American Association of Variable Star Observers (AAVSO)
Sat, 11/05/2011 - 21:42

The web site shows 221 potential targets for observation.  I checked about ten of them and very few observations have been made since the YSO forum started.  Do you have a priority list?  What frequency is appropriate?  Are multi-band observations valuable or is a single filter preferred?  I know from observing HBC 722 and VSX J2051+44 that these objects tend to be very cool, so if we use a single filter is it better to use I or R?  The two I've been oberserving are much brighter at these wavelengths enabling better measurements and allowing me to use a smaller scope for observations.

Also, is there a good text or set of introductory articles about YSO's beyone what is discussed on the web site?  I think many of us would like to know more about them, and also understand how photometric measuarements can be utilized to better understand these objects.  In particular, are the measurements of value "stand alone" or do they need to be coordinated with professional spectral observations?



American Association of Variable Star Observers (AAVSO)
Hi Gordon,

That's right,

Hi Gordon,

That's right, most of the stars on the list are under- or even un-observed! One of the purposes of the group is to change that state of affairs. A priority list is something that I am supposed to be working out with Bill Herbst (so mea culpa!) along with a FUOR campaign. Since there are so many underobserved stars, I'd say pick a few that float your boat.

Frequency - every clear night, even though T Tau stars typically vary on a slower scale than the rest, they have been known to exhibit rapid changes. INA and INB stars, definitely every night. Some, such as CQ Tau, can even change over the course of a night.

Wavebands... Yes, both R or I are good; and there's a good article on UXORs at:

There will probably be some coming activity on the pro-am front. Colin Aspin (University of Hawai'i) has expressed some interest in this direction, though the YSO group is quite new, and things such as collaboration, priority targets and suchlike may take a little while to 'settle in'. The more people who are involved the better. At the moment I am of necessity more involved in job searching than astronomy unfortunately!

American Association of Variable Star Observers (AAVSO)
Thanks - and Colin Aspin

Thanks for the info.  FYI, Colin Aspin is the person I've been in contact with for the HBC722 and VSX J2051+44 observations over the last year.

Good luck with the job hunt!  I have some spare time, so if I can help you in any way on this YSO Forum let me know.

American Association of Variable Star Observers (AAVSO)
Cheers Gordon,

Any help is

Cheers Gordon,

Any help is always welcome(d). Spreading the word is top of the list just now. Us VS people can be a bit set in our ways sometimes and a lot of folks don't appreciate just how interesting YSOs are! Obviously there are exceptions (DI Cep and AD Tau never seem to do very much) but with only about a dozen regular and intense AAVSO members concentrating on them, what we really need at the moment is more hands to the pump!

I have just uploaded sequences for stars in Per and Tau, and these should all be on VSP soon. I have also updated the database used on my YSO website so that the stars in Per will now carry links to VSP rather than the on-site charts. This may take a day or so before Simo okays and uploads the sequences to VSP. I also sent him all the non-AAVSO stars in Taurus (quite a few of these!) and the same goes for them, though I have not yet updated my database for Tau. Auriga is next, and then Orion! Most of my Ori stars are in the T1 and T2 associations near lambda Ori - the M42 region is a no-go area.

I'm doing voluntary web design/programming until a 'real' job comes along. Always need to keep those skills honed!

American Association of Variable Star Observers (AAVSO)
Setting Priorities

I have a suggestion as to how to prioritize your YSO program to begin. I would start with stars that DO have a substantial amount of data first, and work my way down the list to stars with lesser amounts. The reason being this- a handful of observations on a bunch of stars is not very useful, scientifically speaking. Whereas, better coverage on a smaller number is a good thing.

No one will be interested in your data if it is the only data and it is sporadic and can't be used to create a long-term light curve. But the data for stars that have good to excellent coverage over a longer time will more likely be used in analysis.

Contrary to popular misconception, there are not that many observers submitting data on these or any other variable stars. One of the reasons for having observing sections is to marshall our observer resources to the best advantage. Lots of people covering a smaller set of stars adequately is far better than everyone observing ten different stars and none of them getting adequate coverage.

I'm not saying don't observe under-observed stars, and I'm not against picking one or two for yourself that you can adopt as your own. But, if you are going to do this, make a commitment to observe them as often as possible for a long, long time. That is where the payoff is in the end. And that is why this is the perfect kind of observing program for an amateur; because professionals just don't do years to decades long campaigns.

My 2 cents, for what it's worth. But I am not the section leader, nor am I any kind of expert on YSOs. 

American Association of Variable Star Observers (AAVSO)
Yes Mike, I'd go along with

Yes Mike, I'd go along with this. Stay with the standbys like RR Tau, UX Ori and so on. Ignore the Orion Nebula! That's not to say you shouldn't observe the neglected ones though. Maybe introduce a few at a time. There are lots to go round!

