M1 Crab Nebula - Altair Wave 115 Triplet

[David_Pickles]

At last, a clear (ish) night last night and the opportunity to do my first deep sky image since changing my scope to the Altair Wave 115 Triplet.  Seeing was moderate, with some moisture in the air making the horizon look very poor, but looking straight up it was nice and clear. The image is the result of 14 x 300s exposures captured using a QHY8L camera and Planostar field flattener, stacked in Nebulosity 3 and processed in Photoshop CS6.

The Crab Nebula (M1) by David_Pickles, on Flickr

[reddoss]

Nice detail in the filaments. The Altair 115 APO is a great imaging scope, I have one myself  . Olly Penrice gave it a rave review in Astronomy Now a few years ago.

[David_Pickles]

Yes - Olly's review is one of the reasons I decided to go for this scope. I am really impressed with it so far.

[Dr Hamzonian]

nice detail for such scale, great work.

[sloz1664]

Hi David,

Nice image. I like my AA 80ED Triplet and that's combined with the planostar and my QHY 8pro.

Just a side note, do you use flats in your processing as I can see the odd dust specks from your sensor dotted about the image.

cheers

Steve

[Guest]

...and I too have the 115 (a result of Olly's review) and the QHY8 (toaster version :-) ...a result of not being able to afford the better one

Really happy with both and looking forward to trying this object - thanks for posting - gives me a benchmark to work with :-)

David

[David_Pickles]

Thanks for all your comments - much appreciated!

Steve, I use darks but I have never used flats - i really should get around to making a light panel so I can get rid of those pesky dust specks. [emoji4]

[Guest]

These are fantastic and much easier than trying to make a light panel :-)

http://www.gerdneumann.net/english/astrofotografie-parts-astrophotography/aurora-flatfield-panels/uebersicht-aurora-flatfield-panels-overview.html

David

[David_Pickles]

Thanks for that link David - that looks like a promising solution. Do you have one yourself? If so, have you noticed any issues with the lead connections breaking? I have looked them up online and there are lots of comments about the cable connections being very fragile.

[Guest]

Thanks for that link David - that looks like a promising solution. Do you have one yourself? If so, have you noticed any issues with the lead connections breaking? I have looked them up online and there are lots of comments about the cable connections being very fragile.

I have one and it works really well. As for the cable I did have a problem with that but just re-enforced it and it's been fine - in fact the design may have been improved since I bought mine - but it wasn't a massive problem and worth it for such a perfect solution.

p.s. I noticed on my own website that I'd imaged this object in the past too - old age is creeping in (see my post above! lol - I reprocessed it in my newly discovered image processing saviour - PixInsight :-)

[David_Pickles]

Thank you David - I will certainly consider getting one of these.

I tried a trial of PixInsight sometime ago and didn't really get on with it. That said, I have seen some very impressive results from people that use it so I guess that if you have the patience to work out how to use it then it reaps massive rewards.

Sent from my iPhone using Tapatalk

[David_Pickles]

p.s. I noticed on my own website that I'd imaged this object in the past too - old age is creeping in (see my post above! lol - I reprocessed it in my newly discovered image processing saviour - PixInsight :-)

Great image David and I like your setup - I was also thinking of the TSQ65 for wider field shots. One day maybe, when I get around to building a permanent obs.

[Guest]

Thank you David - I will certainly consider getting one of these.

I tried a trial of PixInsight sometime ago and didn't really get on with it. That said, I have seen some very impressive results from people that use it so I guess that if you have the patience to work out how to use it then it reaps massive rewards.

Sent from my iPhone using Tapatalk

I tried the trial version of PI too and abandoned it because I couldn't figure it out - then a friend of mine beat me until I agreed to buy it and use the tutorials at Harry's Astroshed - can't believe the difference they made - I get it now and am a converted disciple and PI evangelist :-)

David 

[ollypenrice]

A very crisp image from what I honestly found to be a fine set of optics. Look at those nice field stars...

I'm going to be picky. I don't believe the dark halo around the Crab to be genuine. I've had it myself on this target and asked about it on here many years ago because I couldn't decide if it were real or not. I now think it's something that seems to creep in during processing, but how? SInce I haven't imaged it since that time I really don't know. A flattening routine like DBE or GradX? Deconvolution?

But it's a fine image.

Olly

[Guest]

O

A very crisp image from what I honestly found to be a fine set of optics. Look at those nice field stars...

I'm going to be picky. I don't believe the dark halo around the Crab to be genuine. I've had it myself on this target and asked about it on here many years ago because I couldn't decide if it were real or not. I now think it's something that seems to creep in during processing, but how? SInce I haven't imaged it since that time I really don't know. A flattening routine like DBE or GradX? Deconvolution?

But it's a fine image.

Olly

I was wondering that too Olly - but my efforts in photoshop were usually very clipped so the background is very dark - I can't tell where/what step it's originating at.

Worth establishing as with the myriad of different settings for each calibration step in PI - there may be a solution :-)

I may do some tests - confidence with PI is bordering on the adventurous with me :-)

David

[ollypenrice]

If it's PI then I'll bet a fiver that your DBE (or ABE) background sky markers were too close to the nebula.

Try DBE with fewer markers and keep all of them WELL away from the nebula. Before applying the DBE or ABE model to the image, look at it. If it shows the slightest hint of the nebula bin it. You are looking for pure sky gradient. I'd say that an image like this could be DBE'd with 16 sky markers or even fewer.

Olly

[Guest]

I think you may have nailed it with that assessment Olly - I'll give it a shot :-)

Thanks

David

[swag72]

I agree about there being no dark halo around the Crab having imaged it recently in NB.

[David_Pickles]

A very crisp image from what I honestly found to be a fine set of optics. Look at those nice field stars...

I'm going to be picky. I don't believe the dark halo around the Crab to be genuine. I've had it myself on this target and asked about it on here many years ago because I couldn't decide if it were real or not. I now think it's something that seems to creep in during processing, but how? SInce I haven't imaged it since that time I really don't know. A flattening routine like DBE or GradX? Deconvolution?

But it's a fine image.

Olly

Thanks for your feedback Olly - much appreciated coming from you. I hadn't noticed the black halo before - it was not visible when I was processing it on my iMac, but I see it now I have turned the brightness up. I don't use PixInsight, so I think it was just me overdoing the processing in an attempt to draw out some of the finer nebulosity. Everyday is a school day and it's all helping me develop my skills, so thanks again!