AB Aur campaign supporting HST observations - Alert Notice 809

Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 01/17/2023 - 23:14

AAVSO Alert Notice 809 announces an observing campaign on the YSO AB Aur beginning immediately. Please see the notice for details and observing instructions.

There are threads for this campaign under the following AAVSO forums:

- Campaigns & Observation Reports: https://www.aavso.org/ab-aur-campaign-2023
- Young Stellar Objects: https://www.aavso.org/ab-aur-campaign-2023-01

Please subscribe to these threads if you are participating in the campaign so you can be updated. Join in the discussion or ask questions there!

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

 

Affiliation
American Association of Variable Star Observers (AAVSO)
AB Aur November Campaign and Dr. Biddle Video?

I missed the Nov 19 webinar.  Is there a video posted somewhere?

 

Gary

WGR

Affiliation
American Association of Variable Star Observers (AAVSO)
Scatter of HA

Walt et al:

As I'm sure you have noted, the HA magnitudes are all over the place compared to other filter mags!

Do you think the HA observers are reporting individual mags with no thought to stacking/smoothing? Are they all using the specified comp? Does the check star vary similarly?

Is it real variation?

Ken

Affiliation
American Association of Variable Star Observers (AAVSO)
Ha data scatter

Hi Ken.  The  Ha work of individual observers seems consistent from night to night but, as you say, there is a lot of scatter between different observers.  I think a lot of that is because the Ha photometry is quite sensitive to the bandwidth of the Ha filter.  I've taken a set of simultaneous data on three different systems and am working on the reductions.  I expect to find that the data for each system is internally consistent but that differences show up between systems like we see in the AAVSO community data.  Will post some info when I get that analysis complete.

-Walt

Affiliation
American Association of Variable Star Observers (AAVSO)
Ha data scatter

Walt and Ken,

I have the same concerns with the quality of my own data, and my collection/analysis technique. I uploaded three sets of data and noticed average magnitude differences between my measurements and others, which I also reasoned may be due to Ha bandwidth differences. But looking closer I see, what I think are significant,  variations in the check star, comp and the variable. So I'm investigating my time series and will follow-up with more quantitative summary of the variations I'm seeing in these measurements, and a description of my equipment and process. I'll also remove the observations that are most questionable. Is there a way to share plots or figures in this forum? Thank you.

Dan (BIY)

Affiliation
American Association of Variable Star Observers (AAVSO)
Update

I have reduced the data for the three systems.  The Ha magnitude for all three systems was steady all night.  The average magnitude for the three systems was

Madrona Peak  (24" RC, Apogee Aspen 16803, Astrodon 6nm Ha)                                  Ha (average) = 6.63

Starry Night Observatory (20" RC, QHY-600M, Astrodon with unknown bandwidth Ha)    Ha (average) = 6.58

Houston Astronomical Society 16RC (16" RC, QHY-268M, Baader 6.5nm Ha)                  Ha (average) = 6.65

These three systems agreed quite well.  Note that I had to use last year's comp star because of pointing issues, but I did use the same comp for all three systems.  The filter bandwidth for SNO is unknown unfortunately.  I bought the system used and I don't know the filter bandwidth.  Will have to pull the filter wheel to see if the bandwidth is marked on the side of the filter.  I have assumed it is a 3nm Ha but that may not be right.

-Walt

Affiliation
American Association of Variable Star Observers (AAVSO)
Few Details

Walt:

Could you provide a little clarification and a guess:

1. How long is all night (10 hours?)?

2. What were exposures?

3. What were std deviations for these means? I bet your results were all the same within std dev?

4. IF they were that stable / non-variable, what is going on with the rest of the HA submitted results?

5. Could you recommend a shifted position for FOV center in campaign forum to get 104 comp in field? I shifted mine to get everything roughly centered.

Ken

PS: I use RA 04 56 21.84  DEC 30 31 15.4  My FOV is about 25'.

