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LPV maser campaign

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weo
weo's picture
LPV maser campaign

AAVSO Alert Notice 645 announces a campaign on LPVs in support of a maser study. Please see the notice for details and observing instructions.

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

pablotwa
pablotwa's picture
NSVS J2041274+511326

I observed (tried) NSVS J2041274+511326 last night the magnitude range was given in the 11 to about 13 range so I selected a 30 second exposure in V...the upshot I had to stack 112 subs in VPhot just to get a SNR of 3....hmmm I think the magnitude is more like 20....

Pablo

Eric Dose
Eric Dose's picture
That does seem faint. VSX's

That does seem faint. VSX's 2000 ephemeris predicts that we are at minimum, and the given 11-13 range is in R. The spectroscopic class isn't given, so assuming a typical Mira V-I color at minimum of perhaps 6-8, thus a minimum V-R of about 3-4, the VSX data suggest a current V mag of about 16-17.

Unfortunately, the VSX data is old, and AAVSO's Light Curve Generator v.1 is down today, so that's about the best we can predict for now. All I can suggest for this extremely red star is to try to observe in R or I as well.

pablotwa
pablotwa's picture
Thanks Eric

Thank you Eric. I will try I sometime next week.  Here are a couple of screen captures of the 112 sub stacked photometry. I was able to eek out an SNR of 5 in V. (All subs are fully calibrated , Vphot does not recognize AstroimageJ calibration headers so that's why it says calibration non..but they are fully calibrated..)

Pablo

 

 

 

lmk
lmk's picture
Hi Pablo, Thats amazing

Hi Pablo, Thats amazing capture from the Los Angeles basin! You might want to take a look at your collimation or parabolic corrector settings, I notice some off-axis coma-like distortons

Mike

 

pablotwa
pablotwa's picture
Nope. the collimation is perfect

It's not a collimation problem is a filter adapter problem, the collimation on my setup is near perfect. The filters are supposed to be unmounted 36mm and the Photometric filters are 1.25 and mounted through an adapter which is off a little. Still pretty good for this kind of work and Exoplanet work.

HQA
HQA's picture
NSVS J2041274+511326

If you look up this star on VizieR, you will see that it is very red (V-I~6).  NSVS was observing unfiltered, and with no filter, red stars are much brighter than their true V magnitude.  I am not surprised if this star is at minimum and you are using a true V filter that you are measuring 19th magnitude.  You might try an I filter just to confirm the red color!

Arne

pablotwa
pablotwa's picture
Thanks Arne!

I will try an I filter next time and report the results.

Take care

 

Pablo

nkrumm
nkrumm's picture
Trouble with Transformations

I'm used to submitting transformed V magnitudes, usually based on the B-V colors of the variable and comparison stars. These maser stars are so red, however, that I am using V-R and V-I colors instead. Last night (JD 245837.692) I got the following results for V349 Vul:

   V = 12.875 (untransformed)

          12.384 (transformed based on V-R)

           13.121 (transformed based on V-I)

This seems like an awfully big range! Is one of these numbers likely to be better than the others? Should I go with the untransformed number? Should I submit the average?

   I presume that the large differences stem from large deviations from a blackbody curve, due to absorption bands and interstellar reddening. Also, my transform coefficients are based on stars in M67, few of which are as red as the maser stars. So what is the best thing to do?

Eric Dose
Eric Dose's picture
Yes, that's a good move. B-V

Yes, that's a good move. B-V colors make for very poor transforms (other than for B) for red stars, for which B magnitude has little to do with the vast bulk of the photon flux. Using > 100 model star spectra I demonstrated this in my SAS 2014 talk:

https://github.com/edose/Spectral/blob/master/SAS%202014%20Presentation%...

V-I color is pretty ideal for transforming V, R, and I observations of very red stars. Of course settings exposure times can be a headache, and one frequently has to bracket the first time around, but that's a different concern.

V-R can work too but the statistics are not as precise.

mstroh
Great turn-out so far!

I wanted to say thanks for the great work by everyone so far with this campaign. I wanted to mention a couple of notes.

First, V Cas is also one of the sources on our list. It historically has great coverage by AAVSO, so I expect we'll be fine, but feel free to help out on that one if you can.

Second, the start of our VLA campaign was pushed back to November from October. They made some hardware upgrades at the VLA this summer and they need a little more time to finish up the current observing programs.

