Charles LilloComment

Planetary Astrophotography: The Next Level

Charles LilloComment

Ok so it has been almost a year of learning since I wrote the past blog (http://theastrogeeks.com/dark_sky_journal/2010/4/17/planetary-astrophotography.html April Blogs). A lot of things have happened since then.

But first it is important to clarify something. I have been doing Planetary for around a year and a half. A ton of help from some excellent imagers at SFAAA (www.sfaaa.com). So I am far away from being an expert in these topics. But one thing struck me in this learning process. Every time I went to the internet to research information, gear or techniques, I found myself reading articles from guys that have been doing this for years and they have very clear advice on what the Dos and Don’ts are. But for some reason, there were some things, especially basic concepts that were not mentioned. The reason is simple.  All these guys understand these concepts very clearly and it is embedded in their genes now. To me it isn’t, so I have a bit more of a hard time understanding certain things that to the experts are obvious.

So that is the reason I feel I should write about this. My only experience is my 15 months or so getting involved in Planetary but it is a recent experience that if anyone is willing to read it might help a lot to understand the basic things. I am a beginner, much like, I suppose, you are. So it might be that we speak the same language and have the same trouble understanding the same concepts.

First: The Changes

The first change I see in what I have been doing is that I managed to go from this:

To this:

 

It is the most rewarding thing to see that all the carrying scopes around, asking questions, researching the internet etc,  give you results that are clearly better than what you were doing a few months back.

Many things have changed in my process. New scope, new mount, new camera, new processing software and new work flow.  So there is a point in which you start asking yourself. “OK I have practiced a lot, I want to see what else is out there and I am willing to invest and try”. Here is an important concept. Invest!!

Invest in a higher level camera, maybe a better scope (not necessary but helps), learning new processing techniques and also spending time at the scope. Let’s organize the concepts here one by one:

Investment in Time: One thing I have learned is that practice, as in other fields of human life, is one of the most important elements in Planetary and in Astrophotography in general. It seems obvious but astronomy is no different than any other hobby or activity. We need to understand that there are restrictions, so time practicing becomes an investment. The restrictions in our hobby are many, family life and activities, work, home chores, weather and location are just a few. Planetary AP has a very appealing factor. You can do it from your backyard so driving far is not an issue plus you actually “stay at home”, light pollution doesn’t really matter, so those factors give you the possibility to invest more time and practice a lot, weather permitting!!  There is one other thing. I have seen some of my friends at SFAAA do exactly this. In some cases doing Deep Sky imaging from light polluted areas in their backyards, and yes light pollution is a huge issue for them, but they get the practice time at the scope and later at their computers processing. They get to fix bugs or mechanical problems. They notice that something in their imaging setup is not working well etc. Those guys are accumulating valuable scope time that has given them the ability to be shooting like the pros in a short period of time. When it comes to go out on those very few perfect nights away from light pollution, well they have a load of experience that will help them make the most of their time outside.

Practice time is a matter of will. If you don’t have it well then…….

Investment in gear: I was not misleading anyone in my first blog. To get started in Planetary AP you don’t need a fortune which is true!! Now, in the next level you move to, this requires some investment but it is, and by far, less than what would be needed to do DSI (Deep Sky Imaging). A mid level DSI camera might cost more than all the stuff I have, not counting the scope and the mount. Some cameras can run up to $12,000 or more.  Apogee CCD cameras range from $2,000 to well over $10,000. A Orion Star Shoot Pro at $1,300, and so on. Plus add the guiding scope, guider device etc etc…..Don’t get me wrong, DSOs are beautiful photographic objectives and the guys I know take amazing photographs and for the enthusiast, those price entry barriers are not an issue. But that is not true for everyone.

Now, you have gone and done your practice time with a webcam (Neximage or ToUcam etc) and now you are into a better camera. You have sort of mastered in a way the software for  capture, Registax and Photo Shop and you are getting some nice images of Saturn, Jupiter and the Moon. The excitement is there  and you want to take shots like the big names around the world. So where to go???

