Mon, 01/29/2024 - 22:43
Hi folks,
The next CV Section meeting has been moved out from Feb 4 to Feb 25 at 2PM EST, 7PM UT. Dr. Enrique de Miguel will be our guest for a discussion on observing coverage and analysis of Intermediate Polars. Many of you know Enrique as the Center for Backyard Astrophysics shepherd for Intermediate Polar observing. I'm really looking forward to the meeting.
Clearest skies,
Walt
Very interesting indeed…
Hi!
Very interesting indeed!! Will there be a zoom-option?
Magnus
Yes, for sure. A link will be posted here on the forum as the date gets a little closer.
-Walt
The link for the CV Section meeting can be found here!
https://www.aavso.org/programs-events
-Walt
Hi - trying to contribute to the SDSS J080449.49+161624.8 campaign, but I need to use CV to get SNR >20. My V images are cleaner but SNR isn't great (like, 10).
Is reporting CV as simple as using a sequence with V comp stars in Vphot?
Thanks!
Jeff
Jeff:
Yes, simply use the V magnitudes of comps on your C images. Make sure the aavso report identifies filter as CV not V.
When I use C filters, I map them to V filter in the telescope setup page.
Ken
PS: Confirm that the mapping works for you. If not, we'll get George involved again with this issue.
Thanks Ken, i've got it. I just wanted to make sure it wasn't more complicated than that. I contributed to the AB Aur campaign using R mags for HA, so i'm comfortable editing the photometry output field.
Clear skies!
Jeff
Hi Ken
I don't see any kind of option for mapping in my "Equipment" link under my profile. So I don't know what you are referring to.
What I do is change the FITS header for "FILTER" to "V" and then run the photometry in Vphot, output a reprot, and then edit the report file to change "V" to "CV" before submitting.
Jeff
Jeff:
You mentioned using VPhot. My comment has nothing to do with your AAVSO Profile page.
Look in the VPhot Telescope Setup page under Admin link.
What you are doing to edit the AAVSO Report is fine but in VPhot there is a Telescope Setup page where you can map C to V automatically. Take a look.
Ken
I just wrote a long message that didn't post. here is the short version - Thanks, I found the telescope setup in Admin, did the filter mapping (and hit "save"), and basically it does not work. It just says this image was taken without photometric filter. the mag of the target and check are 0.000. I tried clicking on "for magnitude estimation use" and selecting V, and refresh, same outcome (tho the check star now has a magnitude in parens next to it, but still 0.000 in the Mag column). Pretty frustrating. I even closed my browser and started "from scratch." same outcome.
Thanks for your help and patience. I like to use AAVSO tools, but this is a bit frustrating...
Jeff
I just wrote a long message that didn't post. here is the short version - Thanks, I found the telescope setup in Admin, did the filter mapping (and hit "save"), and basically it does not work. It just says this image was taken without photometric filter. the mag of the target and check are 0.000. I tried clicking on "for magnitude estimation use" and selecting V, and refresh, same outcome (tho the check star now has a magnitude in parens next to it, but still 0.000 in the Mag column). Pretty frustrating. I even closed my browser and started "from scratch." same outcome. and i also tried clicking 'report as" V in addition to the "for mag..." and no joy.
Thanks for your help and patience. I like to use AAVSO tools, but this is a bit frustrating...
Jeff
Without testing this myself but having seen zeros for the target and check mag, I suspect if you go to the comp list at the bottom of the photometry page, you will note that the comps are not active. Check the box active and refresh. I believe you will get results.
Share a few of the images to me at MZK.
Ken
holy cow - it works. And the report even says "CV"!
Thank you very much. I have read the Vphot manual but maybe I missed something.
I shared an image to MZK. the image name is PGC 1504543, this is a galaxy near the target that is good for slewing in my system (SkyX).
Hi folks,
A reminder that our CV section meeting with Dr. Enrique de Miguel is this Sunday. Link above. You don't have to register to attend. The direct link to the zoom meeting is posted on the programs-events page. That also means it doesn't get put on your calendar automatically though.
