Hi all--
Since there's no other group or committee assigned to working on manuals, that responsibility falls to the Equipment and Instrumentation Section. The current manual dates to 2014, and it's very good. But as we all know, CMOS cameras and new filter types are changing the field of photometry. The manual needs updating.
I looked over the AAVSO Guide to CCD Photometry, and it looks to me that photometry using CCD and CMOS sensors need not be covered in separate manuals. By organizing the material on the peculiarities and particularities of CCDs into one chapter and those of CMOS into another chapter, the taking an analysis of images would be essentially the same. This not only saves a lot of work, but would also reduce fears among newly minted photometrists that everything is different. Mostly everything is the same: once acquired, images are images.
The process of revision would also help clarify in our minds some of the points we do not yet understand about imaging with CMOS. In other words, the manual revision team can push work on the known unknowns and spotlight the unknown unknowns. I estimate the process will take a yea
I am posting this note here asking for volunteers to be part of a team to revise and update the current manual.
--Richard
Richard, I'd be glad to be a part of the team. (And I agree that one manual can cover both camera technologies.)
- Mark Munkacsy (MMU)
Richard,
I began a project a while ago to re-write the section of the manual related to transforms. The current manual's presentation is inadequate and just plain confusing.
Keep me advised on how I can get my work into the new manual.
Thx,
George
Mark and George--
We'll be hosting a Zoom meeting to get organized. Keep an eye out for it....
--Richard
If you're interested in discussing filters, CMOS camera, and helping with the revision of the AAVSO Photometry Manual, click on the Doodle Poll to indication a Date and Time you could attend a section Zoom meeting.
https://doodle.com/poll/h84abkd5xhe57drc?utm_source=poll&utm_medium=link
I will pick a date/time when as many of those responding can attend. I will post a Zoom link on Thursday.
--Richard
AAVSO Equipment & Instrumentation Zoom Meeting: Sat Oct 16 at 10:00 a.m. PDT / 1:00 p.m. EDT
Potential attendees: John Downing, Rick Diz, Mark Munkacsy, Gary Walker, Ken Menzies
Gordon Myers, Phill Sullivan, Ed Wiley, Arne Hendon.
Please invite others who may be interested. We will be discussing Filters, CMOS cameras,
the revision of the AAVSO Photometry Manual.
Richard Berry is inviting you to a scheduled Zoom meeting.
Topic: AAVSO Equipment & Instrumentation Zoom Meeting
Time: Oct 16, 2021 10:00 AM Pacific Time (US and Canada)
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Eight members of the E&I Section met via Zoom to discuss filter, CMOS filters, and the revision of the Charge-Coupled Device (CCD) Camera Photometry Guide (aka, the AAVSO Photometry Manual). Arne Hendon reported that he's working on synthetic photometry software that is taking longer than expected (usually the case with software development). Various participants noted that Johnson/Cousins UBVRI Bessel dyed glass filters are available from Custom Scientific for $375 each in 1.25 inch mounted, 5 mm thickness, with a 2 to 3 week delivery. Optolong offers interference filters that have band-passes that mimic the filter curve of the Bessel filter, and Chroma offers bandpass filters with center wavelength and bandpass matching Bessel filter, but with square passbands.
Various participants noted that CMOS cameras are confusing to beginners because they offer more setup options (especially gain settings). Ken Menzies showed that he has collected a lot of material toward a handbook on using CMOS cameras. We agreed to set up a private Forum group to assemble, write, and edit such a document. The document can be posted in this Section's Forum page for initial review and upon completion.
Various participants noted that the current CCD Camera Photometry Manual focused so strongly on getting precise and accurate results that it appeared daunting to those new to photometry. Others noted that a less rigorous approach could produce valuable science (EBs, SPPs, and Exoplanets) and this should be clear in the photometry guide. My sense of the room was that everyone agreed with this goal, with reservations about the length, page count, and complexity. We agreed on starting work on a CMOS User Handbook on Ken's notes and Ed Wiley's experience teaching the use of CMOS cameras, as a worthwhile project and basis for beginning work on a longer-term CCD/CMOS Camera Photometry Guide.
I trust that I have reported events fairly. I can host further Equipment and Instrumentation Section Zoom meetings as needed for this work, and for general discussion of matters concerning equipment and instrumentation, on a month basis or more often as needed. Thank you all for attending and for your contributions.