Affiliation
American Association of Variable Star Observers (AAVSO)
More info

How long "all night" was actually depended.  For MPO it was really just 3 hours.  I didn't think it was warranted to stay on AB Aur all night at MPO to establish how it compared to the others.  That allowed us to get some observations for AAVSOnet observers of other objects.

For SNO all night meant about 7 hours.  For the HAS RC16 it meant about 6 hours.

Exposures were 30 seconds at MPO and 90 seconds at SNO and at HAS.  Seeing is substantially better at MPO than at the Houston Astronomical Society dark site where SNO and the HAS RC16 are.

The standard deviation at all three observatories was about 0.02.

If you can get both AB Aur and the comp in your system's field of view, then a field center of 04 56 22  +30 30 36 is about half way between them. 

-Walt

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Update on Ha Observations

Below is a summary of three evenings of Ha observations made over the past couple weeks. My setup consists of a 10" AT-RC and QHY268M with Chroma Ha 5nm filter. Photometry is performed with Lesvephotometry and I use Pierre's AddImages (MaximDL interface) to calibrate and average multiple images. My observations are made with AB Aur above 50 degrees altitude.

For the three nights I have calculated Mean and Standard deviation for the Magnitude estimate of the Variable. And the same statistics for the Instrumental Magnitudes of the Variable, the Comp Star and the Check Star.

This is my first serious participation in a campaign, so curious if these results are expected or comparable with others. Especially with using Ha for photometry.  The observation for 2023-12-07 have much lower STDs.  According to the VSP photometry table the 104 Comp star Rc error is (0.050) and the 120 Check Star Rc error is (0.054) so maybe these results are reasonable?

I plan on making a couple adjustments; my FOV center was set for using the other 120 check star, so I will update that to better position all three stars. Also I can increase my sub-frame exposure from 60 sec to 80 sec without saturating.

Hopefully this is helpful to others. I appreciate your comments or suggestions. Thank You

D. Bailey (BIY)

The following were computed from sets of 15 to 30 observations each with a Variable Magnitude error of 0.007 or 0.008, per Lesvephotometry)

HDJ:    2460282.  ('2023-12-04)

  Variable Magnitude  Mean =   6.650, Std =  0.038 

  Variable Instr.     Mean =  15.512, Std =  0.096 

  Comp Instr.         Mean =  18.932, Std =  0.126 

  Check Instr.        Mean =  20.330, Std =  0.128 

 

HDJ:    2460285.  (2023-12-05)

  Variable Magnitude  Mean =   6.661, Std =  0.035 

  Variable Instr.     Mean =  15.623, Std =  0.102 

  Comp Instr.         Mean =  19.033, Std =  0.129 

  Check Instr.        Mean =  20.421, Std =  0.101

 

HDJ:    2460288.  (2023-12-07)

  Variable Magnitude  Mean =   6.680, Std =  0.025 

  Variable Instr.     Mean =  15.512, Std =  0.033 

  Comp Instr.         Mean =  18.903, Std =  0.050 

  Check Instr.        Mean =  20.303, Std =  0.047 

 

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Consistent Results

Dan:

1. Target mags are consistent from one night to the next (< std).

2. IM C-CK are similarly stable. IM's will vary during night with changing airmass.

3. Mean mag 6.67.

4. I bet the std on 12/07 may be from the shortest run? or best clear night?

5. 5 nm bandwidth.

Ken

Affiliation
American Association of Variable Star Observers (AAVSO)
Results Review

Ken,

Thank you for reviewing these results. I have uploaded additional observations that are consistent with these. There are some night when the variances are low, this does not seem to be dependent on number of observations, maybe sky conditions those nights.

