First narrowband attempt: Elephant's Trunk (Happy, but not happy...)

[NigeB]

Hi All,

The last couple of nights have been kind, so I took advantage and tried out narrowband imaging for the first time, with a recently acquired Altair Wave 80. Target was the Elephant's Trunk nebula in IC 1396. Here's the result. The signal levels are quite low - I used mainly 10 min subs, though a couple of 5 and 20 min frames crept in (there's a bit of star saturation from the latter). Total times were:

SII: 2 hr 50 min
Ha: 2 hr 5 min
OIII: 1 hr 35 min

(I messed up part of the OIII run, hence the shorter time). Acquisition was with Artemis Capture. Alignment & stacking in DSS, then combining and colour adjustment in Photoshop. I know the colour is OTT - I got carried away, but I was drawn to narrowband because of the pretty colours, and my other half likes this version more than the less nauseating alternative I produced afterwards, so I've kept as-is .

I was pleasantly surprised with what could be stretched out of the low signal. What I'm less happy about is what appears to be really bad field curvature at the edges, particularly in the right hand corners. This was taken *with* the Planostar field flattener, but there's probably ~10 cm or more between the flattener and the focal plane of my Atik 460ex because of the filter wheel, OAG and spacing between the two. I think is about twice the recommended distance. I'm hoping that this is the reason, but would be interested in anyone's thoughts. (I have the same problem with my TOA-150 and field flattener, and it affected both the 460ex and the QHY8 I had before.)

 

Any views on the field curvature issue or other image criticism welcome!

 

Nigel

 

 

[swag72]

A good narrowband for your first attempt - Well done!!!

Can't help on the flattener problem I'm afraid, apart from checking that the spacing from the flattener to the sensor on your camera is correct. This is always the hardest and most frustrating part of introducing a flattener or reducer.

[NigeB]

Thanks Sara!

I'm pretty sure that spacing is quite different to the recommended value. The problem is I can't see a way of reducing the distance, given the thickness of the filter wheel and the OAG (actually it's not the OAG itself, it's the space I have to add between EFW and OAG so that the Lodestar clears the filter wheel...)

I'll see what adaptors Bern might have to help.

Nigel

 

 

[swag72]

Sometimes we have to accept that there's just not enough space to put in the things we want in the order that we want .......

 

[Gina]

Oh that's so true!!  Something I'm struggling with too.

Great first NB image

[PatrickGilliland]

It a good start for first NB image.  The palette needs some work lose some if not all the green and purple also - you can work on this though in your chosen tool at your leisure.  Example of mine here if you want for reference. http://www.astrobin.com/230412/B/

Nice start and welcome to the NB world.

Paddy

[NigeB]

Thanks Everyone!

Wow, Patrick - what an image. Do you get that area of coverage from a single frame of the QSI or is this a mosaic? The field is amazing. 

I'm going to build up more subs and see if I can rework the processing and make the colours a little more calm, now that I've got the psychedelic phase out of my system now...

Nigel

[PatrickGilliland]

1 hour ago, NigeB said:

Thanks Everyone!

Wow, Patrick - what an image. Do you get that area of coverage from a single frame of the QSI or is this a mosaic? The field is amazing. 

I'm going to build up more subs and see if I can rework the processing and make the colours a little more calm, now that I've got the psychedelic phase out of my system now...

Nigel

Single frame more FOV less detail but then more subs == more detail to a point anyway.

Just read up on some processing tutorials in NB will advise better on colours and tools to help with them - if you get stuck let me know happy to help but bedtime now!  

Paddy