Best camera / scope for planetary

[davidpretorius]

Hi, I'm new to the forum and no doubt this question is always asked

Ice has hinted that he is going DMK camera. Lester has a colour DMK.

At the moment, my 1250 focal length 10" newt with a powermate @ 7.7x plus the 6mm focal length of my toucam means I am imaging @ f38.5. Damian Peach seems to be at around f39 plus some resampling.

At the moment, i have very little room on a 640 x 480 chip of the toucam with Jupiter. In ppmcentre, i cut it at 440px instead of the default 400px.

Bird seems to have gone smaller size on his firewire, but more detail is present

I am in a quandry for next years Jupiter. Short of getting a 10" or 12" mewlon ( in my dreams ) or c14 (in my dreams again ), i am thinking of building a new aluminium OTA that is easily transportable. I have the dob driver II so tracking is not an issue. But what will the DMK's dictate to be the best ratio and diameter for planetary?

Is 16" fraught with hassles??? Is 10" at f5 and a DMK as good as you can get it. Should I try and mimic a c14 and go 14" but not at f10???

:screwy: I am starting to lose it!

[matt]

DP

How did you calculate that figure of f38.5???

Your scope is f5. With your 5x powermate that's f25

[davidpretorius]

7.7x (5x with the 100mm extension tube ) x f5 = f38.5

[matt]

So the extension tube combines with the powermate to become a 7.7x powermate?

You got a chart which shows what effect different length extension tubes have on powermates/barlows etc?

[davidpretorius]

yup

about 1/2 way down page

http://televue.com/engine/page.asp?ID=42

[Lester]

Better late than never. Hi Dave,

Why do you mention C14 instead of Meade SCT14. The Meade is about half the price of the Celestron. Have you seen better results with the C14? I haven't!

[davidpretorius]

Hi Lester,

purely from what a few planetary imager guys (not iis) have said ie the 9.25 vs meade 10" and also that Damian Peach recently went to barbados with a c14?

Probably, the best images from Australia this year have been from a c14 and a toucam in melbourne. Maurice contributes to the ALPO projects overseas. Lovely work

http://www.lpl.arizona.edu/~rhill/alpo/jupstuff/alert/jup060416c.jpg

[Lester]

Thanks for the reply David,

Wow that is a fantastic image of Jupiter, and taken from good ol-Melbourne. I will have to look around for of Maurice's images.

[asimov]

Boy, are you guys are in for a shock when Lester finally gets an 8 or more seeing with his Meade 14" :D

[Lester]

Asi,

hush up, try and keep a lid on it.

[asimov]

oh....Sorry, wrong Lester! I was talking about another Lester down the road a bit with a C14!

MEADES SUCK! :D

[davidpretorius]

ummmm asi, might want to tighten those dove plate screws up again on the 14" if there is a 8+!

[asimov]

I went one better Dave by super-glueing the secondary collimation screws in..:D

He'll have to rely on the primary mirror flop to collimate! :lol:

[Lester]

:poke: :help2: :argue: ;) Have a good one mate.:thumbsup:

[davidpretorius]

:d

[anthony2302749]

Hi All

What telescope/camera do you need to do planetary imaging? There are probably many combinations that can be used. Meade, Celestron, Obsession, Takahashi, ToUcams, Lumenera, DMK, Point Grey, colour or RGB the list goes on.

Any combination of the above mention equipment will achieve that goal. What will make the difference between an average image and award win one is technique. You may wish to purchase the same equipment as used by Damien Peach but by buying such equipment will not mean instant success.

Technique is the key to success; it starts with the choice of mount, then optic, then camera (colour or monochrome), chip size, pixel size, sensitivity, dynamic range, frame rate, filters, collimation, temperature, weather conditions, processing etc.

I have been imaging the planets since 2001 with varying success and have learnt a lot over the years. I have been using a 10” LX200 but am now leaning towards a larger scope preferable the 14” Meade LX200R, not because it is a Meade, but because of the aperture. Large aperture, more light gathering area, better resolution and brighter image. Which means I can turn down the gain, hence less noise in the final processed image. Also while the Lumenera colour camera that I am currently using is great, there are limitations with using a colour camera mainly due to the fact that you are not able to image in full 640x480 resolutions per each colour channel. Again I am now leaning towards a monochrome camera plus RGB filter wheel. The three things that I will be looking for in my next camera will be “Frame rate” “resolution” “Pixel Size” and “Dynamic Range”

I have look at and am considering the DMK camera which has a frame rate of 60fps, resolution of 640x480, pixel size of 5.6 and a dynamic range of 10 bit and are well priced at about A$700. But I like the Lumenera which has the similar specification as the DMK except that it has a pixel size of 7.4 and a better dynamic range of 12 bit but is double in price. The Lumenera looks to be the win as it offer better dynamic range than the DMK.