  HDJ:    2460294 

  Variable Magnitude  Mean =   6.633, Std =  0.007 

  Variable Instr.     Mean =  15.436, Std =  0.018 

  Comp Instr.         Mean =  18.874, Std =  0.016 

  Check Instr.        Mean =  20.257, Std =  0.030 

  HDJ:    2460295 

  Variable Magnitude  Mean =   6.651, Std =  0.010 

  Variable Instr.     Mean =  15.198, Std =  0.021 

  Comp Instr.         Mean =  18.617, Std =  0.027 

  Check Instr.        Mean =  20.019, Std =  0.033 

  HDJ:    2460296 

  Variable Magnitude  Mean =   6.668, Std =  0.008 

  Variable Instr.     Mean =  15.515, Std =  0.126 

  Comp Instr.         Mean =  18.918, Std =  0.128 

  Check Instr.        Mean =  20.312, Std =  0.128 

Affiliation
American Association of Variable Star Observers (AAVSO)
HA Filter Bandwidth vs Mag?

Walt et al:

My eye is seeing 2 (or 3) different sets of HA as Rc mags in LCG2. At approx. 6.45 vs 6.75 (and vs 6.65)??

The few at 6.65 are near BIY mag with HA 5 nm filter as reported above.

Are the other two more obvious sets at 6.45 vs 6.75 from different HA bandwidth such as at 3 nm vs 6 nm, respectively?

Could others report their HA filter bandwidth? In forum post, but ideally in AAVSO Report Notes field?

Ken

Affiliation
American Association of Variable Star Observers (AAVSO)
Hi Ken

I noted the 6.5nm…

Hi Ken

I noted the 6.5nm bandwidth of my Ha filter within my second AAVSO report. I’ll make a point of including it as a note for each observation going forward. I am using the specified comp and check stars and average-combining > 5 images for each magnitude determination. I’ve asked whether these should be run as ‘time series’ or individual observations but don’t believe there’s been a response yet so I continue with 5 individual reports spread over 3-4 hours. Do you happen to know if time-series would be preferred?
Thank you,

Gary

Affiliation
American Association of Variable Star Observers (AAVSO)
Procedure?

Gary:

I think you indicated that you are taking ~5 sequential images over a short period of time (few minutes?) and then "average-combining" these 5 images to calculate one reported magnitude. Have you "average-combined" these 5 images by stacking the five images together into one stacked image and measured the single stacked image magnitude OR have you calculated the magnitude of each of the five images and then averaged (average-combined?) the 5 individual magnitudes? In fact, either procedure is reasonable. Both reduce/smooth the uncertainty of each reported magnitude measurement.

I think you indicated that you then collected additional sets of ~5 images at an interval of about 1 hour (5 sets over 3-4 hours) over the night and reported these as separate magnitudes.

Is this correct? If so, I think you are following the recommended procedure from the PI as clarified during the webinar. You collected a few images (~5) at each 'snapshot time' and then repeated that procedure at several intervals during the night.

Now, can you clarify what 'time series' vs 'individual' observations means to you? Are you getting hung up by what 'time series' means in your mind? Do you think a time series 'only' occurs when you collect images continuously over a long period of time (many hours)? That may be a common understanding but is it critical to define it that way in your photometry software?

Comments?

Ken

Affiliation
American Association of Variable Star Observers (AAVSO)
Yes Ken, I’m collecting a…

Yes Ken, I’m collecting a minimum of 5 images sequentially and then pausing for 45 - 60 mins and then repeating the process so I end up with at lease 5 sets of at least 5 images that get average-combined in Maximdl. Then I’ve been processing and reporting each as a single observation. I’m avoiding saturating AB Aur while getting the SNR of the check and comp close to or above 100. I check the ‘peak’ pixel value and SNR of each of the three stars on every image. Although my cmos sensor is linear to 60,000, I have decided to toss several images in a few of these series where I found the target star saturated or close to saturation. 
 

The term ‘time series’ was mentioned in the Alert 842 text I recall but the discussion during the webinar suggested a process more like what I’ve been doing versus the continuity of 15 sec images carried out over a 3-5 hour timespan then analyzed as a time series as VPHOT handles it. The discrepancy between the Alert and the webinar, lead me to asking the question. So far neither Walter or Lauren have responded so I continue on as described above.