Clearest skies,
Walt
Can you post the link. Mine from the email did not work.
Thanks, Dick
Dick,
Sorry. Just seeing your forum posting now. I'll send you an email directly so that we can figure this out offline and resolve it for future meetings.
-Walt
Zoom said that the link to the meeting that was saved to my calendar was invalid. I couldn't find it posted elsewhere. I guess that I have missed this one. I don't know if anyone else had a similar problem. JOHN
John,
Will get back with you in a direct email to help figure out what happened...
-Walt
Hi folks. Great meeting yesterday. Thanks to Enrique for a terrific presentation and lots of good discussion. I'll put out some notes on the discussion later today. In the meantime, Enrique sent me a copy of his slides. If you'll contact me via the AAVSO contact functionality and let me know your direct email address, I can send you a copy. You can click on my cwt username above and it will take you to my profile. That has a contact tab on it. I'd rather not post my email directly to the forum. I get more than enough spam already.
Clearest skies,
Walt
Here are a few notes from the discussion yesterday. Enrique's slides are available upon request. See above. Some of the results and figures in the slides have not been published yet. Please respect that.
About 90 to 95% of the amateur time series on IP's are high enough quality to be used to determine white dwarf spin rates. When a time series can't be used, it's usually because weather interfered.
Most of the time series submitted and used for Enrique and Joe's IP spin rate analysis come from scopes in the 10-12" aperture range. They produce very good data.
Aperture is not critical. A Fourier analysis can often pull the WD spin rate out of data that looks like nothing but noise.
A brighter IP is not necessarily easier than a faint IP to get good data from. The amplitude of the WD signal is a much bigger factor.
Enrique showed us a tool that he uses to determine quickly when different IP's and other targets are available from month to month. He plans to add a few columns to that like WD amplitude and spin rate to make it more helpful and then will make it available to folks.
We have a very big need for better tools to help amateurs with target selection. Enrique's spreadsheet will help. Walt will work with the AAVSO to see if the AAVSO target tool can be modified to make it more helpful.
Walt asked about a rule of thumb he had heard that you should target a S/N of about 50 on a CV in a time series to optimize data quality and high cadence. Joe Patterson noted that S/N of 50 is very good and it can be as low as 20 to 25 and be very useful data. We've seen this really clearly with the data that people have gotten on V1674 Her. That system is rising before dawn now and is an important target.
There was discussion on fourier analysis tools that amateurs can use to see the periodic signals in their data and do a bit of their own quality check. The AAVSO's VStar, Tonny Vanmunster's Peranso, and NASA's Exoplanet Archive are three available of many. Several others were mentioned, but I didn't get them down in my notes.
The accuracy of your computer's time synchronization was discussed. The gist of that is that internet time synchronization via Windows or programs like Dimension 4 are sufficient. Generally a synchronization before a run or once per day is good enough. If you don't have access to the internet when observing, there are very cheap USB GPS dongles that can be used to synch your computer to GPS time. Brian Skiff and Brian Kloppenborg talked about how getting incredibly accurate computer
time synchronization can only be as good as the various other timing issues that come in to play when taking an image. Other factors that affect timing include things like shutter actuation timing, read-out time, and USB delays.
Several potential future speakers for the meetings were suggested. Walt will follow up.
I'd appreciate if attendees would post any further notes to what I have above.
Clearest skies,
Walt
Was the meeting…
Hi!
Was the meeting recorded? Living in Europe, the time difference made live participation very challenging for me...
Magnus
Sorry Magnus. We don't record section meetings. Our meeting time is set to try to make the meetings as accessible as possible to folks from a wide variety of time zones, but there isn't a perfect time unfortunately.
-Walt
Ok, thanks for quick…
Hi!
Ok, thanks for quick response. The powerpoint presentation then, is it possible to see that?
Magnus