Starless NGC3372 - Page 2

renormalised (Carl) · #21 26-01-2009, 08:01 PM

Pity you've got a 12" LX200R, Fred. If you had a normal GPS or classic, or even the ACF, you could've gotten a hyperstar lens system and converted a 10" or 14" f/10 into a 10" or 14" f/1.8!!!!...even if you had to retrofit it with a conversion kit, there'd be your fast widefield system

They're looking to make a hyperstar for the Meade 8" and 12" models soon.

AlexN · #22 26-01-2009, 08:02 PM

shorter FL? Nah mate... wack a 2x barlow in it!!

I want to see a close up pic of the fickle finger beside the keyhole !

AlexN · #23 26-01-2009, 08:04 PM

renormalised - saying something like that to Fred is going the right way for a smacked bottom!

Short focal lenghts are for sissies (and learner imagers like myself..) I'm getting there though.. Next image I do will be at 1760mm... Hoping to go 2800mm by the end of this year.

renormalised (Carl) · #24 26-01-2009, 08:19 PM

Quote:

Originally Posted by AlexN

renormalised - saying something like that to Fred is going the right way for a smacked bottom!

Short focal lenghts are for sissies (and learner imagers like myself..) I'm getting there though.. Next image I do will be at 1760mm... Hoping to go 2800mm by the end of this year.

You notice how most of the professional imagers (i.e. astronomers) take pics with instruments with FL's as low as f/2. All the shots from the prime focus cages are about that long in FL. Shots at short FL's are probably harder as you need excellent focus (and look at how hard that can be to get)....long FL's are either for peeps who like imaging planets and such, or for people with the patience of Job, who like to sit around for hours trying to get enough photons just to see anything!!!

Don't me wrong...I like both. They both require practice and have their good and bad points

renormalised (Carl) · #25 26-01-2009, 08:26 PM

Like long FL...get them to make a x9 or x10 Powermate...then you'll have heaps of focal length, and the FoV equivalent of a single photon!!!

Bassnut (Fred) · #26 26-01-2009, 08:34 PM

Renormailsed (sheesh mate, whats your real name, I forget......). Yeah, despite my adversion to the sissy (I like that, so appropriate) FL, the hyperstar conversion is attractive, F1.8 with an 85% QE cam and megadata, insane, would be very interesting

. The ST10 would provide rather a large obstruction tho

.

Alex, actually tried a 5* Power mate on the finger, a blurry mess (might post it, for a laugh), Id need to get the PME back home to try that again.

Go for it Alex, long FL is a buzz, cleans the soul. Super sharp WW stuff is for sissies, bang on there, 2800mm?, right on, I await with expectation

.

gregbradley · #27 26-01-2009, 08:45 PM

Hi Fred,

I like it. I've done a few of these starless images myself and they are an interesting effect and serve to highlight the nebula.

The 3nm Ha really pulls out some subtle folds in the gas cloud that don't normally show.

Greg.

AlexN · #28 26-01-2009, 08:46 PM

Fred : I've done a couple of shots with the C11 @ 6.3 1764mm F/L and even though they are much harder to capture, the detail in the images in extreme! I love it to death... Just waiting on my phone call from Astrophysics for my AP1200, Then I'll be removing the focal reducer and going for broke with C11 F/10

I too await!

Might be a year or so, but when it happens it should be very exciting!

I do like my wide field sissy shots, as they are teaching me a lot about processing and the ins and outs of my system, but they just lack impact for me.. Long FL + Small Sensor = Awesome!

Bassnut (Fred) · #29 26-01-2009, 09:00 PM

Oh yeah, the AP1200 is a killer, thats the key, serious match for the PME, and would make the C11 shine, nice pick Alex, welcome to the zoom-in club

.

Greg. Yes, 3nm is a bietch on sub exposure length, but in a world of same-as, it makes the effort worth it IMO. Come to think of it, 3nm Ha on the new Tak, would render insane detail, especially at your dark site, gaud, please try that

.

gregbradley · #30 26-01-2009, 09:05 PM

Quote:

Originally Posted by Bassnut

Oh yeah, the AP1200 is a killer, thats the key, serious match for the PME, and would make the C11 shine, nice pick Alex, welcome to the zoom-in club

.

Hey I thought Anacortes had an AP1200 ready to ship within a week or so. Check it out.

Greg.

Greg. Yes, 3nm is a bietch on sub exposure length, but in a world of same-as, it makes the effort worth it IMO. Come to think of it, 3nm Ha on the new Tak, would render insane detail, especially at your dark site, gaud, please try that

.

I was thinking of that. Astrodon make a 3nm Ha but its US$1000 for a 50mm square. But then I don't like swapping filters between cameras.

I just found out to my amazement that the reason I was getting dim "Ha" from my Microline was not because it isn't sensitive to Ha - it is.
It was because I had mistakenly installed the S11 filter thinking it was the Ha (both red but S11 darker red -grrrr).

Greg.

strongmanmike (Michael) · #31 26-01-2009, 11:59 PM

Quote:

Originally Posted by AlexN

I want to see a close up pic of the fickle finger beside the keyhole !

