Astro-viewing night for family and friends

[TheCrazedLog]

Hey all:

My sister has asked me to bring my telescope stuff across to her place in Ryde (Sydney) so her family and some friends can look through it. This will be sort of a sciencey type thing for them all.

Probably looking at 10-15 kids, maybe 5 adults. So lets say 20 people all up. I've got a 10" Dob, an ED80 on a EQ6 and a 8x40 pair of binocs.

My question is: What do I do? I've never really do anything like this before and I want them to come away from it all interested and happy to have gone. I reckon I've got maybe... 2 - 3 hours at the most?

Do I pick only a few solar system targets? What about DSO's (47 Tuc?)? Moon's an obvious target. My wife can run one scope while I run the other.

Has anyone done anything like this before? What is the sort of stuff I should read up on (I've had a quick read of the SanFran Sidewalk Astronomy's page, but that isn't quite what this is). Should I have a set list of targets, or let them roam?

Thanks

Anthony

[doppler (Rick)]

Start with the bright stuff, jupiter, saturn then around the southern cross, point out the easy constellations, scorpius, sagittarius there are lots of nebula etc to keep you going and 2 hours goes pretty fast. If you are timing for the moon before 1st quater is best or a week after full. The moon rising at the end of a viewing sesion is always cool. Our local group does a few school viewing nights each year, we usually start with a talk about the telescopes a bit of basic sky orienteering (a laser pointer is great for this but most of us are cautious now aka the law) then start observing. You need to expect a few questions about sizes and distances of objects etc. Its handy to compare the nearest star say 2 light years away to say the small magellenic cloud 180,000 light years away (these are not the exact distances) good luck. I have a local church youth group star night this friday about 12 teens and a few parents our worst enemy is the clouds.

[malau (David)]

Perhaps download Stellarium and see if there are interesting stuff you can show them apart from planets. How about some bright nebula?

[madwayne (Wayne)]

Hi Anthony

I have done a few public open nights with our society. My suggestion would be as follows;
ED80 moon then Omega Centauri as another option.
Dob Saturn and perhaps a galaxy, M83 or M104 or 5128 something bright relatively easy to find.
Binos (assuming you have a tripod) point them up around Crux or Carina around Eta Carina.

Definitely have things planned so if you are asked how far is it, what constellation is what (particularly zodiac) you can answer with confidence. Also a laser pointer can be very handy.

God luck with your mini public night you'll have a ball.

Wayne

[mental4astro (Alexander)]

Hi Anthony,

As you will be hosting the viewing night from Ryde, you will be facing two big challenges: significant light pollution, and folks expecting bright images. You really need to select targets that will best suit the scopes you have. This will take some careful explanation on your part too.

But, before using the scopes, take some time to point out some naked eye objects. This will help set the tone, and show folks that there is a lot to see just naked eye. Point out the Southern Cross and the pointers. There is a lot to be said about these seven stars. Not only can we determine the position of the south celestial pole, and the direction of true south, but Alpha Centauri is the closest star to us at 4.3 light years. And Alpha Cent. Is also a tertiary system, two of which can be easily seen through a scope (good target of your ED80 push in magnification as it will be tracking). The five stars of the Southern Cross are also much, much bigger stars than Alpha Cent. and much further away. The star of the cross that is closest to the Pointers alone is some 458 light years away.

Also point out the constellation Scorpio – one of the easiest constellations that show the shape it is name for. Point out Antares as a star that is a star like our sun that is reaching the end of its life, and its red giant phase is what awaits our Sun after its main sequence.

If the timing of the viewing works out, let Sagittarius rise some more, and hopefully the Cloud of Sagittarius will be softly visible. This cloud is in the direction of the core of the Milky Way, but is actually in an arm of the Milky Way that cuts in between us and the core of the MW. The core of the MW is 30,000 light years distant in the direction of and through the Cloud of Sagittarius.

Ask folks if they know what a ‘light year’ is. While some may, you should still cover this, and put some things into context off the size of the MW alone. Mention how the little space probes Voyager I and II took 36 years to travel what would take light just 2 months to cover. Some other distances I’ll cover below too.

