Interesting Objects -Some Information

Interesting objects for observations

This section brings together some interesting and informative web links, documents and notes on some of the more interesting objects available to the amateur.

Francois' great webpage has some very good content (Be stars and novae) and links to the current and previous notes from Prof. Steve Shore. Well worth the read.

Wolf-Rayet Stars

These interesting emission stars are well worth observing. Since their discovery in 1867, there are now approx 227 catalogued. Many are found in the Cygnus area and the brightest is in the southern hemisphere - Gamma Vel, a WC8 type star..

WR VII Catalogue This is the latest and up-to-date WR catalogue.

The typical WR emission lines which can be recorded depends on the type of WR star (WC WO or WN), the typical spectra of WR stars (WC and WO types) can be found here and information on the WN type here.

The recent campaigns on WR 140 are documented here. Robin Leadbeater also has a nice HiRes WR140 on his website.

http://kookaburra.phyast.pitt.edu/hillier/publications/Wolf_Rayet_paper.pdf

Be Stars

The June 1975 issue of S&T contained a good overview of the emission Be stars by Su-Shu Huang.

There's a good overview of Shell Stars on this website, as well as some great links for further reading.

The BeSS database contains all the Be stars and is the repository of all the amateur (and professional) data.

There's a VO (Virtual Observatory) add-in available for the planetarium programs C2A and CdC which plot all the Be stars and identify the one's needing observation.

Deneb has been regularly observed and is a good target. See Noel Richardson's report here

Novae and SN

These transient phenomena present a great opportunity to contribute useful data to the community. Details of new discoveries are published in the Astronomer's Telegram and listed on the websites below.

Rochester Astronomy Provides details of all the latest SN discoveries

Super Nova Another listing of all SN

Novae This link provides practical information on the observing and recording of novae.

Nova Cygni is covered in the Nov75 Sky and telescope

Gelato SN A must have comparison site for any SN spectral images. Defines type 1 and type 2 SN.

SNID A SN Identification software by Stephane Blondin. Runs under Linux etc.

Paul Luckas recently observed the nova in Centarus

This clearly shows the hydrogen emission lines and the "Iron curtain" of Fe emissions around 5000A. Typical of a nova close to maximum.

Robin Leadbeater recorded SN2017eaw with a 200 l/mm modified ALPY and compared his data with GELATO

Variable Stars

Under construction

Meteors

Some interesting meteor spectra appear in the following issues of Sky and Telescope.

Aug74 Sky and Telescope

Jun74 Sky and Telescope

Nov75 Sky and Telescope

The BAA article 1991 Perseid meteor spectra is also informative.

The Millman document 115 years of meteor spectroscopy covers a lot of the historical ground.

Comets

The recent 2019/2020 comet NEOWISE was well observed by observers in the northern hemisphere. It also allowed many amateurs to obtain their first comet spectra. It was interesting to record the changes in the comet spectrum as it swung round the Sun.

The Swan bands (and Cyanogen (CN) are commonally recorded in comet spectra. The Na emission was also visible in NEOWISE.

Christian Buil: UVEX spectrograph, annotated to show the prominent comet emission lines.

Robin Leadbeater: HiresIII spectrograph, Sodium (Na) emission, compared with stationary background street lamp emission. Note the wavelength change - the comet was moving towards us (blue Doppler shift).

Torsten Hansen: SA200 grating, 135mm telelens. Shows the reduction to the Na emission and the increased intensity of the Swan bands.

Bajastro: LowSpec spectrograph, annotated to show the prominent Swan band comet emission lines.

Quasars

Maurice Gavin (UK) was the first amateur to record the spectrum of a Quasar, 13th mag 3C273 in 1998. By using a Vega comparison spectrum he determined the redshift (z) as 0.16.

Planetary

A spectrum of the moon or planets is a reflection spectrum of the Sun. If the spectrum is divided by a standard G2V spectrum, the planet's atmospheric make-up can be established. The Uranus spectrum above shows the method (Maurice Gavin)

If a slit spectrograph is used, we can measure the rotational speed of Jupiter or Saturn. By placing the slit across the planet's disk the red/ blue doppler shift can be recorded, as shown below.(Gingerich)

https://arxiv.org/pdf/1705.06323.pdf

Solar and Zeeman effect

Under construction

Nebulae

The emission lines of the brighter nebulae are usually dominated by hydrogen and oxygen. A slit spectrograph gives cleaner emission lines as shown below (A&A,94,12).