I also haven’t seen any posts from them yet about their HST reservation schedule so I take images whenever I have clear skies to give as much data as I can. All the data is 6.5nm wide Ha data except for one V observation that I reported early on. 
Happy Holidays Ken..

Gary

Affiliation
American Association of Variable Star Observers (AAVSO)
Apologies Walt. I have…

Apologies Walt. I have searched far and wide and cannot find a response regarding my question about analyzing the night’s observations as VPHOT time series versus individual observations. The webinar presentation seemed oriented to individual observations, spaced over the night with each based on a stack of images to achieve minimum SNR of 50-100. Elsewhere in Alert text, the terms ‘time series’ has been used.

cheers

Gary
 

 

ps: I agree that the Forum structure makes it very easy to miss posts and responses. I’m not even sure how to subscribe to a specific topic. When they revamp the website, I hope they will scrap this Forum and go with something with a clearer structure that’s easier to use. Something like the ‘Cloudy Nights’ Forum structure would be wonderful. 

Affiliation
American Association of Variable Star Observers (AAVSO)
time series

My post is back on the first page of this forum topic now.  Here's just a cut and paste of it:

--------------

Hi Gary.   We are still some time away from the Hubble windows of observation (January and forward).  It's not critical to observe AB Aur all night continuously right now.  "Snapshots" (maybe really multiple images stacked) several times during the night are plenty.   Continuous time series would be -very- helpful however during the Hubble observations.  Dr. Biddle is understanding of the amount of time and effort that it takes for people to do this work and so doesn't want to ask for more than necessary.

All that said, the extensive observations people are doing now are helping to understand how the photometry of the different systems compare.  That will be very important to the later analysis.

--------------

To say it maybe more clearly, what you are doing now with stacked sets of observations to get S/N of the comp star above 50 and taken several times over the course of the night is what's being asked for now.  When we are in the HST observation window, continuous time series over as long as you can cover would be preferred.

-Walt

Affiliation
American Association of Variable Star Observers (AAVSO)
Thanks Walt, I finally…

Thanks Walt, I finally stumbled onto your note.

I've uploaded about 15 HA observations so far and all have been stacks of images taken continuously. I believe these have all resulted in SNR of the check star >100. Each stacked group is starting out with 21 images at 0 gain and around 45 secs exposures. If I get some bad images or ray strikes, I drop those before doing any stacking. So far this has kept the Target below saturation and yielded good SNR's and low error. Many of these have been uploaded and reported but I'm now having VPHOT problems and my last two nights worth of stacked images (7 of 9 total observation groups) are not able to be uploaded. Ken has looked into it but so far has no solution. All I can do is keep capturing the groups and trying to upload the resulting final stacks.

I gather from your note above that, going forward, I should perhaps change strategy and capture continuous groups of, say 10 images, to be later stacked and processed, each group of 10, as a 'time series' with a cadence of ( 10x45 secs ) amounting to a final stacked-image reported for every 8-9 minutes. Am I getting the concept correctly?

regards & and Happy Holidays,

Gary

Walt: What I mean is that each group of 10 ends up as a single datapoint in a time series where each image is made up of 10 images  averaged....hope its clear.

Affiliation
American Association of Variable Star Observers (AAVSO)
Yes, that's it.  And now…

Yes, that's it.  And now that we're in the HST observation window, take your 45 second Ha images continuously.  When you have the chance to do the photometry, stack them in subsets and do the photometry.  Really, you can just stack to get the comp star at about S/N of 100 and let the check star (fainter) be less than that.  No need to stack to get the check star above 100.

After 0 UT Jan 2 you can go back to doing a stacked image after every hour or two if you like.  Full time continuous coverage won't be needed.  That gives you time to work on other variable stars!

-Walt

Affiliation
American Association of Variable Star Observers (AAVSO)
HA filters

Hi I'm using a Baader 7 nm bandwidth HA filter  - seems like same or similar to Gary's. 

