This year I am going to provide all of the images needed to complete the CCD1 course to all students via a Dropbox link. They will be taken with my C11/Moravian1600 system with Johnson B and V filters. Why do I take this step?
(1) Those who do not have CCD cameras but who might be interested in trying CCD photometry can gain some insight into how we go about processing images. So, if you now have an OSC or DSLR camera but are on the fence about making the investment in a monochrome CCD, you can spend a trivial amount to see if its “for you” by working with actual CCD images.
(2) The images will provide a backup for those with suitable cameras but lousy winter observing. You can learn the basics even if you don’t wish to challenge subzero temperatures to obtain your images. (This pertains especially to light and flat frames.)
(3) We can try some group exercises using the same images to see if everyone gets the same results. This will provide a nice check on your ability to use your software in calibration processing.
Hope to see you in the class and Happy New Year,
Ed Wiley
Hello Ed,
I just signed up for your course and look forward to participating.
Scott
Thanks, Scott, looking forward to your participation.
Happy New Year, Ed
Ed
I plan to sign up also.
I have done the course before (3 years ago) but didn't really get to put it into practice, so I'm doing it again.
I don't have a CCD camera. I have a Celestron Edge HD 8-inch with UBVRI filters and a CMOS camera (a ZWO ASI 1600 MM Pro), but am not confident (given the weather here) that I will be able to capture appropriate images during the course itself. Therefore, I would be likely to want to use "images provided by the instructor" as per the course description.
The other thing is: Although I have read the caveats about the course not being for DSLRs or CMOS, I reckon the bulk of it will be quite applicable to my situation (CMOS). And since there is, as yet, no course on CMOS cameras where else can one go for guidance on using CMOS cameras?
Paul
Paul:
There is considerable interest in CMOS for photometry. I do hope you have some time to do some imaging with your 1600. I would love to see the results. My inexperience are with setting parameters such as gain and offset. There is no reason CMOS cameras should not be peachy for photometry, its just that I have never used one for photometry. But, I am very interested!
Ed
I have an Orion Starshoot G4 Monochrome camera. Would that do?
Sure, it shoud be fine.
Ed
Ed and I switched classes for 2020. I'll be teaching CCD1 in Janurary. Ed will teach CCD2 in February.
Phil Sullivan
What specifications do I have to see in a monochrome CCD camera for Photometry and Exoplanets Observation? I am planning to acquire it so that I can take the CCD photometry Part 1 class first. ( I have a SCT 14" telescope ). Any suggestions? Thanks you
First, I should say to other potential CCD1 students that if you already have a monochrome CCD camera, even if it is a bit mismatched for your seeing and telescope, it most likely will still work for the course. Use what you have.
Now, on to your question about desirable specifications for a CCD camera to use with a 14” SCT.
Pixel Size
You have a telescope with a long focal length, so you should avoid cameras with small pixels. I also have a 14 inch SCT. My camera has 24 micron pixels. This is just about ideal for my normal seeing conditions, i.e it produces an image scale (1.34 arcsecs/pixel) that works well for the size of the typical stellar seeing disk at my observing site.
I have also used a camera with 9 micron pixels with the 14 inch SCT. To get an appropriate image scale for that camera required using a focal reducer and 2X2 pixel binning. i.e. setting the camera to use a “super pixel" composed of 4 smaller pixels. This camera also worked very well with my telescope and seeing.
I would recommend you look for a camera with pixels no smaller than 9 microns for the 14 inch SCT..
Cameras with large pixels (20-25 micron pixels) are rare in the used market, but cameras using the KAF1001e chip (24 microns) are still available new ($$$). Cameras with 9 micron pixels are common, new and used.
ABG (antiblooming) vs NABG (non-antiblooming)
Either will work fine for the courses and for doing normal photometry or exoplanet photometry. All else being equal, the NABG camera would have the advantages of greater sensitivity and larger dynamic range. I would not let this be a deal breaker if everything else about an ABG camera fits your situation.
Cooling
The cooling must be regulated, i.e. controlled by the camera and software to maintain a set temperature. I have seen even some new budget cameras being sold with unregulated cooling. This really should be a deal breaker. Colder is better, but this is less important than regulation.
Bit depth
16 bits (i.e. 65536 grayscale levels) is now considered the standard. That said, I have a 12 bit camera (an SBIG ST-237) that I think would be fine in the courses if it were used with a short focal length telescope (~600-800mm FL). If someone has an older computer (XP or earlier) with a parallel port, I’d be happy to see it go to a good home gratis.
For a CCD camera to use with your 14 inch SCT you should probably be looking for 16 bits. Shortcuts here could mean other shortcuts you don’t know about.
CCD chip size
The physical dimensions of the chip and the telescopes effective FL determine the size of the field of view. For the CCD courses I think you could get away with a FOV as small as ~ 12 X 9 arcmin. This is a small FOV by modern standards, but would work for the courses.
For a “keeper” camera to be used for photometry after you finish the courses, I’d suggest a minimum size of at least 18 X 12 arc minutes. 20 X 13 arc minutes would be better. I am happy with my FOV of 23 X 23 arcmin, but some would think this too small.
I find the easiest way to calculate FOV’s is to start with the image scale using the “206” equation shown on page 19 of the CCD Photometry Guide. You can then calculate the size of each axis (in arc seconds) by multiplying the image scale by the number of pixels across each axis, and thus get to arc minutes for each axis when you divide by 60. All this will be covered in CCD1.
