Viewing through glass

[Kermit]

I'm currently building an office / study in my garden. I'll be putting a glass roof onto the structure to get in as much natural light as possible during the day. This is also where my scope is going to live as it will give me a much wider viewing panorama than it's current location. Am I right in assuming that I won't be able to observe through the glass roof? I'm aware there would be localised slight distortion - but I was wondering if the focal length of the scope might overcome it? I can put an opening into the roof of approx 1 metre sq. but I'd need some sort of bond type mount to get up to the 2.5m high roof - suggestions etc more than welcome

[Whippy]

Viewing through an open window is a non-starter due to thermal distortions caused by warm air inside hitting colder air outside. As you say, glass will distort it anyways. Really, your scope needs to be outdoors to get the best out of it.

Tony..

[Talitha]

I wouldn't recommend viewing through glass as a permanant arrangement, but it can be quite satisfactory if you're ill or it's too cold/windy to go outside. Using the 11x70s, 22x100s, 80ST and 90mm ETX Mak, I've done in-house viewing through my patio door, windows and skylights. Granted, the view was distorted a bit, but when it's -40°F outside I'll settle for a bit of distortion.

[Whippy]

Minus 40? Where abouts are you Carol?

Tony..

[The Warthog]

Carol is in the Midwest US, IIRC. I usually stay indoors if it's colder than -18 C, and then I go outside only if there is something really interesting to look at, otherwise -10 C. I took my 65mm Mak onto my front porch last year to look at the moon. It was about -20. In short order the zoom ep froze solid, and the focuser got really hard to move.

[Talitha]

Approximate co-ordinates have been added to my signature line. I'm in north central Wisconsin in the States, and in the winter we get a lot of blasts coming down from Canada (they feel pretty good during the summer, though ).

[Astroman]

Talitha, I went to school in Eau Claire and lived for a year in Appleton! Guess I had you surrounded.

It gets brutally cold in the winter. You need to keep warm outside, (layers), and inside, (Schnapps). 8)

[Whippy]

Approximate co-ordinates have been added to my signature line. I'm in north central Wisconsin in the States, and in the winter we get a lot of blasts coming down from Canada (they feel pretty good during the summer, though ).

Not been to Wisconsin yet, but I've been to the Rockies a few times for Skiing and loved it .

Tony..

[Talitha]

It's a Small World After All !!!

[jonifive]

I won't even get out of bed if its below -6 C...never mind your North American temperatures!!!!

JV (Keeping warm in Wales)

[daz]

I'm very strange as I love all types of weather. I like my summers hot and dry, winters cold and biting, autumn windy and spring a bit of all three!!!

Except rain. Not fond of rain. Or too much cloud, of course!

Anyway, back to topic........

[Xlracer]

Kermit

Float glass which is the main type around is pretty much parallel as its made by floating molten glass on a bath of molten tin and isn't mechanically polished at all, parallelism of the two surfaces is important for minimising distortion. Any minor bowing of the glass tends towards self cancelling in terms of distortion. A problem is its not anti reflection coated so reflections can get in the way

Dave

[philsail1]

I too have used my 90mm Skywatcher Mak through a closed double glazed window. I found it wasn't too bad if I could keep the scope as near to 90 degrees to the window pane (with about a 10 degree band either side). Outside of this, definite distortions and double vision would creep into the view. As others have said, opening the window is a non starter - warm air currents escaping from inside your house, will instantly cause severe turbulence in the views.

As Dave implies - fitting good quality glass will give you some oppotunities for "indoor" viewing - if the viewing aspect of your property merits the extra expense.

Regards,

philsail1

P.S. "talitha" and "warthog" - I'm never going to moan about how cold our winters are in the UK!

[tinvek]

i ikeep my original telescope, a prinz optics reflector in my bedroom and occasionally use it through the window. rather bizarely the distortion of the glass actually seems to help with the fact that its never been colminated since 1971 as the viewing is better than when its outside

[Rusty Strings]

I think another issue with viewing through a glass roof would be the build up of muck, if my conservatory roof is anthing to go by.

John