M78 Tec180fl

[gregbradley]

3 very clear nights this weekend and good seeing on 2 of them.

M78, an interesting reflection nebula with some dust and emission nebula nearby.

TEC180mm fluorite, field flattener, Apogee U16M camera at -10C (it was a hot night), Baader LRGB filters, Tak NJP mount, Robofocus digital focuser seeing was average and improved to reasonable. Some of the subs were taken the next night under good seeing (60mins blue, 30 mins green and 10 mins red).

LRGB 60 60 60 60. From my dark site observatory in remote NSW.

http://www.pbase.com/gregbradley/image/108830442/large small 1200 x 1210


http://www.pbase.com/gregbradley/image/108830707/original large 2000 x 2017

Greg.

[peter_4059]

Top image Greg. Great detail and very sharp.

Interested in your thoughts on the Baader LRGB filters. I recall a thread some time ago suggesting they were not much good although this image has me believing otherwise.

Peter

[AlexN]

Very Very nice... as good an M78 as I've seen anywhere!

Top job.

[Hagar]

WOW That is nice Greg. As sharp as a TEC. I was going say a Tak But thought better of it.:rofl:

Really is the best image I have seen of this area. Beautiful
Well done.

[h0ughy]

WOW, THAT IS AMAZING. Scott alder i think took a dslr image of that area a few weeks ago but this is just breathtaking

[jjjnettie]

Ooooh Aaaaah!

[AlexN]

I was speaking to Peter Ward earlier today via pm regarding filters for a mono CCD, and he recommended Baader to me.. Can't be bad I figure.. :)

[renormalised]

Another exceptional image....this is the stuff worthy of inclusion in textbooks of astronomy and imaging. Great work:D:thumbsup:

[renormalised]

Just out of curiosity, what's the resolution of your Apogee per px?? Just want to do some quick calculations:)

[gregbradley]

The Baaders are interesting. They give very good red response compared to other filters. They don't have many reflections.

But I find the colour combine with them can be a bit difficult. They are not 1:1:1 exposure time as advertised with my system. I was advised by another imager for his similar setup it was 1.3:1:1.9. That helped and the colour seemed fine. I also find I need to normalise the RGB before combining otherwise I can get unusual colours and effects. I did not have to do that with Astrodons and my STL11. I have to do that with the Astronomiks as well.

I got them because of the reflection problems a lot of filters were giving with the large chipped 16803 cameras. You have to use a flattener with almost any scope (RCOS excepted perhaps) with these large chips and reflections from some brands were horrendous.

So these filters are good once you know their idiosyncrasies but not as user friendly as the Astrodons. I was thinking of getting Astrodon Gen 11 filters.
If they don't have reflection problems then the colour combine and colour is very easy.

Greg.

[Rigel003]

Stunning photo Greg, and it looks like the new scope is just fantastic. No hint of colour at all that I can see. I've always thought that m78 was a pretty boring object but it certainly isn't in this shot.

[gregbradley]

Why thank you.



Thanks Houghy.




Thanks Jeanette



Overall they are good.



Wow, thanks.



1.47 arc seconds per pixel. The scope is 180mm, 1260mm focal length and F7. The camera has a KAF16803 chip which has 9um pixels 4096 x 4096 pixels in a chip that is 36.9mm square (quite large hence the need for 50mm square filters and a 50mm square filter wheel).

The camera comes standard with the chip having no cover slip (slightly more QE and less reflections and slightly sharper). The QE of the chip is around 60+ % and it is quite sensitive in the Ha band. It is also very low noisehe chip tends to show a slight amp glow on the sides of the image but this processes out and is seen more in the bias frame. These chips though tend to get a line or two from hot pixels like the STL11. The lines tend to disappear with lower temps. -10C is as low as I have used it as it was a hot night. I only get 1 line really and it processes out with accurate flats and bias. Flats are more sensitive and a bit harder to achieve with the large chip camera. I also found that I got a very even flat using the Apogee and an adpater at the correct metal back distance from the flattener (Precise Parts) without the FLI PDF focuser in the imaging train. I installed a robofocus which helped enormously on getting accurate focus. The Starlight focuser which is adjustable, tends to slip a bit using the microfocuser under the weight of the camera gear. Adjusting the focuser is not obvious as to how to do it.