Your ED80 I don’t think is best suited to Omega Centauri. It just doesn’t have the aperture grunt to make Omega a real showpiece from Ryde. What it is great for is a thin crescent Moon. While we dedicated astro nuts would not consider high power viewing with such an instrument, I think your refractor will be a fine instrument pushed real far with the Moon.

There are two other targets I would suggest for your ED80, both as wide field targets, and both very, very different targets. These are Eta Carina and M7.

Eta Carina is a great target to tag team with your dob. The ED80 with a nebula filter and with low power and wide field, it will show just how big a system it is, and the dob can zero in for details. I’ll expand on details here for your dob. The Eta complex has a whole cross section of stellar life cycles. Death – the star that lends its name to the nebula is a Super Giant that is in its death throes. It is experiencing a series of eruptions. Having exhausted its nuclear fuel, its gravitational/energy production balance is being compromised, with the outer layers now not being pushed out by energy production and crushing the core. The eruptions are precursor ‘flutterings’ that will eventually not be able to be sustained by the failing core, and will result in Eta going Supernova, in some 10,000 years or so. Main sequence – the small, bright cluster close to Eta is Trumpler 14. These stars have ‘recently’ kicked off their nuclear fires. These fires have blown the gas and dust that from these stars, and a ‘cosmic bubble’ can be seen expanding around and away from Trumpler 14. Birth - resisting the intense solar wind form this cluster are dark pillars that cut into the bright nebula. There are protostars inside these dark pillars, evidenced by their gravity holding onto their stellar gas cocoon. These protostars will soon have their nuclear fires start.

M7: This is an easy naked eye target off the tip of the stinger of Scorpio. While the main cluster stars are easily visible, keener eyes bay be able to make out the fainter star clouds behind it. Really drop the magnification as much as you can and wide field too.

Dob – Omega Centauri for sure. Mention how every GC has its own ‘signature’ features and characteristics. Omega has an ‘eye’ almost dead centre that is always washed out in long exposures. Mention also how Omega is thought to be the remnant core of a galaxy swallowed long ago by the MW. It is just too big to be a ‘normal’ GC, and the age and chemical composition of its stars are just too varied to be a normal GC. You can lead from here to say how the MW is also in the process of swallowing up some six separate galaxies. The SMC and LMC don’t appear to be in the process of being consumed by the MW, and could just be satellite galaxies of the MW.

The Jewel Box is a great target for your dob. Not just for the lovely cluster it is, but that it has a couple of red stars in it, one in particular being very brilliant. You can ask the people ‘if they can see the ruby in the mass of diamonds?’.

One last dob object I would recommend is Saturn. Put the magnification at between 120X to 150X. This will be sufficient for a longish period of drift across the field of view, and will allow for anything from three to six of Saturn’s satellites to be seen, including Titan. Cassini division is also capable of being spotted. I like to mention to people that the gap that is the Cassini division is large enough to have the entire continent of South America, north to south, fit inside this gap, but with several hundred kilometres to spare (over 4,000km!).

I actually wouldn’t recommend making any galaxies a visual target for you. Galaxies are just not bright enough to overcome the light pollution at Ryde. While there are some that are visible, they just require too much experience for most novices to actually see. And certainly, novices will have no chance to make out any details at all. Galaxies are really only a very small group proposition. M104 is just too small. M83 and Centaurus A are too low in surface brightness. Galaxies from Sydney, with novices, and in large groups, are really only video astronomy options. Astronomical video cameras are very much capable of showing galaxies relatively easily, even with an 80mm scope.

I hope this helps inspire you.

If you have any questions, please ask. Try not to get too technical with your explanations or answers, but don’t dumb down. I love doing astro viewing nights with both kids and adults as it gives me a chance to tune my own explanations to easy to understand and not to intimidate. Astronomy isn’t about rocket science. It just needs us to demystify the NASA appearance of things.

Cheers,

Mental.