Why consider “dynamic range” well it is all about raw data. A 8 Bit monochrome camera will produce 256 level of grey, 10 bit - 1024 level of grey and 12 bit – 4096 level of grey. By increasing the dynamic range, image quality improving.

Finally, I took the time to scour the net to fine example of images taken with both Celestron 11”and Meade 10” to see if there is a difference between competing brands (see attached photos). Secondly I looked for the best and worst image the net has to offer (again see attached photo). I will let you make your own decision about these images.

Anthony

[davidpretorius]

thanks anthony, i have been chatting offline with a few guys, the c9.25 and c14 are apparently ideal setups for planetary in terms or mirror setups, but not the c11.

I not sure I understand fully why?

Damian Peach is apparently selling his lumenera, I wonder what new technology in cameras is about to launch???

[anthony2302749]

Hi David

I agree with what is being said about the C9.25 and C14. But I think you would agree with me that technique is the most important factor when imaging the planets. I have spent quite a bit of time scouring the net and looking at image quality produce by various types of scopes/camera combination. From what I have seen there is a wide range of image quality produce by amateur around the world but it looks like only a small percentage of these can produce high quality planetary image on a regular basis.

As a point of interest here are three image of Saturn taken by Edward Roach (you will find his work posted on Astromart Forum). He used a Meade LX90 8" SCT @ f/35, seeing 6-8/10, transparency 3/5, DMK 21AF04 for luminance, ToUcam 840 for RGB. These images are as good as Damian’s work and he is only using an 8” SCT.

While equipment is an important factor in planetary imaging, I would say that technique is a winning factor in producing high quality planetary image on a regular basis.

I think with the right camera plus technique your 10” GSO would probably produce the same quality of work.

Anthony

[asimov]

Another major factor is seeing. Where I am it rarely gets above 5/10. On average 4/10.

That severely narrows your chances of getting good shots, despite having the great equipment.

[Lester]

Hi Anthony,

Like to download some of the information inbetween your ears.;)

Very interesting indeed. Fantastic shots of Saturn with Meade 8".:eyepop:

Did you see that David and Asi; Meade.:whistle:

[anthony2302749]

Correct, weather condition can severally effect the final out come but there is aways to limit this problem. If you look at the high end camera, such as the DMK and Lumenera, they have one thing in common - high frame rate eg 60fps. This increase the chance of capture more frames which are unaffected by the weather as appose to the 5 or 10fps you would get with a TuCam. For example I can collect up to 1600 frame in 90sec when imaging jupiter as appose to 450 to 900 frame with a webcam. If I take the top 10% of the 1600 frame I will have 160 I can use for my final image were as with the webcam you will only have 45 to 90 frame to play around with.

The final result, more frame that are collected which are unaffected by the weather, the better quality image.

Anthony

[Lester]

Hi Anthony,

Been doing some imaging with neximage at 20fps, what looks unexceptable at 5 and 10 fps is resonable at 20fps. The image even appears smoother at 20fps than 15. Cannot explain it.

30 and 15 fps always produce low quality images with neximage. People talk about compression and that 5 & 10 is all that can be used where commpression isn't a problem. But why is 20 fps performing so well?

[davidpretorius]

Anthony, i agree 100%.

Just say someone is a newbie with a stack of cash, you can not go out and buy a c14, lumenera camera and start producing damian peach images.

Technique is a major factor as with any hobby / sport / business etc.

When i got into astronomy July last year, I had in my mind to start with a DOB and then from there upgrade. I would still recommend for anyone that this is the path to follow ie cut your teeth on a dob, push it around, learnt to collimate, estimate seeing, cool it, work out imaging without tracking etc etc.

The next step after that is the hard one.

It is a multiple $1000 step. A BIG STEP and one i hope to make only once or twice over the next 15 years.

Is there a correct answer for everyone, of course not.

Bird with his reflector, damian and chris go with c11's and c14.

I have heard Mewlons are the best mirror setups of all for planetary and I only know of Rob_T's

It is a fantastic fast paced hooby, cutting edge! We only have the last 3 or 4 years of Damian Peach lifting the imaging bar and now a lot are catcing up. We becomes adept at studying the weather, image processing, electronics, programming for filter wheels.

A lot of fun!

[davidpretorius]

lester, purely the seeing i would presume. Have you had a night of imaging in 8/10 or better?

There is always a trade off from number of frames for stacking and quality of frames.

In say 5/10 or 6/10 seeing. 10 or 15 or 20 fps will be great as you get more and more frames to try and get rid of the crap. Compression plays very little effect here, as you would never notice it!

