Catanonia

Added another 60 or so mins to the image and re-processed. Now about 150mins in 5min 2xbin subs

Not sure if I am going to get anything else out of this. But will add some more next time as it is a good early target in the night for me waiting for main targets to appear.

On 19/01/2022 at 19:02, TakMan said:

Well done for trying.... suppose the RASA hoovers up the moonlight as much as the target signal, so good on you for having a go....

Think I'll stay away though with my f/5 and stick with something brighter!

Damian

Yeah, light is light and the 8 hovers it up big time. The 7nm Ha filter was a failure, it turns out I need a fast Ha filter for the rasa @f2. See my other thread on this.

I have a ZWO 2600 MC Pro OSC camera and normally image with the Optolong lEnhance filter that gives RGB images along with Ha and OIII data.

Specs are here

The Major Emission Lines of Nebulae: H-α 656.3nm, H-β486.1nm, OIII 495.9nm, OIII 500.7nm 
The Major Emission Lines of Artificial Light Pollution: Hg 435.8nm, 546.1nm, 577nm, 578.1nm, Na 598nm, 589.6nm, 615.4nm, 616.1nm

Now with the recent moonlit nights, even this filter gets washed out by the moon.

So I decided to replace the lEnhance filter with a generic Ha 7nm filter and take some images with the hope of combining this with the original data.

As I started to process the images, I noticed that the Ha data and the Red channel of the lEnhance data were basically the same. Ie no difference and if anything the lEnhance filter Red channel was better than the Ha 7nm data

Here is a picture explaining it.

• Left is Ha data in 25x 5min subs @bin2  (needed this length of sub to get a decent signal) - Rasa 8 @F2 - warning that the filter is not working with the Rasa @F2 ?
• Right is the lEnhance Red channel in 74x 1min @bin2 (needed shorter subs to achieve same signal) - Rasa 8 @F2
• Both images have had exactly the same cropping, DBE, stretching done to them on starless images to make it easier to see.

As you can see, the lEnhance Red channel is just as good if not better than the 2+ hours of Ha 7nm data

So in summary, no point whatsoever in using the Ha 7nm filter to gather extra if you have a lEnhance filter. If you want Ha data on a moonlit night, use the lEnhance filter and extract out the Red channel.

Also you don't get those horrid halos that some Ha filters give you.

Either that or the 7nm Ha filter I am using is blocking too much of the sharply angled fast F2 light the Rasa delivers - Thoughts ?

edit

After some research, found this about highspeed F2 filters

Baader f/2 Highspeed H-Alpha Filters

Available in 1 ¼", 2", H-alpha / O III and S II are designed especially for the delicate requirements of extremely fast astrograph optics, in particular Hyperstar and Celestron's New RASA.

Conventional narrowband filters cause a heavy loss in transmission due to the strong CWL shift (CWL= Center wavelength).

In extreme cases the CWL even does shift out of the FWHM (FWHM= full width half maximum).

Therefore these filters have a CWL preshift which matches f/2 to f/3 perfectly.
Also the FWHM is optimized. In spite of the typical line broadening with such fast optical trains they are able to deliver maximum contrast. For the first time these filters allow to use fast optics really effectively with high contrast emission nebulae imaging. Using these filters between f/1,8 and f/3,5 shows a dramatic improvement compared to any regular set of narrowband-filters.

Thanks all. 

Trying a Ha 7nm filter in front of the OSC 2600 MC Pro to see if that is worth the effort tonight since it is a bright and almost full moon

A quick question for you experts as I am not sure of the answer.

• I have a One Shot Colour Camera (OSC)  ZWO 2600MC Pro
• I have a 7nm Ha filter in place

The subs come out red, sort of expected.

How do I process these subs ?

Debayer then extract the Red channel from the sub leaving a mono Ha / Red channel ?

Any help would be appreciated

On 14/01/2022 at 21:18, vlaiv said:

Loads of reading

Thanks buddy, will take a bit to read / re-read and process

I stumbled across Abell 85 whilst searching for targets and a bit more investigation revealed that this is a very challenging target

Images I have seen on the web are usually with narrowband filters, from the desert with good skies and well over 12+ hours integration time.

Full moon last night, Bortle 6 skies, but I have a Rasa8 and lEnhance filter. How difficult can it be........

It turns out VERY after a quick test of 12x 5min subs at bin 2 (to increase SNR) on Rasa8 and ZWO 2600MC Pro

The structure hardly appears even with 5min subs x2 bin on an F2 Rasa. So many stars too make it a real PITA to process. I can see why people use narrowband filters for this target.

But here is what I have for only 12 subs 1 hour with a OSC camera in full moon, so gives me hope I can do better with better conditions. (Didn't concentrate on the processing too much as this was a test)

I will definitely re-try this under better conditions

Just watched this and well worth a view for those interested in what sub lengths you should use depending on your scope, camera, light pollution and other factors.