The Apogee camera just got a new firmware update that speeds up the cooling time which is still slow compared to other brands but much better than what it was (at least 45 minutes). Now its about 30 minutes or so. My FLI camera slams down to -35C in about 2.5 minutes. The cooling of the Apogee is the only area I think the camera could be improved on as it performs great in all other ways. It goes 36 or 37C below ambient not 40C as advertised. But it has a buffer and keeps itself going once started without need of the computer so if it accidentally disconnects from the computer - no worries, reconnect it and no settings are lost and it is still going. I like that a lot. The FLI camera is the same that way.

Greg.

[renormalised]

At 1.47" per pixel, the smallest object you're seeing/imaging (at an accepted distance to M78 of 1600ly) is 0.0114ly in size or 721.05AU:)

[gregbradley]

Interesting. That's pretty small in the cosmic scale of things.

Greg.

[strongmanmike]

That's pretty nice Greg, a lovely big FOV :thumbsup: It is such a majestic and mysterious object and you have captured this pretty well. I hope to image it too but maybe not till next year now?

Lovely dot like stars all over the field too and no out of field star reflections, in this shot atleast, so looking good.

I see you are getting the same small halos around the brighter stars like I do with the AP..? This article at Astrodon suggests these are from light refecting off the cover slip and back to the chip but you say the Apogee has no cover slip..? Are you sure?

http://www.astrodon.com/articles_faq/articles_faq/press_release:391,355,49#STL11

Mike

[gregbradley]

I see you are getting the same small halos around the brighter stars like I do with the AP..? This article at Astrodon suggests these are from light refecting off the cover slip and back to the chip but you say the Apogee has no cover slip..? Are you sure?

http://www.astrodon.com/articles_faq/articles_faq/press_release:391,355,49#STL11

Mike[/quote]

Hi Mike,

Yeah there are a few there but not really that bright and they don't particularly bother me. I get a few with the Astronomiks as well but really pretty minor. They both seem to perform well in this regard.

I posted the question on the Apogee group to make sure there is no cover slip but I did read that in a post a long time ago when I was evaluating the cameras.

The reflections are almost certainly between the filters and the flatteners.

I would take that Astrodon article with a grain of salt. Sounds to me like somebody using techno talk to hide a weakness.

If you have ever seen an Astrodon filter there would be no question where the reflections come from. They are like mirrors, like Ha filters. I have seen some horrendous reflections far far worse than anything in either of our images from Astrodon Gen 1 and APOs.

Reflections from the cover slip give tiny little reflections hardly worth bothering with but a small gain regardless. After all the slip is only a few mm from the chip. It couldn't physically give a largish reflection. There are posted examples on the net just not sure where now. Perhaps the Apogee site.

As you must use a flattener with these large chipped cameras reflections become a real point to check out.

Gen 11 Astrodons may well be different although I had someone send me an image with them that showed really bad reflections. I forget what APO it was -perhaps an FSQ106ED.

Greg.

[gregbradley]

Here you go Mike:

1. Apogee cameras do not have cover slips:

http://tech.groups.yahoo.com/group/apogee/message/502

2. Here is a sample mask one guy made (U16M camera comes standard with a professional aluminium black mask and they supplied one free after the sale to me)

http://astro.ihermans.com/test/reflections/mask.html

3. Tests showing the results of with and without a mask on reflections:

http://astro.ihermans.com/test/reflections/filter-comparison.html

4. Comparison of reflections between Astrodon Gen 1 and Gen 11 filters on a Tak TOA 130 with field flattener:

http://astro.ihermans.com/test/reflections/gen1gen2-comparison.html

There is also a post somewhere with a TEC180 and Astrodon Gen 11 reflections. I'll have to find that myself before I get some.

Greg.

[glenc]

Wow :thumbsup:

[strongmanmike]

Hmm? quite compelling..? I may have to send my ProLine back for the FLI aperture mask to be installed - FLI cameras come standard with an aperture mask now but unlike Apogee, FLI cams are hermetically sealed units and filled with Argon gas so must go back to be opened up and backfilled after the install. The new Astronomiks on their way seem like they will be very welcomed though so that's good.