--Richard Berry
Thanks for working on this.
'm still interested in this topic. I missed the zoom meeting as I got the time wrong in my schedule. I hope the meeting was recorded and will go on youtube at some point.
So I presume we will have three basic manuals at some point? CCD, CMOS, & DSLR?
Jim (DEY)
The plan is to…
Hi Jim--
The plan is to revise and update the current CCD Camera Photometry Guide (https://www.aavso.org/ccd-camera-photometry-guide) as the AAVSO Photometry Guide. It will address the needs of different type of photometry, filters, sensors, and software from newcomers to photometry to those wishing to do the most accurate transformed photometry. In the decade since it was begun, so much has changed. It would cover CCDs, CMOS, OSC, and DSLRs as devices that produce high-quality images suitable for photometry. For the details of making photometric-quality images, we're addressing CMOS camera with a separate CMOS Camera Guide to using CMOS camera that we can update because the CMOS scene has been changing so rapidly.
The current DSLR Observing Manual is an excellent guide to using DSLRs, and we are certainly not going to replace it. Instead, we'll supplement it and perhaps bring DSLRs into the fold as good ways to produce photometric-quality images, just as CCDs and CMOS camera are. We'll need to do some background work to see how we can integrate OSC cameras into the mix. We'll welcome input from all users as to what sort of information and guidance you would like and the best ways to deliver it.
--Richard
Maybe in the future the manual for DSLR can also include OSC cameras since there should not be a big difference in obtaining and separating the color channels for photometry.
Barbara
I agree: OSC cameras should be included.
These are often the way observers get into doing AAVSO observations. They are basically the same as DSLR photometry, with the same caveat, namely that you have a UV/IR rejection filter so that TG is not overwhelmed by IR leakage.
That said, even with IR leaks, there are plenty of project that OSC cameras can do. Anything that aims at producing a timing, and anything that relies on basic differential photometry is a candidate.
The devil is in the details, of course. But it's not as if CCD and CMOS cameras are free of gotchas. We're simply familiar with the CCD gotchas, and the OSC gotchas are new.
--Richard
Several years ago I asked AAVSO for the code to do photometry and read the CCD manual. The requirements were so difficult to meet that they scared me and I quit.
Some time later I decided to make an attempt and I realized that it was not as complicated as I thought. Now I have sent about 20,000 observations (V and CV) and they are similar to the rest.
I ask those who reform the manual to soften the content to encourage those who are interested, because the current wording scares everyone away.
Mario
P/D: Sorry my English is bad.
Mario--
We think you are not the only person to have been scared away by demanding requirements described in the manual. One of our goals is to make it clear that photometry is not so difficult, and that many observing programs would welcome new observers.
I am glad that you stuck with it and have become a very productive photometrist!
--Richard
As someone who is just getting started (although I am 72) with astrophotometry, I look forward to the revision of the manual. Like many, I have a CMOS color camera and am really itching to do some meaningful observation submissions.
John:
You should really just read the DSLR guide and get started. Virtually everything you need is provided in this manual in significant detail. Effectively, you have a temperature controlled DSLR. The most difficult process is separating the individual color channels from your CMOS ONE-SHOT COLOR camera! The CCD Guide is really designed for monochrome cameras.
Ken
While separating the color channels of a one-shot-color camera (DSLR or dedicated astronomy camera) is a bit confusing at first, there are several (free) software packages that do that very thing for you. I found the program ASTAP to be quite convenient, because it can calibrate images (raw DSLR or fits files) using darks, flats, etc., plate-solve them, extract each color channel, identify stars using the AAVSO database, and then even do the magnitude calculations and generate a file ready for submission to the AAVSO for a group of images of a target. I have prepared a step by step tutorial based on the help file and my own experience that I am happy to share. Rick
Hi Rick,
I would be interested in a copy of your ASTAP tutorial. I'll contact you off-line. Cheers,
Mark
Rick,
The ASTAP documentation seems to imply that callibration (darks, flats, bias frames) is automatically followed by stacking.
Can callibration be performed, with saving of the callibrated images, without subsequent stacking?
Roy
ASTAP will do it either way: it will calibrate only and not stack, or it will calibrate and stack as is done with astrophotography images resulting in a single image. Rick
Thanks Rick, that's good.
Roy