Tuesday, November 01, 2005

Central Park Observing - 30 Oct. 2005

Location: TotL - Central Park's Great Lawn (north end)
Date/time: Sat-Sun, 30-31 Oct. 2005 (~6:10p-12:45a)
Optics: 10x70 Fujinon's (mounted)
Observers: Charlie R., Peter T., Kin L.
Conditions: winds mainly variable & from the southwest 3-12 m.p.h., temperature 64°-58°F

First day of ‘standard time’ observing with friends. The skies were clear with a few patches of light cloud which cleared as the temperature dropped.

The first part of the evening was spent nova hunting in Perseus. The current search area (SALC 34N) was completed in 2h00m (6:40p-8:30p). This area is 50 minutes in ‘right ascension’ by 5 degrees of ‘declination’. I took a ten minute break around 7:25p. The whole area was covered with the binocular limiting magnitude (BLM) a few tenths short of ideal due to the light cloud cover for part of the session.

The balance of the night was spent talking and observing.

Peter's 10" dobsonian was mainly aimed at Mars and the views were spectacular when seeing allowed. I don't know much about the topography of Mars but a lot was seen including a few glimpses of Hellas. Hellas was only visible when the dusky markings near the southern limb were clearly seen. These markings were not visible while the disk was skipping about. The appearance of Hellas was as if it were being held in the arms of a spider.

A lighter gap along the dark bar, well east of Syrtis Major, was obvious. This appears to be between Mare Cimmerium and Mare Tyrrehenum.

It was good to have the 10" to view this close approach of Mars. I haven't taken out the Televue-76 in awhile. It would probably have been a bit frustrating, but nonetheless satisfying, to have viewed Mars solely with a 3" glass.

Objects observed with the 10x70's:

Globular Clusters:

Both M15 in Pegasus and M2 in Aquarius were placed in the 10x70's for all to view.

Open Clusters:

M34 in Perseus was looked at early on in the 10x70s's.

NGC 2281 in Auriga (mag. 5.4): star hopped from Gemini to an asterism that looked like the five on the side of a dice. To it's lower left was a peaked roof-like asterism with the cluster sitting on the right edge of the roof. Fairly obvious, elongated and small with some stars resolved. With averted vision the cluster was more easily picked out from the background stars and appeared nebulous. This was a pleasure to view in the 10x70's. Peter was able to see it but no one else felt they saw the object.

Solar System:

At least half a dozen Taurid meteors were seen. The ones spotted naked eye were bright, fast and fairly white. Two were seen in the binoculars.

Uranus was seen by star hopping from the ‘Water Jar’ in Aquarius. Some movement has been noticed over the past month. This is probably due more to our motion than to Uranus'.

Saturn was placed in the 10x70's with the Beehive Cluster at the top edge of the 5.3° field of view.

Double Stars:

ψ Draconis (mag. 4.9 & 6.1 / sep. 30") easily split with the 10x70's and clearly seen by the majority of the group.

π Andromedae (mag. 4.4 & 8.6 / sep. 35.6) not so easily split since the secondary is near the limit of the 10x70's. The large four magnitude difference doesn't make the task any easier. Both Peter and myself were able to see the dimmer star in the correct position. We confirmed this with a view in the 10" dob.

η Persei (mag. 3.8 & 8.5 / sep. 28.3) tried in the 10x70's but not successful. Splits easily with the 10". The problem with this pair is probably the 4.5 mag. difference between the components.

Nova Hunting:

Category 2 - Stars needing effort to see:

Seventeen stars were not plotted on the chart and they all fell under this category. The magnitude range was 8.88 - 9.47. Excluding five outliers, two with bright magnitudes of 8.88 & 8.91 plus three with dim magnitudes of 9.36, 9.38 & 9.47, the ‘core’ range for stars needing some effort to view was 9.03 - 9.23.

After taking a closer look at the three dimmest stars I found that two are close doubles with incorrect combined magnitudes:

• BU 1294, TYC 3311-1731-1, SAO 38740, BD +46 0734
RA 03h 20m 40.6s / Dec +46° 40' 47.5"

This star is listed as mag. 9.47. The bright stars in this multiple are 9.66 & 10.28. Separation of the components was 8.1" / P.A. 237° in 1991 & 5.4" / P.A. 54° in 1896. The combined magnitude is 9.17. This falls well within the ‘core’ range listed above. This star is located in the ‘Small Witch's Hat’.