If you are going to use a focal reducer to get the right image scale for your seeing, remember to use the FL produced by the FR in your calculations.
Here are some examples using older SBIG cameras and a focal length of 3690mm. This is the effective FL of my C14 when using my STL1001e camera. These cameras are no longer produced by SBIG, but they can be found for sale on Cloudy Nights and Astromart. The chips used in the STL 1001e and ST 8xe cameras can still be found in current production cameras from SBIG an other manufacturers
Camera Pixel size number of pixels each axis effective FL FOV
STL 1001e 24 micron 1024 X 1024 3690 23’ X 23’
ST 9xe 20 micron 512 X 512 FR 0.7X 2583 13.6’ X 13.6’
ST 8xe 9 micron 1530 X 1020 FR 0.7X 2583 19.3’ X 12.2’
If you have questions you can contact me by going to my profile and clicking on the contact tab.
Phil
Tim,
For the courses, I'd say this would be fine. For data submission to the AID, I think this would probably result in slight under sampling for most amateur observing sites. It would depend on your seeing. Under sampling could be corrected by a little bit of defocusing ( or maybe just not being too careful to get really good focus).
If you already have a 9 micron camera and a 730mm FL telescope you could test this. Contact me by email I we can discuss how to do it.
Short answer, yes, I think it would work.
Phil
Is there a reason why a 12-bit CCD camera would be okay with a scope with a short focal length?
Yes, that statement is misleading. Thanks for pointing that out.
I should have written, "I have an SBIG ST-237 that I think would work fine for the course if used with a scope of 600-800mm FL. (...thus giving an image scale of ~2.0 to 2.5 arcsec/pixel.) This is a 12 bit camera, but that would not be a problem for CCD1."
The FL has nothing to do with the bit depth.
Someone has claimed that camera and will be using it in the course.
Phil
Great answer, Phil. I am looking forward to our CCD series of CHOICE courses. Miguel: you are in good hands with Phil.
Ed
The CCD1 class, is that with scheduled times/dates, or is that a "self-paced/self-taught" style class?
Clear skys,
Exciton
The CCD classes are taught via an AAVSO forum which is open only to class members. The classes use discussion topics, and class exercises and assignments (i.e. making and discussing calibration frames).. There are no on line meeting times. Class members just check the class forum at their convenience and participate in the discussions by posting comments there.
CCD1 students usually need to spend about an hour a day with the discussions (and posibbly a bit longer when doing exercises). There may be quizzes, and there is a final exam. CCD1 is designed for photometry beginners, but you should have a least some experience using a CCD camera before starting the course.
The text book for CCD1 and CCD2 is the AAVSO CCD Photometry Guide which you can find here:
https://www.aavso.org/ccd-photometry-guide
CCD1 covers the first four chapters.
There will also be a syllabus, but the discussions are wide open for questions. I will post discussion topics and offer explanations or clarifications, but there are no official lectures. I encourage students to ask questions, and these often lead to new discussions. Two or three new topics or exercises are introduced each week. All the topics remain open for continued discussion for the whole 4 weeks of the class.
Despite what you may have been told, CMOS cameras are not supported in the class. If you are experienced using a CMOS cameras, you are free to use yours, but I will not be able tell you how to use a CMOS camera.
For students without a suitable camera (a monochrome, temperture controled, CCD camera) , I will provide images you need for the course.
Students need to use their own software to analyzie images. Examples of appropriate software are listed in the CCD Guide.
Phil
Thank you for the detailed information on this class. It sounds very interesting.
From your description, and that provided on the Choice classes website, it seems that a person can take the class any time they want, and it is coordinated with others who happen to be taking it at the same time. No specific start or end dates exist, each person studies at their own pace (I cannot find class dates listed anywhere). Thanks,
Exciton
There are usually between 6 to 10 students in the class. in 2020 the CCD1 class will be Jan. 6 to Jan. 31. There is another finals week after the course ends to submit answers to the final exam.
Go back to the CHOICE in Astronomy page. You'll see links to the members and non-members registration pages. The dates of all available courses are shown there.
Phil
No CHOICE course is self-paced. We instructors are all volunteers who allot specific times during the year to teach for AAVSO. During that time, we are there for you. We assign projects, pose discussion questions, field any other questions and seek advice when we do not know an answer. It can, and should be, both fun and challeging. I know I enjoy it and I think my students do also.
But, if you cannot devote that block of time; the manuals are always there and there is a mentor program, so if someone wants to learn photometry and cannot devote a block of time to taking a formal course, then studying the manual and asking for a mentor to help get over the rough spots is another strategy. On top of that, Dr. Arne Henden has a wonderful series of videos taken from his photometry workshop. I have them and have learned a lot from them, convincing me that even after a number of years doing CCD photometry I have much more to learn.
Ed (CCD2)
Is there still a place left? I would like to be included.
Jim Gage
I don't think there should be a problem. I usually don't get information about the class size until about one week before it is scheduled to start unless there is a problem. You can sign up here:
https://www.aavso.org/choice-course-descriptions#CCD1
Don't be concerned if you don't hear back from AAVSO HQ right away. People at HQ are starting to go out on holiday vacations, but we'll get you in.
If needed, you can contact me directly by clicking on the mug shot, then the "contact" tab.
Phil