American Association of Variable Star Observers (AAVSO)
Setting Priorities

Apropos this thread, I have been refining my observing list for my computer controlled C-14.  I went through the list of program stars looking for the "most interesting."  My two criteria were a) visible from mid-Missouri and b) "some" following as revealed by the AAVSO LCG.  I came up 47 stars, none of which are South of -2 Dec.  I also added the RA and Dec coordinates which are easier for me to figure out where they are instead of merely constellation.  For your consideration,


Star Range Rank RAhr RAmin RAsec DECdeg DECmin DECsec


MQ Cas 11.70 - 13.6p a 0 9 37.6 58 13 11

NSV 87 10.30 - 12.1v a 0 12 56.8 63 46 30

NSV 93 10.30 - 11.6p a 0 13 51.5 63 45 28

V642 Cas 10.30 - 11.3p a 0 15 4.7 63 50 38

V545 Cas 11.40 - 12.6p a 0 20 16 59 23 14

VX Cas 10.70 - 13.3p a 0 31 30.7 61 58 51

V594 Cas 10.90 - 12B a 0 43 18.3 61 54 40

RZ Psc 11.29 - 13.82v a 1 9 42.1 27 57 2

IS Per 11.70 - 12.8v a 1 32 10.2 54 16 35

CF Per 10.50 - 12.5v a 2 3 23.6 57 43 21

V443 Per 13.20 - 14.5p a 2 46 42.3 37 17 49

EO Per 11.20 - 12.4v a 2 50 38.6 57 20 10

V369 Per 10.50 - 13.7p a 2 51 17.2 38 14 41

IP Per 10.40 - 11.5p a 3 40 47 32 31 54

XY Per 9.80 - 11.0v a 3 49 36.3 38 58 56

BP Tau 10.70 - 13.6b a 4 19 15.8 29 6 27

RY Tau 9.30 - 13p a 4 21 57.4 28 26 36

T Tau 9.00 - 13.5v a 4 21 59.4 19 32 6

AA Tau 12.20 - 16.1p a 4 34 55.4 24 28 53

DN Tau 11.50 - 14.7p a 4 35 27.4 24 14 59

VY Tau 9.00 - 15.26b a 4 39 17.4 22 47 54

CO Ori 10.30 - 13.8p a 5 27 51.3 11 25 39

RY Ori 10.80 - 13.9p a 5 32 9.9 -2 49 47

AD Tau 12.00 - 13.7p a 5 34 17 25 36 16

CQ Tau 8.70 - 10.5p a 5 35 58.5 24 44 54

BN Ori 8.80 - 13.9p a 5 36 29.4 6 50 2

RR Tau 11.00 - 13.6v a 5 39 30.5 26 22 27

WW Vul 10.90 - 12.6p a 19 25 58.8 21 12 31

V1514 Cyg 12.60 - 14.9p a 20 7 1.3 58 16 41

V771 Cyg 13.00 - 14.9p a 20 22 25.2 59 20 21

V1515 Cyg 13.50 - 17.7b a 20 23 48 42 12 26

V561 Cyg 11.80 - 14.5p a 20 25 58.2 52 8 41

V1977 Cyg 10.80 - 11.4p a 20 47 37.5 43 47 25

V517 Cyg 12.50 - 15.3p a 20 47 24 43 44 40

V1057 Cyg 10.30 - 16.5B a 20 58 53.7 44 15 28

V1331 Cyg 10.60 - 13v a 21 1 9.2 50 21 45

V1982 Cyg 12.00 - 13.8B a 21 3 54.3 50 15 9

V1910 Cyg 11.40 - 15.9p a 21 32 32 38 57 55

V1938 Cyg 13.80 - 15.2p a 21 32 37.5 39 40 6

V488 Cep 12.40 - 13.4p a 21 35 19.2 57 36 39

BH Cep 10.79 - 12.7p a 22 1 42.9 69 44 36

BO Cep 11.00 - 13.7p a 22 16 54.1 70 3 45

YZ Cep 12.00 - 13.5p a 22 18 1.2 57 17 17

SV Cep 10.35 - 12.15v a 22 21 33 73 40 27

V628 Cas 10.90 - 11.8v a 23 17 25.6 60 50 43

Start with the stars with long-term light curves

Hi Jim,

This is a good list.  I would concur in starting with the stars with long-term coverage, in particular the ones with visual data.  Rapidly scanning your list, things like RR Tau, T Tau, WW Vul, VX Cas, and V1057 Cyg catch my eye.  They've all got interesting long-term light curves and the visual observers have established them visually.  Additional CCD coverage that overlaps what the visual observers are doing will help in interpreting past and future visual data, especially if you can do photometry in two or more filters.

I wouldn't necessarily go by the total number of data points in our light curve -- V545 Cas has a lot of data, but much of that is (extremely) rapid time series by a single observer.  I'd use the time span and density of existing coverage, particularly if most of our data are visual.


Minor points: filters, and the Orion Nebula

Just to briefly follow up on this thread, I'd like to ask that observers with multicolor capability please do use at least two filters, and transform your data to a standard system if at all possible.  V and I (or their Sloan equivalents) are fine; R is also fine, although with that you may start noticing odd colors caused by H-alpha emission.  Many of these stars are irregulars, and so long time series can only give so much information beyond telling you how quickly they vary and by what amount.  But photometry in multiple filters may give you some additional astrophysical information about why they're varying.

Also, I want to slightly contradict Michael's suggestion of avoiding the Orion Nebula.  The Trapezium is a difficult target and I don't recommend it unless you have pretty good seeing, but there are some other stars in the region that are good targets, T Ori being a fine (rapidly-varying) example.  Again, multicolor photometry is encouraged if possible.

American Association of Variable Star Observers (AAVSO)
Priortizing Targets YSO's

Hi Gordon,

I've observed variables from around 1974-19?? mostly long period. Haven't done anything in the last ten years.  I am getting back to this but I want to try something new.  I am interested in YSO's and will do some visually but I want to eventually try video as an observing tool.  I should be observing by the end of the summer (visually) and am putting together a list of YSO's to work on. 

Bob (DEA)