iceman
Post Laureate
Reged: 03/07/04
Posts: 4357
Loc: Gosford, Australia
|
|
Quote:
Yes the price difference does not yeld a 50% increase in performance, but there is in my mind at least a 20% increase in performance.
You're right - 20% is a big difference if that is your experience. You sold your DMK didn't you? It would've been good to see a side by side comparison test like the one in the link in this thread.
In the comparison test here, there is certainly not a 20% difference. In Sean Walker's review, he stated that the difference was very small (certainly not a 20% difference).
Bird has used both, as well as his ptgrey. I don't think his side by sides yeileded a 20% difference either.
Maybe the seeing was 20% better on the night you used the skynyx for good results 
--------------------
Mike
. mikesalway.com.au - Astronomy and Photography by Mike Salway
. IceInSpace - The Australian Amateur Astronomy Community
. My Bio | My Jupiter 2007 Gallery | My Image Gallery
|
Bird
Carpal Tunnel
Reged: 08/07/03
Posts: 2621
Loc: Canberra, Australia
|
|
I own a DMK21AF04.as, a Dragonfly2 and a Dragonfly Express. Side by side testing shows a clear win for the Dragonfly2/Draonfly Express cameras, both in sensitivity and lower noise and more features (ie format7 support which I use all the time).
But on the other hand they are 2x more expensive than the DMK. Seems pretty clear that if you want to spend around $US350 then get the DMK, but if you have $US750 to spend then get the Dragonfly2.
It's hard to directly compare the Dragonfly2 and Dragonfly Express, they are very different cameras. My personal opinion is that the Dragonfly Express is a perfect lunar camera cause it can do up to 200fps in capturing, and lunar work is probably the only place you'll get enough light to do that.
For other planetary work the Dragonfly2 is practically the same as the dragonfly express and a bit cheaper.
I don't own any of the usb cameras, so I can't compare them to the firewire ones. Also I use these cameras exclusively under Linux, so I can't compare the Windows software for each of them. My linux capture program (Coriander) works with all firewire cameras.
Jon - there's no reason for sensitivity or noise to depend on the data interface (usb or firewire). If anyone told you otherwise then I'd be suspicious.
cheers, Bird
--------------------
Deep Sky Optics 13.1" f/5.5 newtonian,
PGR Dragonfly Express, PGR Dragonfly 2
RedHat Linux + Coriander
http://www.acquerra.com.au/astro/
|
davidpretorius
professor emeritus
Reged: 09/25/05
Posts: 575
Loc: Tasmania, Australia
|
|
i know I would like to go SKYNYX just so i can not have the gain at 100% in RGB at 30fps
the extra sensitivity would be nice...........
so would birds setup in linux!!!
--------------------
Davo
10" peltier cooled Next with dob driver II, Lu075 camera
|
Gendo
Post Laureate
Reged: 12/12/05
Posts: 3231
Loc: Rexburg, ID
|
|
I see about a 10% difference in the visibility of fine detail in the comparison images, and that's mainly just in the red channel. SkyNyx displays a little bit better image overall. However, I also see a bit of an onion ring effect in the SkyNyx camera (low right).
It is possible though that seeing slightly fluctuated between the DMK captures and the SkyNyx captures. I see that happen often in the span of 20-30 minutes.
The end all debate test would be 2 identical telescopes imaging the same target at the same time, and then swap cameras on the scopes (since even identical scopes won't have identical optical quality), and repeat. That's pretty much the most objective way to really compare them. Now's a good time with Venus, Saturn, and especially Mars in the predawn sky so as to have a multiple planet comparison.
|
Lunatiki
Pooh-Bah
Reged: 08/07/05
Posts: 1252
Loc: Amarillo, TX
|
|
Quote:
i know I would like to go SKYNYX just so i can not have the gain at 100% in RGB at 30fps
Perhaps I'm missing something, but there is no way I could capture at 100% gain with the DBK. The result would be burned out with no details. Lately for Mars, Its been at about 650, or what I would call 60% gain.