BUT in 9/10 seeing, when you can capture 400 frames that are all great in their own right, then you want them to be as uncompressed as possible, hence 5 fps is best. There are no distortions to try and stack out! Each and every image in that avi is the same size

See the attachment, it is a converted jpeg from the avi. I had nearly 400 of these frames to work with. The moon stayed in focus nearly the whole time. So, the only thing i can improve here is making sure it is not compressed. Stacking 200 perfect frames compared to 2000 perfect frame will have very little difference. The only difference is the compression.

Damian Peach captures in barbados due to the seeing, Chris Go captures in the phillipines where he has 7/10 or better nearly every night. Very little processing is needed. Into registax, and a little wavelets and thats it.

So, you are spot on, 20fps works well, except if your seeing is great, then compression effects will come into play. You don't need 2000 frames if the seeing is great, even 100 frames will produce a great image. The DSO guys might take 5, 10 or maybe 20 frames and stack them and produce great results.

[Lester]

Thanks David,:thumbsup:

The best seeing I have had has been 6/10, which looks fantastic after all the 1,2,3 and 4/10. I have had 3 nights of 6/10 since I started imaging.

I use to rate the seeing better, until Asi gave me some advice. Counting how many frames are sharp out of ten.

Hope you get another good one soon.:)

[asimov]

100 frames Lester ;) A better average is derived from it.

[anthony2302749]

Hi

This is an image I did the other night. I had better one but due to dumd thumbs I accidentally deleted them from the HD. :doh: This is a stack of about 400 from a total of 1600.

[anthony2302749]

I was just pondering the above question. If we say that all things are equal then there would be no difference between any of the SCT on the market. But if you look at the specs of the competing scopes you may see some interesting stats.

Just working with Secondary Mirror obstruction by area (could not find relevant info on obstruction by diameter to I will leave in out of the equation) you will notice there is quite a variation in centre obstructions.

Celestron 9.25” @ f10 = 13%
Meade 10” @ f10 = 13.7%

Celestron 11” @ f10 = 12%
Meade 12” @ f10 = 11.1%

Celestron 14” @ f11 = 10%
Meade 14” @ f10 =12.4%

If a smaller centre obstruction will give you better contrast then you can infer the following.


There is little difference between the C9.25” and the M10” and in the right hands should produce quality images if everything is equal e.g. collimation, camera, weather etc.
When it comes to the C11” verse the M12” it looks that the M12” would be the better choice for planetary imaging due to the smaller central obstruction.
And finally the big one, the C14” verse the M14” again the C14” is the better choice for planetary imaging again due to the smaller central obstruction.
So apart for the size of your bank account, if we go on the premise that a smaller centre obstruction will give you better contrast when imaging the planets then the C9.25”, M10” M12” or the C14” would be the scopes of choice. But remember technique makes up 90% of the imaging process.

Me may need to rethink my decision about my next scope for planetary imaging. :confuse3: Maybe a M12” or, yes you guessed it, a C14”.


Anthony

[iceman]

I'd say seeing is #1, then technique and processing :)

[davidpretorius]

thanks Anthony.

I got a quote today for an aluminium tube that breaks down for transport. I think that I am yet to see convincing proof that the SCT's beat reflectors in the planetary game.

A c14 would be great, but $$ and a mount = more $$$. In the immediate future, I will follow the lead, get a better camera, new tube with integrated peltier cooling system and also bigger ALT bearings for more accurate tracking with the dob briver II

When i have lotsa money a titan and a c14 would be great!

[Lester]

Hi Anthony,

very interesting. Don't know how much 2% greater obstruction would be noticeable when imaging.

Why hasn't some one perfected the un-obstructed reflector? Would have potential to perform as good as a refractor with extra diameter and not too long a tube if you use a folded reflector.

[asimov]

Yep. I totally agree.

[davidpretorius]

not quite,

having mates to brag to then Seeing then technique then equpiment then processing then family!

[asimov]

Gotta get the seeing first in order to brag! :P

[anthony2302749]

Hi Mike

I agree, understanding the weather is important, it is all part of the technique. But as you will find out with the DMK, as I have discussed earlier, the high frame rate can over come some of the blurring effect of the weather. So on night were you think it will be no good for the ToUcam due to its slow frame rate it will be ok for the DMK. The DMK is capable of imaging up to 60fps so there is a greater chance of capturing more image free of the blurring effect of the weather as apposed to the ToUcam which on average is 10fps. This mean instead of 100 frame you will have 300 of 400 frame usable for stacking and processing.

This is one of the reasons why people who are using these camera have great success.

[[1ponders]]

Someone has Lester :)
It's called a Schiefspiegler scope (http://www.videoastronomy.org/schiefspiegler/kutter_en.htm)

[Lester]

Yes Paul I thought there would have to be some sought of unobstructed reflector kicking around. But they don't seem to have taken off. If they are as good as they should be in theory there would be more of them around.

Thanks anyway for bring it to my attention.