposure until it is just about to be saturated.  Some of the crater lips are still blown out, but I don't know how to prevent this without losing a lot of the dimmer bits.

Thanks everybody for the lovely comments - it's very encouraging.

I'm very pleased with the image, but then I see some of the other images that people take with similar equipment.  I have a 1.6 extender which I will try squeeze into the imaging train.  However, the thought of 40-50 frames puts me off.   So,  I'll probably just go for some small areas.

This is my latest moonshot from Tuesday night.  I ended up with a black slot in the middle (Doh!) which I have filled in with a bit of the previous night's effort.  Naughty - I know.

I slowed down the capture in Sharpcap because I read somewhere that this would improve the quality.  I think that it worked, but I cannot be certain.  I'm also wondering if I can do anything to improve the quality of the captured image.  Would a barlow/extender improve things, or is the OTA limiting things?  The scope is a Tal200K (8").  I'm also wondering if binning the capture would degrade the quality.  3.7u pixels would be too small for normal deep sky work.

I still have no real method for knowing which bits I have imaged and whether I have missed any bits, so I am gathering far too much data.  Even then, I missed a bit on this attempt.

Any advice very welcome.

I'm off to Argos to buy an external 5T drive now!

Thanks.

46 minutes ago, michael.h.f.wilkinson said:

Nice shot, and very sharp indeed. I do notice a few stitching errors. You could try Microsoft Image Compositing Editor (MS-ICE, which is free), which does a great job of automatically stitching images.

 

 

Thank you!

I do have ICE installed.  I'm not sure why I didn't try it already.  I'll try it on my next attempt - hopefully tonight.

47 minutes ago, geoflewis said:

Are you trying to use Registax to process the raw video, or just to apply wavelets to tiffs out of Autostakkert?

Just the wavelets.

The videos were processed in Autostakkert, which  has the "Sharpening" box ticked.

I did try the direct export tickbox to Registax from Autostakkert, but it didn't appear to work at all.  (Perhaps it was just taking too long.) 

I used Registax on the assembled jpeg.  The effect was too harsh, so I blended the Registax version back into the original at about 20% opacity.  This was far quicker than trying to adjust the wavelets sliders.

3 hours ago, geoflewis said:

Donal, you have every right to be pleased that image, it is lovely and a huge improvement over the earlier trial versions that you shared - you clearly are a quick learner 😉. There are a few very minor misalignments towards the south (bottom) of the image which reveal themselves at full resolution, so maybe you could fix those, but otherwise it is a very pleasing, crisp, but not overly sharpened image. Well done.

Thanks Geof.  I had some good advice - which really helped a lot to speed up progress.

I'm goin to work out a processing workflow before I go back to fix the alignment issues - otherwise I will be going round in circles.  I also need to figure out why Registax isn't really useable.

Hopefully, I'll have another go this evening if the sky clears early.

I've had 3 attempts over the past three evenings at capturing a mosaic of the Moon.  Last night I got a result that I am pleased with.  I do feel that I can improve a lot further because I have little experience at this, or the software used.  Any advice would be very welcome.

This was captured using Sharpcap,  a Tal200K at 2000mm and an ASI120mc.  The panels were assembled in Gimp.  A mild Registax6 wavelets was applied.

Thanks for looking.  Click for full resolution (4000 x 5000 px)

Another vote for the Gimp.

You can try it for free, and if you like it, you've saved yourself some money.  As far as I can tell, it is very similar to Photoshop.  I have used many PS tutorials and hardly notice that I am using a different package.

I think that there is some reflection stuff around the central stars.  It might be worth getting a load of Blue data to see if it would add a splash of colour???

Lovely!

3 hours ago, gorann said:

Thanks Don!

Have to find out what the Hyperleda data base is.....

It's just another catalogue.  The ASTAP download page has instructions for downloading and using it.  No special knowledge required.

Lovely image.  I especially like the "bridge".

ASTAP shows about 150 galaxies in your image from the Hyperleda database which are clearly visible. 

Nice job.  I've had a couple of attempts at this, but haven't got anywhere.

Lovely image... and new to me too.

7 minutes ago, Gina said:

Absolutely!!!  With knobs on!  Nearly made me ill seeing that.  Disgusting. 

I've never seen the point in making a vegetarian food look like meat! 

A butcher in Wales has been producing meat that looks like vegetables.  A "Carrot" made from spiced pork seems to be going down very well with his customers.

19 minutes ago, Andy R said:

Whatever his belief was, does this tragic death really warrant such satirical ridicule  from members and moderators. 

If so, please remove my account as I’m not sure I want to be part of this group anymore   

 

I have to say that I am also surprised at the reactions.

The Royal Society's motto is "Nullius in Verba".  This guy was just trying to investigate for himself.

Even if I think that he was wrong, he actually built a rocket.  We need far more people like him.

15 hours ago, JSeaman said:

Well we have differing views about black point, I know it's widely popular to avoid dark backgrounds but I like it so that bit stays

Don4l - thanks that's useful to know, I am just starting out in nb so finding my feet.

The focus was set with a Bahtinov and I can indeed measure FWHM, although I've never used the numbers, what does that give over the mask?

PA is something I worked on last time and I considered flexure too and have tied the guide scope down harder

I might well play with the Ha short stack you mentioned and see how I get on - thanks for your thoughts

 

If you have a reliable way of measuring FWHM, or HFD, then you will always be able to see how are doing as the night goes on.  I used to only find out the next day that my subs were rubbish.

I use CCDCiel to capture the images from the camera.  As each image is downloaded, CCDCiel measures the HFD and FWHM of the stars in the image.  If the HFD is 2.8, or below, then all is fine.  If the HFD is 2.9, or above, then I need to refocus.  If the HFD is 3.1, then I know that I will be able to see that the stars are big and round.

Don't ask me what HFD, or FWHM are.  The only answer that I can give is that they tell you something about the size of the stars, and the smaller the number, the better.