But thanks again everyone for the already great looking work! I can't wait to have the radio observations so that we can start comparing our results.

LMA
LMA's picture
Some observations

I have just submitted one measurement for each of the following:RT Aql, SX Cyg and AU Cyg. Acturally the pictures were shot by a friend, Remi Lacasse,whom I hope eventually will convert to variable stars.
He doesn't have photometric filters yet. Since he normally do color photos with RGB filters, I suggested he use the R filter for his pictures.

He also took pictures of V1655 Cyg and V1659 Cyg, but 5 minutes exposures were not enought to show these variables.Can they be that faint?

Damien

wkautter
Alert Notice 645 stars in Target Tool

Hi Elizabeth,

There are 19 stars in the AN 645 list, which only the top 4 appear to be in the Target Tool. Many others in the list are being actively observed as evidenced by their light curves. Would it be possible to have the rest of the AN 645 stars included in the Target Tool to make it easier to find those that have not been observed recently?

Best regards,

Bill Kautter

weo
weo's picture
Alert Notice 645 stars are now in Target Tool

Hi Bill,

Thank you for letting me know that some of the target stars from Alert Notice 645 were not in the Target Tool - I must have been sidetracked while entering these stars and didn't finish! I have now added all of the stars in the campaign to the Target Tool for V and visual observations.

Thanks again, and Good observing!

Elizabeth

 

mstroh
Thanks and update to source list

Thanks everyone who has contributed to this effort. There are some really nice light curves for some of the sources. I try to download the light curves once a month to update my own records, but if I happen to forget, and you don't receive the alert, please be reassured that your observations are crucial to this campaign!

It looks like V1301 Cyg and V1659 Cyg are particularly difficult, and the light curves are needed to put the radio observations in context. Thus, I'm switching out those two sources from the radio program and am adding in the following two sources. They still may not be great, but maybe they are a little better.

  • V0657 Cas
  • V0850 Cas

All sources in this program should be very red so trying redder filters such as R and I might help for the weaker ones.

 

Thanks again for all of your help!

weo
weo's picture
Sequences for V657 Cas and V850 Cas

V657 Cas and V850 Cas do not have sequences. Once the Sequence Team has created them, I will issue a revised Alert Notice and will post here.

Good observing,

Elizabeth

weo
weo's picture
Alert Notice 660 - LPV maser campaign update w/new targets

AAVSO Alert Notice 660 gives the revised target list for the LPV SiO maser campaign announced in AAVSO Alert Notice 645. The stars added, V657 Cas and V850 Cas, now have sequences; the stars V1301 Cyg and V1659 Cyg have been dropped. Please see Alert Notice 660 for details and observing instructions.

Many thanks, and good observing,

Elizabeth O. Waagen, AAVSO HQ

mstroh
Project update!

Thanks again to everyone who has contributed to this project. Our VLA observations have been successful so far, and we've been able to detect SiO maser emission for all of the stars in the sample. This is hopefully a good sign for our continued monitoring with the VLA until October 2019.

We recently submitted a second VLA request for a 2nd year of observations of these sources. This would take us from October 2019 to October 2020.

Your observations are vital to this program and I am grateful for everyone's hard work!

mstroh
Thanks again!

I wanted to say thanks again everyone for successfully observing the two new stars we added, V657 Cas and V850 Cas! The data look great!

weo
weo's picture
Alert Notice 687 - LPV Maser campaign extended + target added

AAVSO Alert Notice 687 announces that the LPV Maser campaign (AAVSO Alert Notices 645, 660) has been extended, and that a star has been added to the target list. Please see the notice for details and observing instructions.

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

nkrumm
nkrumm's picture
VX Cep in outburst?

There has been a dramatic brightening of VX Cep by about 3 magnitudes over the last month or so. There isn't much historical data on this star's variability, so it's hard to tell if this is "normal" behavior or not. Perhaps more of us should be watching.

weo
weo's picture
VX Cep behavior

If you plot the AAVSO data of VX Cep from 245000 to the present, it can be seen that there have been several other maxima as bright as the current one. However, the earlier maxima did not have coverage of the complete cycle of variation, so observations are encouraged to provide this coverage and to assist in Dr. Stroh's maser campaign (AN 687)!

Many thanks, and Good observing,

Elizabeth

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