I'm wondering if it would be useful to collect the (HA) contributors' filter bandwidth.  In Vphot, when generating a photometry report, there is a window "Create Photometry Report" and a field for Notes - I will put my filter bandwidth there, as it appears that his field does show up in the lightcurve generator.  Then we could see what filter the HA submitter is using.

I'm going to try to do HA at 1 hour intervals, looking like i need about 45 sec also, but my camera (STF-8300M) is likely different from Gary's.

Jeff

Affiliation
American Association of Variable Star Observers (AAVSO)
HA filters

Hi I'm using a Baader 7 nm bandwidth HA filter  - seems like same or similar to Gary's. 

I'm wondering if it would be useful to collect the (HA) contributors' filter bandwidth.  In Vphot, when generating a photometry report, there is a window "Create Photometry Report" and a field for Notes - I will put my filter bandwidth there, as it appears that his field does show up in the lightcurve generator.  Then we could see what filter the HA submitter is using.  [EDIT - I see now that Gary has been doing exactly that!  Thanks, and I will now do so going forward.)

I'm going to try to do HA at 1 hour intervals, looking like i need about 45 sec also, but my camera (STF-8300M) is likely different from Gary's.

Jeff

Affiliation
American Association of Variable Star Observers (AAVSO)
More complexity for H-Alpha narrow band

Greetings,

Some YSOs, not sure about AB Aur specifically, have Doppler shifting due to system motions.  So when observing with fixed wavelength, narrow band filters combined with any Doppler shifting of the spectral line must be considered.

Jim (DEY)

Affiliation
American Association of Variable Star Observers (AAVSO)
HST observations scheduled for AB Aur - Alert Notice 844

AAVSO Alert Notice 844 reports on the HST observations that have been scheduled for the bright YSO AB Aur. Please see the notice for details and observing instructions.

There are threads for this campaign under the following AAVSO forums:

- Campaigns & Observation Reports: https://www.aavso.org/ab-aur-campaign-2023
- Young Stellar Objects: https://www.aavso.org/ab-aur-campaign-2023-01

Please subscribe to these threads if you are participating in the campaign so you can be updated. Join in the discussion or ask questions there!

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

Affiliation
American Association of Variable Star Observers (AAVSO)
Partial Night Observations Uploaded

Walt,

I just up loaded a partial night of observations with Ha (Chroma 5nm) . Thin clouds here central NM cut the session short.

Happy New Year!!!

D. Bailey(BIY)

Affiliation
American Association of Variable Star Observers (AAVSO)
Hi Walt

I submitted 46 - 60 second Ha (3nm) images of AB_Aur, clouds rolled in ending the session early. All SNR's of Check-120 were 69 or better.

Date range - 2024-01-02 01:03:10  to  2024-01-02 01:59:33

Steve Hoffman - HSTG

 

Affiliation
American Association of Variable Star Observers (AAVSO)
AB Aur HST scheduled Jan 17-18 - Alert Notce 846

AAVSO Alert Notice 846 announces the exact timing of HST observations scheduled for 2024 January 17-18 UT on the YSO AB Aur. Please see the notice for details and observing instructions.

There are threads for this campaign under the following AAVSO forums:

- Campaigns & Observation Reports: https://www.aavso.org/ab-aur-campaign-2023
- Young Stellar Objects: https://www.aavso.org/ab-aur-campaign-2023-01

Please subscribe to these threads if you are participating in the campaign so you can be updated. Join in the discussion or ask questions there!

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

 

Affiliation
American Association of Variable Star Observers (AAVSO)
AB Aur HST Jan 17-18 obs CANCELLED

Dr. Biddle has just informed us that the HST observations of AB Aur scheduled for today (Jan 17-18) have been CANCELLED. HST has gone into safe mode, for reasons not yet given. When more information is available about future scheduling, it will be shared here.

Please continue to observe AB Aur according to the cadence given in Alert Notice 846.  Many thanks!

