Herbig-Haro 555 in bi colour

[swag72]

Following on from the Ha I managed to get on this rather interesting Herbig -Haro object, I was lucky to have a completely wrong forecast and so managed to get some OIII to complement it. I was going to crack open the SII filter for some proper HST palette, but the weather turned.

I am loving this long focal length experience but do wonder if I'm just leaving the overall imaging time too short at f10. Perhaps I need to do a marathon image, but I'm just being dealt some strange weather for June.

Not to everyone's cup of tea, this is a bright one! Would welcome any comments.

Details

M: Avalon Linear Fast Reverse

S: Celestron C9.25

C: QSI690 WSG with 3nm Ha and OIII filters, SXAO

11x1800s Ha

9x1800s OIII

[gingergeek]

Lovely work as always Sara 

[lensman57]

Great balls of fire Sara, that is lovely.

A.G

[Gina]

Beautiful

[ChrisLX200]

Lovely, looks like a forrest fire going on in there!

ChrisH

[peter shah]

super  close Sara...got to love that focal length...nicely captured

[Sandancer10]

Great image Sara, as usual.

Is it just me, or does it look like a head with horns and fire coming out of the top of it - Dante's Inferno perhaps   ?

[Adamar98]

What a corker! That's great.

[swag72]

Thanks all for your comments. This is a great focal length and I have to say I am really enjoying it!

[StuartJPP]

My eyes!!!......

Nice work Sara, looks like you are managing quite well at those focal lengths...

[ollypenrice]

Oooooohhhh!!!!

You have it!

Olly

[swag72]

Thanks Stuart and Olly.

Apologies for the blindness Stuart

[PhotoGav]

That's a beauty Sara, looking truly excellent, great depth and the light is stunning. I had a look following your Ha post at exactly what this area is and realised just how tiny a portion of sky you are imaging here! Impressive!

As for f10... What are you thinking in terms of the marathon - much longer subs or many more of them? Very keen to see the thoughts on the best approach to f10 imaging, though I have a sneaking suspicion that you, Sara, are probably the current authority on this particular field of astrophotography!

Another recent thought that is vaguely related... The SCT f10 route was primarily a solution to long focal length with no diffraction spikes. I read that curved spider vanes don't create spikes..... Thoughts please!

[Owmuchonomy]

Very dramatic. Now you've persuaded me not to part company with the 9.25! I'm tripping over optical tubes waiting for the darker nights.

[Coco]

Smashing Sara, looks terrific..

[swag72]

Thanks Gav, Chris and Guy

As a marathon in the C9.25 I'm thinking probably total amount of data. I always bin at 2x2 and the signal is OK, so definitely overall subs. I have found working with this scope to be a little on the noisy side, which we all know can be combatted by extra exposures. With my refractor (running at f3.9) I'd spend one night on the Ha. Not sure why I think I can get away with that at f10! I think because the weather has been so dire since I got this scope I've really not given it a fair chance.

[PhotoGav]

I look forward to seeing the results and how long the marathon needs to be to make the difference!

[morimarty]

A real top notch image Sara, Beautifully processed!

[Steve 1962]

Beautifully smooth, detailed and VIVID,

Just great Sara!

Steve

[ChrisLX200]

Just out of interest Sara I thought I would look at what I might be missing by imaging at just 660mm f/l, so I reprocessed my data to similar appearance to your image and the result is below. However, this is just a small section of the full frame produced by the 490EX but I found there was good detail despite the smaller scale. I was imaging at 1.15 arc-sec/pixel with the NP127is. The full frame is here: http://i970.photobucket.com/albums/ae183/ChrisLX200/Astro%20-%20Images/PelicanST_zps96dbf03d.jpg

[swag72]

Thanks Martyn and Steve - Apreciate you looking and commenting.

@Chris - an interesting post, these things always go over my head though. Are you saying that with a scope of say 700mm I can get exactly the same image at the same resolution as at 2.3m? Oh my head hurts!!!

[ChrisLX200]

Thanks Martyn and Steve - Apreciate you looking and commenting.

@Chris - an interesting post, these things always go over my head though. Are you saying that with a scope of say 700mm I can get exactly the same image at the same resolution as at 2.3m? Oh my head hurts!!!

Well that's what I found interesting - it seems unlikely a smaller 5" scope @ 1/4 the focal length could do that but the results look surprisingly close (though I believe your image does show better resolution). However, the refractor is just so much easier to image with!   I do use an autofocus which squeezes the last drop of resolution out of the scope but on the other hand I would not have said my conditions were 'excellent' - what with LP and hazy skies. I also think I'm imaging at an over-sample resolution for the seeing @ 1.1 arc-sec/pxl but I'm just guessing there. I've got a 10" SCT so I'll try taking images of the same area so I can compare under the same conditions.

I'm not trying to be clever here and it doesn't detract from your wonderful image, I'm just curious what I can expect to gain by going with a longer f/l scope as I'm considering the purchase of a R/C OTA, but should I be going for a 6" f/7 refractor instead? Is a larger aperture/longer f/l OTA going to perform better under my local conditions?

ChrisH

[swag72]

Interesting - So why do I bother at 2.3m? I could just get a nice Tak refractor and have done with it - Sharper images generally and easier all round!

I hope someone can come and dispel this idea, it really can't be true surely?

[michael.h.f.wilkinson]

Superb image. Love to see this sort of DSO imaging performance out of an SCT. Gives me hope for the future (although I would seriously need to update both mount and imaging + processing skills)

[michael.h.f.wilkinson]

Regarding the different image scales: neither scope is being used near its theoretical resolving power (or alternatively the image is being sampled well below the Nyquist frequency), so the pixel scale on the chip dominates the resolution, not the aperture of the scope. As physical pixel sizes differ, I would not be surprised if small-pixel chips can produce similar resolution on short focal lengths compared to larger-pixel cameras on a longer focal length. It is all a matter of image scale on the chip. Where the C9.25 will probably shine is when you try to resolve very small objects, like smaller planetary nebulae, and distant galaxies (i.e. real narrow field objects).

On planetary imaging matters are very different, and you always try to sample some way above the Nyquist frequency (F/20-F/25 is common), and I guess a C9.25 would beat a TEC 140 easily (and certainly a 5" Tak).