• HLD 8, TYC 3320-1240-1, HD 21539, BD +49 0950
RA 03h 30m 34.7s / Dec +49° 47' 21.2"

This star is listed as mag. 9.38. The bright stars in this multiple are mag. 9.42 & 9.79. Separation of the components was 2.3" / P.A. 177° in 1998 & 1.9" / P.A. 177° in 1881. The combined magnitude is 8.84 making it 0.2 brighter than the ‘core’ range listed above. This star is located in the bottom ‘left’ extention of the ‘Bromeliad’.

• TYC 3326-1645-1
RA 03h 46m 46.1s / Dec +46° 29' 54.1"

This star is listed as mag. 9.36. The catalogs don’t show that this as a multiple star. Maybe the mag. of the star is incorrect or it is slightly variable. It is over a full tenth of a mag. dimmer than the ‘core’ range listed above. This star is located in the ‘tail end’ of the ‘Nautilus’.

Fourteen stars were plotted on the chart and took some effort to notice. The magnitude range of these were 8.51 - 9.01. Excluding the two brightest at magnitudes 8.51 & 8.58 the ‘core’ range for stars needing some effort to view was 8.70 - 9.01.

Category 1 - Stars easily seen:

This category is difficult to quantify without looking at all of the stars at the dim end of this group. Looking at the data above I would say the stars in this range are probably all brighter than approximately 8.7. Analysis of all the stars in this group should reveal some discrepancies as seen in the group above. Over the two hour session the BLM appeared to fall short by a few tenths due to some very sparse and light cloud cover. This cleared up towards the end of the task.

Variable Stars:

Only 4 variables are looked for in this region on a regular basis and I only noted whether they were seen or not:

• Y Per (mv 8.4 - 10.3, var. type Mira, per. 248.6 days) was visible in the ‘Bowtie’ asterism and was in the magnitude range 8.6 - 8.9.

• V410 Per (mv 8.8 - 9.4, var. type SRB:, per. 110 days) was not visible in the eastern most of the ‘Three Boxes’ asterism.

• NSV 15682, SAO 38803, BD +48 0908 (mv 8.4 - 9.6, var. type E:) was visible and possibly brighter than 8.7. This is in the ‘Bromeliad’ asterism.

• NSV 15684, BD +47 0819 (mv 8.5 - 10.0) is easily visible each time I'm out observing. I assumed from the note ‘Flared on 9 Jan 1992’ meant it was at or below mag. 10.0 and shot up once to mag. 8.5 in 1992. I'll need to look into this star a bit more. This star is in the tail of the ‘Segmented Dog’ asterism.

The last two stars are New Suspected Variables (NSVs) and aren't accepted variable stars yet.

The total number of stars plotted in SALC 34N was 342 in 24 separate asterisms.

Overall a very successful evening out. It was enjoyable having the full TotL crew in attendance.


Tag said...

Happy Birthday, Ben!

1 Nov. 2005 marks the beginning of a new orbit around the Sun, and a fraction of the Milky Way :^D

Thanks for the report on the objects. The 10x bins offer a good balance of light grasp, magnification, and field for both the doubles and DSO's. In addition to novae-task data, the variable star reporting is interesting. Seeing this kind of change is reserved for the patient, consistent observer. As always, nice work!
Your report of Hellas is right on. You were able to spot it pretty consistently, however, over 2 evenings I haven't gotten it to pop out like the way you were. My observations agree with yours where the "spider legs" extend from the Iapygia, (and elsewhere along the south side) but I can only detect the strong contrast of tone and two maybe three rare moments of seeing the shape on Hellas' north and west side.


Ben C. said...

Thanks for remembering Peter! I know your b'day is coming up soon, fellow Scorpio.

Glad to hear you enjoy the views in the binoculars. I had a target list for that night and plowed through them all which worked out nicely. It's always best to share the views with others and each of the targets were shared with the group.

If only I had the ability to drag in the scope I would.

Part I - nova hunting
Part II - everything else.

See you soon.