I have seen three cameras that really get my attention and that I have read good reviews. I have only used one so I have no experience with the other two. I post here the  basic specs of each one and the regular price at which you can find them.

Manufacturer                         Imaging Source                       Lumenera                                Point Grey

Model                                     DMK21AU.AS                          SKYnyx 2-0M                            Dragonfly 2

Max Frame rate                     60fps                                      60fps (or more with ROI)          60fps (or more with ROI)

Resolution                               640x480                                 640x480                                    640x480

CCD                                         1/4" Sony ICX098BL                1/3" Sony ICX424                       1/3" Sony ICX424

Pixel Size                                5.6 microns                             7.4 microns                                7.4 microns 

Digital Output                         8 bit                                         8 or 12 bit                                 8 or 12 bit

Connection Type                     USB2.0 or Firewire                  USB 2.0                                                     Firewire 

Price                                      US$390                                 US$995                                    US$795 

So here we are with three very good choices. Personally I chose the Imaging Source for these reasons:

1-Price: But not just the price, I was not sure that I would be able to go through the learning curve and have the will to keep carrying the scope plus all the gear out and have a bunch of clouds sit right on top of my backyard. Also keep in mind for planetary imaging you want to have a large aperture scope or at least a scope with long focal length. The reason is to get a nice size of these planets since they are really tiny. So carrying a 11 inch SCT with a CGEM mount plus three boxes with dew heater, focusers, barlows, battery pack, filter wheel, etc and have the night ruined just as you have finished aligning the scope…it is not fun!! And paying a high price for a camera and then go through the frustration….no no!! Besides I had to prove myself I could actually take good pictures. It is not just the nice gear, the guy pushing the buttons at the computer and using the scope makes up most of the final result.

2-Technically this is a huge step above my Neximage. First it is a monochrome camera with same chip size as the Neximage so it has much more resolution. Second, I had the opportunity to see the experienced guys at our club use it and see the results. Also and relating to price, I wanted to go through the filter RGB process and get a high resolution color image. But that is a personal choice. You can always go with a color camera and avoid the processing of 4 images (L,R,G,B) plus the acrobatics of shooting all four channels in only a few minutes (like for Jupiter). So less money in the camera means more to get the filters. The camera performs VERY well and it is very easy to use. It is also highly regarded in the amateur community. But, and I say this as I write, I am already looking into a higher level camera. But I need to get more hours under the stars before I do that.

So what about the other two? They are definitely a step above the Imaging Source. It is a matter of seeing the images on the internet. You can achieve better results when the camera introduces less noise which is one advantage of these two cameras. They are close to three times more expensive and I am not sure they are three times a better camera. The big names you see on the internet use these cameras but they also use the Imaging Source.

An additional investment done was to purchase a dual speed Crayford, a set of filters and a filter wheel. I did get a beginners set of filters for less than $100 in Cloudy Nights. I also bought a manual filter wheel too. One thing IMHO that is not justified is to add a motorized filter wheel. Some people may say it is important, my point is save the extra bucks, buy a manual good quality filter wheel and use the extra money to buy a motorized focuser. And try to be gentle when changing the filter as you shoot so you don’t get the planet out of your screen. Being careful is not difficult. With practice you will be changing filters quickly with very little movement. Place your table close to the scope so you don’t have to stand all the time. I manage to organize my work area so that I can access the back of the scope and my computer without standing up.

Some of you may be asking: Why would you place a Crayford in a SCT scope?? I had the same question until someone made me realize something. When moving the native focuser on the SCT, you are actually moving the mirror. If you have a planet in the center of your screen with the magnification given by one of these cameras, the slightest movement of the mirror, will send the image of the planet like a rocket out of your screen forcing you to accommodate your scope to get the planet in the field of view again. Lots of time wasted, believe me. When trying to focus by hand, you accomplish two things, One is you are moving and shaking the scope and second you are moving the mirror so the planet starts to travel all over your computer screen. Try getting focus with an image bouncing plus a planet that doesn’t stay in the same place and you need to reach for your hand controller (or your computer) to be able to get it back in the screen. It is very hard and it is not an activity for someone that is not loaded with huge amounts of will, determination and patience. The experience may vary depending on the scope you have. This is mine!! And it can become very frustrating to the point where many people quit.

