Observing report 21-22 11 2008

[lunator]

Finally managed to get some observing in this weekend. Hope you enjoy the report. Cheers

Ian

Observing Report 21-22/10/2008

More Doubles in the Square of Pegasus

The last 2 nights have been excellent in terms of transparency and seeing. You can always rely on the ‘cold artic blast’ to give the best views J.

Friday night was very clear and cold. The seeing very good definitely II on the Antoniadi scale. I was not able to get out early as family commitments had to come first. There was no Moon present and I could see Mag 5.5 stars with averted vision.

The first target STF180 (Gamma Aries), this is a beautiful pair of stars that were discovered by Robert Hooke whilst he was following a comet. The 2 stars were points of light with a pure white colour. They were easily split in the 24mm Hyperion and the surrounding field is scattered with faint stars.

The next target was STF 333 (Epsilon Aries). I had not viewed this pair for several months. They are a tight pair that requires quite high magnification to split. The stars are both white and are of similar magnitudes. My previous best split on this pair was at x200 but using the 12.5mm orthoscopic (x180) I could get a good clean split. A good 100mm scope and x200 magnification should split the pair but it will need to be a good seeing night.

Saturday Night was also clear and whilst the seeing wasn’t quite as good as Friday the seeing was still better than average at II/III on the Antoniadi.

I had photocopies of Pegasus doubles from Burnham’s and this was a continuation of the observation session from October. All these doubles are within a few degrees of 74 & 75 Peg and are easy to find.

The First Target(s) was STF3013 & 3012. These stars are very close to each other only separated by just over 50 arc seconds. The stars are like another (Epsilon Lyra ) double-double. All 4 components are visible is creamy white with one star being significantly brighter than the others. The 2 pairs are separated by 2.8 and 3.2 arc seconds respectively so do require a medium level of magnification I found the 18mm (x125) gave the best overall view.

The next target was STF3020. This is an uneven pair. The primary is a magnitude 8 white star and the secondary is a 10^th magnitude star just over 2” away. The secondary showed no colour and was quite difficult to spot at medium magnitudes. To get a clear view required the 12.5mm orthoscopic (x180). Due to the closeness of the secondary it does look fainter than the 10^th magnitude listed.

I then moved onto the next pair STF3021. This pair had a subtle colour contrast and the secondary seemed to vary in colour as I rechecked my sketching. The primary was white and most of the time the secondary had a subtle colour contrast. The pair are separated by around 9” so any moderate magnification will split them and they would suit a view in a small scope.

Moving steadily up the numbers the next target was STF3023. This was a tight pair that took some splitting. The pair are separated by only 1.6” and the difference in magnitude is around 2 mags. The best split was in the 12.5 orthoscopic (x180). The primary is white but the secondary did not have a clear colour.

The next 2 targets were slightly to split. STF3044 is a pair of even magnitude stars both of which are white. The separation of nearly 20” means that a small scope and low magnification will make this look a nice sight. The surrounding field was relatively sparse. I used the 18mm to split them but the 24mm would have been better.

The final Struve pair I observed in Pegasus was STF3048. The pair does show a subtle colour contrast the primary is white and the secondary is orange. Using the 24mm gave the best view as the separation is 9” and the surrounding the star field is quite rich.

The final target I observed was HJ321 (I couldn’t leave John Herschel out of this report J) The primary is a white star and the secondary appeared blue/grey. The pair are nice and wide but should be split-able in most scopes. One interesting point was just to the north is pair that is not listed. The primary of this pair is TYC 1174-371-1 and whilst the pair are quite wide they do have a very similar proper motion.

[/]

[] [/] [] [/] [][/] [] [/] [][/] [] [/] [] PMRA[/] [] [/] [] errRA[/] [] [/] [] PMDec[/] [] [/] [] errDec[/] [] [/] [] PM[/] [][/] [] [/] [] [/] [] Star1[/] [] [/] [] USB1.0[/] [] [/] [] 30[/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []-4[/] [][/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []30.27[/] [][/] [][/] [] [/] [] [/] [] Star2[/] [] [/] [] USB1.0[/] [] [/] [] [/] []26[/] [][/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []-4[/] [][/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []26.31[/] [][/] [][/] [] [/] [] [/] [] Star1[/] [] [/] [] UCAC2[/] [] [/] [] [/] []30.6[/] [][/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []2.6[/] [][/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []30.71[/] [][/] [][/] [] [/] [] [/] [] Star2[/] [] [/] [] UCAC2[/] [] [/] [] [/] []26.7[/] [][/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []-4.1[/] [][/] [] [/] [] [/] []0[/] [][/] [] [/] [] [/] []27.01[/] [][/] [][/] [] [/] [] [/] [] Star1[/] [] [/] [] Nomad[/] [] [/] [] [/] []30.5[/] [][/] [] [/] [] [/] []1.1[/] [][/] [] [/] [] [/] []-2.6[/] [][/] [] [/] [] [/] []1.1[/] [][/] [] [/] [] [/] []30.61[/] [][/] [][/] [] [/] [] [/] [] Sta2[/] [] [/] [] Nomad[/] [] [/] [] [/] []26.7[/] [][/] [] [/] [] [/] []3.4[/] [][/] [] [/] [] [/] []-4.1[/] [][/] [] [/] [] [/] []1.5[/] [][/] [] [/] [] [/] []27.01[/] [][/] [][/] [][/][] I will add this in my next report to the Webb Society. By this time Pegasus was setting in the West so I moved onto Aries. The first target was STF174. This is an Orange/pale blue colour contrast, although not quite Albireo contrast. The pair could be split in the 18mm (x125) but the best view was in the 12.5 (x180). The background field is quite sparse. I moved onto STF175 & STF180, both of these pairs are evenly matched pairs and are white in colours. STF 180 is a showpiece double, first found by Robert Hooke whilst he was tracking a comet. Both pairs are suitable for small scopes and low magnification. STF 180 is one the pairs to start or end a session. [/]

[Doc]

Reminds me that I must get my refractor out more.

Great report Ian.

Some very interesting doubles you don't see everyday.

[russ]

Wow Ian that is a list and a half! I've only seen a fraction of those. Great stuff.

About time i tracked down some of those, i enjoy the doubles.

Russ

[lunator]

Cheers Mick & Rus

I have started an excel spreadsheet to review number of doubles I have viewed.

I have observed an logged around 250 pairs :shock:

I hope to be able to pull together a document that will list them by constellation etc.

Rus most of these doubles were within a few degrees of each other so it is very easy to move from one to the other.

Cheers

Ian