Lunar Images 14th May

[Roy Foreman]

Shot between the clouds about an hour before sunset, with frequent use if the pause / resume button as the clouds passed by.  This is becoming the norm these days.

The result is images that are not as sharp as those in my last post, but I am reasonably happy with the results considering the conditions.

 

Celestron C11 Edge at f/10

ZWO ASI 183mm at 19 fps

Proplanet 642 IR filter

15% of 2000 frames.

5 pane mosaic.

Selective enlargements from the main image.

 

Thanks for looking.

 

 

[Roy Foreman]

Just looking at the full disc image and there appear to be stripes and squares on it.  These do not appear on the original, so I assume the artifacts are an uploading issue.  Anyone else had this ?

[michael.h.f.wilkinson]

49 minutes ago, Roy Foreman said:

Just looking at the full disc image and there appear to be stripes and squares on it.  These do not appear on the original, so I assume the artifacts are an uploading issue.  Anyone else had this ?

I see them too. If you look very carefully at the full-resolution images, some parts do seem to have a very fine stripe pattern. This could cause Moire effects when subsampling in a simplistic way. Very nice images. This is not good for my latent aperture fever.

[Roy Foreman]

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

I see them too. If you look very carefully at the full-resolution images, some parts do seem to have a very fine stripe pattern. This could cause Moire effects when subsampling in a simplistic way. Very nice images. This is not good for my latent aperture fever.

I did wonder if it might be an interference effect. I might try resizing the original and reposting. Glad you like the images. You don't need large aperture for good lunar results. A 7" mak or mak Newt will give stunning results too !

[michael.h.f.wilkinson]

27 minutes ago, Roy Foreman said:

I did wonder if it might be an interference effect. I might try resizing the original and reposting. Glad you like the images. You don't need large aperture for good lunar results. A 7" mak or mak Newt will give stunning results too !

I have a Celestron C8, and I have had good results, but I feel I have pushed it to its limits, and want more.

[Kon]

Very nice images and processing. You have pulled some nice details.

 

I see the stripes on the embedded image but at full resolution there is nothing.

[Roy Foreman]

15 minutes ago, Kon said:

Very nice images and processing. You have pulled some nice details.

 

I see the stripes on the embedded image but at full resolution there is nothing.

I saw the same thing, so I guess it must be a resolution thing.  Thanks for your favourable feedback, much appreciated 

[Roy Foreman]

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

I have a Celestron C8, and I have had good results, but I feel I have pushed it to its limits, and want more.

Is your C8 in perfect collimation as that makes a huge difference with SCTs. When I first got the C11 I checked the collimation and thought I'd got it nailed but the resulting images were less sharp than your posted result.  For lunar bigger isn't always better as the larger aperture is more affected by seeing. The C9.25 is supposed to be the sweet spot. Are you using an IR filter? It makes a big difference. I like the Proplanet 642 as it let's through more light than the stronger versions. My images we taken before sunset so the sky was quite bright, and yet appears almost black even before processing.   Just a few pointers, but I know only too well what aperture fever feels like !

[michael.h.f.wilkinson]

44 minutes ago, Roy Foreman said:

Is your C8 in perfect collimation as that makes a huge difference with SCTs. When I first got the C11 I checked the collimation and thought I'd got it nailed but the resulting images were less sharp than your posted result.  For lunar bigger isn't always better as the larger aperture is more affected by seeing. The C9.25 is supposed to be the sweet spot. Are you using an IR filter? It makes a big difference. I like the Proplanet 642 as it let's through more light than the stronger versions. My images we taken before sunset so the sky was quite bright, and yet appears almost black even before processing.   Just a few pointers, but I know only too well what aperture fever feels like !

I have checked collimation and it cannot be far off if you get albedo spots on Ganymede. I didn't use IR on the above image (this was taken with my ASI182MC, and it has subtle colour). 

[Kon]

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

I have checked collimation and it cannot be far off if you get albedo spots on Ganymede. I didn't use IR on the above image (this was taken with my ASI182MC, and it has subtle colour). 

Looking at your image above, I think it is more the case of bad seeing (if you think collimation is good). You should be able to get a lot more out of your C8 under good conditions.

[Roy Foreman]

2 minutes ago, Kon said:

Looking at your image above, I think it is more the case of bad seeing (if you think collimation is good). You should be able to get a lot more out of your C8 under good conditions.

I agree. Also a colour camera may not give as fine a resolution as monochrome. Supposed to be clear here tonight so I might dust off my C8 and see what I get out of it

[Kon]

6 minutes ago, Roy Foreman said:

I agree. Also a colour camera may not give as fine a resolution as monochrome. Supposed to be clear here tonight so I might dust off my C8 and see what I get out of it

If you refer to IR imaging  that is not true as you only use a narrow wavelength. You should be able to pull more details in either colour or mono with rgb filters. IR might perform better under bad seeing as its wavelength is not affected as much from the weather (although my IR is ofter 'boiling' under UK skies).

[LukeTheNuke]

Wow, fabulous shots again! The mosaic is epic! Well done!

No idea about the funny stripes and squares. The original looks sweet to me, can't see why it would cause that banding, other than it's a huge image (8221 x 12332, 56 MB). It scales just fine in GIMP.

I just tried a little test to see if compressing it would help - I tried 70% compression (6.5 MB, down from 56 MB), but it had the same banding issue viewed on SGL.

re: aperture and seeing conditions, for a while I would image the moon with either a 120 mm frac, or 8 inch Edge SCT. Most nights, it felt like the 8 inch SCT had no advantage in resolution. I don't think my sky at home is very good for high res planetary. Perhaps because we're surrounded by rooftops in every direction? The best view I've ever had of Jupiter by far was at a star party (Kelling Heath), with a 12 inch dob. I've never had anything close to the detail at Kelling from home, even with a 16 inch dob. So I wonder if location matters as well for the close-up stuff?

