I am teaching an astrophysics course at Bridgewater State University and I am building in a project for learning photometry so we can eventually do photometry on our own images. However, we do not yet have enough images to practice using VPhot. Mike Simonsen suggested I put a call out on the board to ask if anyone would be willing to share a batch of images with me so I can share them with my students to practice on.
We will not submit the results of the work the the AAVSO, nor are we planning on doing anything with the data other than practice learning how to use VPhot. We do not care what the object is, though our ultimate goal is to take our own images of the WTF star from BSU and process them.
Thanks in advance for your help! If you need the observer codes for my students as well, I will be happy to share those, too.
This summer, I did a lot of work -unfiltered- on DQ Her. There are 21,353 images still on VPHOT. The oldest is dated June 30 and the newest August 21. Exposures were short - less than 20 sec, the telescope unguided so the images tend to wander slowly from image to image. There is no airmass on them, but I have written an excel spreadsheet that will take the data from the AAVSO Extended report and produce it. I can send you a copy if you need it.
I also produced an Excel workbook that exhaustively analyses the data. It will produce the nightly extinction coefficient (which varies drastically from here) and a whole plethora of other stuff.
Let me know if you need the images.
Hi Lew - thank you so much for responding to my post! I have never heard of DQ Her before and it sounds like a fascinating object. Given that you still have so many images on VPhot, would it be possible - and easy - for you to share them with me and my students? And the additional workbook may come in handy, too. Thanks for sharing it!
I am not sure if you need just my observer code or all of the students' as well, so just in case, here they are:
Thank you again for your generous offer!!
I have plenty of CCD images that have been processed - dark frames subtracted and flat field corrected. In particular I have images of southern clusters: NGC 2516, 3532, 4755, 6067 and M25. Happy to send on optical disc. Please email if interested (email@example.com). Would also be happy for your students to report any measurements of variables to AAVSO as I've uploaded tens of thousands of observations this year and don't know when I'll get around to measuring the variables in these clusters.
Tex (Dr Terry Moon - retired research scientist)
I got busy with other stuff and haven't checked this forum lately, and VPHOT is giving me trouble trying to list them, so I'll share those that I can so you'll get just a few at a time.
I STARTED WITH THE OLDEST FIRST, but VPHOT is taking 4ever on sharing just ~900.
Can't share >2000 at a time :-(.
Sharing 1-2 nights at a time. You MAY want to assign the oldest data first BEFORE IT IS REMOVED FROM THE SERVER. The AAVSO sez the images will be removed after 4 months, and we're past that for the oldest.
Well, I ran into a VPHOT "Not enough space on the disk" error when I tied to share Aug. 14, so I'm not going to continue today.
Now that I've found that you are using an AAVSO forum for communication on CCD images for your students I will use that rather than email. When disc arrives let me know and I will provide any information you need about how they were obtained. The images are of southern clusters in Johnson V and Cousins I bands. V-I is an excellent temperature indicator across a wide range of spectral types and I is a useful 'surrogate' for luminosity for M giants.
Arne has just loaded standard field of NGC 3532 into VSP so that will be useful for checking my transformation constants derived from all-sky photometry.
In the images of NGC 6067 there is QZ Nor. Unfortunately there are no comparison stars assigned but I have good measurements of some stars in the field that could be used for setting up a sequence. In the images of M25 U Sgr may be saturated but V3508 Sgr would be a suitable target. There are comparison stars assigned but only B and V derived from Tycho. Again, can help with measurements suitably transformed to standard system.
Happy for students to use their observer codes to report measurements of any variables in the image but suggest reference in the notes section as to the provenance of the images.
As I indicated in my email happy to continue to take images of southern clusters or other suitable targets.
I responded to your recent email - I hope you got it! Based on what trouble I think Lew is having with all the space images take up on VPhot, I am very excited to get the CD - should make sharing the images a little easier as well.
I think the data that you, Ken, and Lew have shared are a phenomenal start. At this point, we are over halfway done with the semester, so I am not sure we will have enough time to ask you to take additional images, but thank you for the offer. Who knows, maybe the kids will be inspired to expand their work to a summer research project....
I am part of the VPhot team trying to keep the system running and was watching with dismay as it appeared to fail Lew's sharing of files to you.
The guideline I can offer at this time is that you should keep your image list on VPhot below 5k files. If someone shares files with you that you are not ready to study, download them to your computer and delete them from VPhot; you can upload them later when you are ready.
What we've discovered with Lew's recent experience is that VPhot simply cannot manipulate a users image list with out blowing memory constraints if the list is much over 10k. So, until we can fix that, this is a constraint we must live with.
Good luch with your class!
Did you receive email giving you access to the Southern Clusters folder on my Google Drive? Were you able to download sample images I put there? If this works I can load the rest of the images onto that folder on my Google Drive.
Do you intend to run this exercise again next year?
As indicated previously, I'm happy to continue to image these clusters and provide the images for your students' use and report on AAVSO WebObs using their observer codes (or yours).