--------------------
Mars Watch
All images taken with:
Celestron NexStar 8i SCT
DBK 21AF04.AS
K3ccd/Registax4/PSP8
ALPO Member #4287
|
Gendo
Post Laureate
Reged: 12/12/05
Posts: 3231
Loc: Rexburg, ID
|
|
^^ Yeah, maxing the gain doesn't look good on the DMK either, at pretty much any framerate. Some things work well with 600-700, others I set at 800-900. I've yet to find an acceptable setting with gain at anything past 1,000 (I think it goes to 1,024 or so).
|
rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2295
Loc: South Australia
|
|
Luna, all this depends on the image scale you are working with. If you go above 10,000mm with a 9"-11" scope, you will have significantly less light than say at 5000-7000mm. This will result in having the gain at 100% most of the time.
Dave works at 10,000mm and above and this is the reason for the gain being so high. unfortunately you need high focal lengths to get significant detail increases in images. You simply cannot get detail out of images that are too small and don't cover enough pixels.
Justin, yes getting scopes side by side might be instructive, but the fact that I have owned both units; the DMK I was the second to use it here and the first in Australia. I used this for 16 months at a variety of focal lengths and am very confident in my assessment. The skynyx I have owned for 3 months and have used it extensively and have seen immediate results. So in this respect I am well qualified to give my word that the skynyx is better and well worth the extra money. I cannot say it plainer than that. My images have not only improved from larger aperture but also from a better camera.
--------------------
EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
|
Lunatiki
Pooh-Bah
Reged: 08/07/05
Posts: 1252
Loc: Amarillo, TX
|
|
RR, I will certainly take your word for it because of your experience and of course your images, because they speak for themselves, but can you explain to me how Larry's images came so close to each other in every aspect if there is a big difference between the cameras? Thanks....
Joel
--------------------
Mars Watch
All images taken with:
Celestron NexStar 8i SCT
DBK 21AF04.AS
K3ccd/Registax4/PSP8
ALPO Member #4287
|
gazerjim
Postmaster
Reged: 02/12/04
Posts: 7726
Loc: About where I thought I was......
|
|
My 2 worth: The skynyx shows up slightly better in contrast and tonal range on my screen. Whether the difference is worth the price is a value judgement. Also, one test does not make for a valid comparison between cameras. We would need to see the cameras tested under a variety of conditions with various targets IMHO.
--------------------
Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
|
rumples riot
Carpal Tunnel
Reged: 07/01/04
Posts: 2295
Loc: South Australia
|
|
One certain factor that I have mentioned and not explained totally is that planets like Jupiter you can only really image for 35-40 seconds per channel (sometimes more like Bird does); rotational issues come into play and so with such a short time you can only really get a limited number of frames in poor to above average seeing. Maybe a 1500 frames if you are imaging at 7000mm and 1000 frames if you have a 14" (at 12000mm +) per channel (this is for a fully exposed histogram). Of which you would use maybe 4-700 frames depending on the seeing conditions. Most commonly around 400 frames. This really is not enough frames to use on the DMK and Jupiter. You really need 550+ frames for a really smooth image to start with. Bird I think uses something like 1200 frames + in really good seeing. (I don't get that sort of seeing consistently)
Now planets like Mars which rotate at a similar rate to earth can be imaged for much longer. You can image for a total of 4-5minutes worth of data. This means that you will easily in average seeing conditions get 7-800 frames per channel to stack out of runs over 2-3000 frames taken per channel.
With this amount of frames you cannot help getting great results from the DMK on Mars. Aside from the fact that we have not considered the guys individual talents in processing.
However, generally the more frames you can get the better the image. And; the more frames that are clean of distortions the larger you can resample from a 12000mm standard fl. A good example is Anthony's images this year in great conditions he can resample a lot to attain the massive image scale. Damian Peach's images this year are larger still and show fantastic detail (he uses a skynyx too)
Now on top of all this is that each image contains more data because of the well depth of the pixels. The deeper the well the better the images. So when you combine this with lower noise, more frames andwell depth you get great images.