The Crayford I bought is a Dual Speed GSO Crayford for SCT at www.agenaastro.com  Yes some people are fans of a nice Feather Touch (I replaced my native Celestron focuser with a FeatherTouch) or a Moonlite and they are wonderfully made focusers. They are the best in the market. But again the same question. Are they twice or three times better than a GSO? I decided to save some bucks as well here, and go for the motorized focuser.

The next thing you want to consider is adding a motorized focuser to move the Crayford you are placing on the back of the scope or on the side if using a reflector. You have less movement and easier focus. You will use the native focuser to get rough focus or to get a round image once you connect the camera. Remember that when you have a camera it is like using a very small eyepiece so it is likely that you will be out of focus and you are looking into a very small field of View. That is why I decided to change my native focuser with a Feathertouch. Less shake when I see the big fuzzy white ball of an indistinguishable planet on the screen, so as I try to reach rough focus there is much less movement of the scope although the mirror still moves. But it is much better. You then move to the Crayford to do the focusing to start imaging. An interesting low cost alternative for the motorized focuser is the Rigel Systems (www.rigelsys.com or at www.scopestuff.com/ss_rnfs.htm). There are many more out there so do your research. No matter if you have an SCT or a Newtonian, they have the appropriate model to match your OTA and your brand of Crayford. Also if budget is not an issue go for the Moonlight or the Feathertouch.

Investment in research: One very important thing you need to do is research. Not only for the best alternatives in all sorts of gear and accessories. You also should go and see what other people are doing and how they do it. Talk to your friends at the astronomy club or join one if you haven’t done it yet. What cameras they use, which scopes. Read in the usual astronomy sites such as www.iceinspace.com or at www.cloudynights.com.

There are several articles written by some very experienced astrophotographers that actually explain what you need to do to shoot an image. I mean the actual process of sitting in front of your computer and start imaging. Many people get frustrated in the beginning because they see a big fuzzy ball in their screen and no matter what they do they can’t get a discernable image. Sometimes it is the white perfectly round disc with no features etc.  Or the typical “I can’t get the planet in my screen” (it happened to me!!) Sometimes the planet is not in the FOV of the camera. Sometimes it is but the settings of the camera are such that you only see a black screen. Here is where research and practice (two very important investments) can avoid frustration.

Investment in Software: So here is a part where you can definitely discover if you were actually doing things right after some time. I have gone back to images taken months ago and reprocessed them with what I know today and the software I currently use.

For the basic settings, you need Registax to process most planetary images. It is not the only one but it is by far the most popular. Two pieces of software you might want to get to process are NINOX and Virtual Dub, both free. Virtual Dub is used to take your AVI video that you get from your camera and transform it into hundreds (or thousands) of individual pictures in the Bitmap format. The reason for this is to be able to use those images in NINOX. What NINOX does is to get those Bitmaps, format them to whatever size you decide (I do 400pixel by 400 pixel square images) and then it centers the planet in the picture so all the frames look almost the same with same size and the planet right in the middle. It also performs a renaming of each frame according to quality of image. This makes the process easier and faster for Registax. If you use a monochrome camera and LRGB filters, you might want to use a combination software, Photoshop can do the job to get all 4 into a color image. I personally use Astra Image because it also has a Deconvolution routine which is very nice to sharpen images. I also recombine LRGB using Astra Image. More on the software and how to use them as well as sequence can be found in a few articles at www.iceinspace.com.

Hope you got some information in this article. If you decide this is what you want to do, don’t forget, practice and good seeing are King (and Queen). More on how to shoot in the next blog.

Keep looking up!