Cheers for that mate!

Mike

[gregbradley]

Hi Mike,

The Apogee CCD chamber is sealed and filled with gas - not sure if argon or something else. The mask went on the outside of the CCD chamber and behind the shutter and you could do it yourself. Perhaps they have a different type of mask. Does it go inside the CCD chamber? Or is the whole body of the camera sealed?

Greg.

[atalas]

Nice work Greg!

[strongmanmike]

If the Apogee CCD chamber is filled with gas then you can't open it and place the mask diectly around the chip then either..? So does the mask supplied by Apogee for their cameras fit on the "outside" of the CCD window?

Mike

[gregbradley]

That's correct Mike. The mask goes behind the shutter and attaches to it and that is in front of the CCD chamber.

Greg.

[gregbradley]

Thanks Louie!

Greg.

[peeb61]

Very nice Greg, love the colours...very very nice.

Paul

[gregbradley]

Thanks Paul. The Baaders are good that way - especially with the reds but perhaps underperform slightly in the blues.

Greg.

[gregbradley]

Thanks Glen.

Greg.

[RB]

Gregory.........That Is Absolutely Stunning my friend !!

Absolutely wonderful to look at !

:thumbsup: :thumbsup:

[marc4darkskies]

Lovely image Greg!!! :thumbsup::thumbsup:

Being picky ... perhaps the star colours could be enhanced a tad though?

Cheers, Marcus

[multiweb]

Wow! :eyepop: So cool. Very very nice picture. Love the colors and the details. Top work. :thumbsup:

[gregbradley]

Thanks Marcus. I did enhance them to the extent I felt comfortable with. I think with all the nebulosity and dust around that is the colour. I have seen other images of the area and they also show the stars the same. Its one of those areas where the stars are simply not colourful due to dust and gas.





Thanks Marc.

Greg.

[richardo]

Top stuff Greg,
nice to see what this scope can do!
Really good fov showing all the extended areas around M78.
Even fit McNeils neb in.

Yes, I do love this object......
Lots of stuff goin' oonn

More please!

All the best
Rich

[gregbradley]

Thanks Rich.

Greg.

[Matty P]

That's beautiful Greg. I've never seen such a detailed image of M78 before.

So much to see. Well done. :thumbsup:

[Peter Ward]

Very nice work Greg, pretty much as good as it gets.

The stars at lower left are a little eggy....... very hard to avoid with mega CCD's due to orthogonality errors that creep into places unknown.

A keeper for sure :thumbsup::thumbsup:

[gregbradley]

Thanks Matty.



Yuri did a detailed test of the feathertouch focuser recently for sag in different orientations (it rotates). After reading that I would normally try to have it so the focuser is upside down as this gives the least sag. How it worked out with the screw on adapters was it was more side on. This may have given very slight sag as it is a fairly heavy camera with the filter wheel as well. I will try to orient it next time so the focuser is upside down and that slight eggy corner star may well go.

Greg.

[strongmanmike]

They are...?

I am looking at this image and the stars by eye are absolute pinpoint corner to corner to me. :shrug:

http://www.pbase.com/gregbradley/image/108830707/original

Or have you fixed them Greg?

Mike

[gregbradley]

No haven't done anything.

In the narrowband images I notice they are pinpoint corner to corner. I think Peter is referring to very slight elongation on the bottom left. Very minor and could have been from one sub or two but not generally as I was checking for that. It was the first use of an adapter that set the camera at the correct metal back distance. Its possible a few may have copped a bit of wind as well. Surprisingly sharp considering how windy it was. I am talking 40kmh + winds.

Cheers,

Greg.

[astroron]

Greg I think you have captured the reappearance of McNeill's Nebula in your image.:thumbsup:

[strongmanmike]

I am at a loss why anyone would bother saying anything about those stars...?

Perhaps Peter has astigmatism in his eyes? I do and if I am a certain distance from pinpoints on the screen they do indeed look elongated, moving much closer to the pinpoints reveals their true nature and turning your head 90deg elongates them in the other direction confirming your astigmatism...So Peter, try putting your head close to the screen and turning it and have another look.

:lol:

Mike

[gregbradley]

Interesting. I read that it had reemerged.

Greg.