...ok, done with an almost wide angled 1140mm FL and just a few 10min exposures

:

http://www.pbase.com/strongmanmike20...71681/original

and just to prove the point - even closer:

http://www.pbase.com/strongmanmike20...25889/original

Not just FL that counts but good quality unobstructed optics with a mono chip cam help too

long live the refractor

Incidentally, this data was taken with Eta still pretty low (< 40deg) in the sky early last year, must try again this year when it is nearer the meridian and hopefully in good seeing

Mike

atalas · #32 27-01-2009, 06:40 AM

Quote:

Originally Posted by strongmanmike

Oh dear................over half a a day of exposure ..for that?

In-ter-es-ting I guess..?

Maybe another APOD?

Mike
luv ya Fred

Oh come on big Mike ! you got to be scratching you head at some of the APODS...surely.
I'm sure the was a time there you were thinking only Sbig cameras could score and APOD eh?

Ric · #33 27-01-2009, 04:47 PM

Very nice work Fred, I quite enjoy these starless images.

Cheers

AlexN · #34 27-01-2009, 04:56 PM

Quote:

Originally Posted by strongmanmike

...ok, done with an almost wide angled 1140mm FL and just a few 10min exposures

:

http://www.pbase.com/strongmanmike20...71681/original

and just to prove the point - even closer:

http://www.pbase.com/strongmanmike20...25889/original

/Snip!

Mate, not bad... However a 6" AP refractor is not a sissy toy

Oh, and imagine what that would look like if that was not a crop, but full frame of the KAF0900 sensor, or your KAI11002...? Obviously the seeing require to capture an image like that would greatly exceed what we could ever expect on earth.. BUT, IF we could, longer focal length would produce a better image...

Also - something like the C11 would get beaten by a 6" triplet APO, but exchange the C11 for a 12.5~17" RC or CDK and you're looking at a big big contest for the better image

I personally look forward to Greg Bradley doing a direct comparision between his TEC180FL and TAK BRC-250...

My money says the big mirror wins

(only because I want the mirror to win!

)

strongmanmike (Michael) · #35 27-01-2009, 05:55 PM

Quote:

Oh come on big Mike ! you got to be scratching you head at some of the APODS...surely.

Yes sometimes they present some pretty ordinary images and of the same objects over and over again but most of the time they are real crakers!

Quote:

I'm sure the was a time there you were thinking only Sbig cameras could score and APOD eh?

Me?? neeeever

strongmanmike (Michael) · #36 27-01-2009, 06:01 PM

Quote:

Mate, not bad... However a 6" AP refractor is not a sissy toy

Quite right and I feel very lucky to have one, truly.

Quote:

Oh, and imagine what that would look like if that was not a crop, but full frame of the KAF0900 sensor, or your KAI11002...? Obviously the seeing require to capture an image like that would greatly exceed what we could ever expect on earth.. BUT, IF we could, longer focal length would produce a better image...

Ah yes but those sort of conditions are pretty rare and a longer FL instument will show little improvement over this image untill the aperture significantly increases and really only then in good seeing. The added advantage of what I call the "sweet spot" in imaging focal length (ie about 1200mm FL) is that with say a 35mm size chip you can also fit a lot more in the 1.8 deg wide FOV then make several images from one.

Quote:

Also - something like the C11 would get beaten by a 6" triplet APO, but exchange the C11 for a 12.5~17" RC or CDK and you're looking at a big big contest for the better image

I personally look forward to Greg Bradley doing a direct comparision between his TEC180FL and TAK BRC-250...

My money says the big mirror wins

(only because I want the mirror to win!

)

Yes looking forward to that too...I already know the winner though

Mike

Terry B · #37 28-01-2009, 09:48 AM

Quote:

Originally Posted by renormalised

You notice how most of the professional imagers (i.e. astronomers) take pics with instruments with FL's as low as f/2. All the shots from the prime focus cages are about that long in FL. Shots at short FL's are probably harder as you need excellent focus (and look at how hard that can be to get)....long FL's are either for peeps who like imaging planets and such, or for people with the patience of Job, who like to sit around for hours trying to get enough photons just to see anything!!!

Don't me wrong...I like both. They both require practice and have their good and bad points

I like the longer focal length imaging but then I like to see images of galaxies and PNs (and most are pretty small). Not much point taking widefield images when the subject only fits on 10 pixels.
You can always take the same image throught the slower scope and bin it for exactly the same brightness as taking it through the shorter focal length scope.

renormalised (Carl) · #38 28-01-2009, 04:57 PM

Quote:

Originally Posted by Terry B

I like the longer focal length imaging but then I like to see images of galaxies and PNs (and most are pretty small). Not much point taking widefield images when the subject only fits on 10 pixels.
You can always take the same image through the slower scope and bin it for exactly the same brightness as taking it through the shorter focal length scope.

That's true....you're only going to use those short FL's on large, extended objects and others that can take it. Most PN's would just be starlike points at f/2. That's why the SCT's f/8 is a compromise between fast optics/widefields and good detail on small objects using slower FL's. Trying to be best of both worlds.

However, you can have too much of a good thing with FL...go too long and you end up with either a blur or so little FoV you're virtually straining photons through the front of your scope!!