Like I said the DMK is good but the Skynyx and the Dragonfly express are better again. The images from Damian, Bird show that is the case. And I really think that Jupiter would be a better test comparison given the short duration of exposure.
Did I explain that well?
Paul
--------------------
EARTH AND COSMOS
My Solar System Imaging BLOG
How to peltier cool a C14 SCT
SOUTH CELESTIAL POLE
|
Lunatiki
Pooh-Bah
Reged: 08/07/05
Posts: 1252
Loc: Amarillo, TX
|
|
Yes, very well, and excellent information. Thanks!
Joel
--------------------
Mars Watch
All images taken with:
Celestron NexStar 8i SCT
DBK 21AF04.AS
K3ccd/Registax4/PSP8
ALPO Member #4287
|
gazerjim
Postmaster
Reged: 02/12/04
Posts: 7726
Loc: About where I thought I was......
|
|
Indeed you did, Paul.
--------------------
Jim Fisher
If you're not part of the solution, you're part of the precipitate.
Henry J. Tillman
|
David Rivas
Carpal Tunnel
Reged: 05/29/04
Posts: 2004
Loc: Lima, Peru
|
|
Paul,
No doubt direct experience and your own latest splendid results count a lot when it comes to a great Skynyx-DMK comparison!
When someone sees Mr. Peach's amazing images, one might guess Skynyx high quality is superb... but when someone looks at your latest Jupiter images and read your explanation above... one can be completely sure of it!!!!!!!
You could be one of the best Skynyx sellers in the world:o)
Even though there's no big secrets in planetary imaging...Thanks for sharing "your secrets" Paul!!
Not many imagers do that...
Best regards,
David
|
davidpretorius
professor emeritus
Reged: 09/25/05
Posts: 575
Loc: Tasmania, Australia
|
|
yup, well explained rumpius riotus
--------------------
Davo
10" peltier cooled Next with dob driver II, Lu075 camera
|
Bird
Carpal Tunnel
Reged: 08/07/03
Posts: 2621
Loc: Canberra, Australia
|
|
Quote:
One certain factor that I have mentioned and not explained totally is that planets like Jupiter you can only really image for 35-40 seconds per channel
...
Did I explain that well?
Paul
Spot on. The DMK requires a lot more frames to get a smooth image compared to more sensitive cameras like the Dragonfly2 or SkyNyx (from what I know about the SkyNyx, I've never used one).
This is a double-edged sword, cause with a more sensitive camera you can shorten the exposure and get more frames, and the real secret to good images is to use the absolute shortest exposures you can. This year I was using 2.5ms on Jupiter, and I'd like to shorten that even more if I can...
cheers, Bird
--------------------
Deep Sky Optics 13.1" f/5.5 newtonian,
PGR Dragonfly Express, PGR Dragonfly 2
RedHat Linux + Coriander
http://www.acquerra.com.au/astro/
|
Alan Friedman
sage
Reged: 08/30/07
Posts: 351
Loc: Buffalo, NY
|
|
Hi all -
My sense is that most can spend a great deal of time with a DMK camera and not reach the limits of image quality that can be drawn from its data. I haven't had the pleasure of shooting Jupiter above 30 degrees in elevation for a few years, but I had reasonable success at that altitude with a 10" telescope and the DMK at 66ms shutter:
http://www.avertedimagination.com/img_pages/jupiter040906.html
There are many ways to skin the cat!
cheers,
Alan
--------------------
Alan Friedman
www.avertedimagination.com
|
swalker
Imaging Editor - Sky & Telescope
Reged: 01/22/07
Posts: 366
Loc: 42.9225°N, 71.2242°W
|
|
I agree with Paul-
pretty much what I felt comparing the Lumenera and DMK.
for the price, the DMK is a great value.
You do get more from the SkyNyx, but at a serious cost.
--------------------
12.5" f/5.1 Newt
10" f/4.5 Newt
4.25" f/4 Astrograph
80mm f/10 refractor
70mm Mak Cass
40mm PST
Millennium Mount EQ
TI ProDome #002
|
Previous
Index
Next
Threaded
[Re: 
Edit
Reply
Quote
