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Indoor Observing?

Posted: Thu Mar 08, 2012 12:16 pm
by Tim Chamberlain
I was intrigued to read Martin Mobberley's article in last month's Astronomy Now: "A Window on the Sky" about astronomers who observe from indoors. Maybe this is the next step up from "armchair astronomers"??

I'm fortunate enough to have quite big windows fairly high up which give me a good view of most of the eastern half of the sky, and London light pollution not withstanding, I'm often able to make quite good observations looking out of my open windows.

I wondered how many SPA members were sometimes indoor observers?

Posted: Thu Mar 08, 2012 2:26 pm
by David Frydman
Dear Tim,
I have been observing from indoors from about the beginning of time, well it seems that way. And the majority of my astro photos are from indoors.
Anything up to 6 inch Maksutovs and 5 inch refractors.

Thousands of nights outdoors also.

They are not mutually exclusive.

Regarding the views of planets in daylight mentioned elsewhere today, using just the unaided eyes. This is easier and more successful from inside a room rather than outdoors.

Best regards, David

Posted: Sat Mar 10, 2012 10:02 am
by brian livesey
Is this because there's less glare indoors? Or because indoors is darker, so the pupils open more than they would outdoors?
Or, for that matter, is it a combination of both?

Posted: Sat Mar 10, 2012 10:50 am
by David Frydman
Dear Brian,
It is both of these plus the fact that indoors you can fix a position by holding your vision onto a window frame etc.

In the open air the sky is so enormous the eye wanders constantly and it is almost impossible to fix your vision on one spot. The eye scans constantly.

If you find Jupiter from indoors, either by accident or locating first with a binocular you can position it with reference to a window frame or marking a dot on the window, or say a cross hair.
The whole task is then much easier.

The only time you could find Jupiter with the Sun above the horizon outside is to fix it with reference to a tree or T.V. mast or ideally if it was very near Venus.

Now is ideal as Venus and Jupiter are closing.

But you don't have the indoor help you mentioned.

And have a go for Mars, it is just bright enough but needs very careful planning.
I saw Mars from indoors about 1991 or 1992 I think, and my Jupiter sightings were from inside a hall with glass panels. I used the building itself to shield my eyes from the Sun and also used clouds when they covered the Sun but not Jupiter. Jupiter was really easy.

It is essential with all these observations that your eyes focus exactly on 'infinity'
I can only do this nowadays with glasses.

Regards, David

Posted: Sat Mar 10, 2012 11:12 am
by David Frydman
I have tried to follow Saturn into daylight with unaided eyes on numerous occasions but never succeeded or even got close.
Sirius should be possible.
I think the limiting magnitude for a very good observer to see a star or planet with the Sun's disc just above the horizon is magnitude minus 0.5
in ideal conditions with the star or planet in an ideal position.

One should note that published sunrise or sunset times may be for mid Sun's disc and may or may not include refraction, so it is important to establish oneself that the whole of the Sun's disc is above the real horizon, i.e discount houses roofs etc.


Posted: Sat Mar 10, 2012 2:16 pm
by David Frydman
It seems that with the rings wide open near opposition Saturn can reach manitude minus 0.49, say mag minus 0.5. This will happen it says on the internet in 2018.
It might just be possible with careful planning for someone to see Saturn then with unaided eyes with the Sun just above the horizon.

I do not recall any claimed unaided eyes sighting of Saturn in daylight, which I define as the Sun at least being completely above the horizon and stritly a sea horizon.
Also say on mount Teide in I think Tenerife or on the top of La Palma the Sun may be about 1 degree below the horizon compared to the view from sea level at the same time.

For southern observers, Canopus might just be visible with the Sun just above the horizon.

Regards, David

Posted: Sat Mar 10, 2012 9:07 pm
by mike a feist
As have mentioned previously, I very frequently observe through the window glass....esp for Mercury recently and many other observations where the extra height of the upstrairs room can be a great advantage. maf

Posted: Sat Mar 10, 2012 9:13 pm
by mike a feist
Rather than a "next step up" from armchair astronomer, it is more likely to a "next step down" for the veteran observer who really cannot take the cold and exposed nature of going outside all the time, and knows when he can get away with locating his targets from a more comfortable location. maf

Posted: Mon Mar 12, 2012 10:28 am
by brian livesey
There's always a sheet of BAADER TurboFilm ( but pricey ) that can substitute for the window glass for the length of the observation.
This material is said to be as good as a one-tenth wave, glass, optical window.

Posted: Mon Mar 12, 2012 1:09 pm
by David Frydman
I am not sure if the Baader film will take kindly to repeatedly marking the position of Jupiter on it with the Sun above the horizon on many days.
The ball point might go straight through. Perhaps a felt tip marker is needed here.

Regards, David

Posted: Mon Mar 12, 2012 5:11 pm
by brian livesey
I wasn't thinking of using the film that way David. I meant with regard to straightforward binocular and telescope indoor observations through the film.

Posted: Tue Mar 13, 2012 10:31 am
by Tim Chamberlain
Like Mike, I find the added height of observing from indoors (where I'm on the fourth floor) is a real bonus. I don't have to crane back quite so far and the window frame often allows me to steady my bins better.

Mars has been particularly well positioned for viewing from indoors for me the last few nights.

Posted: Wed Mar 14, 2012 5:48 pm
by Ender Of Days
I have my 125 in front of my Velux loft window,it gets used a lot as its always set up ready and waiting,the warm currents from inside can play havoc but its nearly always freezing up there so not as bad as it sounds,
nothing beats being outside in the garden with it,but for ease of use its OK where it is for now :wink:
Virtually no stray light gets to the mirror too,

Its not quite an observatory set up as the Tripod legs do get the occasional bump :oops:
but a lot of my observing is grab and go so the loft if a good place till I get the obs built (yeah .. can see my gf agreeing to that :cry: )

JJ.. :D

Posted: Sun Apr 01, 2012 4:22 pm
by David Webb
I have had 2 Telescopes and none of those were ever used outside, and I think seeing as my scope is set up aiming towards the sky ready to use I use it more.
I feel that having to pick it all up, drag it outside, set it up, and recover from all that hard work I would soon go off the idea of sky watching, apart from that would the sky still be clear by the time I got it ready? maybe not.