@vlaiv Any thoughts on this buddy as you are normally very hot on these topics

Thanks

Spider Vane for Diffraction Spikes on a Rasa

6 hours ago, vlaiv said:

Like the solution, but completely baffled by this detail:

 

I use a similar 3d printed semi circle cradle to route my Rasa cables. The spirit level is interesting...

On 13/01/2022 at 20:27, Adam1234 said:

Nice capture

Thanks buddy, was quite impressed with the subs, it literally took me 20mins to process they were that good despite the moon.

13 hours ago, newbie alert said:

M81/ m82 are quite small at 400mm fl

Markarians chain is a nice fit even thou they're still quite small you fit the majority of them all in.. 

So you was looking something east of Orion,  not west

DOH !!!!!!!!  yes East of Orion.  Stupid me

M81/82 were done to capture the IFN and it works well at 400mm, see the image.

Got some subs on Leo's and Markarians (about 2 hours each) and yet to process

So back into the hobby after 10 years and typical of me, I go and buy big (lucky I can, although bank balance does not agree)

Well since June, I have been getting some great images on the rasa 8, but there is this nagging thought telling me I should have got the rasa11

So with a ZWO2600 MC Pro and a rasa8 in Bortle 6 skies, would I actually see any difference with the 11inch version of the rasa11 ?

If I would, what would the differences be other than the slightly longer focal length and F2.2 compare to the 8's 2.0

I understand that 3 inches more = more light gathered, but in my skies, is it actually worth it (ignoring the cost) ?

Thanks

3 hours ago, Phillyo said:

Yeah I was thinking RGB stars might be nice? I might give it a go and see how I do.

Ha, yeah I ended up only doing DBE in a few select points around the edge due to all the dusty stuff. To be honest though there wasn't much of a gradient anyway. It was a moonless night and I stacked everything using the NSG script which helps with gradients anyway, but thank you. It's one of my favourite images so far. 

Yes this is a single image. Thinking about doing a mosaic but to be honest due to such poor weather combined with it being so low in the sky, I'm not sure how long it would take me to add a few frames around it? Maybe I can add to it over the years and just expand it out a bit

Thanks.

Trick I learnt with DBE is to stretch it with ScreenTransfer and adjust the sliders to limits to show the areas where the nebulosity is. This makes DBE point selection MUCH easier and of course does not affect the image as it is still in a linear format.

3 hours ago, Phillyo said:

Just curious, would adding RGB data to this help to improve it? If I were to extract the Ha data and use that as a luminance layer, or maybe add it as the red layer?

Phil

Starmask and replace wirh RGB stars would be nice. 

You could to a HaRGB, but be careful it doesn't end up too pink. That might give you more "colour" and interest in the M42 / IC434 regions

But that is a cracking image and yeah I bet DBE was a PITA to do on this.

I am guessing this the 135mm that this is a single shot and not a mosaic ? 

Nice work.

I did a test run last night on this with the rasa and it is a very faint and difficult target.

Great effort and result, especially from a DSLR.

What Bortle skies are you in and was there any moon around ?

With many targets to image last night, I decided in between targets to re-do the Horsehead and Flame region with the Rasa 8 to see what it would do in a short amount of time.

I was quite impressed with this and the processing didn't take too long either as the data was pretty darn good despite the 3/4 moon right next door to it.

Image IC 434 Horsehead and Flame Nebula in Orion

• Bortle 6 skies
• 3/4 moon next door to Orion
• 83x1 min 2xbin subs
• Rasa8 scope, ZWO 2600MC Pro and ASI Air on a NEQ6 Pro mount
• lEnhance Optilong Filter - Works very well at cutting out some of the moon shine

Hope you like it as I am very impressed at how well the Rasa gives quick and good data.

17 minutes ago, ONIKKINEN said:

M81/M82? NGC2403 would be available too, if a bit small for your focal length.

Thanks, got M81/82 in the back and is a goto to leave running through to dawn.

After a lot of searching with Stellarium, got 2 targets to choice between

Markarians Chain or the Leo Triplets will allow me to image from about 1am through to early dawn.

I store only the following that massively reduces the space needed.  If long storage, they get compressed too (zip)

• Raw Files
• Master Flat, Bias, Darks
• Final Image

From that I can re-produce anything I like and if I was to re-produce I would not want to produce the same image, but something different with new techniques or more data.

2 hours ago, scotty38 said:

Just had a quick look, Flaming Star Nebula???

On the list and can image that until about 1am. Need something more west

For tonight 12th January 2022 - UK BASED

At a complete loss and a brain melt and just can't think of some targets to image tonight. So can anyone give me some pointers please ?

Up until about 1am I will be imaging the Orion / Rosette region, but after 1am this all goes out of view in my location and I am at a loss as to what to switch to.

I am after something widefield (400mm) that is fairly high up in the sky and West - Southwest - South 

Many thanks for any suggestions

oh wow, that is nice and some dedication and reuse / addition to / of  data.

Yes the witch looks like it is a bit flat and looks like to much of a sharp mask addition. Just my opinion, but wow, amazing work there

Very nice, love the colour