Edited May 15 by LukeTheNuke

[Roy Foreman]

1 hour ago, Kon said:

If you refer to IR imaging  that is not true as you only use a narrow wavelength. You should be able to pull more details in either colour or mono with rgb filters. IR might perform better under bad seeing as its wavelength is not affected as much from the weather (although my IR is ofter 'boiling' under UK skies).

Actually I wasn't thinking in terms of using IR with colour camera, but if one did then would it be the case that blue and green cells would not receive any light ?  IR does help, but I agree that under UK skies turbulence is still very much in evidence. 

[Kon]

9 minutes ago, Roy Foreman said:

Actually I wasn't thinking in terms of using IR with colour camera, but if one did then would it be the case that blue and green cells would not receive any light ?  IR does help, but I agree that under UK skies turbulence is still very much in evidence. 

Yes effectively the camera behaves like mono. I haven't seen a difference between my IR with the 462 mono or colour but again both have the same response in IR (I use the mono for UV imaging).

[Roy Foreman]

1 hour ago, LukeTheNuke said:

Wow, fabulous shots again! The mosaic is epic! Well done!

No idea about the funny stripes and squares. The original looks sweet to me, can't see why it would cause that banding, other than it's a huge image (8221 x 12332, 56 MB). It scales just fine in GIMP.

I just tried a little test to see if compressing it would help - I tried 70% compression (6.5 MB, down from 56 MB), but it had the same banding issue viewed on SGL.

re: aperture and seeing conditions, for a while I would image the moon with either a 120 mm frac, or 8 inch Edge SCT. Most nights, it felt like the 8 inch SCT had no advantage in resolution. I don't think my sky at home is very good for high res planetary. Perhaps because we're surrounded by rooftops in every direction? The best view I've ever had of Jupiter by far was at a star party (Kelling Heath), with a 12 inch dob. I've never had anything close to the detail at Kelling from home, even with a 16 inch dob. So I wonder if location matters as well for the close-up stuff?

I have imaged the moon with scopes from 6" ED refractor up to 16" reflector and to be honest I can't really say that one does any better than the others. It just seems that the atmosphere is the limiting factor in each case. At my location seeing is best at twighlight so that is when I try and image, clouds permitting, which is what I did for the images in this post. But I am looking over Exmoor rather than houses which must help.

As for those stripes, they only shop up on the jpeg. The original tiff file doesn't have them at all. And it is nearly 300Mb in size !  That's what you get when using a 20Mpx camera !

Glad you like the images, again. Supposed to be clear tonight so watch this space!

[LukeTheNuke]

25 minutes ago, Roy Foreman said:

That's what you get when using a 20Mpx camera !

I had a look at the ZWO cameras the other day (I sold my cameras a few years ago, alas, and it's tempting to get back to it, with the help of a windfall due soon, with any luck). There are so many to choose from! So you have the ZWO ASI 183MM.  19 FPS at 5496 x 3672. Hmmm. Seems like some folks had problems with it for solar h-alpha, some not. I might want to get back to solar h-alpha if my windfall stretches to a new solar filter as well. Gosh, I think I have the windfall spent five times over already!

Good luck for tonight! Lots of rain here today so far. I wouldn't mind a peek at the moon tonight.

[Roy Foreman]

20 minutes ago, LukeTheNuke said:

I had a look at the ZWO cameras the other day (I sold my cameras a few years ago, alas, and it's tempting to get back to it, with the help of a windfall due soon, with any luck). There are so many to choose from! So you have the ZWO ASI 183MM.  19 FPS at 5496 x 3672. Hmmm. Seems like some folks had problems with it for solar h-alpha, some not. I might want to get back to solar h-alpha if my windfall stretches to a new solar filter as well. Gosh, I think I have the windfall spent five times over already!

Good luck for tonight! Lots of rain here today so far. I wouldn't mind a peek at the moon tonight.

The 183mm is a superb camera. Tiny pixels and a relatively large sensor mean very high quality results, but there is a downside - huge file sizes. I can easily use up half a terabyte on an imaging run, and each file takes 40min to stack, even on a high end PC.  I've had no problems with my camera but I only use it for lunar.

And yes I too am guilty of spending my money in my head before I've even earned it !

Cheers and good luck.

[LukeTheNuke]

18 minutes ago, Roy Foreman said:

The 183mm is a superb camera. Tiny pixels and a relatively large sensor mean very high quality results, but there is a downside - huge file sizes. I can easily use up half a terabyte on an imaging run, and each file takes 40min to stack, even on a high end PC.  I've had no problems with my camera but I only use it for lunar.

And yes I too am guilty of spending my money in my head before I've even earned it !

Cheers and good luck.

Thanks for the info on the camera. It's certainly singing for you on lunar! (some folks seem fine with it for h-alpha, others not - I don't know the full story there). It's a slippery old slope. I start off at under £300, then if I spend a bit more, I can get a ... And before I know it, cameras costing around the £1K mark no longer look bananas, LOL! Or do I get one that can do a bit of deep sky as well as lunar and h-alpha?

I wonder if the stacking software uses the GPU? Also on my shopping list is a powerful desktop PC and a midrange lappy, unrelated to the astro, but that make getting back into astro imaging that bit more tempting. Gosh, I'll need to do a re-mortgage at this rate. I might as well buy an Edge 14 as well, LOL!

Edited May 15 by LukeTheNuke