Good observing,

Elizabeth

Affiliation
American Association of Variable Star Observers (AAVSO)
Checking in and Thank You

Hi AB Aur Observing Team, project lead, Lauren here!

We're deep into the AB Aurigae (AB Aur) observing season, and I just want to check in with y'all and give a quick update on what we know (and don't know) about our Hubble Space Telescope (HST) observations so far this season.

But first, I wanted to extend my appreciation to everyone who has contributed to this program so far. Please be assured that your efforts this season have not gone unnoticed, and I am excited to see what results come from this large-scale effort! Looking forward, I would like to coordinate with AAVSO and host another webinar together at the conclusion of AB Aur's observing season to showcase what we've accomplished together and chat with you about some preliminary results of the program, so please keep an eye out for a notification about that later this year. Farther beyond that, the timeline for the in-depth analysis for the science publication will likely extend into late 2024/2025 and we will be providing regular updates on our in-depth analysis along the way!

Returning to the current moment, I wanted to clarify some of the events surrounding HST that are relevant to our program at this time.
As you have probably seen in the most recent addition to the alert notice, the recent HST observing dates (originally scheduled for  Dec31-Jan1 & Jan 17-18th) have been delayed as a result of the observatory encountering an issue and automatically switching to "Safe Mode", which halts normal operations until a resolution to the issue is found. In November, HST had gone into Safe Mode as a result of a glitch in one of the gyroscope's readings, however it is unclear whether the most recent issue is related. I have not heard or received any more updates on this specific matter from official sources, but I have been assured that it is unlikely to be a terminal issue, and sometimes problems that result in Safe Mode can happen more often with age (who knew HST could be so relatable!?).

At the moment, the updated observing plan window says our next set of HST observations should take place between Feb 19–23 and March 4-6 with the plan status reading "Flight Ready", meaning that our observing visit has been reviewed by the program coordinator at Space Telescope Science Institute and was made available as a candidate for scheduling within this time frame (with the caveat that the dates I've listed are subject to change). The observing dates do not become "official" until the visit status reads "Scheduled", which typically happens a few days ahead of the now-officially-scheduled dates, so please keep an eye out for updates on the alert notice around that time.

Thanks again everyone for all your hard work as the campaign continues. Let's keep our fingers crossed that our next HST visit is a successful one!

All the best,
Lauren

 

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Hi Gary,

I appreciate you…

Hi Gary,

I appreciate you reaching out – your message is very timely! I'm putting together a message about the HST schedule as we speak. The newly scheduled HST dates are set for February 21–22, with additional details contained in a new comment, which I will post momentarily. Thank you for your diligence! Looking forward to the upcoming observations.

All the best,
-Lauren

Affiliation
American Association of Variable Star Observers (AAVSO)
AB Aur HST Dates (Re)scheduled

Howdy AB Aur Observers!

I'm happy to share that our HST dates to observe AB Aur have been rescheduled to take place on February 21 & 22*.

In order to fully characterize AB Aur's activity leading up to, during, and following the HST observations, we kindly ask for AB Aur observers to prioritize AB Aur during the nights of February 20 – 23.

A short reminder that the optimal observing cadence will depend on the filters you plan to use.
Observers with B, V, and/or Rc filters: 3 – 5 observations spread out roughly equally in time over the course of the night
Observers with HA filters: As many observations as you are willing and able to acquire. If you are observing with an HA filter, please prioritize only the HA filter.

In this context, a single observation is comprised of the full sequence of exposures that will be stacked to create a final image. The comp and check stars for this campaign are several magnitudes fainter than AB Aur, and so we ask observers to take multiple exposures in each filter and stack the exposures to attain a comp star S/N of 100 or more while not overexposing AB Aur.

We thank everyone for their efforts in contributing to this program, and wish you the clearest skies in the coming nights as we observe jointly with HST.

 

All the best,
-Lauren Biddle

 

* The exact time that each observation will take place is given on the HST Visit Information page: https://www.stsci.edu/cgi-bin/get-visit-status?id=17168&markupFormat=html&observatory=HST (You will also see that the next epoch has a tentative plan window between March 4-7, but the status is "Flight Ready", and not "Scheduled", so these dates are not finalized still subject to change. We will post another update when the schedule for those observations are finalized).

 

 

 

 

Affiliation
American Association of Variable Star Observers (AAVSO)
I just submitted B & V…

I just submitted B & V observations from last night (obscode=TBOB).  Surprisingly, after transformation, my B came out slightly brighter than the V.  I went back and double checked things twice and it all looked right.  I definitely have the correct comp and check star.  I was very careful in defining my apertures.

I had a stack of 20 images in V and 10 in B (had some haze blow through in the last half)

Here is the submission:

#TYPE=EXTENDED
#OBSCODE=TBOB
#SOFTWARE=Tycho 11.0.3
#DELIM=,
#DATE=JD
#OBSTYPE=CCD
#Tbv= 1.1700, +/- 0.0200
#Tb_bv= 0.1290, +/- 0.0340
#Tv_bv= -0.0160, +/- 0.0280
#NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES
AB Aur,2460360.66501,7.132,0.027,V,YES,STD,000-BPN-254,-11.472,000-BPN-255,-11.119,1.1130,na,X35992GL,na|VMAGINS=-15.913|VERR=0.027|CREFMAG=11.559|CREFERR=0.040|KREFMAG=11.966|KREFERR=0.033
AB Aur,2460360.66979,7.019,0.063,B,YES,STD,000-BPN-254,-10.403,000-BPN-255,-10.092,1.1250,na,X35992GL,na|VMAGINS=-15.586|VERR=0.063|CREFMAG=12.314|CREFERR=0.037|KREFMAG=12.752|KREFERR=0.043
 

I've recently started using Tycho Tracker to do my analysis so, of course, I wonder about that.  However, 7 other submission I've made since the switch all look as expected.

It doesn't look like others that have submitted recently are using the correct comp/check stars, and they are not transformed.  I will be very curious to see if others can replicate my results.  I should have another clear night Wednesday, so I can try again.

Affiliation
American Association of Variable Star Observers (AAVSO)
I realized the recommended…

I realized the recommended comp star changed for the most recent invocation of the campaign.   I resubmitted my B & V observations using the new comp star.  The B value is still a bit higher than others have recorded earlier, but it is fainter than V.  Here are the transformed results.

#TYPE=EXTENDED
#OBSCODE=TBOB
#SOFTWARE=Tycho 11.1.1
#DELIM=,
#DATE=JD
#OBSTYPE=CCD
#Tbv= 1.1700, +/- 0.0200
#Tb_bv= 0.1290, +/- 0.0340
#Tv_bv= -0.0160, +/- 0.0280
#NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES
AB Aur,2460360.66501,7.104,0.064,V,YES,STD,000-BKG-405,-12.590,000-BPN-255,-11.131,1.1130,na,X35992GL,na
AB Aur,2460360.66979,7.144,0.016,B,YES,STD,000-BKG-405,-11.858,000-BPN-255,-10.129,1.1250,na,X35992GL,na

B-V is 0.04 which is more inline with the expected, although still a bit bluer than others have gotten in the past 30 days.
 

 

Affiliation
American Association of Variable Star Observers (AAVSO)
AB Aur HST exact schedule 2024 Feb 21-22 - Alert Notice 852

AAVSO Alert Notice 852 gives the exact HST schedule on 2024 February 21-22 for the YSO AB Aur. Please see the notice for details and observing instructions.

There are threads for this campaign under the following AAVSO forums:

- Campaigns & Observation Reports: https://www.aavso.org/ab-aur-campaign-2023
- Young Stellar Objects: https://www.aavso.org/ab-aur-campaign-2023-01

Please subscribe to these threads if you are participating in the campaign so you can be updated. Join in the discussion or ask questions there!

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